Wash. Admin. Code § 51-11C-40321 - Section C403.2.1-Zone isolation

C403.2.1 Zone isolation required. HVAC systems, DOAS and exhaust systems serving areas that are intended to operate or be occupied nonsimultaneously shall be divided into separate isolation areas. Zones intended to be occupied simultaneously may be grouped into a single isolation area provided the combined total area does not exceed 25,000 square feet (2323 m²) of conditioned floor area and does not include more than one floor. Each isolation area shall be equipped with isolation devices and controls configured to automatically shut off the supply of conditioned air and outdoor air to and exhaust air from the isolation area. Each isolation area shall be controlled independently by a device meeting the requirements of Section C403.4.2.2. Central systems and plants shall be provided with controls and devices that will allow system and equipment operation for any length of time while serving only the smallest isolation area served by the system or plant.

EXCEPTIONS:

1. Exhaust air and outdoor air connections to isolation areas where the fan system to which they connect is not greater than 5,000 cfm (2360 L/s). 2. Exhaust airflow from a single isolation area of less than 10 percent of the design airflow of the exhaust system to which it connects. 3. Isolation areas intended to operate continuously or intended to be inoperative only when all other isolation areas in a zone are inoperative.

Notes

Wash. Admin. Code § 51-11C-40321

Amended by WSR 16-03-072, Filed 1/19/2016, effective 7/1/2016 Amended by WSR 19-24-040, Filed 11/26/2019, effective 7/1/2020 Amended by WSR 22-14-091, Filed 7/1/2022, effective 7/1/2023

Statutory Authority: RCW 19.27A.020, 19.27A.025 and chapters 19.27 and 34.05 RCW. 13-04-056, § 51-11C-40321, filed 2/1/13, effective 7/1/13.