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SECTION IV—SYSTEM DESIGN UL EX. 5174 6-5-98 Page 4-5 REV 1 DUCT PROTECTION ELECTROSTATIC PRECIPITATOR PROTECTION(ESP) 1 Single Nozzle Duct Protection. Some restaurant ventilating ducts have an electrostatic precipita- ► One "DL" nozzle, Part No 426093, will protect rectangular, tor installed at or near the base or it may be installed midway or at square, or round ducts with a maximum perimeter of 100 in. the end of the duct system.These precipitators are used to aid in (254 cm). The nozzle must be installed 0-8 in. (0-20 cm) into the cleaning of exhaust air the duct opening and 0-3 in. (0-7.6 cm) from the front edge, Normaliy electrostatic precipitators do not require protection but and aimed at the center of the opening. See Figure 7 should the "authority having jurisdiction" require protection, use AIMATCENTER the following guidelines. �/ OF DUCT Ducts with precipitators located at or near the base can be pro- tected using a"D"nozzle above the precipitator and an "AP"noz- FRONT OF DUCT zle(Part No 423480)for the precipitator One"AP"nozzle must be �I used for each cell being protected. 0-3 IN.FROM FRONT If the area above the precipitator is a duct, the nozzle(s) must be OF DUCT positioned according to duct protection guidelines. � The "AP" nozzle (Part No 423480) must be centered 10 to � 26 in. (25 to 66 cm) below the precipitator and aimed to discharge o-a iN. at the center of each precipitator ceil. However, if it is physically oP�NGT impossibie to mount the nozzle at 10 to 26 in. (25 to 66 cm) due to precipitator placement, the nozzle may be mounted closer than � ?0 in. (25 cm) See Figure 9. � HOOD „p„ SEE DUCT FOR FIGURE 7 NOZZLE � PROTECTIO N ooisas , 2.Multiple Nozzle Duct Protection: (Rectangular or Square Ducts Only) t When rectangular or square ducts exceed 100 perimeter in., PRECIPITATOR modular duct protection can be utilized. The duct must be divided into equal modules with the diagonal dimension of each module not exceeding 37 3/8 in. See Figure 8. � 10-26 IN.' I (25-66 cm) 3�318\N ! �31$�N� �PX\MUM ( 3MP�\M�rt, I "AP"NOZZLE FOF � PRECIPITATOR PROTECTION FIGURE 8 `�F PHYSICALLY IMPOSSIBLE AT 10 TO 26 IN.(25 TO 66 cm),NOZZLE MAY BE MOUNTED CLOSER THAN 1D IN.(25 cm). ooism ► The "DL" nozzle must be installed 0-8 in. (0-20 cm) into the FIGURE 9 duct opening and 0-3 in. (0-7.6 cm) from the front edge and °0Dt96 aimed at the center of the opening. NOTICE In installations where a UL listed damper ' assembly is employed, the "DL" nozzle can be installed beyond the 8 in. (20 cm) maximum, to a point just beyond the damper assembly that will not intertere with the damper Exceeding the maximum of 8 in. (20 cm) in this way wiil not void the UL listing of the system. 3. Transition Protection:When a transition is located between the hood and the exhaust duct, the base or collar of the tran- sition is considered to be the duct opening Follow duct design and nozzle location requirements.