What pipe fastenings are used in the fire extinguishing system. The device of the internal fire water supply system: calculation, installation, maintenance. Water mist fire extinguishing installations
5.7.21. Identification coloring or digital designation of pipelines must comply with GOST R 12.4.026 and:
Water-filled pipelines of sprinkler, deluge and sprinkler-drencher AUP, as well as water-filled pipelines of fire hydrants - green color or the number "1";
Air pipelines of air sprinkler installation and sprinkler-drencher AUPvz-S D - blue color or number "3";
Unfilled pipelines of deluge AUP and "dry pipes" - blue color or alphanumeric code "3s";
Pipelines that supply only a foaming agent or a foaming agent solution are brown or the number "9".
5.7.22. Signal coloring in the areas of connection of pipelines with shut-off and control devices, units and equipment - red.
Note - At the request of the customer, it is allowed to change the color of pipelines in accordance with the interior of the premises.
5.7.23. All AUP pipelines must have a digital or alphanumeric designation according to the hydraulic scheme.
5.7.24. The distinctive color of the marking plates indicating the direction of movement of the fire extinguishing agent is red. Marking plates and digital or alphanumeric designation of pipelines should be applied taking into account local conditions in the most critical places of communications (at the inlet and outlet of fire pumps, at the inlet and outlet of the general piping, on branches, at junctions, at locking devices, through which water is supplied to the main, supply and supply pipelines, at the places where pipelines pass through walls, partitions, at the entrances of buildings and in other places necessary for the recognition of AUP pipelines).
VSN 25-09.67-85 Rules for the production and acceptance of work. Automatic fire extinguishing installations
(approved by the decision of the Ministry of Instrumentation of September 02, 1985 N 25-09.67-85)
3.8. Piping and fittings of installations located at enterprises that do not have special requirements for aesthetics must be painted in accordance with the requirements of GOST 12.4.026-76 and GOST 14202-69.
3.9. Piping and fittings of installations located at enterprises that have special requirements for aesthetics must be painted in accordance with these requirements, while the coating class must be at least VI according to the requirement of GOST 9.032-74.
3.10. Painting sprinklers, detectors, fusible locks, outlet nozzles is not allowed.
GOST R 12.4.026 Signal colors, safety signs and signal markings. Purpose and rules of application. General technical requirements and characteristics. test methods.
(adopted and put into effect by the Decree of the State Standard of the Russian Federation of September 19, 2001 N 387-st)
5.1.3. It is not allowed to use red signal color:
To designate permanently installed fire protection equipment (their elements) that do not require operational identification (fire detectors, fire pipelines, sprinklers of fire extinguishing installations, etc.);
The company "Fire exit" provides services to ensure fire safety and protection of the population and territories. Main principle of our work - an integrated approach that allows you to reduce your costs and reduce the time (providing services and performing work in the field of fire safety). Our company is accredited by the Ministry of Emergency Situations of Russia to conduct a fire audit. We carry out an inspection as an inspector of the state fire supervision and submit an opinion to the Russian Emergencies Ministry on the results of the inspection. This will save you from scheduled inspections by the fire inspector for the next 3 years.
div" data-pause-on-hover="true">
We use only modern equipment and methods to make your facility safe
Highly qualified personnel ensures the highest possible scientific and technical level of the solutions being carried out
Qualitatively performed work guarantees the absence of claims against you from the supervisory authorities
OOO " Fire exit» is a dynamically developing team of professionals. Our company specializes in solving problems of any complexity in the field of fire safety for various objects, taking into account the wishes of customers. High quality, flexible prices, competence and customer focus allow us to successfully develop in the market.
Our team consists of young, talented, out-of-the-box thinking people with high qualifications. Most of the company's employees are graduates of the country's leading university for training specialists in the field of fire safety - the Academy of the State Fire Service of the Ministry of Emergency Situations of Russia, have scientific degrees of candidates of technical sciences.
Our experts have been international internships in Germany, the USA, the Netherlands and France. The company is conducting Scientific research in the direction of modeling the movement of the human flow in case of fire, the development of devices for emergency protection systems, as well as Internet mapping systems for assessing fire risk.
div" data-pause-on-hover="true">
I recently had a fire inspection in my restaurant. The inspector wrote a lot of comments. I was shocked by the size of the fines that threatened my business. As always, in a difficult moment, my friends came to my aid and recommended Fire Exit, with which they already had experience. I was very surprised when the company's specialists explained to me that some comments were included without justification. The company's specialists helped me make my restaurant, on the one hand, safer, and on the other hand, save precious money. Thank you Fire Company. You are truly a professional helper in difficult times!
1. WATER AND AQUEOUS SOLUTIONS
No one will doubt that water is the most famous substance for extinguishing fire. The element resisting fire has a number of advantages, such as high specific heat capacity, latent heat of vaporization, chemical inertness to most substances and materials, availability and low cost.
However, along with the advantages of water, its disadvantages should also be taken into account, namely, low wetting ability, high electrical conductivity, insufficient adhesion to the extinguishing object, and, importantly, causing significant damage to the building.
Extinguishing a fire from a fire hose with a direct stream is not the best way to fight a fire, since the main volume of water is not involved in the process, only the fuel is cooled, and sometimes the flame can be blown out. It is possible to increase the efficiency of extinguishing a flame by spraying water, however, this will increase the cost of obtaining water dust and its delivery to the source of ignition. In our country, a water jet, depending on the arithmetic mean droplet diameter, is divided into atomized (droplet diameter more than 150 microns) and finely atomized (less than 150 microns).
Why is water spray so effective? With this method of extinguishing, the fuel is cooled by diluting the gases with water vapor, in addition, a finely atomized jet with a droplet diameter of less than 100 microns is capable of cooling the chemical reaction zone itself.
To increase the penetrating power of water, so-called water solutions with wetting agents are used. Additives are also used:
- water-soluble polymers to increase adhesion to a burning object ("viscous water");
- polyoxyethylene to increase the capacity of pipelines ("slippery water", abroad "fast water");
- inorganic salts to increase the efficiency of extinguishing;
- antifreeze and salts to reduce the freezing point of water.
Do not use water to extinguish substances that enter into chemical reactions with it, as well as toxic, combustible and corrosive gases. Such substances are many metals, organometallic compounds, metal carbides and hydrides, hot coal and iron. Thus, in no case do not use water, as well as aqueous solutions with such materials:
- organoaluminum compounds (explosive reaction);
- organolithium compounds; lead azide; alkali metal carbides; hydrides of a number of metals - aluminum, magnesium, zinc; calcium, aluminum, barium carbides (decomposition with the release of combustible gases);
- sodium hydrosulfite (spontaneous combustion);
- sulfuric acid, termites, titanium chloride (strong exothermic effect);
- bitumen, sodium peroxide, fats, oils, petrolatum (increased combustion as a result of ejection, splashing, boiling).
Also, jets should not be used to extinguish dust in order to avoid the formation of an explosive atmosphere. Also, when extinguishing oil products, spreading, splashing of a burning substance can occur.
2. SPRINKLER AND Drencher FIRE EXTINGUISHING INSTALLATIONS
2.1. Purpose and arrangement of installations
Installations of water, low expansion foam, as well as water fire extinguishing with a wetting agent are divided into:
- sprinkler installations are used for local fire extinguishing and cooling of building structures. They are usually used in rooms where a fire can develop with the release of a large amount of heat.
- Deluge installations designed to extinguish a fire over the entire given area, as well as create a water curtain. They irrigate the source of fire in the protected area, receiving a signal from the fire detection devices, which allows you to eliminate the cause of the fire in the early stages, faster than sprinkler systems.
These fire extinguishing installations are the most common. They are used to protect warehouses, shopping malls, production facilities for hot natural and synthetic resins, plastics, rubber products, cable ropes, etc. Modern terms and definitions in relation to water AFS are given in NPB 88-2001.
The installation contains a water source 14 (external water supply), a main water feeder (working pump 15) and an automatic water feeder 16. The latter is a hydropneumatic tank (hydropneumatic tank), which is filled with water through a pipeline with a valve 11.
For example, the installation diagram contains two different sections: a water-filled section with a control unit (CU) 18 under the pressure of a water feeder 16 and an air section with a CU 7, the supply pipelines 2 and distribution 1 of which are filled with compressed air. Air is pumped by compressor 6 through check valve 5 and valve 4.
The sprinkler system is activated automatically when the room temperature rises to the set level. The fire detector is a thermal lock of the sprinkler sprinkler (sprinkler). The presence of a lock ensures the sealing of the outlet of the sprinkler. At the beginning, the sprinklers located above the source of fire are turned on, as a result of which the pressure in the distribution 1 and supply 2 wires drops, the corresponding control unit is activated, and water from the automatic water feeder 16 through the supply pipeline 9 is supplied to extinguish through the opened sprinklers. The fire signal is generated by the alarm device 8 CU. The control device 12, upon receiving a signal, turns on the working pump 15, and when it fails, the backup pump 13. When the pump reaches the specified operating mode, the automatic water feeder 16 is turned off using the check valve 10.
Let us consider in more detail the features of the drencher installation:
It does not contain a thermal lock like a sprinkler, so it is equipped with additional fire detection devices.
Automatic switching on is provided by the incentive pipeline 16, which is filled with water under the pressure of the auxiliary water feeder 23 (compressed air is used instead of water for unheated premises). For example, in the first section, the pipeline 16 is connected to the start-up valves 6, which are initially closed with a cable with thermal locks 7. In the second section, distribution pipelines with sprinklers are connected to a similar pipeline 16.
The outlets of deluge sprinklers are open, so the supply 11 and distribution 9 pipelines are filled with atmospheric air (dry pipes). The supply pipeline 17 is filled with water under pressure of the auxiliary water feeder 23, which is a hydraulic pneumatic tank filled with water and compressed air. The air pressure is controlled by electrocontact pressure gauge 5. In this image, an open reservoir 21 is selected as the source of water for the installation, water is taken from which is carried out by pumps 22 or 19 through a pipeline with a filter 20.
The control unit 13 of the drencher installation contains a hydraulic drive, as well as a pressure indicator 14 of the SDU type.
The automatic switching on of the unit is carried out as a result of the operation of sprinklers 10 or the destruction of thermal locks 7, the pressure drops in the incentive pipeline 16 and the hydraulic drive assembly CU 13. The CU valve 13 opens under the pressure of water in the supply pipeline 17. Water flows to the deluge sprinklers and irrigates the protected room. installation section.
Manual start-up of the drencher installation is carried out using ball valve 15. The sprinkler installation cannot be turned on automatically, because. unauthorized water supply from fire extinguishing systems will cause great damage to the protected premises in the absence of a fire. Consider a sprinkler installation scheme that eliminates such false alarms:
The installation contains sprinklers on the distribution pipeline 1, which, under operating conditions, is filled with compressed air to a pressure of about 0.7 kgf / cm2 using a compressor 3. The air pressure is controlled by an alarm 4, which is installed in front of the check valve 7 with a drain valve 10.
The control unit of the installation contains a valve 8 with a membrane-type shut-off body, a pressure or liquid flow indicator 9, and a valve 15. Under operating conditions, the valve 8 is closed by the pressure of water that enters the valve 8 starting pipeline from the water source 16 through the open valve 13 and the throttle 12. The starting pipeline is connected to the manual start valve 11 and to the drain valve 6, equipped with electric drive. The installation also contains technical means(TS) automatic fire alarm (APS) - fire detectors and control panel 2, as well as starting device 5.
The pipeline between valves 7 and 8 is filled with air at a pressure close to atmospheric, which ensures the operation of the shut-off valve 8 (main valve).
Mechanical damage that could cause a leak in the distribution pipe of the installation or the thermal lock will not cause water supply, because. valve 8 is closed. When the pressure in pipeline 1 drops to 0.35 kgf/cm2, the signaling device 4 generates an alarm signal about a malfunction (depressurization) of the distribution pipeline 1 of the installation.
