To extinguish a fire, water is often used, which is taken from artificial or natural sources. In cities, the easiest way to provide fire-fighting water is to use public water supply. Sometimes a water supply system is specially constructed for a strategically important facility or in cases where it is not possible to connect to a conventional pipeline.
Water sources
Natural sources include rivers and lakes. You can even draw water from the sea, if the location allows. The advantage of such sources is a large supply of water, but it is not always possible to connect to them. Piers and platforms 12 by 12 m in size are being built near natural sources, with a hard surface, so that at least two fire engines can easily drive up.
The lack of water in arid areas or under other difficult conditions is compensated by the construction of artificial sources of fire-fighting water supply. These include reservoirs, ponds, canals, wells, pools, wells. Tanks are also installed, in which there must be at least 50% of the calculated volume of water required for fire extinguishing.
In settlements, on the territories of enterprises, large institutions, organizations, fire-fighting water pipelines are built and connected to industrial, household or drinking pipelines. This is a simple and reliable way to ensure timely fire extinguishing.
Internal and external water pipes
Article 68 of the Fire Safety Rules (No. 123-FZ) states that cities, towns and villages must have fire water supply systems.
Features of their organization depend on the sources of water supply and objects that are subject to fire protection. In rural areas, there may be no main water pipes, while it is difficult to imagine a city without them. Gravity water pipelines are built in mountainous areas, and pressure systems are used in flat areas.
In the general case, fire water supply includes pumps that pump water from a source, a system of pipelines that supply water to a destination, and water intakes.
If the water supply is laid outside the building (often underground), then it is called external and is used to connect fire equipment - hydrants, machines, pumps.
External fire networks are combined with public water supply systems. This prevents water stagnation, slows down corrosion processes, increases the service life of pipes and reduces repair costs. The combination with household and drinking water pipelines is justified by their wide distribution network, in contrast to the industrial one.
The pressure in the combined water supply, pipe diameter and pressure are calculated based on the maximum load on the network. How external fire water sources should be organized is described in Code of Practice 8.13130.2009.
It is allowed not to arrange in settlements where less than 50 people live, and at separate facilities with a volume of less than 1 thousand cubic meters. m. Such objects can be residential buildings, hotels, boarding schools, hospitals, and other buildings in which people stay. Functional fire hazard classes are listed in detail in Art. 68 of regulation No. 123-FZ.
Indoor plumbing is called internal and is used to supply water to fire hydrants located in the building. Water from internal water supply systems is used for automatic fire extinguishing systems. With their help, the source of ignition can be extinguished in a timely manner, and the fire is prevented.
Internal water pipes are specialized when they are used only to extinguish a fire, and multifunctional if water is taken for other needs.
In some cases, it is not necessary to install it. The normative water consumption is described in section 6 of SNiP 2.04.01-85.
Pressure differences
Depending on the pressure of the water in the pipe, the fire-fighting water supply can be of high and low pressure. For fire extinguishing systems, low-pressure pipelines are more often used.
To use them, you must connect a pump or motor pump to the hydrant. Do this through the suction sleeves. In this case, a jet with a height of at least 10 m, counting from the surface of the earth, should be formed.
High-pressure water pipelines are built for industrial facilities with an increased risk of fire - oil refineries, woodworking enterprises, paper mills, and so on.
The fire pipeline is connected to the household one, and the pressure is increased only at the necessary moment. In high-rise buildings and structures, pumps are installed, which are turned on during a fire. We can say that these are specially designed pumping stations.
In rare cases, fire-fighting water pipes of constant high pressure are built. For their operation, there is no need for an additional connection of an imported pump. The sleeve can be connected directly to the column hydrant. The water jet is fed to the burning point, its height is at least 20 m, provided that the barrel is at the level of the roof of the tallest building.
Importance of pumping stations
An important part of the fire extinguishing system is the pumping station. It creates the necessary pressure of water in the pipe, which allows you to extinguish the fire on the highest floors of buildings. The station is a room or a separate building that houses the pumps, the power supply system and the branching of the pipes. Stations are often located in basements.
Mandatory elements of the system are manometers and vacuum gauges. The former determine the pressure in the system created by the pump for pumping water, and the latter measure the rarefaction of the air.
Measuring instruments should be freely accessible so that replacement, verification, and other necessary manipulations can be carried out. A diagram of the fire extinguishing system, a diagram of internal fire fighting installations, and instructions for their use should be hung on the wall of the station.
