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    The Business End of Systems: Nozzles

    By Mark Conroy

    A restaurant system nozzle is a device that delivers a specific quantity, flow rate, and discharge pattern of wet chemical. System nozzles are designed with special spray patterns such as cone, spade, and deluge in order to provide adequate coverage to specific protected areas. A replacement nozzle must be an exact match for the original nozzle and every nozzle must be free of blockage and contaminants. They also need to be aligned correctly and pointed at the protected fire area.


    Each nozzle must have a blow-off cap or a foil seal (frangible disc) to keep the nozzle orifice free of cooking grease build-up. Rubber blow-off caps can be used where temperatures are less than 350°F (176.6°C) and metal blow-off caps for higher temperatures. Some systems only have metal. Any damaged or missing caps must be replaced, while discolored or hanging caps often need to be replaced. All caps or foil seals must be listed for the nozzle to ensure that they will blow-off upon system actuation (foils break open).


    It is common in the field to find nozzles with missing caps and/or rubber caps hanging from their tether. An uncapped nozzle should never be recapped without a thorough cleaning and examination. Typically, in order to clean a nozzleto bare metal, it is soaked in degreaser, rinsed with hot water, and then blown out with compressed air. If that is not possible to do at the restaurant, the nozzle is generally removed and replaced with a matching nozzle. The restaurant owner will more often than not absorb the cost of a new nozzle rather than the cost of waiting for it to be cleaned at your shop. The restaurant can’t function without an operational fire protection system.


    When properly aimed, the nozzles will deliver the appropriate flow rate over the protected surface. A nozzle is easily aimed if it is fitted with a Nozzle Swivel Adapter. The adapter is comprised of three basic parts—the body, swivel adapter, and retainer nut. The retainer nut is first loosened and then tightened with a wrench after aiming is complete. Typically, all nozzles may be used with swivel adapters without any change in the nozzle’s listing. Refer to the design and installation section of the manufacturer’s manual to verify nozzle placement and aiming relative to each protected appliance.


    For Pyrochem and Ansul systems, a Nozzle Aiming Device is used for proper aiming of system nozzles. The Nozzle Aiming Device tool is easy to use and should be in every technician’s toolbox. Slip it over the nozzle and point the laser light at the target. Correctly aim and then use a wrench to tighten the pipe fitting that was loosened to aim the nozzle. A matching adapter must be used with the Nozzle Aiming Device. These adapters are easily identified too (black for Pyrochem and white for Ansul).

    Under the right circumstances, nozzles will deliver the necessary amount of extinguishing agent. During service calls, be sure to check for damaged and clogged nozzles as well as missing blow off caps. By having a supply of nozzles and caps in each service van, you can increase your revenue and ensure that the work gets done immediately and the pre- engineered system works as designed.

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