Water Fire Suppression Systems
Automatic Water Fire Suppression Systems are designed for fire detection and suppression with concurrent warning signal release to inform staff on duty. Water is used as an extinguishing agent.
Water Fire Suppression Unit consists of the following parts:
- Deluge sprinklers
- Shutt-off valves
- Water flow detectors
- Control valves
- Control devices
- Pump station
- Fire vessel
Sprinklers and Deluge sprinklers.
Calculation of sprinkling intensity is needed to define sprinklers lay-out and their amount. A distance between sprinklers depends on design specifications, construction of a ceiling, ventilation system design and lights arrangements, but generally it should be not less than 1.4m from walls and 2.8m between adjacent sprinklers.
Maximum sprinklers amount that can be operated with one alarm valve is 1200 taking into account utilizing water flow annunciator.
The system is equipped with shut-off valves; water flow is adopted according to SP 10.13130.2009, Appendix 2.
Fire control valves are installed in such a way as to provide sprinkling all areas from different valvesых кранов.
Pump station provides required water pressure in a system and generally is installed in the basement.
Pump room has to be separated from other compartments by fire walls with fire rating 0.75 hr. The main exit from pump room must lead outside.
The following environmental characteristics must be provided in pump room: temperature 5-350C; RH 80%; illuminance minimum 100lx with back-up power supply.
Pump room has to have telephone communication with duty staff room.
Pump room entrance must have a display board with “Pump room” sign.
Pump station may include one or several pump units.
Minimum water line pressure is 0.1MPa.
Auxiliary water supply must be arranged for filling up fire line.
Water Fire Suppression System operating concepts.
The layout diagram of Pump Station:
If fire pump does not operate failing to provide working pressure, auxiliary pump starts in ten seconds.
After starting-up of the main pump jockey-pump is disabled.
Sprinklers system operation.
If a fire breaks out in protected area and temperature begins to increase, thermal lock breaks down; water starts flowing and pressure in the pipeline decreases. When the pressure reaches a predetermined value, pressure detector generates signal to start main fire pump. At the same time, fire alarm signal goes off.
Drencher curtain is not operable in automatic mode. If drencher curtain is needed it can be operated locally or remotely from fire fighting station.
Drencher unit operation.
When a fire occurs drencher curtain can be created by opening the electromagnetic valve with fire annunciator signal.
Control valves operation.
When a fire occurs and control valve opens, the pressure in the system decreases to P=0.3MPa. Pressure detectors trigger and fire pump starts providing required flow rate. Concurrently the signal is sent to the fire alarm system specifying which control valve has operated.
Water Fire Suppression System calculation.
Water flow and water pressure calculations are needed to select proper equipment and define system layout. A hydraulic calculation is performed in accordance with SP 5.13130.2009 to determine pipeline parameters and pressure values in different spots.
The hydraulic calculation is based on the farthest sprinkler (master-sprinkler).
Water flow for master-sprinkler is determined by the formula
где К – sprinkler performance factor.
The flow rate for other sprinklers located on the same branch as well as on the other branches is calculated with the view of master-sprinkler pressure.
The total flow rate is derived from the formula:
qi – individual rate.
Pressure losses for specified pipeline part are determined by the formula:
qi – water flow rate, Bm – pipeline factor, which in turn is derived by the formula.
The characteristic of the pipeline is determined by the formula:
Km – pipeline specific factor, l – pipeline length
The required total pressure in the system is determined by the formula:
P1 – pressure in master-sprinkler; P2 – pressure amounting to reference height of master-sprinkler; P3 – linear pressure loss in the pipeline; P4 – local pressure loss;
P5 – pressure loss in alarm valve; P6 – pressure loss in pump unit; Pm – back-up pressure in the pipeline.
Pump unit calculation (example).
Pump supply pressure with allowance for back-up pressure must be not less than 0.865MPa.
The present choice is GRUNDFOS pump model NB 100-250/261 with the following characteristics: flow rate 320m3/h; supply pressure 0.88MPa; input power 110kW.
The choice for automatic feed pump is GRUNDFOS CR 5-16 with the following characteristics: flow rate 5.0m3/h; supply pressure 0.89MPa; input power 2.2kW.
Water Fire Suppression System electrical calculation.
Control devices are needed for booster pumps control:
- Electric cabinet
- Display console
Automatic Fire Station Control provides the following:
- Automatic start of master pump
- Automatic start of an auxiliary pump in case of a failure of the master pump.
- Automatic start and stop of jockey-pump.
- Manual pump control on electric cabinet and remote control on display console.
- Electric system performance monitoring.
- Suction line and pressure mains shut-off valves monitoring.
- Keeping events log in non-volatile memory
Water Fire Suppression Systems installation.
Installation and operation of Fire Suppression Systems are regulated by Manufacturer’s specifications and following standards: GOST 12.1.019, GOST 12.3.046, GOST 12.2.005.
Installation, construction and commissioning works have to be carried out in accordance with a working schedule.
It is recommended to perform installation in the following order: preliminary works; measuring protected area; pipelines layout; pipelines installation; pipelines flushing; hydraulic tests; dyeing.
Preliminary works include:
- Removal from protected area highly inflammable materials;
- Erecting scaffold (if needed);
- Stocking construction materials and preparing working site.
It is permissible to use metal pads by welding them under pipes supports to ensure required inclination.Pipes connections should be located no closer than 200mm to mounting spots.
The following must be ensured upon installation:
- Strength and air-tightness of pipes connections and also fittings and devices connections;
- Reliable pipes support;
- Easy access for maintenance and repair works;
Compliance with Health and Safety Regulations.
Personal get admittance to system operations only through safety training; training log must be kept.
Installation and disassembling can be executed under following conditions:
- There is no pressure in relevant part of the system;
- Tools are safe and operable.
Hydraulic and pneumatic tests are to be carried out according to State Technical Authority regulat.
The main purpose of maintenance is to keep all Water Fire Suppression System parts in good working order ready to operate at any time. Maintenance works schedule is to be observed to prevent failures.
There are the following types of maintenanc:
- Technical maintenance;
- Scheduled repair;
- Scheduled overhaul;
- Emergency repair.
“Regulations for Scheduling and Executing of Technical Maintenance of Fire Suppression and Fire Alarm Systems” and RD 25.964-90 “Technical Maintenance of Fire Suppression Systems, Smoke Removal Systems and Fire Alarm Systems” are to be observed upon executing any maintenance works.
The scope of application of Water Fire Suppression Systems:
- Residential Buildings
- Office Blocks
- Shopping Malls
- Sport Facilities
- Air Terminals
- Exhibition halls
- Industrial Buildings
- Sea Vessels and Submarines
Our friendly well-qualified staff will assist you in choosing all system components and making the right decision. We will do our best to protect your valuable property and to save your money.