Special attention is paid to safety, since the pump is powered by a high voltage network. The location of all parts must be such that, in the event of a fire, the fire is quickly extinguished.
At modern stations, the control is automatic, which eliminates the influence of the human factor. Automation controls pumps, electricity supply, emergency shutdown. At the right time, the alert system is triggered. The performance of the pumps is checked monthly with the results recorded in the reporting log.
Application of regulations
According to building codes SNiP 2.04.02-84, a fire pipeline is laid in settlements and at economic facilities. The same SNiP prescribes. It depends on several factors:
- the number of people living in the village or city;
- possible number of simultaneous fires;
- the height of the buildings of a part of the settlement;
- fire resistance and purpose of structures and buildings.
These dependencies are given in the SNiP table. They are used to calculate main water supply lines, organize water intake points, and install hydrants. To fight fire in factories, warehouses, agricultural facilities, the largest volume of water is required.
For small settlements, villages, where the number of inhabitants does not exceed 1 thousand, and all buildings have 1-2 floors, a water flow of 5 l / s is assumed. If we consider a residential 10-storey building in the city, then extinguishing it requires a consumption of 10-15 l / s, depending on the total volume. Taking into account the degree of fire resistance, the flow rate can increase up to 30-40 l / s for low degrees of fire resistance of industrial buildings.
Consumption is provided taking into account the consumption of water for other industrial or domestic needs. A fire can happen during the hours of the highest consumption of water by the population, and this should in no way affect the fight against the disaster.
Examination
The fire water supply system must be in working order at all times. Fire safety and the ability to extinguish the flame in a timely manner depend on this.
To ensure that the fire extinguishing system is working properly, it is checked twice a year. In winter, hydrants are insulated, cleared of ice and snow drifts.
Check the availability of access roads to the source of water supply. They should be free, not cluttered with transport, foreign objects. The road must have a smooth hard surface. In summer, hydrant wells are opened and their condition is checked.
Fire water systems are "on call" 24 hours a day, seven days a week. After all, a fire can occur both day and night, at any time of the year - even in winter, even in summer. Therefore, such systems must be absolutely reliable, without discounts for weather conditions, time of day, temperature and other factors.
And in this article we will consider the most common types of fire fighting systems, paying attention to the design nuances, performance, as well as the cost of such equipment.
Sources of fire fighting water supply
The primary classification of fire water supply networks can be built according to the type of source from which water will be “scooped”.
At the same time, typical water supply networks for fire extinguishing systems, as a rule, “feed” from the following sources:
- A natural body of water - rivers, lakes or even seas. Such a scheme involves connecting to an almost unlimited source of water. Therefore, with the help of water supply networks, "fed" from a natural reservoir, you can put out any fire. However, the very possibility of “connecting” to a river, lake or sea does not always appear. Therefore, such a “tie-in scheme” is implemented only in a few cases.
- An artificial reservoir - a pond, a pool, a dig, a reservoir. Such a scheme can be implemented anywhere, subject to the presence of aquifers in the soil and the corresponding area of the land plot, where a pit for a man-made reservoir will be dug. This artificial pool contains a fairly large volume of liquid - at least 5000 cubic meters. That is, in terms of fire fighting, an artificial reservoir is not inferior to a natural lake. But the arrangement of a man-made fire pond will have to spend significant funds.
- Fire-fighting water supply - a network of high-pressure pipelines supplied to a column - a hydrant. At the same time, it should be noted that the fire network contains an almost unlimited volume of liquid - it is connected to a river or lake. And the pipeline itself and the hydrant can be placed almost anywhere.
As a result, it turns out that the fire water supply is the most effective source, since a river or a lake is far from being everywhere, and the construction of artificial ponds is very expensive, even without taking into account the cost of the land.
In addition, one should not forget that systems connected to water bodies must be equipped with expensive pressure units - pumps, and in water fire extinguishing systems, pressure is generated by a hydrant.
Therefore, almost all buildings with a height of more than 6 floors are equipped with plumbing fire extinguishing systems. And with a 12-story (or more) construction, the presence of a hydrant is a prerequisite for the commissioning of an object.
External and internal fire water supply
Another way to classify fire extinguishing systems is to sort networks according to the method of “planting” liquid into an object. At the same time, any fire extinguishing system can be "powered" using an external or internal source.
