Codes and Standards

Buckley Rumford Fireplaces
Washington State Building Code
4/10/09

Washington State Ventilation And Indoor Air Quality Code
as it pertains to masonry fireplaces. For full text click here.
SECTION 402 - SOLID FUEL BURNING APPLIANCES AND FIREPLACES
402.1 General: Solid fuel burning appliances and fireplaces shall satisfy one of the following criteria.
402.2 Solid Fuel Burning Appliances: Solid fuel burning appliances shall be provided with the following: .
.
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402.3 Fireplaces: Fireplaces shall be provided with each of the following:

a) Tight fitting flue dampers, operated by a readily accessible manual or approved automatic control.

Exception: Fireplaces with gas logs shall be installed in accordance with the International Mechanical Code section 901, except that the standards for liquefied petroleum gas installations shall be NFPA 58 (Liquefied Petroleum Gas Code) and NFPA 54 (National Fuel Gas Code)

b) An outside source for combustion air ducted into the firebox. The duct shall be at least six square inches, and shall be provided with an operable outside air duct damper.

Exception: Washington certified fireplaces shall be installed with the combustion air systems necessary for their safe and efficient combustion and specified by the manufacturer in accordance with the Washington state building code standard 31-2 (WAC 51-50-31200) and International Building Code Section 2114 (WAC 51-50-2114).

c) Site built fireplaces shall have tight fitting glass or metal doors, or flue draft induction fan or as approved for minimizing back-drafting. Factory built fireplaces shall use doors listed for the installed appliance.

402.4 Masonry Heaters: Masonry heaters shall be approved by the Department of Ecology and shall contain both of the following:
a. Primary combustion air ducted from the outside of the structure to the appliance.
b. Tight fitting ceramic glass or metal doors. Flue damper, when provided, shall have an external control and when in the closed position shall have a net free area of not less than five percent (5%) of the flue cross sectional area.

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Comments:
Combustion air "ducted into the firebox" is rarely a good idea. Inadequate at best, it causes bad smells, blowing ash, turbulence enough to make the fireplace smoke and can be a fire hazard if it can backdraft. We have been successful in arguing that, as with masonry heaters, the combustion air can be brought "to the appliance" but not necessarily into the firebox or by following the IRC which allows the combustion air outlet to be located within 24" of the firebox.
We've been successful at eliminating glass doors in western Washington by arguing that, if the space is designed to have positive indoor pressure (as are most commercial buildings, lots of high end homes and any home on the upper floors), then, in essence, we do have a "flue draft induction fan or as approved for minimizing back-drafting" - only our fan is in the mechanical room (or wherever) not at the top of the chimney.
Mark Walker, Spokane, WA building official , will approve Rumfords without glass doors provided the house does not exceed 8 Pascals negative pressure (the limit on our guarantee), says Don Manfred of Design Works. Jerry Ensminger of TestCom (509 533 0498) will do the pressure test.

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