In this sample MEP specification section, Mechanical Fire Fighting Services have been described in detail under construction contract work. Main Highlights of this MEP Specification for Fire Fighting Services are: Pipework Generally, Dry Risers, Hose Reels, Fire Hydrants and Sprinkler Installation.
1. Pipework Generally in Fire Fighting Services of MEP
Unless otherwise specified, all fire fighting services above ground shall be of Galvanised Mild steel as and below ground shall be of UPVC Class “E” as Clause uPVC (Pressure Type) Pipes.
2. Dry Risers in Fire Fighting Services
The dry riser installation shall comprise the following components:
- The inlet box shall be constructed from 1.5mm thick galvanised sheet steel, and shall be suitable for recessed mounting, with 3mm thick x 40mm wide architrave.
- The box shall be provided with a hinged, lockable door, with a centre panel glazed with wired glass and having the words “DRY RISER INLET” in 50mm high red letters on the inside face.
- The lock shall be opened from the inside after the glass has been broken and the box constructed so that the hoses can be connected to the inlets after the glass has been broken without the door being opened.
- The box shall be of the vertical or horizontal pattern as required, and shall be large enough to provide access for maintenance and to operate the drain valve.
- The box shall be finished in stove enamel to the required colour, and shall be supplied by an approved manufacturer of fire equipment.
- A two inlet breeching, horizontal or vertical pattern as required, shall be provided, with each inlet comprising a 65mm dia. instantaneous male coupling with back pressure valve, blank cap and chain.
- The body of the breeching piece shall be fitted into a 25mm gunmetal gate valve for drain purposes, with plug and chain.
- Landing valves shall be gunmetal gate pattern valves to BS5041 Part 2, with 65mm flanged inlet and 65mm instantaneous female outlet with blank cap and chain. Valves shall be straight or oblique pattern as required, and shall be fixed in the closed position by a leather strap and padlock.
- Each landing valve shall be provided with a 36m long x 65mm dia. lined and coated woven synthetic fibre hose and diffuser branchpipe nozzle.
- The valve, hose and nozzle shall be accommodated in a recessed box supported on purpose made hangers and ready for immediate use. The box shall be generally constructed as for the inlet breeching, but with the words “DRY RISER OUTLET” in 50mm high red letters on the inside face of the glazing.
Air release valves
The top of each dry riser shall be fitted with a 25mm automatic air release valve, of brass construction, with internal solid rubber ball.
3. Hose Reels in MEP Fire Fighting Services
- The Contractor shall supply and fix, in the position indicated on the drawings, first aid hose reels. These shall be of the type specified in the Particular Specification, and shall be supplied complete with cabinet where indicated.
- They shall comply with BS. 5274 and comprise a reinforced rubber hose, 30m long 25mm dia. suitable for a working pressure of 1000 kN/m², coiled on a revolving drum. The outer end of the hose shall be fitted with a “shut-off” control nozzle and the inner end of the hose shall be connected through the reel to the water supply.
- The reel shall incorporate a valve that automatically turns on the water supply when more than approximately 3 m of hose is unreeled, and shuts off again when the hose is re-wound onto the reel. A manual shut off valve of the wheel type shall also be installed on the service pipe to each hose reel.
- An instruction plate shall be supplied with each reel indicating the method of use.
4. Fire Hydrants in MEP Fire Fighting Services
External underground Fire Hydrants
- Hydrants shall be to BS750, type 1 or type 2 as required, with cast iron body, bronze spindle, gunmetal internals, 80mm flanged inlet, and 65mm BS round thread male outlet for standpipe connection.
- The Contractor shall include for each hydrant the appropriate size of cast iron surface box, cover and frame, together with a light alloy standpipe with swivelling head and single 65mm instantaneous female outlet.
Internal Fire Hydrants
- Hydrants shall be gunmetal globe valves to BS1400 LG2, with 65mm flanged inlet and 65mm instantaneous female outlet with blank cap and chain. Valves shall be angle, straight or oblique pattern as required, and shall be fixed in the closed position by a leather strap and padlock. Each hydrant shall be provided with a 36mm long x 65mm dia lined and coated woven synthetic fibre hose and diffuser branch pipe nozzle.