And in the first case, artificial reservoirs and high-pressure conduits are usually used as sources, the hydrants of which are located outside the walls of the building. And in the second case - only fire water pipes brought directly into the building. Moreover, internal hydrants should be located in increments of 20 meters along the horizon on each landing.
As a result, outdoor fire-fighting water supply is economically justified only if it is possible to connect to a river, lake or public high-pressure water supply. And internal networks are present in any multi-storey building "by default".
However, especially important objects have to be nourished from both external and internal sources. At the same time, guided by the arguments already described, external hydrants and internal fire hydrants (PC) should be used as the optimal “source”.
Performance characteristics of the fire water supply network
Regardless of the source or type of system, the performance of the domestic fire piping network must be maintained at the following levels:
- In terms of productivity - at least 5 liters per second.
- By pressure - at least 10 meters of the height of the water column.
- In terms of the volume of "reserves" of liquid - at least 250 cubic meters of liquid for the building of I and II categories of fire safety and at least 5000 cubic meters for a summer cottage.
At the same time, sources of external fire-fighting water supply or internal networks that feed the fire extinguishing system of warehouses of combustible or highly combustible materials must maintain a capacity of 60 to 240 liters per second. Warehouses with containers are extinguished from sources that can provide a feed rate of 10 to 25 liters per second. Well, to eliminate a fire in a garage box, a supply of 20-40 liters per second is needed.
The volume of liquid reserves “saved” in sources of an external or internal type must ensure that a fire is extinguished for at least an hour.
Thus, the maximum volume of the fire network source can be up to 500,000 cubic meters. And in the case of extinguishing a fire by means of calculations with carriages, the volume of water consumption increases by at least a quarter.
Typical models of fire water supply systems
The most common models of fire water supply systems include the following types of structures:
At the same time, each design scheme has its own way of implementation, its own type of source and its own approach to technical maintenance. Therefore, further in the text we will consider these three options in more detail.
- this is an intermediate reservoir raised above the roof of the protected building. Moreover, water is pumped into the tower using pumping equipment, and the “feeding” of fire water pipelines drained from the tank is carried out either by gravity (under the action of gravity) or by means of pressure pumps embedded in the body of fire fittings. That is why such a design rises above the roof of the building.
Due to the described structural features, it is practically impossible to “accumulate” a serious supply of water in the tower, since an excessively heavy tank will simply destroy the supporting shaft of such a structure. However, in this case there are no problems with pressure - water discharged from a height of 10 to 40 meters flows at a very high speed, providing no less noticeable performance - tens of liters per second.
Therefore, the "tower" water supply system is used for "local" needs, serving a specific warehouse, house or workshop. Moreover, the tower can be “fed” both from rivers and lakes, and from wells and water pipes.
The price of building a water tower depends on many factors, including the density of the supporting soil, the volume of the reservoir, the productivity of the aquifers, and so on.
Typically, the cost of such projects starts from 500,000 rubles.
A network of hydrants (fire hydrants) - this is the "outer" side of a typical fire water pipeline, organized on the basis of a public water supply network, reinforced by an intermediate pressure station. Pipes with a diameter of 50-65 mm go to the hydrants, through which almost any volume of liquid can be supplied under a pressure of 10-15 atmospheres.
Internal fire hydrant
External hydrants are made in the form of columns or caissons. At the same time, column cranes are found in southern latitudes, and caisson hydrants are found in northern latitudes. This separation is due to the risk of liquid freezing.
Internal hydrants are made in the form of fire cabinets - boxes, inside of which there is a direct-flow or angle valve made of brass or cast iron, a sleeve - a fabric hose that can withstand a pressure of 6-10 atmospheres, a trunk - a tapering, cone-shaped tip on the sleeve, accelerating the flow of water to very high speeds, guaranteeing sufficient pressure.
The cost of only one internal valve reaches 1000 rubles. The cost of a hydrant mounted in a caisson reaches 10,000 rubles. The cost of a sleeve is 2000-4000 rubles for a 20-meter segment.
Fire fighting pumping stations collected on the basis of horizontal centrifugal units. Moreover, the number of pumps in the station reaches six units, which are connected to a common pressure manifold, "feeding" the sleeve or a network of pipelines associated with spray nozzles.
The station itself can be a node of a “tower” or “tap” water supply system, or an “independent” player providing liquid supply from a reservoir with a capacity of up to 165 liters per second. In this case, the station can be both stationary - mounted in a basement or an extension, and mobile - mounted on a truck chassis.
