MVWS and HVWS Water Spray System in Bhopal

Both are deluge systems: open nozzles on dry pipes, fed through a deluge valve that opens when the detection operates. What differs is the nozzle and the droplet. IS 15325, the Indian code for these systems, uses medium velocity spray for flammable liquids with a flash point below about 65°C and high velocity spray for liquids with a higher flash point, such as transformer oil.

MVWS nozzles give a filled cone of fine droplets. They cool the shell of a tank or vessel exposed to a nearby fire so it does not take in too much heat, and they control fires in light oils, LPG and solids such as conveyor belts and cable insulation.

HVWS nozzles, also called projectors, throw a narrow cone of large, fast droplets that cut through the flames and reach the burning oil. The water cools the oil and mixes into its surface until the fire goes out, which is why HVWS is used on transformers, oil fired boilers and lube oil systems.

HD Fire makes UL Listed high velocity nozzles in ¾ and 1 inch, the ¾ inch also FM Approved. Tyco offers the Type HV with its own inlet strainer and the Mulsifyre range, and Aaag brass and stainless steel nozzles for up to 12 bar. Kartar and New Age add brass and UL Listed models.

HD Fire's MV nozzle is UL Listed, FM Approved and Lloyd's Register type approved, in K 18 to 102. Tyco offers the open D3, D4a and MV Protectospray nozzles and the EA-1 with a frangible bulb, and Aaag brass and stainless steel nozzles in K 22 to 102 for up to 10 bar. Balaji Fire Safety, Kartar and New Age add brass and UL Listed models.

HD Fire TS and TSS tank cooling nozzles stand at a distance from the tank wall and stop it taking in heat from a nearby fire. HD Fire revolving nozzles protect the tops of fixed roof tanks, and its reverse action nozzles throw water back towards the inlet. Tyco MV-R and MV-T nozzles protect vessels holding liquids with flash points of 66°C and below, and New Age makes tank cooling nozzles in brass or stainless steel.

Every water spray system is fed through a deluge valve, opened by heat detectors, a pilot line of fixed temperature releases or quartzoid bulb detectors, or a manual release. The deluge system page compares the valves, skids and trim we supply.

Start with what burns and what is around it. Transformers, DG fuel and lube oil call for HVWS, while tanks, vessels, LPG and conveyors call for MVWS. Many sites have both, as separate zones.

Then the design: the water density the standard sets for the hazard, enough nozzles of the right K factor to cover every face of the equipment, safe clearances from live parts on transformers, and a water supply and pumps for the largest zone.

Detection is usually a pilot line of quartzoid bulb detectors or fixed temperature releases around the equipment, or heat detectors through a panel. We survey, design, install and test the system, and keep it ready under an AMC.