- The valve, hose and nozzle shall be accommodated in a recessed box supported on purpose made hangers and ready for immediate use. The box shall be generally constructed as for the dry riser landing valves, but with the words “WET RISER OUTLET” in 50mm high red letters on the inside surface of the glazing.
- For high rise buildings, where the pressure range between lower and upper floors is outside permissible limits, hydrants shall be of the controlled pressure type.
5. Sprinkler Installation in MEP Fire Fighting Services
Specifying Authority of Sprinkler System
The sprinkler system shall comply in every respect with the Rules for Automatic Sprinkler Installation (current Edition) issued by the Loss Prevention Council (LPC) or National Fire Protection Association (NFPA) or other accepted Ruling Organisations. The system shall also comply with the requirements of the local Fire Authority.
Design Details of Sprinkler System Installation
The Contractor is required to complete the hydraulic calculation to determine the pipe size beyond the 16/18 sprinkler point, back to alarm valve.
Sprinkler Heads of the System
- The sprinkler heads shall be of the spray pattern installed in an upright position or pendant position as may be required. Sprinklers in false ceilings shall be flush ceiling pattern to accepted style.
- A set of 24 spare sprinkler heads shall be provided and located in a cabinet adjacent to the alarm valve chamber together with 6 number sprinkler spanners for use in removing and installation of the heads.
- The Contractor shall determine the temperature rating of sprinkler heads.
Sprinkler Head Guards
Sprinkler head guards shall be fitted to all sprinklers. The guards shall be constructed from metal and shall be of a pattern approved by the Fire Insurers.
Control Valve Sets
A control valve set shall be provided for each sprinkler system zone, and shall comprise:
- Sprinkler stop valve of cast iron construction, fitted with an indicator showing “OPEN” and “CLOSE” positions, and complete with padlocked securing straps. The valve shall be mounted on the incoming side of the alarm valve.
- Alarm valve fixed above the main stop valve, on the main supply pipe and before any connection is taken off.
- Alarm devices, including water motor alarm gong, pressure switch.
- Facilities for testing to suit Fire Services Department requirements.
- Dial pressure gauges suitable for the water pressures above and below the alarm valve shall be fitted to the alarm valve set. Each gauge shall be so arranged that it can be easily removed for testing and checking without shutting down the water supply.
- Retarding device of accepted design to obviate false alarms due to mains pressure variations where necessary or where indicated.
Stop Valves in Sprinkler System
- All stop valves fitted to the installation shall be so constructed that in order to shut the valve the spindle must turn clockwise. The hand wheels of all stop valves shall be clearly marked to indicate which direction the wheel is to be turned to close the valve.
- An indication shall also be provided which shows whether the valve is open or shut.
- Each main stop valves shall be secured open by a padlocked or riveted strap.
- All stop valves shall conform to BS.1218, NFPA, or equivalent International Standard.
Alarm Valves in Fire Fighting Sprinkler System
These valves shall be of a type approved by LPC or NFPA
Water Motor Alarms in Sprinkler system
- The sprinkler system shall be fitted with an approved water motor alarm, which shall be located at a distance not exceeding 25m from the alarm valve, and at a height not to exceed 6m above the alarm valve.
- The pipework and fittings used shall be galvanised and to the sizes determined by the LPC or NFPA
- The pipework shall be arranged to drain through a fitting having an orifice not exceeding 3mm in diameter. The orifice plate may form an integral part of the fitting but shall be manufactured from a non-ferrous material to prevent the hole from becoming blocked by corrosion or foreign matter.
- A 15mm test valve shall be installed on the installation side of each alarm valve.
Electric Alarm Pressure Switches in Sprinkler system
- Electric alarm pressure switches shall be installed in the system and they shall be mounted on a vertical branch pipe at least 300mm long.
- The pressure switch may be of the diaphragm bellows or bourdon tube operated type, and shall be sufficiently sensitive to operate when only one sprinkler is discharging.