In terms of the speed of "reaction" to a fire, the station ranks second after the water tower, and in terms of "endurance" - the ability to work continuously - such a water supply scheme has no analogues. After all, the station can work for hours, up to the complete depletion of the source of liquid.
Therefore, either a natural reservoir or a very large pond can be considered as a promising source of water supply for the station. However, the station can also work in tandem with the public water supply, playing the role of a high-performance pressure pump that increases the pressure in the fire branch from the main line.
The cost of a pumping station depends on the performance of the structure, the number of pumps, the degree of mobility and other characteristics. Therefore, the price of this product ranges from 100 to 500 thousand rubles.
Maintenance of fire water supply systems
The set of activities focused on the maintenance of fire water supply networks can be divided into two areas:
- Research and repair of the "hydraulic" component - fittings, tanks, interfaces and other things.
- Research and repair of the "mechanical" component - pumps, valves and so on.
At the same time, studies of the first type involve checking the integrity of the valve body, fittings and tanks with an accompanying assessment of the tightness and ability to withstand the design pressure. Damaged components and parts are dismantled and replaced with new ones. The frequency of inspections is from a quarter (every three months) to a year.
Studies of the second type involve an assessment of the performance of the mechanics of pressure equipment and valves. The frequency of such surveys is once every 2-3 months. Damaged units are replaced with new ones or disassembled and restored to working capacity, replacing worn parts.
Of course, both checks can be combined by generating maximum pressure in the water supply network and monitoring the tightness of nodes and joints. As a result, with the proper level of experience, the maintenance procedure does not cause any difficulties. And if you do not ignore the requirements regarding the frequency of inspections, then your fire water supply system will last at least several decades.
Abstract
for fire-technical training
Topic #10:
Fire water supply.
Study questions:
1. Types of plumbing. Classification of water supply by pressure.
2. Methods for testing water pipes for water loss.
3. The device of a fire hydrant and the requirements for operation in winter and summer.
4. Requirements for the commissioning of new sources of fire water supply.
5. Fire water inspections.
Literature used in the preparation of the topic:
· A.A.Kachalov et al. Fire water supply. M., Stroyizdat, 1985
· A.F. Ivanov et al. Fire equipment in two parts. 1 Fire fighting equipment. M., Stroyizdat, 1988
· MG Shuvalov Fundamentals of fire fighting. M., Stroyizdat, 1997
Order of the UGPS of the Main Internal Affairs Directorate of St. Petersburg and the Leningrad Region dated 09/06/95 №240 “On the Enactment of the Instruction for Accounting and Supervision of Fire Water Supply in St. Petersburg”.
Order of the UGPS of the Main Internal Affairs Directorate of St. Petersburg and the Leningrad Region dated 06.02.98 №44 “On Amendments and Additions to the Order of the UGPS dated 06.09.95 No. 240 “On the Enactment of the Instructions for Accounting and Supervision of Fire Water Supply in St. Petersburg” .
Abstract compiled
Head of 63-PCh 3-OPO UGPS GUVD
St. Petersburg and Leningrad region
major of internal service
A.O. Shevchenko
“_____” _______________ 1999
Presentation of the material
Fire water supply- this is a set of measures to provide water to various consumers to extinguish a fire. The problem of fire water supply is one of the main ones in the field of fire fighting.
Types of plumbing. Classification of water supply by pressure.
According to their purpose, water pipes are divided into household, industrial and fire-fighting ones. Depending on the pressure, fire-fighting water pipes of high and low pressure are distinguished. In the high-pressure fire water pipeline, within 5 minutes after a fire is reported, the pressure necessary to extinguish the fire in the tallest building without the use of fire engines is created. To do this, stationary fire pumps are installed in the buildings of pumping stations or in other separate rooms.
In low pressure water pipes during a fire, fire pumps are used to create the required pressure, which are connected to fire hydrants using suction hoses.
In high pressure pipelines water is supplied to the fire site through hose lines directly from hydrants under pressure from stationary fire pumps installed in the pumping station.
All water supply facilities are designed so that during operation they pass the estimated water flow for fire needs at the maximum water flow for household and drinking and industrial needs. In addition, an emergency supply of water is provided in clean water tanks and water towers for extinguishing fires, and fire pumps are installed in pumping stations of the second lift.
