RP-623 -- Testing Grease Hoods PDF

A field test method for the measurement of exhaust rates through wall canopy grease hoods equipped with baffle filters has been developed. The method consists of measuring a velocity profile at or near the filter face of the exhaust inlet, using a 4" head rotating vane anemometer (RVA) and then applying a k-factor to determine the flow rate. This technique is accurate within + 10% with the use of a k-factor procedure. The k-factor is a function of the distance the reading is taken from the filter face, the average velocity computed from the velocity profile, whether velocity readings are discrete or continuous, the filter slot spacing and width, and the overall area of the filter bank. The technique was verified with AMCA-210 standard nozzle.chamber flow measurements as a reference. Attempts were made to extend this measurement and kfactor correction technique to slot inlet (damper equipped) hoods. Unfortunately, k-factor models developed for the slot hoods predicted exhaust rates that deviated by more than 30% from the AMCA-210 reference flow rates. Consequently, the later technique was ruled out.