A false alarm will also not trigger the system. The control signal from the APS with the help of an electric drive will open the drain valve 6 on the starting pipeline of the shut-off valve 8, as a result of which the latter will open. Water will enter the distribution pipeline 1, where it will stop in front of the closed thermal locks of the sprinklers.
When designing AUVP, TS APS are selected so that the inertia of sprinklers is higher. This is done for that. So that in the event of a fire in the vehicle, the APS will work earlier and open the shut-off valve 8. Next, water will enter the pipeline 1 and fill it. This means that by the time the sprinkler operates, the water is already in front of it.
It is important to clarify that the issuance of the first alarm signal from the APS allows you to quickly extinguish small fires with primary fire extinguishing means (such as fire extinguishers).
2.2. The composition of the technological part of sprinkler and deluge water fire extinguishing installations
2.2.1. Source of water supply
The source of water supply for the system is a water pipe, a fire tank or a reservoir.
2.2.2. Water feeders
In accordance with NPB 88-2001, the main water feeder ensures the operation of the fire extinguishing installation with a given pressure and flow rate of water or aqueous solution during the estimated time.
A water supply source (water supply, reservoir, etc.) can be used as the main water feeder if it can provide the estimated water flow and pressure for the required time. Before the main water feeder enters the operating mode, the pressure in the pipeline is automatically provided auxiliary water feeder. As a rule, this is a hydropneumatic tank (hydropneumatic tank), which is equipped with float and safety valves, level sensors, visual level gauges, pipelines for releasing water when extinguishing a fire, and devices for creating the necessary air pressure.
The automatic water feeder provides the pressure in the pipeline necessary for the operation of the control units. Such a water feeder can be water pipes with the necessary guaranteed pressure, a hydropneumatic tank, a jockey pump.
2.2.3. Control unit (CU)- this is a combination of pipeline fittings with shut-off and signaling devices and measuring instruments. They are intended to start the fire-fighting installation and monitor its performance, they are located between the inlet and supply pipelines of the installations.
Control nodes provide:
- supply of water (foam solutions) for extinguishing fires;
- filling supply and distribution pipelines with water;
- draining water from supply and distribution pipelines;
- compensation of leaks from the hydraulic system of the AUP;
- checking the signaling of their operation;
- signaling when the alarm valve is triggered;
- measurement of pressure before and after the control unit.
thermal lock as part of a sprinkler sprinkler, it is triggered when the temperature in the room rises to a predetermined level.
The temperature-sensitive element here are fusible or explosive elements, such as glass flasks. Locks with an elastic element of "shape memory" are also being developed.
The principle of operation of the lock using a fusible element consists in the use of two metal plates soldered with low-melting solder, which loses strength with increasing temperature, as a result of which the lever system is out of balance and opens the sprinkler valve.
But the use of a fusible element has a number of disadvantages, such as the susceptibility of a fusible element to corrosion, as a result of which it becomes brittle, and this may lead to spontaneous operation of the mechanism (especially under vibration conditions).
Therefore, sprinklers using glass flasks are increasingly being used now. They are manufacturable, resistant to external influences, prolonged exposure to temperatures close to the nominal ones does not affect their reliability in any way, resistant to vibration or sudden pressure fluctuations in the water supply network.
Below is a diagram of the design of a sprinkler with an explosive element - a flask of S.D. Bogoslovsky:
1 - fitting; 2 - arches; 3 - socket; 4 - clamping screw; 5 - cap; 6 - thermoflask; 7 - diaphragm
A thermoflask is nothing more than a thin-walled hermetically sealed ampoule, inside of which there is a thermosensitive liquid, for example, methyl carbitol. This substance under the action of high temperatures expands vigorously, increasing the pressure in the flask, which leads to its explosion.
These days, thermoflasks are the most popular heat-sensitive sprinkler element. The most common thermoflasks of the firms "Job GmbH" type G8, G5, F5, F4, F3, F 2.5 and F1.5, "Day-Impex Lim" type DI 817, DI 933, DI 937, DI 950, DI 984 and DI 941, Geissler type G and "Norbert Job" type Norbulb. There is information about the development of the production of thermoflasks in Russia and the firm "Grinnell" (USA).
Zone I are thermoflasks of the type Job G8 and Job G5 for work in normal conditions.
Zone II- these are thermoflasks of type F5 and F4 for sprinklers placed in niches or discreetly.
Zone III- these are thermoflasks of the F3 type for sprinkler sprinklers in residential premises, as well as in sprinklers with an increased irrigation area; thermoflasks F2.5; F2 and F1.5 - for sprinklers, the response time of which should be minimal according to the conditions of use (for example, in sprinklers with fine atomization, with an increased irrigation area and sprinklers intended for use in explosion prevention installations). Such sprinklers are usually marked with the letters FR (Fast Response).
Note: the number after the letter F usually corresponds to the diameter of the thermoflask in mm.
List of documents that regulate the requirements, application and test methods for sprinklers
GOST R 51043-97
NPB 87-2000
NPB 88-2001
NPB 68-98
The designation structure and marking of sprinklers in accordance with GOST R 51043-97 is given below.
Note: For deluge sprinklers pos. 6 and 7 do not indicate.
Main technical parameters of general purpose sprinklers
|
Sprinkler type |
Nominal outlet diameter, mm |
External connection thread R |
Minimum operating pressure in front of the sprinkler, MPa |
Protected area, m2, not less than |
Average irrigation intensity, l/(s m2), not less than |
|
0,020 (>0,028) |
|||||
|
0,04 (>0,056) |
|||||
|
0,05 (>0,070) |
|||||
Notes:
(text) - edition of the GOST R draft.
1. The indicated parameters (protected area, average irrigation intensity) are given when sprinklers are installed at a height of 2.5 m from the floor level.
2. For sprinklers of installation location V, N, U, the area protected by one sprinkler must be in the shape of a circle, and for the location of G, Gv, Hn, Gu - the shape of a rectangle with a size of at least 4x3 m.
3. The size of the external connecting thread is not limited for sprinklers with an outlet, the shape of which differs from the shape of a circle, and a maximum linear size exceeding 15 mm, as well as for sprinklers designed for pneumatic and mass pipelines, and sprinklers for special purposes.
The protected area of irrigation is assumed to be equal to the area specific consumption and the uniformity of irrigation of which is not lower than the established or standard.
The presence of a thermal lock imposes some restrictions on the time and maximum response temperature on sprinkler sprinklers.
The following requirements are established for sprinklers:
Rated response temperature- the temperature at which the thermal lock reacts, water is supplied. Installed and specified in the standard or technical documentation for this product
Rated operating time- the time of operation of the sprinkler sprinkler specified in the technical documentation
Conditional response time- time from the moment the sprinkler is exposed to a temperature exceeding the nominal temperature by 30 °C, until the activation of the thermal lock.
Rated temperature, conditional response time and color marking of sprinklers according to GOST R 51043-97, NPB 87-2000 and the planned GOST R are presented in the table:
Nominal temperature, conditional response time and color coding of sprinklers
|
Temperature, °C |
Conditional response time, s, no more |
Marking color of the liquid in a glass thermoflask (breakable thermosensitive element) or sprinkler arches (with a fusible and elastic thermosensitive element) |
|
|
rated trip |
limit deviation |
||
|
Orange |
|||
|
Violet |
|||
|
Violet |
|||
Notes:
1. At the nominal operating temperature of the thermal lock from 57 to 72 °C, it is allowed not to paint the sprinkler arches.
2. When used as a temperature-sensitive element of a thermoflask, the sprinkler arms may not be painted.
3. "*" - only for sprinklers with a fusible temperature-sensitive element.
4. "#" - sprinklers with both a fusible and a discontinuous thermosensitive element (thermal flask).
5. Values of the nominal response temperature not marked with "*" and "#" - the thermosensitive element is a thermobulb.
6. In GOST R 51043-97 there are no temperature ratings of 74* and 100* °С.
Elimination of fires with high intensity of heat release. It turned out that ordinary sprinklers installed in large warehouses, for example, plastic materials can not cope due to the fact that the powerful heat flows of the fire carry away small drops of water. From the 60s to the 80s of the last century in Europe, 17/32” orifice sprinklers were used to extinguish such fires, and after the 80s they switched to the use of extra large orifice (ELO), ESFR and "big drops" sprinklers. Such sprinklers are capable of producing water droplets that penetrate the convective flow that occurs in a warehouse during a powerful fire. Outside our country, ELO-type sprinkler carriers are used to protect plastics packed in cardboard at a height of about 6 m (except for flammable aerosols).
Another quality of the ELO sprinkler is that it is able to function at low water pressure in the pipeline. Sufficient pressure can be provided in many water sources without the use of pumps, which affects the cost of sprinklers.
ESFR type fills are recommended for the protection of various products, including non-foamed plastic materials packed in cardboard, stored at a height of up to 10.7 m in a room height of up to 12.2 m. System qualities such as a quick response to fire development and high flow water, allows the use of fewer sprinklers, which has a positive effect on reducing water wasted and damage.
For rooms where technical structures violate the interior of the room, the following types of sprinklers have been developed:
in-depth- sprinklers, the body or arms of which are partially hidden in the recesses of the suspended ceiling or wall panel;
Hidden- sprinklers, in which the body of the shackle and partially the temperature-sensitive element are located in the recess of the false ceiling or wall panel;
Hidden- sprinklers closed with a decorative cover
The principle of operation of such sprinklers is shown below. After the cover has been actuated, the sprinkler outlet under its own weight and the influence of a water jet from the sprinkler along two guides goes down to such a distance that the recess in the ceiling in which the sprinkler is mounted does not affect the nature of the water distribution.
In order not to increase the response time of the AFS, the melting temperature of the solder of the decorative cover is set below the response temperature of the sprinkler system, therefore, in fire conditions decorative element will not interfere with admission heat flow to the thermal lock of the sprinkler.
Design of sprinkler and deluge water fire extinguishing installations.
Detailed features of the design of water-foam AUP are described in the training manual. In it you will find the features of the creation of sprinkler and deluge water-foam AFS, fire extinguishing installations with mist water, AFS for maintaining high-rise rack warehouses, rules for calculating AFS, examples.
The manual also outlines the main provisions of modern scientific and technical documentation for each region of Russia. The statement of development rules is subjected to detailed consideration. terms of reference for the design, formulation of the main provisions for the coordination and approval of this task.
The training manual also discusses the content and rules for the design of a working draft, including an explanatory note.
To simplify your task, we present the algorithm for designing a classic water fire extinguishing installation in a simplified form:
1. According to NPB 88-2001, it is necessary to establish a group of premises (production or technological process) depending on its functional purpose and fire load of combustible materials.
An extinguishing agent is chosen, for which the effectiveness of extinguishing combustible materials concentrated in protected objects is established with water, water or foam solution according to NPB 88-2001 (ch. 4). They check the compatibility of materials in the protected room with the selected OTV - the absence of possible chemical reactions with the OTV, accompanied by an explosion, a strong exothermic effect, spontaneous combustion, etc.
2. Taking into account the fire hazard (flame propagation speed), choose the type of fire extinguishing installation - sprinkler, deluge or AUP with finely atomized (sprayed) water.
Automatic activation of drencher installations is carried out according to signals from fire alarm installations, an incentive system with thermal locks or sprinkled sprinklers, as well as from sensors of process equipment. The drive of deluge installations can be electric, hydraulic, pneumatic, mechanical or combined.
3. For sprinkler AFS, depending on the operating temperature, the type of installation is set - water-filled (5 ° C and above) or air. Note that NPB 88-2001 does not provide for the use of water-air AUPs.
4. According to Chap. 4 NPB 88-2001 take the intensity of irrigation and the area protected by one sprinkler, the area for calculating the water flow and the estimated operating time of the installation.
If water is used with the addition of a wetting agent based on a general purpose foaming agent, then the intensity of irrigation is taken 1.5 times less than for water AFS.
5. According to the passport data of the sprinkler, taking into account the efficiency of the consumed water, the pressure is set, which must be provided at the "dictating" sprinkler (the most remote or highly located), and the distance between the sprinklers (taking into account Chapter 4 NPB 88-2001).