Pump-hose systems, which are collected when extinguishing fires, are also elementary high-pressure fire water pipelines, consisting of a water supply source, a water intake (suction grid), a suction line, a combined pumping station of the first and second rise (fire pump), water pipes (main hose lines), a water supply network ( working hose lines).
water towers designed to regulate pressure and flow in the water supply network. They are installed at the beginning, middle and end of the water supply network. The water tower consists of a support (trunk), a tank and a tent-device that protects the tank from cooling and freezing of water in it. The height of the tower is determined by hydraulic calculation, taking into account the terrain. Usually the height of the tower is 15...40 m.
The capacity of the tank depends on the size of the water supply, its purpose and can vary widely: from a few cubic meters on low-power water pipes to tens of thousands of cubic meters on large urban and industrial water pipes. The size of the control tank is determined depending on the water consumption schedules and the operation of pumping stations. In addition, they include an untouchable fire reserve to extinguish one external and one internal fire within 10 minutes. The tank is equipped with discharge, collapsible, overflow and mud pipes. Often the discharge and collapsible pipes are combined.
A variety of water towers are water reservoirs, which are designed not only to regulate the pressure and flow in the water supply network, but also to store a fire-fighting supply of water to extinguish fires for 3 hours. The tanks are located on elevated places.
Water tanks and towers are included in the water supply network in series and in parallel. When connected in series, all water from pumping stations passes through them. In this case, the discharge and collapsible pipes are not combined, and they work separately. At a minimum water consumption, excess water is accumulated in a reservoir or in a tank, and at a maximum, this reserve is sent to the water supply network.
When connected in parallel to the water supply network, excess water enters the tanks and tanks (at minimum water consumption), and at maximum water consumption it is sent to the network. In this case, the discharge and distributing pipelines can be combined. To control the water level in tanks and reservoirs, measuring devices are provided.
By type of object served water supply systems are divided into urban,settlement, and industrial,agricultural,railway, etc.
By type of natural sources used Distinguish between water pipes that take water from surface sources (rivers, reservoirs, lakes, seas) and underground (artesian, spring). There are also mixed feed water supply systems.
According to the method of water supply water pipelines are pressure with mechanical water supply by pumps and gravity (gravitational), which are arranged in mountainous areas when the water source is located at a height that provides natural water supply to consumers.
According to the purpose of the system water supply is divided into household and drinking that meet the needs of the population; production, supplying water technological processes of production; firefighting and combined. The latter suit, as a rule, in settlements. From the same water pipes, water is also supplied to industrial enterprises if they consume an insignificant amount of water or, according to the conditions of the technological process of production, water of drinking quality is required.
With high water consumption, enterprises can have independent water supply systems that provide their household, drinking, industrial and fire-fighting needs. In this case, they usually construct household fire and industrial water pipelines. The combination of fire water supply with economic, and not with production, is explained by the fact that the industrial water supply network is usually less extensive and does not cover all the volumes of the enterprise. In addition, for some technological production processes, water must be supplied under a strictly defined pressure, which will change when extinguishing a fire. And this can lead either to an increase in water consumption, which is not economically feasible, or to an accident in production equipment. An independent fire-fighting water supply system is usually arranged at the most fire hazardous facilities - enterprises of the petrochemical and oil refining industries, oil and petroleum products warehouses, timber exchanges, liquefied gas storage facilities, etc.
Water supply systems can serve both one object, for example, a city or an industrial enterprise, or several objects. In the latter case, these systems are called group systems. If a water supply system serves one building or a small group of compactly located buildings from a nearby source, then it is called a local system. To supply water under the required pressure to various parts of the territory of the settlement, which has a significant difference in marks, arrange zoned water supply. A water supply system serving several large water consumers located in a certain area is called a district water supply system.
Water network serves for reliable and uninterrupted transportation of water to consumers in the required quantities under pressure sufficient to supply water to the most remote and high-lying point of water intake, as well as to extinguish fires.
Water supply networks are divided into ring and dead-end. In ring water supply networks, unlike dead-end ones, it is possible to turn off emergency sections of pipelines without stopping the supply of water to subsequent sections, in addition, they have less hydraulic shock. At the same time, the total length and, consequently, the cost of ring networks is much higher than that of dead-end networks. In this regard, ring networks are usually used in urban and industrial water supply systems, and dead-end networks are used to supply small towns, livestock farms, etc.
