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<br /> �' ' SECTION 3
<br /> I HAZARD DESCRIPTION AND NOZZLE COVERAGE
<br /> The R�ri�unnt Fin Hwrd and backshelt broilers,chain broilers,some cheesemelters,and
<br /> � charcoal and mesquite wood chunk broilers.Charcoal and mes-
<br /> When the cooking eppliances are in use in a commercial iiite wood broilers are further classified as Class•A appliances
<br /> I kitchen, such as a resteurent or cafeteria, two things normally since these appliances are on fire in normal operation.
<br /> occur. First, the kitchen gets hot, and second, a grease•lilm liances do not require fire protection.These
<br /> buildup accumulates on the walis, cabinets, and olher kitchen BPp�elnc�geneeally release only heat andlor water vapor,and
<br /> surfaces. are not considered grease-producing appliances. Examples ol
<br /> The ezcess heat irom the high vo�ume caoking appliances this type of appliance are steamers,ketlles,and totally enclosed
<br /> would meke the kitchen temperature unbearable unless some conveclion ovens.
<br /> meMod ot ventilation was provided. For this reason, a sheet-
<br /> � metal canopy,or hood,is positioned over the eppliances to cao• Certain terms identifying cooking appliances are too vague lo
<br /> ture the rising heated air. A duct from the hood leads to the be used tor fire protection purposes. An example ot a term of
<br /> exterior of the building, where the heated air is vented. An this type is "stove." To some individuals, a stove may be an
<br /> �� ezhaust ten is provided al the poi�l where the duct ends,to pro• oven,requiring no fire protection.'fo athers,a slove is a ra�ge,
<br /> vide suHicient dreR to remove the excess heeted air. �erm9sagrelstlnesome res aurants ba gelQmay be a flaet-surlece
<br /> The hood•and-duct system also serves to ceplure a large por• appliance for cooking pancakes,egg �elc. — in other words,a
<br /> s
<br /> tion ul the grease•laden vapors produced during cooking. As 9�iddle.Other restauranls may call their broilers grills, requinng
<br /> the heated, grease•laden air is eccelerated end caoied in the diHerent fire proteclion tha� griddles. Because of the diHerent
<br /> hood and duct by the exhaust tan,the grease will setlle out on �ire proteclion requirements ol ihe three general types of
<br /> the sheet•metal surfaces, eventually forming a thick Iayer. Fil• apPliances, precision is necessary in the terminology used.
<br /> ters are usually installed in an attempt to intercepl some of lhis
<br /> ' grease and slow down the accumulation in the hoad and duct. Duct Protection
<br /> ' These filters either hold onto ihe grease, or allow it to drain The duct nozzle, PM 806572, is used lor proteclion of the
<br /> � away.The space behind the filters,which connecls lo the duct, exhaust ductwork. The tip is slamped with P/N 264379. Eech
<br /> is called the plenum.(A plenum is any enclosed chamber for air ducl nozzle accounts lor two flow numbers. Some duct sizes
<br /> handling.) Despite the presence ot filters, lhere will slill be an Permit the use of one appliance nozzle, PM 806573. This
<br /> eccumulation of grease inside the plenum and duct. appliance nozzle accounts for one flow number, and the tip is
<br /> Organic coaking grease, either animal or vegetable in nature, stamped with PM 264377.
<br /> ' is a highly tlammable subslance wilh an unusual characteristic. The duct cross seclion can be any shape (i.e., round, squere,
<br /> �� II heated sufli�ienlly, it will tlash into ilame betore it boils. In en• or rectangular)and Ihe duct itself can be of unlimited length. In
<br /> i gineering tertns,orgenic cooking oil has an auto•ignition temper- accordance with NFPA 96, the exhaust lan should be lett run•
<br /> • ature lower than its boiling point.This auto•ignilion temperature ning al Ihe time ol system discharge. A damper, il present,
<br /> ranges between 600°F - 700°F, well within the temperature should be lett open at system discharge.However,it the damper
<br /> range o1 many common cooking appliances and typical ignition �s closed,the system designer must insure that the duct nozzle
<br /> sour.�s. Once the grease auto•ignites, rapid temperature rise discharge is not impeded by the closed damper.
<br /> occurs. Typically, grease•lined duct fires may reach 2000'F or
<br /> � more. Hoods and ducts are usually inaccessible to normal fire The nozzle requirements lor ducl prolection are as tollows:
<br /> fighting methods such as poAab�e extinguishers or small hose �, pucl Perimeter 0 to 27 Inches
<br /> �� streams. Fires of this inlensity represent significant exposure pne appliance nozzle.PIN 806573,is reqwred lor prolection
<br /> problems to the building's structural elemenls. of a duct with a perimeter up to 27 mches. Reler to Figure
<br /> In addition lo the hood and duct,somo ol the cooking appliances 281T)�
<br /> represent lire hazards as well. p, p�ct Perimeter Be�ween 27 and 75 Inches
<br /> In general, any appliance which produces grease vapors while pne duct nozzle, P/N 806572. is required lor proteclion ot a
<br /> � operating is a potential fire hazard. Grease-producing appli� duct with parimeter grealer than 27 inches and less than or
<br /> ances can be broken down into three general categories —grid- equal l0 75 inches. The ducl nozzle can also be used loi
<br /> dles,IryerS,and broilers.The term"griddles"is meanl to include dur�s with perimeters less than 27 inches. Re1er to Figure
<br /> Ilat griddles as well as griddles with grooves. Multiple burner p8�b).
<br /> and hol-top ranges are included in this category. This type ot
<br /> appliance represents a coated surface — a hot metal surface 3. Dur.t Perimeter Between 75 and 150 Inches
<br /> ' coated with grease, with no liquid in dePfeci b eedepth so that ol ducts with pelreimePe s greate?�han 75 mchesiand less than
<br /> a liquid surlace -- 1he liquid fuel has app or equal l0 150 inches. Refer to Figure 29 for nozzle place�
<br /> food can be completely immersed in the lat. Deep•fat Iryers,
<br /> pressure Iryers, broaslers,Woks, braising pans, and tilting skil- men1.
<br /> �. lets are representative appliances included in this category. II one nozzle is used to protecl a ducl, it is located al Ihe
<br /> "Broilers" represent a three•dimensional fire hazard, since Ihe geometric center ol the cross•sectional area Ihat it is protecting.
<br /> meat or fish being broiled is placed on a grate sudace positioned and is located in the duct within 6 inches o1 Ihe plenum and
<br /> �i usually above heating elemenls and a drip pan. Appliances in ductwork intertace. 11 two dud nozzles are used, they are
<br /> � this category include upright broilers. eledric- and gas-radiant positioned as shown in Figure 29 and are also localed in the
<br /> � broilers, lavarock and ceramic synthetic broilers, salamander duct within 6 inches ol the plenum/duct interface.
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<br /> I U.L EX3559
<br /> �I May.1991
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