System components containing fluids shall be protected with
temperature and pressure relief valves or pressure relief valves. Relief
devices shall be installed in sections of the system so that a section cannot
be valved off or isolated from a relief device. Direct systems and the potable
water portion of indirect systems shall be equipped with a relief valve in
accordance with Section 504 of the state plumbing code. For indirect systems,
pressure relief valves in solar loops shall comply with SRCC 300. System
components shall have a working pressure rating of not less than the setting of
the pressure relief device.
M2301.2.5
Piping insulation. Piping shall be insulated in accordance with
the requirements of the state energy code. Exterior insulation shall be
protected from ultraviolet degradation. The entire solar loop shall be
insulated. Where split-style insulation is used, the seam shall be sealed.
Fittings shall be fully insulated.
M2301.4
Heat transfer gasses or liquids
and heat exchangers.
Essentially toxic transfer fluids,
ethylene glycol, flammable gasses and flammable liquids shall not be used as
heat transfer fluids. Heat transfer gasses and liquids shall be rated to
withstand the system's maximum design temperature under operating conditions
without degradation. Heat exchangers used in solar thermal systems shall comply
with Section 603.5.4 of the state plumbing code and SRCC 300.
Heat transfer fluids shall be in accordance with SRCC 300. The
flash point of the heat transfer fluids utilized in solar thermal systems shall
be not less than 50 degrees F above the design maximum non-operating or no-flow
temperature attained by the fluid in the collector.
M2301.7
Solar thermal systems for
heating potable water. Where a solar thermal system heats potable water
to supply a potable hot water distribution system, the solar thermal system
shall be in accordance with Sections M2301.7.1, M2301.7.2 and the state
plumbing code.
M2301.7.1
Indirect
systems. Heat exchangers that are components of indirect solar thermal
heating systems shall comply with the state plumbing code.
M2301.7.2
Direct systems. Where
potable water is directly heated by a solar thermal system, the pipe, fittings,
valves and other components that are in contact with the potable water in the
solar heating system shall comply with the requirements of Chapter 6 of the
state plumbing code.
Notes
Wash. Admin. Code
§
51-51-2300
Adopted by
WSR
14-24-092, Filed 12/1/2014, effective
5/1/2015
Amended by
WSR
16-03-025, Filed 1/11/2016, effective
7/1/2016
Amended by
WSR
23-23-104, Filed 11/15/2023, effective
3/16/2024