So that the water in the pipes does not freeze in winter, they are laid below the freezing depth of the soil. For example, for the middle zone of our country, the depth of water supply networks is taken to be 2.5 ... 3 m. In permafrost areas, water lines are laid in insulated tunnels or openly on the surface, accompanied by a hot satellite. A reliable way to combat water freezing under these conditions is to preheat the water with its mandatory circulation in all areas.
Before building a water supply network, it is calculated: the diameter of the pipes and the pressure loss are determined for a given water flow. In all cases, the network is checked for the supply of fire consumption at maximum water intake for household and drinking and industrial needs. At the same time, it is taken into account that during a fire, the minimum pressure at the most remote and highly located point of the water supply network must be at least 0.1 MPa (1 kgf / cm 2), and the speed of water movement through pipes can reach 2.5 m / s.
External water pipes are an important part of the fire protection system, along with hydrants and pumping stations. They are laid outside buildings, connecting with water pipes for household and drinking purposes. Outdoor fire water supply cannot be imagined without reservoirs, which are primary sources and help out in the absence of centralized utility lines.
Requirements for plumbing
In temperate and cold climates, outdoor water supply should be laid below the freezing level of the soil. External water supply can be ring and dead-end. In the building rules, it is recommended to arrange low-pressure ring water pipes, since they have less hydraulic shock and it is possible to isolate the emergency area without disturbing the water supply. On a dead-end water supply, it is possible to arrange a water intake point for extinguishing a fire only if its length is 200 m or less.
Fire pipelines are made mainly of low pressure. They should give a jet 10 or more meters high from the ground. Hydrants are installed for water intake, and pressure is provided by connecting pumps that are on fire trucks or other fire equipment.
In rare cases, high-pressure pipelines are installed, providing pressure due to the operation of stationary pumps. The pumps do not run constantly. They must turn on a maximum of 5 minutes after the fire signal is given.
It is recommended to design an outdoor fire-fighting water supply with high pressure in the pipes if there are less than 5 thousand inhabitants in the settlement and there are no fire departments. High-pressure fire water pipelines are also arranged in enterprises with an increased risk of fire. In this case, the automatic system helps to extinguish the fire and prevent its spread. The pressure in the pipeline must be such that the jet rises 20 m above the tallest building in the village or area.
Ensuring stable operation
Before building a fire pipeline, calculations are carried out to determine the optimal pipe diameter. The water flow rate is also determined at the maximum load on the production and utility pipelines.
To take water from the pipeline, they install in the wells. Their numbers are calculated based on the features of the nearest buildings. It is recommended to install hydrants at a distance of 5 m or more from buildings. They are placed along the road or on the carriageway. The location of hydrants is indicated by special signs and plates.
In order for the outdoor plumbing to serve properly, it needs to be maintained. Twice a year, hydrants are inspected and tested, water is turned on, worn out, rusted parts are replaced.
The main sources of outdoor fire-fighting water supply in cities and large towns are municipal water pipes or water pipes for industrial and agricultural work.
But if there is no such system, then it remains to use natural sources directly. If there are no natural sources nearby, then artificial reservoirs are built and huge reservoirs are installed.
If water intake from the surface of the reservoir is difficult due to swampy banks, then a well is built with a gravity pipe and filters that trap all kinds of pollution.
In what cases do they do without plumbing
It is useful to consider cases where it is permitted not to install an external fire fighting water supply. This usually happens when there is no plumbing or when it is impossible to provide the required pressure.
For settlements with a population of less than 5 thousand people and detached buildings and structures, natural, artificial reservoirs, as well as reservoirs can be used as water sources instead of a fire pipeline.
The fence is carried out directly from the reservoir. A platform will be equipped near it, on which at least 2 cars can freely turn around.
It is allowed not to build an external fire water supply system:
- if less than 50 people live in the settlement;
- there are only 1 and 2 storey buildings;
- the building is intended for trade and its area is 150 sq. m or less;
- the building is intended for public catering, with a volume of 1000 cubic meters. m and less;
- for warehouses, parking lots without maintenance, archives with an area of 50 sq. m or less;
- agricultural receiving and procurement seasonal points with a volume of 1000 cubic meters. m and less;
- production and storage buildings with a high degree of fire resistance and the lowest fire hazard with a volume of 1000 cubic meters. m and less;
- for detached hotels, shelters, clinics, railway stations, entertainment and cultural buildings with a volume of 250 cubic meters. m or less.
For all of these categories, other fire extinguishing methods may be provided depending on the circumstances and location. In some cases, all available agricultural equipment is used or the fire department is called.