6. The estimated water flow rate for sprinkler systems is determined from the condition of simultaneous operation of all sprinkler sprinklers in the protected area (see Table 1, Chapter 4 of NPB 88-2001, ), taking into account the efficiency of the water used and the fact that the flow rate of sprinklers installed along distribution pipes, increases as the distance from the "dictating" sprinkler.
Water consumption for deluge installations is calculated from the condition of simultaneous operation of all deluge sprinklers in the protected warehouse (5th, 6th and 7th groups of the protected object). The area of the premises of the 1st, 2nd, 3rd and 4th groups for determining the water consumption and the number of simultaneously operating sections is found depending on the technological data.
7. For warehouse(5th, 6th and 7th groups of the object of protection according to NPB 88-2001) irrigation intensity depends on the height of storage of materials.
For the area of reception, packaging and dispatch of goods to warehouses height from 10 to 20 m with high-altitude rack storage, the values of intensity and protected area for calculating the consumption of water, foam concentrate solution in groups 5, 6 and 7, given in NPB 88-2001, are increased at the rate of 10% for every 2 m of height.
The total water consumption for internal fire extinguishing of high-rise rack warehouses is taken according to the highest total consumption in the rack storage area or in the area for receiving, packing, picking and dispatching goods.
At the same time, it is certainly taken into account that the space-planning and design solutions of warehouses must also comply with SNiP 2.11.01-85, for example, racks are equipped with horizontal screens, etc.
8. Based on the estimated water consumption and the duration of the fire extinguishing, calculate the estimated amount of water. The capacity of fire tanks (reservoirs) is determined, while taking into account the possibility of automatic replenishment with water during the entire time the fire is extinguished.
The estimated amount of water is stored in tanks for various purposes, if devices are installed that prevent the consumption of the specified volume of water for other needs.
At least two fire tanks must be installed. At the same time, it should be taken into account that at least 50% of the volume of fire extinguishing water should be stored in each of them, and water supply to any point of the fire is provided from two adjacent reservoirs (reservoirs).
With a calculated volume of water up to 1000 m3, it is permissible to store water in one tank.
To fire tanks, reservoirs and opening wells, a free access for fire trucks with a lightweight improved road surface should be created. You will find the locations of fire tanks (reservoirs) in GOST 12.4.009-83.
9. In accordance with the selected type of sprinkler, its flow rate, irrigation intensity and the area protected by it, plans for the placement of sprinklers and a variant for tracing the pipeline network are developed. For clarity, an axonometric diagram of the pipeline network is depicted (not necessarily to scale).
It is important to take into account the following:
9.1. Within the same protected room, sprinklers of the same type with the same diameter of the outlet should be placed.
The distance between sprinklers or thermal locks in the incentive system is determined by NPB 88-2001. Depending on the group of the premises, it is 3 or 4 m. The only exceptions are sprinklers under beam ceilings with protruding parts of more than 0.32 m (with a fire hazard class of the ceiling (covering) K0 and K1) or 0.2 m (in other cases) . In such situations, sprinklers are installed between the protruding parts of the floor, taking into account the uniform irrigation of the floor.
In addition, it is necessary to install additional sprinklers or deluge sprinklers with an incentive system under barriers (technological platforms, ducts, etc.) with a width or diameter of more than 0.75 m, located at a height of more than 0.7 m from the floor.
The best performance in terms of the speed of action was obtained when the area of the sprinkler arches was placed perpendicular to the air flow; with a different placement of the sprinkler due to the shielding of the thermoflask with the arms from the air flow, the response time increases.
Sprinklers are installed in such a way that water from one sprinkler does not touch the neighboring ones. The minimum distance between adjacent sprinklers under a smooth ceiling should not exceed 1.5 m.
The distance between sprinklers and walls (partitions) should not be more than half the distance between sprinklers and depends on the slope of the coating, as well as the fire hazard class of the wall or coating.
The distance from the floor (cover) plane to the sprinkler outlet or the thermal lock of the cable incentive system should be 0.08 ... 0.4 m, and to the sprinkler reflector installed horizontally relative to its type axis - 0.07 ... 0.15 m.
Placement of sprinklers for suspended ceilings- in accordance with the TD for this type of sprinkler.
Deluge sprinklers are located taking into account their technical characteristics and irrigation maps to ensure uniform irrigation of the protected area.
Sprinkler sprinklers in water-filled installations are installed with sockets up or down, in air installations - sockets only up. Horizontal reflector fills are used in any sprinkler installation configuration.
If there is a danger of mechanical damage, sprinklers are protected by casings. The design of the casing is chosen so as to exclude a decrease in the area and intensity of irrigation below the standard values.
Features of the placement of sprinklers to obtain water curtains are described in detail in the manuals.
9.2. Pipelines are designed from steel pipes: according to GOST 10704-91 - with welded and flanged connections, according to GOST 3262-75 - with welded, flanged, threaded connections, and also according to GOST R 51737-2001 - with detachable pipeline couplings only for water-filled sprinkler installations for pipes with a diameter of not more than 200 mm.
It is allowed to design supply pipelines as dead ends only if the design contains no more than three control units and the length of the external dead end wire is not more than 200 m. In other cases, the supply pipelines are formed as annular and divided into sections by valves at the rate of up to 3 controls in the section.
Dead-end and ring supply pipelines are equipped with flush valves, gates or taps with a nominal diameter of at least 50 mm. Such locking devices are provided with plugs and installed at the end of a dead-end pipeline or in the place most remote from the control unit - for ring pipelines.
Gate valves or gates mounted on ring pipelines must pass water in both directions. The presence and purpose of shut-off valves on supply and distribution pipelines is regulated by NPB 88-2001.
On one branch of the distribution pipeline of installations, as a rule, no more than six sprinklers with an outlet diameter of up to 12 mm inclusive and no more than four sprinklers with an outlet diameter of more than 12 mm should be installed.
In deluge AFSs, it is allowed to fill the supply and distribution pipelines with water or an aqueous solution up to the mark of the lowest-lying sprinkler in this section. If there are special caps or plugs on deluge sprinklers, the pipelines can be completely filled. Such caps (plugs) must release the outlet of the sprinklers under the pressure of water (water solution) when the AFS is activated.
It is necessary to provide thermal insulation for water-filled pipelines laid in places where they are likely to freeze, for example, above gates or doorways. If necessary, provide additional devices for draining water.
In some cases, it is possible to connect internal fire hydrants with manual barrels and deluge sprinklers with an incentive switching system to the supply pipelines, and deluge curtains for irrigating door and technological openings to the supply and distribution pipelines.
As mentioned earlier, the design of pipelines from plastic pipes has a number of features. Such pipelines are designed only for water-filled AUP according to the specifications developed for a specific facility and agreed with the GUGPS EMERCOM of Russia. Pipes must be tested at FGU VNIIPO EMERCOM of Russia.
The average service life in fire extinguishing installations of a plastic pipeline should be at least 20 years. Pipes are installed only in rooms of categories C, D and D, and their use is prohibited in outdoor fire extinguishing installations. The installation of plastic pipes is provided both open and hidden (in the space of false ceilings). Pipes are laid in rooms with a temperature range of 5 to 50 ° C, the distances from pipelines to heat sources are limited. Intra-workshop pipelines on the walls of buildings are located 0.5 m above or below window openings.
It is forbidden to lay intrashop pipelines made of plastic pipes in transit through premises that perform administrative, domestic and economic functions, switchgear, electrical installation rooms, control and automation system panels, ventilation chambers, heat points, stairwells, corridors, etc.
Sprinkler sprinklers with a response temperature of not more than 68 ° C are used on the branches of distribution plastic pipelines. At the same time, in rooms of categories B1 and B2, the diameter of bursting flasks of sprinklers does not exceed 3 mm, for rooms of categories B3 and B4 - 5 mm.
When sprinkler sprinklers are placed open, the distance between them should not exceed 3 m; for wall-mounted sprinklers, the allowable distance is 2.5 m.
When the system is concealed, the plastic piping is hidden by ceiling panels, the fire resistance of which is EL 15.
The working pressure in the plastic pipeline must be at least 1.0 MPa.
9.3 The pipeline network should be divided into fire extinguishing sections - a set of supply and separation pipelines, on which sprinklers are located, connected to a common control unit (CU).
The number of sprinklers of all types in one section of the sprinkler installation should not exceed 800, and the total capacity of pipelines (only for air sprinkler installation) - 3.0 m3. The capacity of the pipeline can be increased up to 4.0 m3 when using the AC with an accelerator or an exhauster.
To eliminate false alarms, a delay chamber is used in front of the pressure indicator of the sprinkler installation.
To protect several rooms or floors with one section of the sprinkler system, it is possible to install liquid flow detectors on the supply pipelines, with the exception of the ring ones. In this case, it must be set shut-off valves, information about which you will find in NPB 88-2001. This is done to issue a signal specifying the location of the fire and turn on the warning and smoke exhaust systems.
A liquid flow indicator can be used as an alarm valve in a water-filled sprinkler installation if a non-return valve is installed behind it.
A sprinkler section with 12 or more fire hydrants must have two entries.
10. Drawing up a hydraulic calculation.
The main task here is to determine the water flow for each sprinkler and the diameter of the various parts of the fire pipeline. Incorrect calculation of the AFS distribution network (insufficient water flow) often causes inefficient fire extinguishing.
In hydraulic calculation, it is necessary to solve 3 tasks:
a) determine the pressure at the inlet to the opposite water supply (on the axis of the outlet pipe of the pump or other water feeder), if the estimated water flow, the pipeline routing scheme, their length and diameter, as well as the type of fittings are given. The first step is to determine the pressure loss during the movement of water through the pipeline for a given design stroke, and then determine the brand of the pump (or other type of water supply source) that can provide the necessary pressure.
b) determine the water flow rate at a given pressure at the beginning of the pipeline. In this case, the calculation should begin with determining the hydraulic resistance of each element of the pipeline, as a result, set the estimated water flow depending on the pressure obtained at the beginning of the pipeline.
c) determine the diameter of the pipeline and other elements of the pipeline protection system based on the calculated water flow and pressure losses along the length of the pipeline.
In the manuals NPB 59-97, NPB 67-98, methods for calculating the required pressure in a sprinkler with a set irrigation intensity are discussed in detail. At the same time, it should be taken into account that when the pressure in front of the sprinkler changes, the irrigation area can either increase, decrease or remain unchanged.
The formula for calculating the required pressure at the beginning of the pipeline after the pump for the general case is as follows:
where Pg - pressure loss in the horizontal section of the AB pipeline;
Pb - pressure loss in the vertical section of the BD pipeline;
Ro - pressure at the "dictating" sprinkler;
Z is the geometric height of the "dictating" sprinkler above the pump axis.
1 - water feeder;
2 - sprinkler;
3 - control units;
4 - supply pipeline;
Pg - pressure loss in the horizontal section of the AB pipeline;
Pv - pressure loss in the vertical section of the BD pipeline;
Pm - pressure loss in local resistances (shaped parts B and D);
Ruu - local resistance in the control unit (alarm valve, valves, gates);
Ro - pressure at the "dictating" sprinkler;
Z - geometric height of the “dictating” sprinkler above the pump axis
The maximum pressure in the pipelines of water and foam fire extinguishing installations is no more than 1.0 MPa.
Hydraulic pressure loss P in pipelines is determined by the formula:
where l is the length of the pipeline, m; k - pressure loss per unit length of the pipeline (hydraulic slope), Q - water flow, l / s.
The hydraulic slope is determined from the expression:
where A - specific resistance, depending on the diameter and roughness of the walls, x 106 m6 / s2; Km - specific characteristic of the pipeline, m6/s2.
As operating experience shows, the nature of the change in the roughness of pipes depends on the composition of water, air dissolved in it, operating mode, service life, etc.
The specific resistance value and the specific hydraulic characteristic of pipelines for pipes of various diameters are given in NPB 67-98.
