(Effective until July 1, 2023)

PDFWAC 51-11C-403235

Table C403.3.2(5)—Minimum efficiency requirements—Gas- and oil-fired boilers.

Table C403.3.2(5)
Minimum Efficiency Requirements—Gas- and Oil-Fired Boilers
Equipment Typea
Subcategory or Rating Condition
Size Category (Input)
Minimum Efficiency
Test Procedure
Boilers, hot water
Gas-fired
< 300,000 Btu/hd,e
82% AFUE
10 C.F.R. Part 430
 
 
≥ 300,000 Btu/h and
≤ 2,500,000 Btu/hb
80% Et
10 C.F.R. Part 431
 
 
˃ 2,500,000 Btu/ha
82% Ec
 
 
Oil-firedc
< 300,000 Btu/he
84% AFUE
10 C.F.R. Part 430
 
 
≥ 300,000 Btu/h and
≤ 2,500,000 Btu/hb
82% Et
10 C.F.R. Part 431
 
 
˃ 2,500,000 Btu/ha
84% Ec
 
Boilers, steam
Gas-fired
< 300,000 Btu/hd
80% AFUE
10 C.F.R. Part 430
 
Gas-fired - All, except natural draft
≥ 300,000 Btu/h and
≤ 2,500,000 Btu/hb
79% Et
10 C.F.R. Part 431
 
 
˃ 2,500,000 Btu/ha
79% Et
 
 
Gas-fired-natural draft
≥ 300,000 Btu/h and
≤ 2,500,000 Btu/hb
79% Et
 
 
 
˃ 2,500,000 Btu/ha
79% Et
 
 
Oil-firedc
< 300,000 Btu/h
82% AFUE
10 C.F.R. Part 430
 
 
≥ 300,000 Btu/h and
≤ 2,500,000 Btu/hb
81% Et
10 C.F.R. Part 431
 
 
˃ 2,500,000 Btu/ha
81% Et
 
For SI:
1 British thermal unit per hour = 0.2931 W.
 
 
 
 
 
Ec
=
Combustion efficiency (100 percent less flue losses).
 
Et
=
Thermal efficiency. See referenced standard document for detailed information.
 
 
 
 
a
These requirements apply to boilers with rated input of 8,000,000 Btu/h or less that are not packaged boilers and to all packaged boilers. Minimum efficiency requirements for boilers cover all capacities of packaged boilers.
b
Maximum capacity minimum and maximum ratings as provided for and allowed by the unit's controls.
c
Includes oil-fired (residual).
d
Boilers shall not be equipped with a constant burning ignition pilot.
e
A boiler not equipped with a tankless domestic water heating coil shall be equipped with an automatic means for adjusting the temperature of the water such that an incremental change in inferred heat load produces a corresponding incremental change in the temperature of the water supplied.
[Statutory Authority: RCW 19.27A.020, 19.27A.025, 19.27A.160 and chapter 19.27 RCW. WSR 19-24-040, § 51-11C-403235, filed 11/26/19, effective 7/1/20. Statutory Authority: RCW 19.27A.025, 19.27A.160, and 19.27.074. WSR 16-03-072, § 51-11C-403235, filed 1/19/16, effective 7/1/16. Statutory Authority: RCW 19.27A.020, 19.27A.025 and chapters 19.27 and 34.05 RCW. WSR 13-04-056, § 51-11C-403235, filed 2/1/13, effective 7/1/13.]