3120 HEWITT AVE 2018-01-02 MF Import

3 % o2c) l`42 w ,_T+ WASHINGTON NATURAL GAS 815 ,llercer Street (P.O. Box 1869) Seattle, Wasbington 98111 COMPANY Telephone (206) 622.6767 April 5, 1976 Mr. Dean Pittman Chief Mechanical Inspector Snohomish County Building & Plumbing Department Administration Building Everett, Washington 98201 Dear Mr. Pittman: In response to your concerns expressed in our meeting on direct - gas -fired -make-up air heaters, I submit the following: LISTED vs. UNLISTED There is presently only one such listed model available, which was submitted to AGA at our urging on a test basis to analyze the practicality of a standard and listing program for direct -fired units. Due to the fact that each individual unit is a custom unit by specification, and that testing and listing agencies require complete retest for each basic modification, the economics of such a standard and listing program would make "listed" units economically unfeasible at this point. The gas control chains and safety controls for these units can meet FIA (Factory Insurance Association) or FM (Factory Mutual) requirements, and are usually so required by a customer's insurance carrier. Section 1904, Uniform Mechanical Code Section 1904 of the Uniform Mechanical Code, 1973 edition, allows installation of direct -fired (natural gas) units in F-2 or G occupancies such as the restaurant in question, or other occupancies when approved, pro- vided all air is taken from the outside, and other requirements of the sec- tion are complied with, along with electrical interlocking of the gas valve controls with the exhaust fan (Sec. 1904(e)). Thus, occupancies other than F-2 and G may be allowed by the Building Official, under the 1973 UMC. The particular appliance in question (Rupp Temp -Air CFA-15) does meet the other requirements (outside air, gas ratio, and controls) of Sec. 1904(b), (c), (d) and (e).