Exhausting heater gases in enclosed construction

August 17, 1977

Mr. J.P. O'Donovan
Safety Director
Eastern Region
Turner Construction Company
[Recipient address omitted]
Dear Mr. O'Donovan:

This is in response to your letter dated May 3, 1977, to Mr. James J. Concannon, which was forwarded to this office for reply, regarding the interpretation of Paragraph 5.6.4. (1) ANSI A10. 9-1970, as adopted in 29 CFR 1926.700(a). In addition, this confirms a telephone conversation on the subject matter with a member of my staff.

In answer to your two questions, the cover is to be so designed that the effluent gases are guided through the exhaust stack to the out-of-doors. At the same time, (1) the standard 29 CFR 1926.55(a) must be observed in regard to the allowable TLV of the coke gases at the breathing levels of the employees and (2) the precautions outlined in 29 CFR 1926.154 must be exercised. Moreover, Paragraph 5.6.1., ANSI A10.9-1970, specifically states: "When construction areas are enclosed with canvas, plastic, or other flammable materials, open flame or open salamanders shall not be used as a source of heat." Therefore, a grating-type cover would not be permitted under these conditions.

If I may be of any further assistance please feel free to contact me.

Sincerely,
Richard P. Wilson
Deputy Director,
Federal Compliance and State Programs