- The pressure switch shall be provided with volt free contracts to facilitate monitoring by a Building Management System, and wired to the main fire alarm panel.
- The pressure switches shall be of a type that is approved by the LPC or NFPA
Orifice Plates and Assembles in Sprinkler System
- The Contractor is required to check the hydraulic calculations of the distribution system and where considered necessary to assist in hydraulic balancing any system, shall install orifice plates.
- Orifice plates shall be installed to comply with the requirements of the LPC or NFPA
Pressure Gauges in Sprinkler System
Pressure gauges shall be fitted to meet the requirements of the LPC Pressure gauges shall conform to BS1780 or equivalent International Standard. The maximum reading of the scale shall be 150% of the maximum system pressure and each scale shall have divisions not exceeding 0.2 bar.
Fire Service Inlet in Sprinkler System
A Fire Service Inlet shall be fitted to the sprinkler systems in accordance with LPC or NFPA regulations or as directed by the Local Fire Authority.
Location Plan in Sprinkler System
The Contractor shall provide and fix in an accepted position a plan of the risk upon which shall be clearly indicated the location of the main stop valves.
- Location plates shall also be fixed on the outside of the Tank Room walls adjacent to the sprinkler chamber. The location plate shall bear the following words in raised letters:-
- SPRINKLER STOP VALVE INSIDE
- The letters shall be a minimum height of 35mm.
- The location plate shall be of cast iron constructed with raised figures and letters. The figures and letters shall be painted white on a flame red background.
- The alarm valve shall be suitably identified.
Valve Labels and Charts
- The Contractor shall label each stop valve. The number shall relate to a framed glass covered valve chart to be supplied and installed in each sprinkler chamber. The charts shall indicate the function of the valves and shall be to the F.S.D. approval and Engineers acceptance.
- No two valves on the system shall bear the same number.
- All drain lines from test valves, drain down points etc., shall discharge over tundishes. Each tundish shall be connected to a 50mm galvanised mild steel heavy quality drain line which shall discharge over a suitable gully.
- All tundishes, pipe fittings and support clips used for the drain lines shall be galvanised.
The Contractor shall provide and install a complete pressure boosting system, comprising electrically driven main pump, diesel driven standby pump and electrically driven Jockey pump. The pumps shall be of the type indicated in the Particular Specification and shall have a characteristic as defined by LPC or NFPA regulations for the hazard being protected.
Inspectors Test Cocks
The Contractor shall supply and install Inspectors test cocks in accordance with the LPC or NFPA requirements.
Sprinkler Indication Panel
The Contractor shall provide a dedicated sprinkler indication panel for the complete sprinkler installation which shall have the following facilities:
- Schematic diagram showing locations of all major items of plant, i.e. pumps, control valves, sectionalisation valves, electric alarm pressure switches, etc. Each item shall be clearly engraved in the National Language and English.
- Each main pump shall have the following indications:
- Amber Lamp: for fault alarm.
- Red Lamp: for fire alarm.
- Green Lamp: for correct system status
- The Jockey pump shall have the following indications:
- Green Lamp: for pump running.
- Amber Lamp: for fault alarm.
- Each control and sectionalisation valve shall have the following indications:
- Green Lamp: for valve open
- Amber Lamp: for fault alarm, valve closed.
- Each electric alarm pressure switch shall have the following indications:-
- Amber Lamp: for fault alarm.
- Red Lamp: for fire alarm.
- All fault and fire alarm signals shall be sent to the main fire alarm panel and/or Central Building Management System as required.
Water storage facilities shall be provided to suit the given hazard rating which shall be calculated on the maximum water flow and time at this flow rate as indicated by the LPC or NPFA regulations.
- Water supplies must be located to provide a Net Positive Suction Head (NPSH) when the duty pump is running at design flow conditions.
- Water tanks shall be provided with a 1.5m x 1.5m x 1.0m deep suction pit to prevent pump cavitation and to make full use of the stored volume.
- Should hydraulic hose reels or hydrant landing valves be connected to the sprinkler system due allowance must be made for water storage requirements for these systems.