Water consumption
It consists in extinguishing the flame and preventing it from spreading to neighboring houses and buildings. In this regard, it is important to correctly calculate the main pipeline through which water is supplied. The parameters of the water supply, in turn, depend on the flow of water required to extinguish the fire.
Consumption rates are described in detail in the set of rules 8.13130.2009. They must be guided by the organization of external fire water supply.
It should be noted that the consumption in the first table does not depend on the fire resistance of buildings.
It is assumed that with a population of up to 10 thousand people, the probability of two simultaneous fires is extremely small. Usually 1 fire needs to be extinguished, and for this the water flow should be 5-10 l / s. Five liters per second is enough if the buildings are 1 and 2 storey. If the building height is higher than 2 floors, then you need to focus on a larger indicator.
With a population of 10 to 100 thousand people, there is a possibility of 2 simultaneous fires. The consumption increases to 10-35 l/s. If the population exceeds 100 thousand, then simultaneous ignition in three different buildings of the district or quarter is not ruled out.
It will be necessary to provide water supply at a rate of 40-100 l / s, depending on the specific population. For cities with a population of over a million, 5 fires are allowed to occur simultaneously, therefore, for areas with multi-storey buildings, a pressure of 110 l / s is required.
Separately, water consumption is calculated for agricultural facilities, industrial areas, fuel filling points, parking lots, logging complexes. The fire resistance of buildings, the area of the territory and other parameters are taken into account.
Requirements for pumping stations
An important part of the outdoor water supply system is pumps. The place of their installation is called a pumping station. In order to choose the right type of pumps, as well as their number, they analyze the sources of external fire water supply, pipeline parameters, fire extinguishing conditions. It is permissible to install several groups of pumps for various purposes.
When is it necessary to install an internal one and how to properly install it? What do you need to know to get it right? The article will answer these questions.
When is ERW required in a building
The list of requirements for the joint venture of the internal fire water supply is indicated in a number of regulatory documents VP 10.13.130 2009.
- In residential and public buildings.
- In administrative and household buildings.
- At industrial enterprises.
- In industrial warehouses.
When determining the flow rate, knowledge of the number of storeys and volume of the structure is required. In residential premises, the length of the corridor is taken into account.
In industrial buildings and warehouses, the level of fire resistance of the building, the degree of fire safety and the volume of a particular room are taken into account.
In industrial buildings and warehouses, if the height is more than 50 m, and the indicators are indicated with a volume of up to 50 thousand m 3, it is recommended to use four-jet pumps with a head of 5 l / s. If the volume of the room is higher, the use of eight-jet models is recommended.
To determine the amount of water consumed for fire extinguishing, it is necessary to take into account the height of the compact jet and the diameter of the spray. With the free pressure of the fire cock, it is necessary to achieve a compact jet, the height of which will allow the fire to be extinguished at the highest point of the building.
Characteristics of the fire water supply B2
Fire-fighting water supply B2 is necessary in order to extinguish fires with water. In accordance with the requirements of regulatory documentation, such a system must be installed:
- In residential buildings with a height of 12 or more.
- In buildings of administrative structures with a number of storeys of 6 or more levels.
- In club and theater premises where there is a stage, cinemas, on the territory of the assembly and conference halls, which are equipped with appropriate samples of cinematographic equipment.
- In dormitory buildings, at public facilities, the volume of which is more than 5 thousand m 3;
- In administrative and household buildings at industrial enterprises, with volumes from 5 thousand m 3.
Features of the scope of application of SV B2, equipped with a set of fire hydrants
According to regulatory documents, the method of installing the B2 system is subordinate to the B1 and B3 systems. It follows from this that if there are B1 or B3 networks at the facility, it is necessary to connect the B2 fire water supply to the B1 or B3 network riser.
The diameter of the B2 risers must be at least 50 mm. The zone of their placement is the territory of the staircase and the corridor. The location of fire hydrants with a diameter of 50 mm requires a level of 1.35 m above the floor surface.
Their place of placement is lockers. It is important here to have a rolled hemp fire hose, the length of which is from 10 to 20 m. One end of the hose is equipped with a half nut to quickly attach it to the fire hydrant device. The other end is equipped with a cone to obtain a compact water jet, the length of which is from 10 to 20 meters.
