As part of residential, public and industrial buildings, fire extinguishing systems are provided. One of the most effective means of this kind is a water supply channel, which is used for its intended purpose at specific points in the facility. Through the water supply lines, the liquid is directed to the pumping stations and then to the direct diffusers. In order for the fire water supply system to carry out its tasks for a long time, while maintaining the optimum load, it should be regularly tested and maintained.
Water pipe construction
A fire water supply system is not only water supply and supply channels. This is a whole infrastructure of devices, accessories and devices that are not always directly related to the maintenance of water media. Nevertheless, almost all fire water supply systems are formed on the basis of steel pipes or parts thereof connected by welding. An obligatory component of the pipeline is the crane - forged iron is used as the optimal material for this part, or in extreme cases bronze is used. The crane is designed to be connected to fire hoses when it comes to mobile fire extinguishing systems.
As already mentioned, one of the technological points of service of the water channel is a pump. This can be a high-pressure pumping station, capable of serving several stationary sprinklers and mobile water supply channels simultaneously. Also, the structure of the water supply includes control and shutoff valves, switches, tanks, detectors, etc. The configuration of the placement of these devices can vary depending on the scheme according to which the fire water supply is implemented directly in the structure of a particular object. So, there are external and internal ways of placing communication.
Outdoor fire water
The external method of installing and operating a fire water supply system is optimal when it comes to extinguishing large construction projects using special technical means. In particular, most systems of this type are oriented towards servicing buildings up to 1000 m3 in volume. With regard to specific types of facilities, an external fire water supply is used for almost all production facilities of classes B, D and D. It is also allowed to extinguish hangars, terminals, and storage facilities.
The water consumption in this case is about 10 l / s. This is an average value, since theoretically the maximum value can reach 35 l / s. However, in the case of residential and public facilities, there are restrictive requirements for loads on water supply networks and distribution lines. The pressure level with which the water will be supplied is also preliminarily calculated. For example, the recommended value when using low pressure is 10 m. As the number of floors increases, the force can increase at the rate of 4 m per floor. Despite the attractive power indicators, the outdoor fire water supply system is not always effective in combating internal sources of ignition. Accordingly, in such situations, internal water lines are more often used.
Firefighter domestic water supply
The standards for the organization of the internal fire water supply are defined in the corresponding section of SNiP under the number 2.04.01-85. This water supply provides fire extinguishing in industrial and public buildings, regardless of their categories. The height of the water supply can be 50 m, and the volume can reach 50 thousand m 3 . For residential buildings, the internal fire water supply on average delivers water at a speed of 1.5 l / s - provided that the diameters of the hoses and shafts are adjusted to 38 mm.
It is thanks to the narrow stream that such systems can provide the medium to high heights. For the same reason, it is inappropriate to use them in the protection of low buildings from fire. Most often, such structures are introduced into the infrastructure of hospitals, schools, universities, assembly halls, industrial premises.
The main task performed by the internal fire water supply system is to prevent the spread of fire at specific points. Therefore, if in the case of an external water supply system the main goal is to supply mobile lines with sleeves, then the indoor systems are guided by stationary sprinklers integrated into the ceilings of the premises. It can be deluge and sprinkler nozzles with different nozzle designs, oriented to dispersing drops or fog. Such devices are structurally complex, but their advantage is the ability to operate in automatic mode.
Loss test
In the process of checking the system for water loss, it is estimated how much the pressure indicators on the main shaft correspond to the standard pressure. This check allows you to insure yourself against line congestion and prevent accidents. Water loss tests are carried out twice a year. The time for testing is selected based on the period in which the most active water consumption is observed at the facility. For example, in the summer season. At the same time, communications should be checked at a minimum pressure in the main center line. This will allow you to evaluate the channel’s operating capabilities under the least favorable conditions.
In addition to pressure, checking the fire water supply also reveals the height level of the compact jet segment, the volume of water consumption and the pressure at the valve. But in most cases it is not required to make separate measurements separately, since these indicators are interrelated. For example, the pressure on the main barrel will correspond to that in the tap. And at least the data on the flow rate and jet height will fit into the standard.
The check for water loss itself is carried out sequentially on a fire hydrant, which has the greatest distance from the pump station. If the line is loaded by several cranes, each of them must be activated. Including adjacent cranes and communications connected to the riser, which is connected to the fire water supply. Requirements in this case note that pressure should be measured only on the main supply crane. Or, as an alternative to convenience, you can control the most highly located fire hydrant in the system.
Testing devices
Pressure is the main parameter of measurement, so the pressure gauge will also become the main tool in the work of the tester. Typically, measuring inserts with pressure gauges are used for such purposes. The ends of the inserts are provided in advance with special coupling heads.
As for the placement of the fixture, the optimal position will be between the fire hose and the valve. Directly the gauge device is mounted on the insert. If there is no direct connection, then you can use a flexible meter hose, which will also allow you to transfer the degree of pressure to the pressure gauge scale.