Estimated flow rate of water (foaming agent solution) q, l/s, through the sprinkler (foam generator):
where K is the performance coefficient of the sprinkler (foam generator) in accordance with the TD for the product; P - pressure in front of the sprinkler (foam generator), MPa.
The performance factor K (in foreign literature, a synonym for the performance factor - "K-factor") is a cumulative complex that depends on the flow rate and the area of the outlet:
where K is the flow rate; F is the area of the outlet; q - free fall acceleration.
In practice hydraulic design water and foam AUP, the calculation of the performance coefficient is usually carried out from the expression:
where Q is the flow rate of water or solution through the sprinkler; Р - pressure in front of the sprinkler.
Dependencies between performance factors are expressed by the following approximate expression:
Therefore, in hydraulic calculations according to NPB 88-2001, the value of the performance coefficient in accordance with international and national standards must be taken equal to:
However, it must be taken into account that not all dispersed water enters directly into the protected area.
The figure shows a diagram of the area of the room affected by the sprinkler. On the area of a circle with radius Ri the required or normative value of irrigation intensity is provided, and on the area of a circle with a radius Rorosh all the fire extinguishing agent dispersed by the sprinkler is distributed.
The mutual arrangement of sprinklers can be represented by two schemes: in a checkerboard or square order
a - chess; b - square
Placing sprinklers in a checkerboard pattern is beneficial in cases where the linear dimensions of the controlled area are a multiple of the radius Ri or the remainder is not more than 0.5 Ri, and almost all water flow falls on the protected area.
In this case, the design area configuration has the form of a regular hexagon inscribed in a circle, the shape of which tends to the circle area irrigated by the system. With this arrangement, the most intensive irrigation of the sides is created. BUT with a square arrangement of sprinklers, the zone of their interaction increases.
According to NPB 88-2001, the distance between sprinklers depends on the groups of protected premises and is no more than 4 m for some groups, and no more than 3 m for others.
Only 3 ways of placing sprinklers on the distribution pipeline are real:
Symmetric (A)
Symmetrical loopback (B)
Asymmetrical (B)
The figure shows diagrams of three ways of arranging sprinklers, we will consider them in more detail:
A - section with a symmetrical arrangement of sprinklers;
B - section with asymmetric arrangement of sprinklers;
B - section with a looped supply pipeline;
I, II, III - rows of distribution pipeline;
a, b…јn, m - nodal design points
For each fire extinguishing section, we find the most remote and highly located protected zone, the hydraulic calculation will be carried out precisely for this zone. The pressure P1 at the "dictating" sprinkler 1, located further and above the other sprinklers of the system, should not be lower than:
where q is the flow rate through the sprinkler; K - performance coefficient; Rmin slave - the minimum allowable pressure for this type of sprinkler.
The flow rate of the first sprinkler 1 is the calculated value of Q1-2 in the area l1-2 between the first and second sprinkler. The pressure loss P1-2 in the area l1-2 is determined by the formula:
where Kt is the specific characteristic of the pipeline.
Therefore, the pressure at sprinkler 2:
Sprinkler 2 consumption will be:
The estimated flow rate in the area between the second sprinkler and point "a", i.e., in the area "2-a" will be equal to:
Pipeline diameter d, m, is determined by the formula:
where Q is water consumption, m3/s; ϑ is the speed of water movement, m/s.
The speed of water movement in pipelines of water and foam AUP should not exceed 10 m/s.
The diameter of the pipeline is expressed in millimeters and increased to the nearest value specified in the RD.
According to the water flow Q2-a, the pressure loss in the section "2-a" is determined:
The pressure at point "a" is equal to
From here we get: for the left branch of the 1st row of section A, it is necessary to ensure the flow rate of Q2-a at a pressure of Pa. The right branch of the row is symmetrical to the left, so the flow rate for this branch will also be equal to Q2-a, therefore, the pressure at point "a" will be equal to Pa.
As a result, for 1 row we have a pressure equal to Pa, and water consumption:
Row 2 is calculated according to the hydraulic characteristic:
where l is the length of the calculated section of the pipeline, m.
Since the hydraulic characteristics of the rows, made structurally the same, are equal, the characteristic of the row II is determined by the generalized characteristic of the calculated section of the pipeline:
Water consumption from row 2 is determined by the formula:
All subsequent rows are calculated similarly to the calculation of the second until the result of the estimated water flow is obtained. Then the total flow is calculated from the condition of arranging the required number of sprinklers necessary to protect the calculated area, including if it is necessary to install sprinklers under technological equipment, ventilation ducts or platforms that prevent irrigation of the protected area.
The estimated area is taken depending on the group of premises according to NPB 88-2001.
Due to the fact that the pressure in each sprinkler is different (the most distant sprinkler has a minimum pressure), it is also necessary to take into account the different water flow from each sprinkler with the corresponding water efficiency.
Therefore, the estimated flow rate of the AUP should be determined by the formula:
where QAUP- estimated consumption of AUP, l/s; qn- consumption of the n-th sprinkler, l/s; fn- consumption utilization factor at design pressure at the n-th sprinkler; in- average intensity of irrigation by the n-th sprinkler (not less than the normalized intensity of irrigation; sn- normative area of irrigation by each sprinkler with normalized intensity.
The ring network is calculated similarly to the dead-end network, but at 50% of the estimated water flow for each half-ring.
From the point "m" to the water feeders, the pressure losses in the pipes are calculated along the length and taking into account local resistances, including in control units (alarm valves, gate valves, gates).
With approximate calculations, all local resistances are taken equal to 20% of the resistance of the pipeline network.
Head loss in CU installations Ruu(m) is determined by the formula:
where yY is the coefficient of pressure loss in the control unit (accepted according to the TD for the control unit as a whole or for each alarm valve, shutter or gate valve individually); Q- estimated flow rate of water or foam concentrate solution through the control unit.
The calculation is made so that the pressure in the CD is not more than 1 MPa.
Approximately the diameters of the distribution rows can be determined by the number of installed sprinklers. The table below shows the relationship between the most common distribution row pipe diameters, pressure, and the number of sprinklers installed.
The most common mistake in the hydraulic calculation of distribution and supply pipelines is the determination of the flow Q according to the formula:
where i and For- respectively, the intensity and area of irrigation for calculating the flow rate, taken according to NPB 88-2001.
This formula cannot be applied because, as already mentioned above, the intensity in each sprinkler differs from the others. It turns out this is due to the fact that in any installations with a large number of sprinklers, with their simultaneous operation, pressure losses occur in the piping system. Because of this, both the flow rate and the intensity of irrigation of each part of the system are different. As a result, the sprinkler, located closer to the supply pipeline, has a higher pressure, and consequently a higher water flow. The indicated unevenness of irrigation is illustrated by the hydraulic calculation of rows, which consist of successively arranged sprinklers.
d - diameter, mm; l is the length of the pipeline, m; 1-14 - serial numbers of sprinklers
Row flow and pressure values
|
Row calculation scheme number |
Section pipe diameter, mm |
Pressure, m |
Sprinkler flow l/s |
Total row consumption, l/s |
|||||||||||
|
Uniform irrigation Qp6= 6q1 |
Uneven irrigation Qf6 = qns |
||||||||||||||
Notes:
1. The first calculation scheme consists of sprinklers with holes 12 mm in diameter with a specific characteristic of 0.141 m6/s2; distance between sprinklers 2.5 m.
2. Calculation schemes for rows 2-5 are rows of sprinklers with holes 12.7 mm in diameter with a specific characteristic of 0.154 m6/s2; distance between sprinklers 3 m.
3. P1 denotes the calculated pressure in front of the sprinkler, and through
P7 - design pressure in a row.
For the design scheme No. 1, the water consumption q6 from the sixth sprinkler (located near the supply pipeline) 1.75 times more than the water flow q1 from the final sprinkler. If the condition of uniform operation of all sprinklers of the system were satisfied, then the total water flow Qp6 would be found by multiplying the water flow of the sprinkler by the number of sprinklers in a row: Qp6= 0.65 6 = 3.9 l/s.
If the water supply from the sprinklers were uneven, the total water flow Qf6, according to the approximate tabular calculation method, would be calculated by sequential addition of costs; it is 5.5 l / s, which is 40% higher Qp6. In the second calculation scheme q6 3.14 times more q1, a Qf6 more than double the Qp6.
An unreasonable increase in water consumption for sprinklers, the pressure in front of which is higher than in the others, will only lead to an increase in pressure losses in the supply pipeline and, as a result, to an increase in uneven irrigation.
The diameter of the pipeline has a positive effect both on reducing the pressure drop in the network and on the calculated water flow. If you maximize the water consumption of the water feeder with uneven operation of the sprinklers, the cost will greatly increase. construction works for the water supply. this factor is decisive in determining the cost of work.
How can one achieve a uniform flow of water, and, as a result, a uniform irrigation of the protected premises at pressures that vary along the length of the pipeline? There are several available options: the device of diaphragms, the use of sprinklers with outlets that vary along the length of the pipeline, etc.
However, no one has canceled the existing norms (NPB 88-2001), which do not allow the placement of sprinklers with different outlets within the same protected room.
The use of diaphragms is not regulated by documents, since when they are installed, each sprinkler and row have a constant flow rate, the calculation of supply pipelines, the diameter of which determines the pressure loss, the number of sprinklers in a row, the distance between them. This fact greatly simplifies the hydraulic calculation of the fire extinguishing section.
Due to this, the calculation is reduced to determining the dependences of the pressure drop in sections of the section on the diameters of the pipes. When choosing pipeline diameters in individual sections, it is necessary to observe the condition under which the pressure loss per unit length differs little from the average hydraulic slope:
where k- average hydraulic slope; ∑ R- pressure loss in the line from the water feeder to the "dictating" sprinkler, MPa; l- length of calculated sections of pipelines, m.
This calculation will demonstrate that the installed power pumping units, attributable to overcoming pressure losses in the section when using sprinklers with the same flow rate, can be reduced by 4.7 times, and the volume of the emergency water supply in the hydropneumatic tank of the auxiliary water feeder can be reduced by 2.1 times. In this case, the reduction in the metal consumption of pipelines will be 28%.
However, the training manual stipulates that it is not advisable to install diaphragms of different diameters in front of the sprinklers. The reason for this is the fact that during the operation of the AFS, the possibility of rearranging the diaphragms is not ruled out, which significantly reduces the uniformity of irrigation.
For internal fire-fighting separate water supply according to SNiP 2.04.01-85 * and automatic installations fire extinguishing according to NPB 88-2001, it is allowed to install one group of pumps, provided that this group provides a flow rate Q equal to the sum of the needs of each water supply:
where QVPV QAUP are the costs required, respectively, for the internal fire-fighting water supply and the AUP water supply.
If fire hydrants are connected to the supply pipelines, the total flow rate is determined by the formula:
where Qpc- allowable flow rate from fire hydrants (accepted according to SNiP 2.04.01-85*, Table 1-2).
The duration of operation of internal fire hydrants, which incorporate manual water or foam fire nozzles and are connected to the supply pipelines of the sprinkler installation, is taken equal to the time of its operation.
To speed up and improve the accuracy of hydraulic calculations of sprinkler and deluge AFS, it is recommended to use computer technology.
11. Choose a pumping unit.
What are pumping units? In the irrigation system, they perform the function of the main water feeder and are intended to provide water (and water-foam) automatic fire extinguishers with the required pressure and consumption of fire extinguishing agent.
There are 2 types of pumping units: main and auxiliary.
Auxiliary ones are used in a permanent mode until large water consumption is required (for example, in sprinkler installations for a period until no more than 2-3 sprinklers are activated). If the fire takes on a larger scale, then the main pumping units are launched (in the NTD they are often referred to as the main fire pumps), which provide water flow for all sprinklers. In deluge AUPs, as a rule, only the main fire pumping units are used.
Pumping units consist of pumping units, a control cabinet and a piping system with hydraulic and electromechanical equipment.
