La description

HVWS systems are often used to protect equipment that incorporates heavy or medium oils. Equipment such as oil type circuit Breakers and transformers, diesel engines and fuel oil storage tanks, turbo alternator lube oil systems, and oil-fired boilers. The high-velocity discharge water jet forms a cone of coarse spray of uniform density. This coarse spray is able to penetrate the flame zone and reach the surface of the burning oil. The turbulence created by the high velocity spray forms an oil-in-water emulsion on the surface of the oil that will not burn. This emulsification is the main way the fire is extinguished along with the cooling and smothering effect.

An MVWS system (short for a Medium Velocity Water Spray System) is a water-based fire protection system. MVWS systems are used to provide cooling and/or control the burning in many large scale industrial applications, such as in thermal power plants. As their name suggests, medium velocity water spray nozzles are designed to spray water at a medium velocity (i.e. the strength of the spray is weaker than HVWS systems). MVWS systems are best suited for protecting hazards involving light oils where emulsification from high-velocity water sprayers (HVWS) is not possible.