C403.3.4 Boiler turndown.Boiler systems with design input of greater than 1,000,000 Btu/h (293 kW) shall comply with the turndown ratio specified in Table C403.3.4.
The system turndown requirement shall be met through the use of multiple single input boilers, one or more modulating boilers or a combination of single input and modulating boilers.
Table C403.3.4
Boiler Turndown
Boiler System Design Input (Btu/h) | Minimum Turndown Ratio |
≥ 1,000,000 and less than or equal to 5,000,000 | 3 to 1 |
> 5,000,000 and less than or equal to 10,000,000 | 4 to 1 |
> 10,000,000 | 5 to 1 |
[Statutory Authority: RCW
19.27A.020,
19.27A.025,
19.27A.160 and chapter
19.27 RCW. WSR 19-24-040, § 51-11C-40334, 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-40334, filed 1/19/16, effective 7/1/16.]