Washington Administrative Code › Title 51 - Enterprise Services, Department of (Building Code Council) › Chapter 51-52 - State Building Code adoption and amendment of the 2021 edition of the International Mechanical Code › Section 51-52-0307 - Section 307-Condensate disposal

Current through Register Vol. 24-14, July 15, 2024
307.2.3 Auxiliary and secondary drain systems.
In
				addition to the requirements of Section 307.2.1, where damage to any building
				components could occur as a result of overflow from the
equipment
primary condensate removal system, one of the
				following auxiliary protection methods shall be provided for each cooling coil
				or fuel-fired
appliance
that produces condensate:
1. An auxiliary drain pan with a separate
			 drain shall be provided under the coils on which condensation will occur. The
			 auxiliary pan drain shall discharge to a conspicuous point of disposal to alert
			 occupants in the event of a stoppage of the primary drain. The pan shall have a
			 minimum depth of 1 1/2 inches (38 mm), shall not be less than 3 inches (76 mm)
			 larger than the unit or the coil dimensions in width and length and shall be
			 constructed of corrosion-resistant material. Galvanized sheet steel pans shall
			 have a minimum thickness of not less than 0.0236 inch (0.6010 mm) (No. 24
			 gage). Non-metallic pans shall have a minimum thickness of not less than 0.0625
			 inch (1.6 mm).
2. A separate
			 overflow drain line shall be connected to the drain pan provided with the
equipment
. Such overflow drain shall discharge to a
			 conspicuous point of disposal to alert occupants in the event of a stoppage of
			 the primary drain. The overflow drain line shall connect to the drain pan at a
			 higher level than the primary drain connection.
3. An auxiliary drain pan without a separate
			 drain line shall be provided under the coils on which condensate will occur.
			 Such pan shall be equipped with a water-level detection device conforming to UL
			 508 that will shut off the
equipment
served prior to overflow
			 of the pan. The auxiliary drain pan shall be constructed in accordance with
			 Item 1 of this section.
4. A
			 water-level detection device conforming to UL 508 shall be provided that will
			 shut off the
equipment
served in the event that the primary
			 drain is blocked. The device shall be installed in the primary drain line, the
			 overflow drain line, or in the equipment-supplied drain pan, located at a point
			 higher than the primary drain line connection and below the overflow rim of
			 such pan.
EXCEPTIONS:
1. Fuel-fired appliances that automatically shut down
						operation in the event of a stoppage in the condensate drainage system.
2. Unducted fan coil units where there is no factory option
						available for water-level detection devices and which are installed directly
						within the occupied space.
307.2.4.1 Ductless mini-split system traps.
Ductless mini-split equipment that produces condensate shall be provided with
				an inline check valve located in the drain line, a trap, or other means of
				condensate drainage in accordance with the manufacturer's
				instructions.
Statutory Authority:
				  RCW
				    19.27.031,
				  19.27.074 and
				  chapters
				  19.27 and
				  34.05 RCW. 13-04-053, §
				  51-52-0307, filed 2/1/13, effective
				  7/1/13.