Fire extinguishing systems of public buildings provide for their own delivery channels of extinguishing agents. The most common among them is water, for the delivery of which, respectively, pipelines are used. Due to the technical complexity and high responsibility of such systems, special requirements for their maintenance are provided. For this purpose, a special test procedure was developed for the internal fire water supply system of the Federal State Institution VNIIPO (research institution of the Ministry of Emergencies), the purpose of which is to test communications for leaks, structural integrity and functional readiness.
What is a fire water supply?
This is an infrastructure formed by devices, assemblies and plumbing communications. With its help, the fire safety of warehouses, schools, hospitals, cinemas, trading floors, etc. is ensured. A key component of any fire water supply system is a pipe network. Communications are connected either to the main water supply line, or to your own tank. The second option of water supply is more preferable, since it makes it possible to ensure complete autonomy.
A pump is also included in the technical infrastructure of the system, and in several versions - for water intake and maintaining sufficient pressure during circulation. The modern test procedure for the internal fire water supply just provides for measures to examine the measuring equipment, which determines the quality and parameters of the interaction of pumping equipment with the pipeline.
The final link in the system are devices for direct reception and flow of water - for example, deluge and sprinkler nozzles that fire automatically when the signs of ignition are detected in the room. Fire water supply, in turn, must constantly provide the ability to use fire extinguishing water material.
Installation of fire water supply
For each system, an installation plan is initially drawn up in the form of a design solution. It makes the calculation of technical and operational parameters, assigns the operating characteristics of the equipment, pipe sizes, etc. Separately, a layout of channels with cranes, valves and measuring devices is compiled. Functional units, for example, are mounted at accessible points on the landing, in the lobby or hallway. Each crane has a special cabinet recessed into the wall. That is, before installation, dismantling operations can also be performed with the expectation of ensuring the possibility of future inspection of the zone in accordance with the test methodology for the internal fire water supply. Installation of systems is usually carried out in 4 stages:
- Installation of pumps.
- Placing and fixing the pipe channels.
- Installation and configuration of a fire cabinet (one or more).
- Insertion of measuring fittings and automation connection.
Some components, like the same measuring equipment and pumping equipment, also involve connecting to an electrical network. To do this, use isolated hidden channels with waterproof pads and the mandatory presence of a safety block.
Fire water requirements
At the first commissioning, the operating parameters of the system must be checked. The test method of the VNIIPO internal fire water supply system is guided by the following regulatory requirements for communications:
- Working pressure - from 0.45 to 1 MPa, depending on the source of water intake.
- The pressure at the water outlet barrel with the valve open is 0.4 MPa.
- The diameter of the fire valve is from 40 to 60 mm.
- Sleeve length - an average of 10 to 21 m.
- The thickness of the fire hose is from 25 to 65 mm.
The differences in the ranges in terms of size are explained by the fact that the conditions of use can be different and largely depend on the layout and characteristics of the room. In each case, the project sets the exact parameters and recommendations for the placement of equipment.
Test conditions
The check with the inspection of the system is carried out twice a year minimum (in autumn and spring), when the air temperature exceeds 5 ° C. The pressure level should be at the minimum point for a particular water supply line. That is, the peak mode of water consumption, if we are talking about the highway, providing the entire building. The key parameter of the test will be the pressure on the main valve. As secondary indicators, the volume of consumed water is taken, as well as the pressure values of the fire barrel and valves. According to the test method of the internal fire water supply, measurements on additional taps are made at the lower nodes of the riser. Checkpoints are determined in advance according to the design documentation for the building under examination.
Testing Instruments
Measurements are made hydraulically using pressure gauges. Device inserts must be provided with heads for connecting to a pipe of a suitable format. The placement of the connecting equipment is carried out at points located between the fire hose and the valve. The device itself is installed either on the insert or with a flexible hose up to 1 m long. The test method of the internal fire water supply system allows the use of other devices for measuring pressure, but in any case, the devices must be initially checked, calibrated and tuned.
Testing Equipment
During the test of the fire water supply line, the following technical means and devices are used:
- Receiving tank. A tank for draining water, which must be connected to a drain, sewer or other drainage channel. The minimum volume is 100 liters. The tank must be provided with nozzles for connection to the tested communications, protective devices and a tight cover.
- Fire trunks. The methodology for testing the internal fire water supply for water loss involves the use of manual fire barrels with a diameter of 13, 16 or 19 mm. The design of the barrel must be intact, tight and compatible with the parameters of the connection channels.
- Fire hoses. Also, when testing the system for water loss, a sleeve up to 20 m long with a nominal diameter of 50 to 65 mm is used.
Test preparation
First, access to the fire cabinet is arranged, where the main valve of the water tap is located. It is necessary to disconnect the standard sleeve from the dictating valve and connect the pressure gauge. By the way, the test method of the internal fire water supply system also allows the connection of the measuring device to the fire barrel. Next, the prepared sleeve is connected to the pressure gauge. A sleeve is brought to the place where the spill of water is supposed to be without bends. It also houses a container for receiving water. It must be checked for leaks and a reliable platform for mounting to the floor or wall should be provided.
Test technology
When everything is ready for work, you can begin to test the line. How is the test procedure for internal fire water supply in standard mode? Two testers participate in the verification process, one of which holds the fire barrel, and the second opens the crane. Initially, the readings of the manometer at the main valve or dictating barrel are recorded. Then a command is given to turn off the pumping unit, the valve is closed through the tap, and water is drained from the sleeve into the tank. The readings are again taken from the pressure gauge, and the standard sleeve is connected to the hand barrel. The fire cabinet closes and is sealed.
Fire water test results
As the main criterion for evaluating the tests carried out, pressure indicators taken from the measuring device are taken. Taking into account the height of the feed stream and the water flow rate, a positive or negative assessment of the system is given in accordance with the applied test procedure. The status of the internal fire water supply at the time of the examination should be active, and after processing the results, it can be changed to a non-working or under repair. Data on the measurements taken are documented.
Testing documentation
After the audit is completed, the results are drawn up in the form of an act with the attached examination protocol. In this document, in addition to the data directly on measurements, the date, place and time of the tests must be indicated, as well as information about the building and the parameters of the target room. There are also certain requirements of the test methodology for internal fire water supply for recording information about the applied technical means. The dimensions of fire barrels, hoses, parameters of valves and measuring instruments are indicated. As for the protocol, it also contains information on the time and place of the test, but in addition to it, the applied technology and the hydraulic diagram of the pipeline infrastructure are indicated. If necessary, the test customer may require an indication of the characteristics of the fire cabinet and the average water flow rate in the served pipeline. These data will allow, when considering test results, to more accurately determine the maximum permissible load on communications.
Conclusion
Tests of fire water supply in a sense are similar to the crimping procedure, which applies to conventional heating and water supply systems. The difference lies only in the fact that in addition to evaluating the channels for leakage, the task is also to set up a technical check of the internal fire water supply. The test methodology for such systems, in particular, focuses on testing the operability of valves and cranes. This allows you to prevent possible sticking shut-off valves during its operation. Often there are situations of revealing mechanical breakdowns directly during the test with sharp pressure drops. In this case, in parallel with the act of checking the system, a project is being prepared to repair or identify a water supply malfunction.