3120 HEWITT AVE 2018-01-02 MF Import

WASHINGTON NATURAL GAS COMPANY tit i Jlrrrer Street (P.O. Box 1869) Seattle, II'osbingron 9811l Telephone (206) 622-6767 May 6, 1976 Mr. Jamie Johnson, Acting Building Official City of Everett City Hall Everett, Washington 98201 Dear Mr. Johnson: Thank you for your response of April 14, 1976 regarding the direct - fired make-up air heater installation at the Brokerage Restaurant in Everett. In reviewing your letter, I see that there are some areas of minor disagree- ment which should be further discussed. If you would consider a conditional permit to allow the gas to be turned on pending resolution of our differences in interpretation, we would appreci- ate it very much and can assure you it will be in the best interest of the customer. A temporary approval will not result in an unsafe condition, and therefore does merit your consideration. I I would like to discuss our view of Items 2 and 3 of your April 14th t letter, which is where our disagreements appear to be. Item 2 Your suggestion of a sail switch in the exhaust fan, if I interpret it properly, would be a more restrictive interpretation of Section 1904 of the 1973 Uniform Mechanical Code than intended. Section 1904(e)l requires airflow sensing devices in the direct -fired unit itself to shut off gas to the burner in case of failure of required airflow through the direct -fired unit. The electrical interlock with the exhaust fan is intended to prevent operation of the unit if the exhaust fan is not operating. The parenthetical part of Section 1904(e)1 applies to the control on the fan motor of the direct -fired unit itself, not to the control on the building exhaust fan, which requires electrical interlock only under the primary paragraph (e). Failure of the exhaust fan would not result in an unsafe condition be- cause a pressure differential switch in the direct -fired unit itself, which senses airflow across the burner profile, is designed to shut down the unit