How to determine the required amount of water for ERW
It is important to take into account the nature of the individual features of the object. If this is an industrial warehouse building, where all fire-fighting water supply devices with a diameter of 100 and a unit weight of kg are installed, it is recommended to increase the minimum flow rates in accordance with the requirements of regulatory documentation. For this, steel frame structures can be used.
Pipeline frost protection
If a well or a plastic pipe of an external fire-fighting water supply system freezes in winter, you can connect an electric cable to the pipes in severe frosts. When installing the system, it is allowed to use additional insulation with special materials. It is necessary to provide frost protection for fire-fighting water supply.
External pipes and water pipes can be insulated with foil tape and a voltage cable, which consists of three cores. The foil serves as a heat sink and prevents overheating. Wrap In order to avoid loads in the trench where the pipeline is located, it is concreted.
There is a faster, but not as convenient way. Cut strips of foil isol or isospan, glue them with tape.
You can wind several layers of mesh on the pipe, coat with glue and wrap it with insulation. This is the most reliable method of frost protection for fire protection pipelines, designed for long-term operation.
Where are fire hydrants used?
This system has been known for over 200 years. The fire brigade always has the nearest hydrant at its disposal. Its presence is mandatory in every region. Their availability, ease of use and visibility on the territory are important.
Hydrants that are located in the residential area must supply a jet of water at 5700 l / min. It is necessary to locate the SG along the length of the road, 2.5 m from its edge and up to 5 m from the wall of the nearby premises.
It is forbidden to install it on the territory that is intended for the movement of cars and on branches from pipeline lines. It is necessary to install a fire hydrant so that at any time it is possible to extinguish a fire that has arisen at an object that is assigned to this network. It is important that at least two hydrant hoses are available with water flow rates for outdoor fire extinguishing from 15 l / s.
About the internal plumbing
The norms of SN and P regarding the internal water supply and sewerage system of the facility are provided in order to design systems that are just being built and to reconstruct existing ones:
- internal water supply;
- sewerage;
- drains.
Mounting Features
Pipelines can be fixed by supporting the wall and partition in the area of the mounting hole. It can be supported on the basement floor through the places of concrete or brick columns, brackets along the entire length of the wall and partition. The pipeline is also supported on suspensions to the surface of the ceilings.
During the installation of a fire-fighting water pipeline, if the pressure of the fire hydrant is over 40 m, a diaphragm is provided between it and parts of the connecting head. This will be required to reduce excess pressure. It is possible to install diaphragms that have the same hole diameter on buildings with three or four floors.
Between the floor and the highest point of the floors there must be a distance not less than that indicated in the table:
How to make a calculation for the VPV in the HydroVPT program
If there is an ordinary internal fire water supply system, which consists of taps and pipes, you can calculate how to install it using an Internet program. Calculation results - flow and pressure indicators.
Consider the scheme of joint venture 10 13130 internal fire water supply. To calculate the required parameters, we introduce the number of cranes that are needed according to the standards.
We switch to the program and indicate that there are, for example, 2 jets of 2.5 liters each. The height of the room is 3 m, crane marks are 1.35 m, there is no control unit. Let's draw a ring with a diameter of 50 mm and a dead end. Pipeline diameter - 65-80 mm.
We enter all the data, do not change anything in the "Regular section" section, since these indicators suit us. Enter the number 0.000005 and simulate a formal sprint sprinkler - the red dot at the top of the screen. It will not be taken into account in the program, but this item is required.
We enter the geometric height of the dictating sprinkler 3 m, the height of the control unit and the coefficient - 0.2 cranes of 2.5 liters each. We choose the minimum values of the diameter for determining the branch pressure - 0.001. The calculations take into account local pressure losses. Open the section "Fire hydrant. Pipeline". We select and substitute automatically the value of the fire hydrant. 2.6 l/s, 0.1 MPa, 50 mm tap are standard values that can be used in our calculations. We confirm the entered indicators and proceed to the choice of the diameter of fire hydrants. We enter an indicator of 50 mm. For supply pipelines - 67 mm.
We finish by determining the length of the sections. The first is the distance to Let's introduce indicators of 2 m at a height of 1.65, since this fire water pipeline has a downward direction. The length of the ring pipeline is 3 m. We enter the same indicators for the second crane.
The whole system is entered, click "Finish", and the program will automatically calculate the necessary indicators.
Summing up
Fire-fighting water supply is a mandatory device for providing buildings and other territories. The installation of such a system implies compliance with the requirements specified in the regulatory documentation on the ERW system.