Depending on the tasks of the test, the fire test may include measurements of other parameters. For example, temperature. But for this it is necessary to use either combined pressure gauges with the function of a thermometer, or industrial bimetal devices with a remote measurement sensor.
Checking system elements
In addition to checking the metrological and operational indicators of the water supply fire infrastructure, the technical condition of its components is also tested. The main object of verification is a fire barrel. They are far from always tested in the framework of a check for water loss, so a separate examination justifies itself.
The absence of gaps, deformations and defects on the barrel surfaces are the main criteria by which the internal fire water supply is also evaluated in this part. Requirements for both external and internal systems initially prescribe that for manual trunks, output diameters should be between 13-19 mm. The average allowable value is 16 mm.
Sleeves are also checked for consistency and size. In particular, the length of the sleeve can be 10, 15 or 20 m. As for the diameters, they range from 51 to 66 mm. The specific size of the barrel and sleeve is selected based on the type of facility being serviced and the requirements for fire fighting tactics.
By the way, checking the internal fire water supply also extends to the analysis of the quality of work of sprinklers having their own design features. Contractors evaluate their tightness, quality of water supply, integrity of the element base and quality of connections. Almost every system also provides for the presence of reservoirs with water, which can be called reserve sources. Tanks of this type are checked for leaks and the quality of the connection to the water supply lines.
Assessment and presentation of verification results
In each case, the positive parameters will be different, since we can talk about an individual water supply project. The pressure indicator is considered as a basic criterion. Its value in accordance with regulatory proportions will be superimposed on the optimal values that appear in the design decision. In any case, a positive check of the fire water supply will be such only if the integrity of the equipment and its compliance with specific technical parameters - length, diameter, etc.
After fixing the results of the verification, a special document is compiled. In particular, the tester writes a protocol in which data on the results of the verification of the potential for water loss are recorded. This document contains information about the pressure at the barrel and valve. Along with this, a fire water supply certificate is drawn up, which indicates the time and place of the test, as well as information about the building and the equipment being serviced. The characteristics of the tested communications are also described in detail - for example, the type of barrel, sleeve material, crane size, etc. Both documents should ultimately be signed by all members of the commission involved in the verification process.
Security requirements
During the test, test participants must comply with safety rules. First of all, the tests themselves are allowed to persons who have undergone appropriate instruction on the handling of fire water supply tools. Each participant must have special clothing with a water-repellent coating. The characteristics of its tissues should correspond to the loads with which the examined water supply works.
Typically, such events are carried out at special training grounds, but in some cases when it is necessary to evaluate the performance of the system as a whole, verification is inevitably carried out at the place of operation of the equipment. In such situations, for example, water loss tests can only be carried out at moments when the flow of the jet does not pose a threat to people and vehicles.
Inside the building, the fire safety of the water supply should also be ensured if the infrastructure of interaction between the source, pump and sprayer is checked. Since a comprehensive check may involve a number of collapsible manipulations, a full set of tools and accessories suitable for a particular type of plumbing fittings should be prepared in advance.
Maintenance Requirements
The technical condition, if the infrastructure is used regularly, should be checked at least twice a year. Pipes, risers, reinforcing elements, connecting fittings, hoses with barrels, fire cabinets and other devices and devices are inspected. If necessary, maintenance staff performs repair work, changes worn parts, updates lubricants in the pump's motor filling and makes structural changes.
It should be borne in mind that the condition of the water supply can negatively affect not only the effectiveness of the fire fighting function, but also the safety of the building itself or the room to which it is attached. For example, under a high pressure load, even without a fire hazard, the pipe circuit can arbitrarily break out of the flimsy joint, causing property damage.
At the same time, the maintenance of the fire water supply system also affects the operability of the line as such. Workers evaluate the quality of the pumping station and the stability of the water supply from the main source. If necessary, they also make adjustments to the pressure and productivity parameters of the equipment so that they optimally meet the fire safety requirements for the current period.
Conclusion
The key to successful verification and effective operation of the fire water supply system is provided at the design and installation stage. Specialists determine the rationality of laying circuits according to one or another scheme, take into account the potential of hydrants, pumping stations and water supply lines. If diligent work was performed at these stages, then it is more likely that the fire water supply system will demonstrate compliance with both water discharge standards and technical requirements.
In the future, the quality of operation of the water supply infrastructure will depend on other factors. For example, how protected are the same hydrants in the winter. Issues with a place for transport are no less acute. Near public buildings and production facilities parking lots for fire engines are mandatory. At the very least, access roads and roads to the nearest water sources should be prepared, regardless of the time of year.
It will be useful to foresee the nuances of energy supply. As a rule, pumping stations with automatic control operate from the mains, so the availability of a backup generator will allow you to insure yourself in the event of an emergency interruption in the current supply from the central line.