Overview
This publication treats the effective design of exhaust hoods for local exhaust systems. It notes the increasing importance of effective hood design as concerns air pollution and operating costs. It also states that recent research work has cast doubt on the accuracy of some of the current design equations. The publication puts forward revised design equations, which experimental evidence shows are more accurate and consistent than those in current use. The equations are for a range of exhaust hoods using the layout of Table B3.5 in the current CIBS Guide. Further tables present guidance on the selection of control velocities for pollution capture, the heat transfer rates required for assessing the performance of canopies over hot sources and the effects that side walls and adjacent surfaces have on hood performance. It also provides general design hints anddiscusses the background to the design information in an appendix.