The pumping unit consists of a drive connected through a transfer clutch to a pump (or pump unit) and a foundation plate (or base). Several operating pumping units can be installed in the AUP, which affects the required water flow. But regardless of the number of installed units in the pumping system, one backup must be provided.
When using in AUP no more than three control units, pumping units can be designed with one input and one output, in other cases - with two inputs and two outputs.
A schematic diagram of a pumping unit with two pumps, one inlet and one outlet is shown in fig. 12; with two pumps, two inputs and two outputs - in fig. thirteen; with three pumps, two inputs and two outputs - in fig. fourteen.
Regardless of the number of pumping units, the scheme of the pumping unit must ensure the supply of water to the AUP supply pipeline from any input by switching the corresponding valves or gates:
Directly through the bypass line, bypassing the pumping units;
- from any pump unit;
- from any combination of pumping units.
Valves are installed before and after each pumping unit. This makes it possible to carry out repair and maintenance work without disrupting the operability of the automatic control unit. To prevent the reverse flow of water through the pumping units or the bypass line, check valves are installed at the outlet of the pumps, which can also be installed behind the valve. In this case, when reinstalling the valve for repair, it will not be necessary to drain the water from the conductive pipeline.
As a rule, centrifugal pumps are used in AUP.
Select the appropriate type of pump characteristics Q-H that are listed in the catalogs. In this case, the following data are taken into account: the required pressure and flow (according to the results of the hydraulic calculation of the network), dimensions pump and the mutual orientation of the suction and discharge pipes (this determines the layout conditions), the mass of the pump.
12. Placement of the pumping unit of the pumping station.
12.1. Pumping stations are located in separate rooms with fireproof partitions and ceilings with a fire resistance limit of REI 45 according to SNiP 21-01-97 on the first, basement or basement floors, or in a separate extension to the building. It is necessary to ensure a constant air temperature from 5 to 35 °C and a relative humidity of not more than 80% at 25 °C. The specified room is equipped with working and emergency lighting according to SNiP 23-05-95 and telephone communication with the fire station room, a light panel "Pumping station" is placed at the entrance.
12.2. The pumping station should be classified as:
According to the degree of water supply - to the 1st category according to SNiP 2.04.02-84*. The number of suction lines to the pumping station, regardless of the number and groups of installed pumps, must be at least two. Each suction line must be sized to carry the full design flow of water;
- in terms of reliability of power supply - to the 1st category according to the PUE (powered by two independent sources of power supply). If it is impossible to fulfill this requirement, it is allowed to install (except for basements) standby pumps driven by internal combustion engines.
Typically, pumping stations are designed with control without permanent staff. Local control must be taken into account if automatic or remote control is available.
Simultaneously with the inclusion of fire pumps, all pumps for other purposes, powered by this main and not included in the AUP, should be automatically turned off.
12.3. The dimensions of the machine room of the pumping station should be determined taking into account the requirements of SNiP 2.04.02-84* (section 12). Take into account the requirements for the width of the aisles.
In order to reduce the size of the pumping station in plan, it is possible to install pumps with right and left shaft rotation, and the impeller must rotate in only one direction.
12.4. The mark of the axis of the pumps is determined, as a rule, based on the conditions for installing the pump housing under the bay:
In the tank (from the upper water level (determined from the bottom) of the fire volume in case of one fire, medium (in case of two or more fires;
- in a water well - from the dynamic level of groundwater at maximum water withdrawal;
- in a watercourse or reservoir - from the minimum water level in them: at the maximum provision of the calculated water levels in surface sources - 1%, at the minimum - 97%.
In this case, it is necessary to take into account the permissible vacuum suction height (from the calculated minimum water level) or the necessary back pressure required by the manufacturer on the suction side, as well as pressure losses (pressure) in the suction pipeline, temperature conditions and barometric pressure.
In order to receive water from a reserve tank, it is necessary to install pumps “under the bay”. With this installation of pumps above the water level in the tank, pump priming devices or self-priming pumps are used.
12.5. When using in AUP no more than three control units, pumping units are designed with one input and one output, in other cases - with two inputs and two outputs.
In the pumping station, it is possible to place suction and pressure manifolds, if this does not entail an increase in the span of the turbine hall.
Pipelines in pumping stations are usually made of welded steel pipes. Provide for a continuous rise of the suction pipeline to the pump with a slope of at least 0.005.
The diameters of pipes, fittings fittings are taken on the basis of a technical and economic calculation, based on the recommended water flow rates indicated in the table below:
|
Pipe diameter, mm |
Water movement speed, m/s, in pipelines of pumping stations |
|
|
suction |
pressure |
|
|
St. 250 to 800 |
||
On the pressure line, each pump needs a check valve, a valve and a pressure gauge, on the suction line, a check valve is not needed, and when the pump is running without backwater on the suction line, a valve with a pressure gauge is dispensed with. If the pressure in outdoor network water supply system is less than 0.05 MPa, then before pumping unit place a receiving tank, the capacity of which is indicated in section 13 of SNiP 2.04.01-85*.
12.6. In the event of an emergency shutdown of the working pumping unit, automatic switching on of the backup unit powered by this line should be provided.
The start time of fire pumps should not be more than 10 minutes.
12.7. To connect the fire extinguishing installation to the mobile fire fighting equipment, pipelines with branch pipes are brought out, which are equipped with connecting heads (if at least two fire trucks are connected at the same time). The throughput of the pipeline should provide the highest design flow in the "dictating" section of the fire extinguishing installation.
12.8. In buried and semi-buried pumping stations, measures must be taken against possible flooding of the units in the event of an accident within the machine room at the largest pump in terms of productivity (or at shutoff valves, pipelines) in the following ways:
- location of pump motors at a height of at least 0.5 m from the floor of the machine room;
- gravity discharge of an emergency amount of water into the sewer or onto the surface of the earth with the installation of a valve or gate valve;
- pumping water from the pit with special or main pumps for industrial purposes.
It is also necessary to take measures to remove excess water from the machine room. To do this, the floors and channels in the hall are mounted with a slope to the prefabricated pit. On the foundations for pumps, bumpers, grooves and pipes for water drainage are provided; if gravity drainage of water from the pit is not possible, drainage pumps should be provided.
12.9. Pumping stations with a machine room size of 6-9 m or more are equipped with an internal fire-fighting water supply with a water flow rate of 2.5 l / s, as well as other primary fire extinguishing equipment.
13. Choose an auxiliary or automatic water feeder.
13.1. In sprinkler and deluge installations, it uses an automatic water feeder, as a rule, a vessel (vessels) filled with water (at least 0.5 m3) and compressed air. In sprinkler installations with connected fire hydrants for buildings higher than 30 m, the volume of water or foam concentrate solution is increased to 1 m3 or more.
The main task of a water supply system installed as an automatic water feeder is to provide a guaranteed pressure that is numerically equal to or greater than the calculated one, sufficient to trigger the control units.
You can also use a booster pump (jockey pump), which includes a non-reserved intermediate tank, usually membrane, with a water volume of more than 40 liters.
13.2. The volume of water of the auxiliary water feeder is calculated from the condition of ensuring the flow required for the deluge installation (total number of sprinklers) and / or sprinkler installation (for five sprinklers).
It is necessary to provide an auxiliary water feeder for each installation with a manually started fire pump, which will ensure the operation of the installation at the design pressure and flow rate of water (foaming agent solution) for 10 minutes or more.
13.3. Hydraulic, pneumatic and hydropneumatic tanks (vessels, containers, etc.) are selected taking into account the requirements of PB 03-576-03.
Tanks should be installed in rooms with walls, the fire resistance of which is at least REI 45, and the distance from the top of the tanks to the ceiling and walls, as well as between adjacent tanks, should be from 0.6 m. Pumping stations should not be placed adjacent to areas where a large crowd of people is possible, such as concert halls, stage, cloakroom, etc.
Hydropneumatic tanks are located on technical floors, and pneumatic tanks - in unheated rooms.
In buildings whose height exceeds 30 m, an auxiliary water feeder is placed on the upper floors. technical purpose. Automatic and auxiliary water feeders must be switched off when the main pumps are turned on.
The training manual discusses in detail the procedure for developing a design assignment (Chapter 2), the procedure for developing a project (Chapter 3), coordination and general principles examination of AUP projects (chapter 5). Based on this manual, the following appendices have been compiled:
Appendix 1. List of documentation submitted by the developer organization to the customer organization. The composition of the design and estimate documentation.
Annex 2. An example of a working design for an automatic water sprinkler installation.
2.4. INSTALLATION, ADJUSTMENT AND TESTING OF WATER FIRE EXTINGUISHING INSTALLATIONS
When performing installation work, the general requirements given in Ch. 12.
2.4.1. Installation of pumps and compressors produced in accordance with the working documentation and VSN 394-78
First of all, it is necessary to carry out an input control and draw up an act. Then remove excess grease from the units, prepare the foundation, mark and level the area for the plates for the adjusting screws. When aligning and fastening, it is necessary to ensure that the axes of the equipment are aligned with the axes of the foundation.
Pumps are aligned with adjusting screws provided in their bearing parts. Compressor alignment can be done with adjusting screws, inventory mounting jacks, mounting nuts on foundation bolts, or metal shim packs.
Attention! Until the screws are finally tightened, no work may be carried out that could change the adjusted position of the equipment.
Compressors and pumping units that do not have a common foundation plate are mounted in series. Installation begins with a gearbox or a machine of greater mass. The axles are centered along the coupling halves, the oil pipelines are connected and, after alignment and final fixing of the unit, the pipelines.
The placement of shut-off valves on all suction and pressure pipelines should provide the possibility of replacing or repairing any of the pumps, check valves and main shut-off valves, as well as checking the characteristics of the pumps.
2.4.2. The control units are delivered to the installation area in the assembled state in accordance with the piping scheme adopted in the project (drawings).
For control units, a functional diagram of the piping is provided, and in each direction - a plate indicating the operating pressures, the name and category of the explosion and fire hazard of the protected premises, the type and number of sprinklers in each section of the installation, the position (state) of the locking elements in standby mode.
2.4.3. Installation and fastening of pipelines and equipment during their installation is carried out in accordance with SNiP 3.05.04-84, SNiP 3.05.05-84, VSN 25.09.66-85 and VSN 2661-01-91.
Pipelines are attached to the wall with holders, but they cannot be used as supports for other structures. The distance between the pipe attachment points is up to 4 m, with the exception of pipes with a nominal bore of more than 50 mm, for which the step can be increased to 6 m, if there are two independent attachment points built into the building structure. And also pr laying the pipeline through the sleeves and grooves.
If risers and branches on distribution pipelines exceed 1 m in length, then they are fixed with additional holders. The distance from the holder to the sprinkler on the riser (outlet) is at least 0.15 m.
The distance from the holder to the last sprinkler on the distribution pipeline for pipes with a nominal diameter of 25 mm or less does not exceed 0.9 m, with a diameter of more than 25 mm - 1.2 m.
For air sprinkler installations, supply and distribution pipelines are provided with a slope towards the control unit or downcomers: 0.01 - for pipes with an outer diameter of less than 57 mm; 0.005 - for pipes with an outer diameter of 57 mm or more.
If the pipeline is made of plastic pipes, then it must pass the positive temperature test 16 hours after the last joint has been welded.
Do not install industrial and sanitary equipment to the supply pipeline of the fire extinguishing installation!
2.4.4. Installation of sprinklers on protected objects carried out in accordance with the project, NPB 88-2001 and TD for a specific type of sprinkler.
Glass thermoflasks are very fragile, so they require a delicate attitude. Damaged thermoflasks can no longer be used, as they cannot fulfill their direct duty.
When installing sprinklers, it is recommended to orient the planes of the sprinkler arches sequentially along the distribution pipeline and then perpendicular to its direction. On adjacent rows, it is recommended to orient the planes of the shackles perpendicular to each other: if on one row the plane of the shackles is oriented along the pipeline, then on the next row - across its direction. Guided by this rule, you can increase the uniformity of irrigation in the protected area.
