Illinois Administrative Code › Title 77 - PUBLIC HEALTH › Part 890 - ILLINOIS PLUMBING CODE › Subpart I - WATER SUPPLY AND DISTRIBUTION › Section 890.1210 - Design of a Building Water Distribution System

Current through Register Vol. 48, No. 28, July 12, 2024
a) Design and Installation. The design and
				installation of the hot and cold water building distribution systems shall
				provide a volume of water at the required rates and pressures to ensure the
				safe, efficient and satisfactory operation of fixtures, fittings, appliances
				and other connected devices during periods of peak use. No distribution pipe or
				pipes shall be installed or permitted outside of a building or in an exterior
				wall or attic unless the pipe is protected from freezing.
b) Size of Water Distribution Pipes. The
				fixture supply for each fixture shall be at least the minimum size provided in
				Appendix A.Table D. The size of all other water distribution pipes shall be
				determined by calculating the water supply demand (in water supply fixture
				units) for that portion of the water distribution system served by the pipe.
				Using Appendix A.Tables M, N, O, P and Q, the cumulative water supply demand or
				load shall be calculated for all fixtures, piping, valves and fittings served
				by the water distribution pipe, and the pipe shall meet the minimum size
				provided in Appendix A.Table N or O, as applicable. Exception: As an
				alternative to using Tables M, N, O, P and Q to design and size the piping in
				the water distribution system, the system may be designed and sized employing
				current engineering practices, provided that the design/plans are approved in
				writing by an Illinois licensed professional engineer, an Illinois licensed
				architect or an individual Certified in Plumbing Design (CPD) by the American
				Society of Plumbing Engineers and approved in writing by the
				Department.
c) Minimum Water
				Pressure. The minimum constant water service pressure on the discharge side of
				the water meter shall be (at least) 20 psi, and the minimum constant water
				pressure at each fixture shall be at least 8 psi or the minimum recommended by
				the fixture manufacturer.
d)
				Auxiliary Pressure. Supplementary Tank. If the pressure in the system is below
				the minimum 8 psi at the highest water outlet when the flow in the system is at
				peak demand, an automatically controlled pressure tank or gravity tank of a
				capacity to supply sections of the building installation that are too high to
				be supplied directly from the public water main shall be installed.
e) Low Pressure Cut-Off. When a booster pump,
				except those used for fire protection, is used on an auxiliary pressure system,
				a low-pressure cut-off switch shall be installed on the booster pump to prevent
				the creation of pressures less than 5 psi on the suction side of the pump. A
				shut-off valve shall be installed on the suction side of the water system and
				within 5 feet from the pump suction inlet, and a pressure gauge shall be
				installed between the shut-off valve and pump.
f) Water Hammer. All building water supply
				systems shall be provided with air chambers or approved mechanical devices or
				water hammer arrestors to absorb pressure surges. Water pressure absorbers
				shall be installed at the ends of long pipe runs or near batteries of fixtures.
1) Air Chambers - An air chamber that is
				installed in a fixture supply shall be at least 12 inches in length and the
				same diameter as the fixture supply, or an air chamber with an equivalent
				volume may be used. An air chamber that is installed in a riser shall be at
				least 24 inches in length and at least the same size as the riser.
2) Mechanical Devices - If a mechanical
				device or water hammer arrestor is used, the manufacturer's specifications for
				location and installation shall be followed.