WAC 296-835-11015   Take additional precautions if you recirculate ventilation system exhaust air into the workplace.  

     You must:

     • Only recirculate air that contains no substance at a concentration that could pose a health or safety hazard to employees.

     • Make sure any exhaust system that recirculates air into the workplace:

     – Passes the air through a device that removes contaminants

     – Sounds an alarm and automatically shuts down the dip tank operation, if the vapor concentration of any substance in the exhaust air exceeds twenty-five percent of its LFL

     – Monitors the concentration of vapor from flammable or combustible liquids with approved equipment.

Note:	• The LFL concentration in the air must be determined after the air passes through the air-cleaning device and before the air reenters the workspace.
	• Most substances will pose a health hazard at a concentration far below twenty-five percent of its LFL.

[Statutory Authority: RCW 49.17.010, [49.17].040, and[49.17].050 . 02-15-102, § 296-835-11015, filed 7/17/02, effective 10/1/02.]