For accelerated and high-quality installation of sprinklers on the pipeline, various devices are used: adapters, tees, pipe clamps, etc.
When fixing the piping in place with clamps, it is necessary to drill a few holes in the desired locations of the distribution piping to which the unit will be centered. The pipeline is fixed with a bracket or two bolts. The sprinkler is screwed into the outlet of the device. If it is necessary to use tees, then in this case you will need to prepare pipes of a given length, the ends of which will be connected by tees, then tightly fasten the tee to the pipes with a bolt. In this case, the sprinkler is installed in the branch of the tee. If you have opted for plastic pipes, then for such pipes special clamp hangers are required:
1 - cylindrical adapter; 2, 3 - clamp adapters; 4 - tee
Let us consider in more detail the clamps, as well as the features of fastening pipelines. To prevent mechanical damage to the sprinkler, it is usually covered with protective casings. BUT! Keep in mind that the shroud may interfere with the uniformity of the irrigation due to the fact that it can distort the distribution of the dispersed liquid over the protected area. In order to avoid this, always ask the seller for certificates of conformity of this sprinkler with the enclosed casing design.
a - a clamp for hanging a metal pipeline;
b - clamp for hanging a plastic pipeline
Protective guards for sprinklers
2.4.5. If the height of the equipment control devices, electric drives and flywheels of valves (gates) is more than 1.4 m from the floor, additional platforms and blind areas are installed. But the height from the platform to the control devices should not be more than 1m. It is possible to widen the foundation of the equipment.
The location of equipment and fittings under the installation site (or maintenance platforms) with a height from the floor (or bridge) to the bottom of the protruding structures of at least 1.8 m is not excluded.
AFS start-up devices must be protected from accidental operation.
These measures are necessary in order to protect the AFS start-up devices from unintentional operation as much as possible.
2.4.6. After installation, individual tests are carried out elements of the fire extinguishing installation: pumping units, compressors, tanks (automatic and auxiliary water feeders), etc.
Before testing the CD, air is removed from all elements of the installation, then they are filled with water. In sprinkler installations, a combined valve is opened (in air and water-air installations - a valve), it is necessary to make sure that the alarm device is activated. In deluge installations, the valve is closed above the control point, the manual start valve is opened on the incentive pipeline (the button for starting the valve with an electric drive is turned on). The operation of the CU (electrically operated gate valves) and the signaling device are recorded. During the test, the operation of pressure gauges is checked.
Hydraulic testing of pressure vessels compressed air, carried out in accordance with TD for containers and PB 03-576-03.
Running-in of pumps and compressors is carried out in accordance with TD and VSN 394-78.
Methods for testing the installation when it is accepted into operation are given in GOST R 50680-94.
Now, according to NPB 88-2001 (clause 4.39), it is possible to use plug valves at the upper points of the piping network of sprinkler installations as air release devices, as well as a valve under a pressure gauge to control the sprinkler with a minimum pressure.
It is useful to prescribe such devices in the project for the installation and use it when testing the control unit.
.jpg)
1 - fitting; 2 - body; 3 - switch; 4 - cover; 5 - lever; 6 - plunger; 7 - membrane
2.5. MAINTENANCE OF WATER FIRE EXTINGUISHING INSTALLATIONS
The serviceability of the water fire extinguishing installation is monitored by round-the-clock security of the building territory. Access to the pumping station should be limited to unauthorized persons, sets of keys are issued to operational and maintenance personnel.
DO NOT paint sprinklers, it is necessary to protect them from paint ingress during cosmetic repairs.
Such external influences as vibration, pressure in the pipeline, and as a result of the impact of sporadic water hammer due to the operation of fire pumps, seriously affect the operating time of sprinklers. The consequence may be a weakening of the thermal lock of the sprinkler, as well as their loss if the installation conditions were violated.
Often the temperature of the water in the pipeline is above average, this is especially true for rooms where elevated temperatures are due to the nature of the activity. This may cause the locking device in the sprinkler to stick due to precipitation in the water. That is why, even if the device looks undamaged from the outside, it is necessary to inspect the equipment for corrosion, sticking, so that there are no false positives and tragic situations when the system fails during a fire.
When activating the sprinkler, it is very important that all parts of the thermal lock fly out without delay after the destruction. This function is controlled by a membrane diaphragm and levers. If the technology was violated during installation, or the quality of the materials leaves much to be desired, over time, the properties of the spring-plate membrane may weaken. Where it leads? The thermal lock will partially remain in the sprinkler and will not allow the valve to fully open, the water will only ooze in a small stream, which will prevent the device from fully irrigating the area it protects. To avoid such situations, an arcuate spring is provided in the sprinkler, whose force is directed perpendicular to the plane of the arms. This guarantees the complete ejection of the thermal lock.
Also, when using, it is necessary to exclude the impact of lighting fixtures on sprinklers when it is moved during repairs. Eliminate the gaps that appear between the pipeline and the electrical wiring.
When determining the progress of maintenance and preventive maintenance work, one should:
Conduct a daily visual inspection of the installation components and monitor the water level in the tank,
Perform a weekly test run of pumps with electric or diesel drive for 10-30 minutes from remote start devices without water supply,
Once every 6 months, drain the sediment from the tank, and also make sure that the drainage devices that ensure the flow of water from the protected room (if any) are in good condition.
Check the flow characteristics of the pumps annually,
Turn the drain valves annually,
Annually replace the water in the tank and pipelines of the installation, clean the tank, flush and clean the pipelines.
Timely conduct hydraulic tests of pipelines and hydropneumatic tank.
The main routine maintenance that is carried out abroad in accordance with NFPA 25 provides for a detailed annual inspection of the elements of the UVP:
- sprinklers (absence of plugs, type and orientation of the sprinkler in accordance with the project, absence of mechanical damage, corrosion, clogging of outlet holes of deluge sprinklers, etc.);
- pipelines and fittings (lack of mechanical damage, cracks in fittings, paintwork damage, changes in the slope angle of pipelines, serviceability of drainage devices, sealing gaskets must be tightened in clamping units);
- brackets (lack of mechanical damage, corrosion, reliable fastening of pipelines to brackets (attachment points) and brackets to building structures);
- control units (position of valves and gate valves in accordance with the project and operating manual, operability of signaling devices, gaskets must be tightened);
- non-return valves (correct connection).
3. WATER MIST FIRE EXTINGUISHING INSTALLATIONS
HISTORY REFERENCE.
International studies have proven that when the water droplets are reduced, the efficiency of the water mist increases sharply.
Finely atomized water (TRW) refers to jets of droplets with a diameter of less than 0.15 mm.
Let's note that TRV and its foreign name "water mist" are not equivalent concepts. According to NFPA 750, water mist is divided into 3 classes according to the degree of dispersion. The "thinnest" water mist belongs to class 1 and contains drops ~0.1…0.2 mm in diameter. Class 2 combines water jets with a droplet diameter of mainly 0.2 ... 0.4 mm, class 3 - up to 1 mm. using conventional sprinklers with a small outlet diameter with a slight increase in water pressure.
Thus, in order to obtain a first-class water mist, a high water pressure is required, or the installation of special sprinklers, while obtaining a third-class dispersion is achieved using conventional sprinklers with a small outlet diameter with a slight increase in water pressure.
Water mist was first installed and applied on passenger ferries in the 1940s. Now interest in it has increased in connection with recent studies that have proven that water mist does an excellent job of ensuring fire safety in those premises where halon or carbon dioxide fire extinguishing installations were previously used.
Fire extinguishing installations were the first to appear in Russia superheated water. They were developed by VNIIPO in the early 1990s. The superheated steam jet quickly evaporated and turned into a steam jet with a temperature of about 70 °C, which carried a stream of condensed fine droplets over a considerable distance.
Now, water mist fire extinguishing modules and special sprayers have been developed, the principle of operation of which is similar to the previous ones, but without the use of superheated water. Delivery of water droplets to the fire seat is usually carried out by a propellant from the module.
3.1. Purpose and arrangement of installations
According to NPB 88-2001, water mist fire extinguishing installations (UPTRV) are used for surface and local extinguishing of class A and C fires. retail and warehouse premises, that is, in cases where it is important not to harm material values with fire retardant solutions. Typically, such installations are modular structures.
For extinguishing both conventional solid materials (plastics, wood, textiles, etc.) and more hazardous materials such as foam rubber;
Combustible and flammable liquids (in the latter case, a thin spray of water is used);
- electrical equipment, such as transformers, electrical switches, rotating motors, etc.;
Fires of gas jets.
We have already mentioned that the use of water mist significantly increases the chances of saving people from a flammable room, and simplifies evacuation. The use of water fog is very effective in extinguishing the spill of aviation fuel, because. it significantly reduces heat flow.
The general requirements applicable in the United States to these fire suppression installations are given in NFPA 750, Standard on Water Mist Fire Protection Systems.
3.2. To obtain finely atomized water use special sprinklers, which are called sprayers.
Spray- sprinkler designed for spraying water and aqueous solutions, the average droplet diameter of which in the flow is less than 150 microns, but does not exceed 250 microns.
Spray sprinklers are installed in the installation at a relatively low pressure in the pipeline. If the pressure exceeds 1 MPa, then a simple rosette atomizer can be used as atomizers.
If the diameter of the atomizer outlet is larger than the outlet, then the outlet is mounted outside the arms, if the diameter is small, then between the arms. The fragmentation of the jet can also be carried out on the ball. To protect against contamination, the outlet of the deluge sprayers is closed with a protective cap. When water is supplied, the cap is thrown off, but its loss is prevented by a flexible connection with the body (wire or chain).
Atomizer designs: a - AM 4 type atomizer; b - spray type AM 25;
1 - body; 2 - arches; 3 - socket; 4 - fairing; 5 - filter; 6 - outlet calibrated hole (nozzle); 7 - protective cap; 8 - centering cap; 9 - elastic membrane; 10 - thermoflask; 11 - adjusting screw.
3.3. As a rule, UPTRV are modular designs. Modules for UPTRV are subject to mandatory certification for compliance with the requirements of NPB 80-99.
The propellant used in the modular sprinkler is air or other inert gases (for example, carbon dioxide or nitrogen), as well as pyrotechnic gas generating elements recommended for use in fire fighting equipment. No parts of gas generating elements should get into the fire extinguishing agent; this should be provided for by the design of the installation.
In this case, the propellant gas can be contained both in one cylinder with OTV (injection type modules), and in a separate cylinder with an individual shut-off and starting device (ZPU).
The principle of operation of the modular UPTV.
As soon as an extreme temperature is detected in the room by the fire alarm system, a control pulse is generated. It enters the gas generator or squib of the LSD cylinder, the latter contains a propellant or OTV (for injection-type modules). A gas-liquid flow is formed in a cylinder with OTV. Through a network of pipelines, it is transported to sprayers, through which it is dispersed in the form of a finely dispersed droplet medium into the protected room. The unit can be manually activated from a trigger element (handles, buttons). Typically, the modules are equipped with a pressure signaling device, which is designed to transmit a signal about the operation of the installation.
For clarity, we present you several modules of UPTRV:
General view of the module for the installation of fire extinguishing water mist MUPTV "Typhoon" (NPO "Flame")
Module for fire extinguishing with water mist MPV (CJSC "Moscow Experimental Plant "Spetsavtomatika"):
a - general view; b - locking and starting device
Main specifications domestic modular UPTRV are given in the tables below:
Technical characteristics of modular water mist fire extinguishing installations MUPTV "Typhoon".
|
Indicators |
Indicator value |
|
|
MUPTV 60GV |
MUPTV 60GVD |
|
|
Fire extinguishing capacity, m2, not more than: class A fire fire class B flammable liquidsflash point vapors up to 40 °С fire class B flammable liquidsflash point vapors 40 °C and above |
||
|
Duration of action, s |
||
|
Average consumption of fire extinguishing agent, kg/s |
||
|
Weight, kg, and type of fire extinguisher: Drinking water according to GOST 2874 water with additives |
||
|
Propellant mass (liquid carbon dioxide according to GOST 8050), kg |
||
|
Volume in the cylinder for propellant gas, l |
||
|
Module capacity, l |
||
|
Working pressure, MPa |
||
Technical characteristics of modular fire extinguishing systems with water mist MUPTV NPF "Safety"
Technical characteristics of modular water mist fire extinguishing installations MPV
Much attention of regulatory documents is paid to ways to reduce foreign impurities in water. For this reason, filters are installed in front of the atomizers, and anti-corrosion measures are taken for the modules, pipelines and atomizers of the UPTRV (pipelines are made of galvanized or stainless steel). These measures are extremely important, because flow sections of UPTRV sprayers are small.
