Description
HD® Reverse Action Medium Velocity Water Spray Nozzles are open type (non-automatic) nozzles, designed for directional spray application in fixed fire
protection system. Reverse Action MV nozzle has external deflector and discharges water in opposite direction of flow. Water is uniformly distributed over the surface to be protected. The Nozzles are effectively designed to apply water to exposed vertical, horizontal, curved and irregular shaped
surfaces to allow cooling to prevent excessive absorption of heat from an external fire and provide structural damage or spread of fire. In some application, nozzles may be applied to control or extinguish the fire depending on water design density as per applicable codes. The nozzle is used in deluge water spray system for special hazard fire protection application. As the design and intent of specific water spray system may vary considerably, the nozzle is made available in several combinations of orifice sizes and spray angles. The minimum desirable pressure to achieve a reasonable spray pattern is 1.4 Kg./Sq.cm. The water distribution pattern as shown in the graph in following pages is at an average pressure of 2.0 Kg/ Sq.cm. The change in pressure between 1.4 to 3.5 Kg./sq.cm. does not affect considerable change in spray angle. The spray pattern shown is considering still air condition. System designer must consider wind velocity while designing the system for outdoor application. Field obstruction if any affecting the spray pattern of the nozzle must also be considered. The nozzle may be oriented to any position as deemed necessary to cover the hazard. The Blow-off plugs can be used to prevent depositing of foreign materials in the water way of the nozzle, which could interfere with the discharge of the spray nozzle. Blow-off plugs are optional and are not UL listed. As per NFPA-15 main pipeline strainer is required for system utilizing nozzle office diameter less than 9.5mm (3/8 inch), i.e HD Nozzle having K-factor 30 and less, and also for the system water which is likely to contain obstructive materials
