Page 654 - 2018_IRC

CHAPTER 28

WATER HEATERS

User notes:
About this chapter: Chapter 28 contains regulations concerning the safety of water heating units and hot water storage tanks. Heated pota-
ble water is needed for plumbing fixtures that are associated with washing, bathing and kitchen activities. Heated water is commonly stored in
pressurized storage tanks that must be protected against explosion by pressure and temperature relief valves specified in this chapter. This
chapter also covers the access requirements to water heaters and hot water storage tanks to allow for the maintenance and replacement of
that equipment.
Code development reminder: Code change proposals to this chapter will be considered by the IRC—Mechanical/Plumbing Code Develop-
ment Committee during the 2018 (Group A) Code Development Cycle. See explanation on page iv.

SECTION P2801 P2801.6.2 Pan drain termination. The pan drain shall
GENERAL extend full-size and terminate over a suitably located indi-
P2801.1 Required. Hot water shall be supplied to plumbing rect waste receptor or shall extend to the exterior of the
fixtures and plumbing appliances intended for bathing, wash- building and terminate not less than 6 inches (152 mm)
ing or culinary purposes. and not more than 24 inches (610 mm) above the adjacent
ground surface.
P2801.2 Drain valves. Drain valves for emptying shall be
installed at the bottom of each tank-type water heater and hot P2801.7 Water heaters installed in garages. Water heaters
water storage tank. The drain valve inlet shall be not less than having an ignition source shall be elevated such that the
3 / -inch (19.1 mm) nominal iron pipe size and the outlet shall source of ignition is not less than 18 inches (457 mm) above
4
be provided with a male hose thread. the garage floor.
P2801.3 Installation. Water heaters shall be installed in Exception: Elevation of the ignition source is not required
accordance with this chapter and Chapters 20 and 24. for appliances that are listed as flammable vapor ignition-
resistant.
P2801.4 Location. Water heaters and storage tanks shall be
installed in accordance with Section M1305 and shall be P2801.8 Water heater seismic bracing. In Seismic Design
located and connected to provide access for observation, Categories D , D and D and townhouses in Seismic Design
2
1
0
maintenance, servicing and replacement. Category C, water heaters shall be anchored or strapped in the
upper one-third and in the lower one-third of the appliance to
P2801.5 Prohibited locations. Water heaters shall be located resist a horizontal force equal to one-third of the operating
in accordance with Chapter 20. weight of the water heater, acting in any horizontal direction,
P2801.6 Required pan. Where a storage tank-type water or in accordance with the appliance manufacturer’s recom-
heater or a hot water storage tank is installed in a location mendations.
where water leakage from the tank will cause damage, the tank
shall be installed in a pan constructed of one of the following: SECTION P2802
1. Galvanized steel or aluminum of not less than 0.0236 SOLAR WATER HEATING SYSTEMS
inch (0.6010 mm) in thickness. P2802.1 Water temperature control. Where heated water is
2. Plastic not less than 0.036 inch (0.9 mm) in thickness. discharged from a solar thermal system to a hot water distri-
bution system, a thermostatic mixing valve complying with
3. Other approved materials. ASSE 1017 shall be installed to temper the water to a tem-
A plastic pan beneath a gas-fired water heater shall be con- perature of not greater than 140°F (60°C). Solar thermal sys-
structed of material having a flame spread index of 25 or less tems supplying hot water for both space heating and domestic
and a smoke-developed index of 450 or less when tested in uses shall comply with Section P2803.2. A temperature-indi-
accordance with ASTM E84 or UL 723. cating device shall be installed to indicate the temperature of
the water discharged from the outlet of the mixing valve. The
P2801.6.1 Pan size and drain. The pan shall be not less
1
than 1 / inches (38 mm) deep and shall be of sufficient thermostatic mixing valve required by this section shall not
2
size and shape to receive dripping or condensate from the be a substitute for water-temperature limiting devices
tank or water heater. The pan shall be drained by an indi- required by Chapter 27 for specific fixtures.
3
rect waste pipe of not less than / inch (19 mm) diameter. P2802.2 Isolation valves. Isolation valves in accordance
4
Piping for safety pan drains shall be of those materials with P2903.9.2 shall be provided on the cold water feed to the
indicated in Table P2906.5. Where a pan drain was not water heater. Isolation valves and associated piping shall be
previously installed, a pan drain shall not be required for a provided to bypass solar storage tanks where the system con-
replacement water heater installation. tains multiple storage tanks.
2018 INTERNATIONAL RESIDENTIAL CODE ® 629
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