When using water with additives that precipitate or form a phase separation during long-term storage, devices for mixing them are provided in the installations.
All methods for checking the irrigated area are detailed in the TS and TD for each product.
In accordance with NPB 80-99, the fire extinguishing efficiency of using modules with a set of sprayers is checked during fire tests, where model fires are used:
- class B, cylindrical baking sheets with an inner diameter of 180 mm and a height of 70 mm, flammable liquid - n-heptane or A-76 gasoline in an amount of 630 ml. The time of free burning of a combustible liquid is 1 min;
- class A, stacks of five rows of bars, folded in the form of a well, forming a square in a horizontal section and fastened together. Three bars are placed in each row, having in cross section a square measuring 39 mm and a length of 150 mm. The middle bar is laid in the center parallel to the side faces. The stack is placed on two steel corners mounted on concrete blocks or rigid metal supports so that the distance from the base of the stack to the floor is 100 mm. A metal pan measuring (150x150) mm is placed under the stack with gasoline to set fire to wood. Free burning time about 6 minutes.
3.4. Design of UPTRV perform in accordance with Chapter 6 of NPB 88-2001. According to rev. No. 1 to NPB 88-2001 "calculation and design of installations are carried out on the basis of the regulatory and technical documentation of the installation manufacturer, agreed in the prescribed manner."
The execution of the UPTRV must comply with the requirements of NPB 80-99. Placement of nozzles, the scheme of their connection to the piping, the maximum length and diameter of the conditional passage of the pipeline, the height of its location, the fire class and the area to be protected, and other necessary information is usually indicated in the manufacturer's technical specification.
3.5. Installation of UPTRV is carried out in accordance with the project and wiring diagrams of the manufacturer.
Observe the spatial orientation specified in the project and TD during the installation of sprayers. Schemes for mounting sprayers AM 4 and AM 25 on the pipeline are presented below:
In order for the product to serve for a long time, it is necessary to carry out the necessary repair work and T.O. given in the manufacturer's TD. You should especially carefully follow the schedule of measures to protect sprayers from clogging, both external (dirt, intense dust, construction debris during repairs, etc.) and internal (rust, mounting sealing elements, sediment particles from water during storage, etc.). .) elements.
4. INTERNAL FIRE WATER PIPE
The ERW is used to deliver water to the building's fire hydrant and is usually included in the building's internal plumbing system.
Requirements for ERW are defined by SNiP 2.04.01-85 and GOST 12.4.009-83. The design of pipelines laid outside buildings for supplying water for external fire extinguishing should be carried out in accordance with SNiP 2.04.02-84. Requirements for ERW are defined by SNiP 2.04.01-85 and GOST 12.4.009-83. The design of pipelines laid outside buildings for supplying water for external fire extinguishing should be carried out in accordance with SNiP 2.04.02-84. General issues of the use of ERW are considered in the work.
The list of residential, public, auxiliary, industrial and storage buildings that are equipped with ERW is presented in SNiP 2.04.01-85. The minimum required water consumption for fire extinguishing and the number of simultaneously operating jets are determined. The consumption is affected by the height of the building and the fire resistance of building structures.
If the ERW cannot provide the necessary water pressure, it is necessary to install pumps that increase pressure, and a pump start button is installed near the fire hydrant.
The minimum diameter of the supply pipeline of the sprinkler installation to which the fire hydrant can be connected is 65mm. Place cranes according to SNiP 2.04.01-85. Internal fire hydrants do not need a remote start button for fire pumps.
The method of hydraulic calculation of ERW is given in SNiP 2.04.01-85. At the same time, water consumption for using showers and watering the territory is not taken into account, the speed of water movement in pipelines should not exceed 3 m / s (except for water fire extinguishing installations, where a water speed of 10 m / s is allowed).
|
Water consumption, l/s |
Water movement speed, m/s, with pipe diameter, mm |
|||||||
The hydrostatic head must not exceed:
In the system of the integrated economic and fire-fighting water supply at the level of the lowest location of the sanitary appliance - 60 m;
- in the separate fire water supply system at the level of the lowest located fire hydrant - 90 m.
If the pressure in front of the fire hydrant exceeds 40 m of water. Art., then a diaphragm is installed between the tap and the connecting head, which reduces the excess pressure. The pressure in the fire hydrant must be sufficient to create a jet that affects the most remote and highest parts of the room at any time of the day. The radius and height of the jets are also regulated.
The operating time of fire hydrants should be taken as 3 hours, when water is supplied from the building's water tanks - 10 minutes.
Internal fire hydrants are installed, as a rule, at the entrance, on the sites staircases, in the corridor. The main thing is that the place should be accessible, and the crane should not interfere with the evacuation of people in case of fire.
Fire hydrants are placed in wall boxes at a height of 1.35. Openings are provided in the locker for ventilation and inspection of the contents without opening.
Each crane must be equipped with a fire hose of the same diameter with a length of 10, 15 or 20 m and a fire nozzle. The sleeve must be laid in a double roll or "accordion" and attached to the tap. The procedure for the maintenance and maintenance of fire hoses must comply with the "Instructions for the operation and repair of fire hoses" approved by the GUPO of the USSR Ministry of Internal Affairs.
Inspection of fire hydrants and their performance check by starting water are carried out at least 1 time in 6 months. The results of the check are recorded in the journal.
The exterior design of fire cabinets should include a red signal color. Cabinets must be sealed.
Modern approaches to the design and installation of fire pipelines are not so unambiguous. In order to reduce costs and simplify installation, Western and domestic manufacturers began to supply pipes, fittings and adapters made of polypropylene and PVC to the market, designed for pipelines in fire extinguishing systems. The elements of the system are connected using "cold welding", that is, special adhesive joints. The main advantage of the technology is that the installation of the pipeline can be carried out in hard-to-reach places. Moreover, the speed, efficiency and cost of work make "non-metallic" fire pipelines economically attractive.
However, the use of plastic elements in fire piping systems causes a controversial attitude of specialists (mostly negative). Although, in accordance with the current set of rules SP 5.13130.2009 “Fire protection systems. Automatic fire alarm and fire extinguishing installations. Design Code” The use of plastic fire piping and individual components is permitted, but only if special fire tests are carried out in licensed organizations and with good results.
So far, few organizations have received Russian certificates of compliance and fire safety. It is not yet possible to talk about the mass use of plastic pipelines in fire extinguishing systems. However, there are advocates of the use plastic pipes with adhesive joints in sprinkler systems, since this technology speeds up installation and significantly reduces the cost of work. At the same time, the scope of plastic pipes and fittings (in the field of fire extinguishing) is limited to pipelines constantly filled with water.
The main advantage of the technology is that the installation of the pipeline can be carried out in hard-to-reach places. The speed, efficiency and cost of work make "non-metallic" fire pipelines economically attractive
When designing and installing plastic sprinkler systems, increased requirements are applied: it is necessary to exclude the presence of voids (unfilled areas with water) at all stages of the operation of the pipeline system.
There is another technology for arranging a sprinkler system that has even greater maneuverability and ease of installation than a plastic pipeline. For water supply, metal connections and connections are used, made on the basis of braided stainless steel hoses or corrugated pipes. The flexible system allows you to arrange the wiring from the main pipeline to the sprinkler heads with minimal cost. In addition, the maneuverability of the system allows you to lay the pipeline in the most inaccessible places, in particular, the wiring can be easily disguised behind false ceilings.
However, "alternative" materials in fire extinguishing systems, although they have maneuverability, speed up installation, but are quite expensive compared to metal wiring. In addition, despite the set of rules that allows the use of non-metallic sprinkler systems, (with a positive outcome of fire tests), it is necessary to obtain permission from the fire authorities. And inspectors are wary of flexible and plastic eyeliners. Therefore, the innovative approach and conservatism of firefighters can make it difficult or significantly slow down the installation of the system.
At the same time, there are technologies that make it possible to simplify the installation of a metal fire pipeline system, and facilitate work in hard-to-reach places. According to the director of the Russian division of Ridgid Andrey Markov, it is advisable to use piping systems with split couplings.
The fact is that Russian standards allow the use of coupling joints in a fire pipeline, but this technology has not yet found wide distribution. The reason is that for quality installation you need a convenient and effective tool for knurling gutters. The connected ends of the pipes must be scrupulously “sharpened” for the coupling, otherwise the high-quality installation of the pipeline and the trouble-free operation of the system will not work. Modern equipment for rolling grooves allows you to quickly process the ends of pre-cut pipes right at the place of installation of the pipeline, and even more so in the workshop.
A good set of tools makes the installation of a metal pipeline much more maneuverable: if necessary, the length of the pipe can be adjusted right at the installation site. In addition, the tool can work with pipelines already installed, for which a distance of at least 90 mm from the wall or ceiling is required. The new technology allows, with the help of a tool, not only to lay new fire protection systems, but also to repair the existing pipeline. Moreover, when installing the pipeline, with the help of quick-coupling couplings, self-centering of the connected pipes occurs. Couplings are very useful in cases where the fire piping system is installed in places where welding is prohibited. For example, in old wooden buildings, in existing archives and similar institutions.
Fire piping systems with detachable couplings are easy to operate and maintain, and are also very resistant to deformation and vibration loads
According to the director of the Russian division of Ridgid, fire-fighting pipeline systems with detachable couplings are easy to operate and maintain, and are also very resistant to deformation and vibration loads. This is especially true when a building fire is caused by an earthquake. The system works despite deformation loads and strong vibration, and at the same time (if the installation of the pipeline was carried out efficiently) there is no loss of tightness in the coupling joints.
No less important is the compensation of thermal expansion of steel pipes, which occurs as a result of a fire. This piping system, complete with quick-coupling couplings, well compensates for the expansion of the fire-fighting pipeline.
Page 9 of 14
Rice. 22. Device for joining pipes for welding. 1 - captures; 2 - handle.
The assembly of elements of fittings and pipelines for welding is carried out on assembly stands and fixtures. The assembled parts are tack welded. The gaps, the number of tacks and welding modes for fittings are selected depending on the wall thickness of the pipes being welded.
Elements and assemblies of pipelines are assembled on a stand equipped with devices for laying, docking (Fig. 22) and tacking parts for welding. When assembling flanges for welding with pipes, attention should be paid to the perpendicularity of the flange surface to the axis of the adjacent part. The end of the pipe should go inside the flange by 5-10 mm. Before assembling the flange connections for welding with pipes, temporary gaskets are installed and the flanges are fixed with bolts. Assembling the assembly before welding ensures that the holes in the flanges of adjacent pipes and valves match.
Electric arc manual welding is used for welding fittings of pipelines. Welding is carried out with metal electrodes with a protective coating. In the conditions of central workshops, it is more expedient to weld fittings with an A-547 semiautomatic device in a carbon dioxide environment.
The number of layers of the seam in manual arc welding depends on the thickness of the walls of the pipes and the angle of cutting the edges:
The first layer of the seam must completely melt the ends of the edges of the pipes to be joined. The top layer of the seam should have a smooth outline without undercuts. Attention should be paid to the correct organization of the workplace of the welder and provide it with the necessary accessories and tools. Welds are visually inspected. External welding defects can be considered: deviations in the size and shape of the working section of the weld, undercuts, sagging and sagging, burns, unsealed craters, cracks, fistulas. Correction of defects in welded joints is allowed: on pipes with a diameter of up to 100 mm, if the crack length is less than 20 mm; on pipes with a diameter of 100 to 300 mm, if the crack length is less than 50 mm.
