Features of the operation of the internal fire-fighting water supply

Internal fire-fighting water supply (ERW) - a pipeline that supplies water to fire hydrants inside buildings and structures. Design features, scope and requirements for ERW are given in the normative document SNiP №2.04.01 "Water supply and sewerage of buildings".

This article discusses the maintenance and testing of a fire water supply system. You will learn what acts must be drawn up when checking the operability of the pipeline and by what method the ERW tests are performed.

Content of the article

The scope of the ERW

The internal fire-fighting water supply system, in accordance with the provisions of SNiP and fire safety standards, must be equipped in the following types of facilities:

residential multi-storey buildings with a height of over 12 floors;
control buildings with six or more floors;
hostels of any number of storeys;
public congestion objects - clubs, cinemas, assembly halls, theaters;
industrial buildings and warehouses;
industrial enterprises and administrative buildings.

Installation of an internal fire safety pipeline is not provided in buildings:

schools, with the exception of boarding schools intended for the permanent residence of students;
in seasonally operating cinemas;
in industrial facilities of 1 and 3 categories of fire resistance and workshops where the use of water can cause an explosion or fire;
in industrial and warehouse buildings, the design of which provides for extinguishing a fire from storage tanks or reservoirs;
in warehouses for agricultural products and mineral fertilizers.

Design features of the fire water supply system

Internal fire-fighting water supply can be performed as a special or multifunctional system. A special ERW is intended exclusively for fire extinguishing, the installation of such structures is made of steel (the use of polymeric materials is not allowed), this is the main type of ERW in multi-storey buildings.

The multifunctional ERW project allows the system to be combined with utility pipelines, production pipelines and water supply pipes for automatic fire extinguishing devices.

In this case, for the installation of pipes supplying water to fire hydrants, and for the installation of adjacent utility pipelines - products made of polypropylene, or PEX pipes laid inside fireproof boxes.

The fire safety pipeline scheme can be dead-end or circular. The dead-end scheme of the ERW is allowed for use if the building design provides less than 12 fire hydrants... When installing the ERW in a ring pattern, an additional one is used, by means of which, as necessary, faulty sections are excluded from the system and the water supply to the risers of utility pipelines is shut off.

In addition to the pipeline and fire hydrants, the following structural elements are used during the installation of the ERW:

pumping units;
shut-off and safety valves;
system control devices - manometers, level gauges;
manual fire detectors, by means of which pumps are activated that pump liquid through a pipeline (detectors are installed in fire cabinets).

The internal fire-fighting water supply must have a pressure that provides the required water loss (pressure of the incoming water) for the normal operation of fire hydrants. If the calculation shows that the head does not correspond to the design, the pipeline is equipped with fire pumps that increase the water pressure in the system. The pumps are installed in a separate room inside the building - the pumping station.

Technical requirements for ERW

Fire safety pipeline cranes are located on the branches of the ERW riser, which are brought out to easily accessible places - lobbies, corridors and entrances to the building. The cranes are installed in fire cabinets at a height of 135 cm from the floor, a fire hose is supplied to each crane, the diameter of which corresponds to the diameter of the crane feed hole, the length of the hose varies within 10-20 m.

If the project provides for the installation of an ERW riser combined with the building's water supply line, it can be made of polypropylene or galvanized pipes.

The ERW project is drawn up taking into account the requirements of SNiP and fire safety standards for the number of trunks (cranes) for each floor of the room. The number of taps depends on the volume, length of corridors and number of storeys of the building:

residential buildings with a height of 12-16 floors - 1 piece, if the length of the corridors exceeds 10 m - 2 pieces;
residential buildings with a height of 16-25 floors - 2 pcs, if the length of the corridors is more than 10 m - 3 pcs.

The minimum allowable fluid loss per fire nozzle is 2.5 l / s. If the diameter of the barrel and fire hose is 38 mm, the rate is reduced to 1.5 l / s.

To determine the pressure capable of providing the required fluid loss, a hydraulic calculation of the pipeline is performed. The calculation is carried out for the most distant fire shaft using the formula: Н = Нвг + Нп + НПП + Нпк, wherein:

Нвг - the height of the water supply from the city network to the fire barrel;
Нп - calculated pressure loss in the pipeline riser;
NPP - pressure loss in the riser in the fire extinguishing mode;
Нпк is the required level of fluid loss.

So that on the fire safety trunks located on the lower floors of the building, diaphragms with the same diameter of the through holes are installed in the pipeline.

The ERW project should be drawn up taking into account the following technical requirements:

the maximum pressure on the lower fire barrel - 0.9 MPa;
diameter of pipes connecting the shafts with the ERW riser - at least 50 mm;
diameter of the fire riser - not less than 65 mm;
fire hydrant diameter: capacity up to 2.5 l / s - 50 mm, over 4 l / s - from 65 mm;
installation is mandatory on the lower and upper parts of the fire riser, at the branch points to the storey pipelines and on the ring distribution network.

The calculation and drafting of the ERW project in each specific case must be performed by specialized specialists in accordance with the requirements of the current SNiP. The finished ERW project is coordinated with representatives of the fire safety service.

Checking the fire-fighting water supply system (video)

Maintenance and testing of fire-fighting plumbing

The internal fire-fighting water supply system during operation is subject to regular maintenance and system performance testing.

ERW services include:

Checking the performance of fire safety valves - every 6 months.
Checking fluid loss and pressure in the pipeline, checking the supplied jet for pressure and range - every 6 months.
Maintenance and rolling of fire hoses - every 6 months.
Service of shut-off valves - every 6 months.
Checking the performance of the pressure boosting pumps - every month.
Checking the complete set of fire cabinets - every 6 months.
Testing of fire hoses for resistance to water pressure - annually.

Based on the measures taken, the relevant regulatory documents are drawn up:

comprehensive examination act;
maintenance report;
fire hydrant performance protocol;
list of detected defects in the fire safety system;

Requirements for maintenance and testing of the operability of the ERW are given in the document "Test procedure for internal fire-fighting water supply" dated 2005, issued by the Ministry of Emergency Situations of Russia.

Checking the ERW for the level of fluid loss is carried out by means of measuring inserts on the coupling heads equipped with pressure gauges with a measuring range of 0-1 MPa. The insert is installed between the valve feed opening and the fire hose. The tests are carried out on the shaft farthest from the boost pump.

The technology for conducting fluid loss tests is as follows:

The fire safety locker opens.
The fire hose is disconnected from the crane.
If there is a lowering diaphragm on the borehole, the compliance of its diameter with the design dimensions is checked. Measurement is taken with a caliper.
An insert with a pressure gauge is connected to.
A fire hose is connected, the hose nozzle is placed in a container for collecting water. One person from the service personnel holds the sleeve, the second one turns on the water supply.
The fire detector activates the pumping unit, the tap valve opens.
According to the readings of the pressure gauge, the water pressure in the system is determined, the measurement is taken 20-30 seconds after the start of the supply at a stable pressure.
The pumping unit is shut down, shut down and the data is entered into the test log, on the basis of which the corresponding act is drawn up. The measuring equipment is dismantled and the devices return to their original position.