Air velocity in Exhaust duct from Kitchen Hood 2

[offshorehvac]

Friend

Can someone directs me to the ASHRAE chapter or any other code where I can find any reference to recommended air velocity in the exhaust duct connected to Kitchen hood. Air will have oil/grease.

Thanks

 

[ChasBean1]

offshorehvac, two references from NFPA 96, Standard for Ventilation Control and Fire Protection of Commercial Cooking Operations (2008):

8.2.1 Air Velocity.

8.2.1.1* The air velocity through any duct shall be not less than 152.4 m/min (500 ft/min).

And better, from Annex A (Explanatory Material):

A.8.2.1.1 ASHRAE Research Project 1033-RP Final Report, “Effects of air velocity on grease deposition in exhaust ductwork,” documented that grease deposition is reduced as air velocity is reduced, primarily due to less turbulence at the duct surface. Tests were performed at velocities of 500 fpm, 1000 fpm, 1500 fpm, and 2000 fpm. The 500 fpm velocity maintains or improves the safety aspect of minimizing grease buildup, while allowing engineers more flexibility in both retrofit and new kitchen design that include variable flow kitchen exhaust systems. According to the report, grease deposition in uninsulated ducts exposed to cold outdoor climates can increase with lower duct velocities, and insulation of R10 or greater was recommended.

and a related/useful link:

http://www.culinairesystems.com/files/ASHRAE_Article_Exhaust_Velocity.pdf

 

[offshorehvac]

Thanks Chasbeab1

appreciated.