Marking finished products and knots is produced with colored paint at the end of the part and contains the order, block, line or assembly numbers. Finished pipeline assemblies are stored in separate sets before being sent to the installation site.
Installation of pipelines of fire extinguishing installations.
Installation of fire extinguishing installations in cable structures of power plants and other electrical premises
carried out before laying the cable. This is done in order to exclude welding of pipe lines and installation of sprinklers in the immediate vicinity of power and control cables. This circumstance should be remembered by the producers of works.
Before the installation of pipelines, the following organizational and preparatory activities are carried out: familiarization with the technical documentation; checking the readiness of the building part for the installation of pipelines; formation of teams and providing them with the necessary assembly tools, fixtures and rigging equipment; obtaining supports, hangers, fittings, assemblies and parts of pipelines in assembly and procurement areas (MZU); receipt, removal and lifting of pipes to design marks in cable structures; arrangement and preparation of workplaces, platforms and scaffolds.
Installation of pipelines is associated with a significant amount of rigging work. Fire extinguishing pipelines are installed in cable tunnels and mezzanines, access to which with pipes and pipeline units is very difficult. Installation is carried out in rooms located at different elevations - the main building of the power plant (minus 3, plus 4, 6, 9, 14 m). 
Rice. 23. Lever winch with a lifting capacity of 1.5 tons.
When installing pipelines, use sets of tools and fixtures. The set includes: spanners sizes from 12 to 27 mm, socket wrenches with interchangeable heads from 12 to 27 mm, chisels, cross-cutting tool, center punch, metalwork hammers 800 and 500 g, sledgehammers 4 and 8 kg, screwdrivers, bastard files, crowbar with a diameter of 10 and a length of 600 mm , metal brush, caliper, metalwork compasses, roulettes 10 and 1 m long, metal ruler, plumb line, lever winch with a lifting capacity of 1.5 tons (Fig. 23), tool box, pipe wrenches, flange square, pipe clamp, level. Electrified tools are widely used - electric drills, electric grinders, electric pipe cutters. 
Rice. 24. Collapsible metal scaffolding.
When working at heights in cable half-floors, at power transformers and in chemical water treatment rooms at a height of 1 m and above, inventory scaffolding and scaffolding are used. Scaffolding and scaffolding must be inspected and allowed for operation by the foreman or technical manager of the site. It is recommended to use a collapsible scaffold (Fig. 24), which can be quickly assembled in the narrow passages of the cable mezzanine and in high rooms. When working, it should be borne in mind that the scaffolding is designed for the mass of 1-2 people, and not for the mass of pipelines being lifted.
When laying out the route, axes and level marks of pipelines are applied and the installation sites of supports, sprinklers, fire extinguishing installations, and detectors are marked. The signs of the axes and elevation marks are applied according to the working drawings, taking into account the laid cable routes. In cable structures, it is sometimes more convenient to lay pipelines along the top of the tunnel. If such a gasket is a deviation from the project, then the changes are agreed with the customer and the design organization.
Supports, suspensions and supporting structures are installed according to preliminary marking. Fixed supports and hangers, as a rule, are welded to embedded parts and steel posts of reinforced concrete structures, and are attached to concrete columns on brackets. The most common is the fastening of pipes with clamps. If there are structures in the cable half-floors for the installation of cable shelves, trays, and ducts, the pipelines are based on pieces of channels welded to the racks of these structures. The position of the pipes is fixed with a round steel clamp welded to the channel. If the slope for the laid pipeline is stipulated in the fire extinguishing installation project, then it is checked by a hydrostatic level or a special device (Fig. 25).
Rice. 25. Device for measuring the slope of the pipeline.
1 - base; 2 - level; 3 - lever; 4 - graduation scale.
Enlargement assembly of pipes into lashes and knots, into blocks is carried out directly in cable rooms.
Centering pipes with a diameter of 50 to 150 mm when assembling joints for welding in a whip is recommended to be carried out using the fixture shown in fig. 22. After joining, the ends of the pipes are seized by electric welding. As a rule, tacking is done by installers, and welding is done by electric welders.
When enlarging units with stop valves, temporary gaskets are installed and all bolted connections at the flanges are fully tightened. For the manufacture of gaskets, a special device is used, shown in Fig. 26.
When installing pipelines, it becomes necessary to lift the elements onto the supports of design marks. 
Rice. 26. Device for cutting gaskets on a drilling machine.
1 - Morse cone; 2 - ruler; 3 - slider; 4 - roller knife; 5 - center.
In cable structures for lifting, it is most convenient to use lever winches with a lifting capacity of up to 1.5 tons and chain hoists. Pipe lashes and long knots are fixed and lifted with two lifting devices. Raised components and parts should be temporarily fixed, and after alignment, permanent fasteners should be installed.
When laying pipes through walls and ceilings, pipelines are enclosed in sleeves made of pipes or sheet steel. Pipe sections enclosed in sleeves should not have welded joints. The gaps are being filled non-combustible material e.g. mineral wool. Laid pipelines should not have bags in which water or extinguishing agent can remain. Especially accurately (on gaskets and immediately for the full number of bolts) flange connections should be assembled. After the assembly and welding of the joints, the pipelines are fixed on the supports.
Installation of pipe fittings is carried out in assembled form - it is already docked with ready-made pipeline nodes. Before installation, the fittings are inspected so that foreign objects and dirt do not remain in it. When installing flanged valves, the correct selection of flanges, fasteners and gaskets is checked, as well as the position of the valve in the direction of fluid flow (arrow). Prior to commissioning, the mounted shut-off valves of the valve type must be in the closed state, and the valve type must be in the open state. On sections of the pipeline that form bags, drainage tubes or traffic jams. To remove air At its upper points, fittings with taps are installed.
When installing pipelines for freon and carbon dioxide fire extinguishing, the requirements for the performance of work increase. The pipelines of these fire extinguishing systems are made of seamless steel pipes.
The installation of the pipeline must ensure: the strength and tightness of the connection of pipes and their connection to fittings and devices; reliability of fixing pipes on supporting structures and the structures themselves on the bases; the possibility of their inspection, purging or washing.
The connection of parts and links of pipelines is carried out by welding, as well as using bolted flanges or threaded connections.
The minimum radius of the inner bending curve of pipes should be: for steel pipes when bending them in a cold state - at least four outer diameters; for steel pipes when bending in a hot state - at least three outer diameters. On the bent part of the pipe there should be no folds, cracks, ovality in the places of bending is allowed no more than 10%.
Threads on pipes and fittings must be clean, free of burrs, breaks or incomplete threads.
The sealing of threaded joints made with couplings, elbows, tees, connecting nuts is carried out with flax fiber wound onto the thread, lubricated with red lead or white paint on drying oil.
Fittings, parts and pipes having an outer taper thread, it is allowed to screw into couplings or coupling ends of fittings having an internal cylindrical pipe thread.
Flange connections pipelines are carried out in compliance with the following requirements: the deviation of the perpendicularity of the flange to the axis of the pipe, measured along the outer diameter of the flange, should not exceed for pipelines with a working pressure of 4 MPa<40 кгс/см 2) - 1,0 мм, для трубопроводов на рабочее давление свыше 4 МПа (40 кгс/см 2) - 0,5 мм. Отверстия во фланцах под болты располагаются на равных расстояниях, смещение по болтовой окружности не более 0,5 мм. Фланцы стягиваются равномерно и параллельно друг другу с поочередным завертыванием гаек крест накрест. Размеры прокладок должны соответствовать размерам поверхности фланцев. Паронитовые прокладки перед установкой натираются с обеих сторон сухим графитом.
Electric arc welding is recommended for joining steel pipes with a wall thickness of more than 3.5 mm. Gas welding is recommended for joining pipes with a wall thickness of less than 3.5 mm. When welding the fitting with the main pipe, the gap cannot exceed 0.5-1 mm. Welding of each pipe joint is carried out without interruption until the entire joint is completely welded. Each section of the pipe before installation in place is viewed in the light in order to identify and remove foreign objects.
Connection by soldering copper pipes of all diameters is made only with hard solders, for example, copper-phosphorus MF-1, MF-2, MF-3. When soldering copper pipes, the connections are made with an overlap with one pipe disassembled or end-to-end with an external coupling.
Pipelines are laid parallel to walls, ceilings and columns. The number of turns and intersections should be kept to a minimum. Pipelines laid on the same surface or structure are laid parallel to each other.
In particularly damp rooms and in rooms with a chemically active environment, pipeline fastening structures are made of steel profiles with a thickness of at least 4 mm. Structures and pipelines are covered with protective varnish or paint.
Fastening of pipelines to building structures is carried out by normalized supports
Distance between supports, m |
|||
Pipe material |
Pipe diameter, mm |
on horizontal lines |
in vertical sections |
non-ferrous metal |
|||
and pendants. Welding of pipelines directly to the metal structures of buildings and structures, as well as to elements of process equipment is not allowed. The distances between the pipeline supports are recommended to be selected according to the data in Table. ten.
When group laying pipes of different brands, a smaller value of the distance between the attachment points is accepted.
Pipelines are laid with a slope that ensures the flow of condensate and residues of the extinguishing agent. The slope of pipelines with a diameter of up to 50 mm must be at least 0.01, and for pipelines with a diameter of more than 50 mm - 0.005. For gas pipelines, the slope direction is taken from risers to outlet nozzles; for incentive pipelines - to risers.
The passages of pipelines through walls and ceilings, depending on the category of adjacent premises, are open or sealed.
Sealing of passages is carried out when passing from an explosion or fire hazardous zone to another explosion or fire hazardous zone; during transitions from an explosion or fire hazardous zone to a non-explosive and non-flammable zone. In these cases, the sealing of single pipes is carried out in sleeves or in glands installed on the side of the heated or dry room, as well as the room, the environment of which should not penetrate into the adjacent room.
To seal the group passages of pipes in the wall opening, a steel plate is installed with pipes or pipe seals welded into its hole. Connection of pipelines to branch pipes is carried out by threaded connections (Fig. 27).
In places where possible vibrations of pipelines occur, it is planned to install soft gaskets in supports or install vibration dampers to change the frequency and reduce the amplitude of vibrations to values that ensure the strength and tightness of the pipeline connections.
Changing the direction of the pipeline is done by bending the pipes or installing elbow fittings or bends. 
Rice. 27. Group passage of pipelines through walls. 1 - wall; 2 - passage plate; 3 - pipeline; 4 - nut; 5 - clutch.
Thermal elongation of pipelines is compensated by turning the pipes, while fastening the pipes at the points of rotation is not allowed. When passing through the expansion joints of buildings, U-shaped compensators are installed on the pipelines.
When laying pipelines, one-piece and detachable connections are used.
When installing detachable connections, the following must be ensured: mechanical strength sufficient to maintain the integrity of the pipeline when exposed to internal and external forces during installation, during testing and during operation; ease of assembly and disassembly; change in the inner diameter is not more than allowed by the normals.
Detachable connections, as a rule, are used to connect pipelines in places where disassembly of the pipeline is necessary during operation and installation.
Do not place pipe connections on expansion joints, on curved sections, on load-bearing structures. Pipe connections are allowed no closer than 200 mm from the reference points.
The application of protective coatings is carried out on a well-cleaned and degreased surface of pipes and metal structures. The film of the painted surface must be smooth, even, without gaps and wrinkles.
All external surfaces of pipelines, except for threads and sealing joints of flange surfaces, are painted to protect against corrosion. Fire extinguishing pipelines are painted red in accordance with the standard "Colors of safety signs" (GOST 12.4.026-76).
Pipelines in fire and explosion hazardous areas are grounded at both ends. In places of detachable connections of pipelines, jumpers made of steel or copper wire are installed, providing a reliable electrical circuit on both sides of the connection. Pipelines introduced from the outside into fire or explosion hazardous rooms are grounded before entering the room.