Hot Water Supply System.
§ 18-29-607.1 Where required.
In occupied structures, hot water shall be supplied to all plumbing fixtures and equipment utilized for bathing, washing, culinary purposes, cleansing, laundry or building maintenance. Every sink and lavatory shall be supplied with hot and cold water. No water exceeding 140F (60C) shall discharge into any lavatory, sink, tub or shower.
Exception: In nonresidential occupancies, hot water or tempered water shall be supplied for bathing and washing purposes. Tempered water shall be delivered from accessible hand-washing facilities.
§ 18-29-607.1.1 Water temperature.
All lavatory faucets for public use shall be provided with an automatic safety water mixing device to prevent sudden unanticipated changes in water temperature or excessive water temperatures. The automatic safety water mixing device shall be either thermostatic, pressure balance or combination controlled, in accordance with ANSI/ASSE 1016 or 1017, ASSE-1066 adjusted to a maximum setting of 115F (46C) at the time of installation.
§ 18-29-607.1.2 Shower compartments and shower- bath combinations.
All shower compartments and shower-bath combinations shall be provided with an automatic safety water mixing device to prevent sudden unanticipated changes in water temperature or excessive water temperatures. The automatic safety water mixing device shall be either thermostatic, pressure balance, or combination controlled, in accordance with ANSI/ASSE 1016 and designed with a maximum handle rotation limit/stop, adjusted to a maximum setting of 115F (46.1C).
§ 18-29-607.1.2.1 Mixed water temperature.
The temperature of mixed water provided to multi- shower units or gang showers shall be controlled by a master automatic safety water mixing device or individually regulated by automatic safety mixing valves for each shower unit. A hot water heater thermostat shall not be an acceptable alternative water temperature control device.
§ 18-29-607.2 Heated plumbing circulating system.
Hot water supply systems in buildings other than one-family and two-family dwellings shall be of the return circulation type in buildings where the developed length of hot water piping, from the source of hot water supply to the farthest fixture supplied, exceeds 100 feet (30.5 m).
§ 18-29-607.2.1 Return piping.
The return piping shall be sized for a maximum temperature drop of 20F (6.67C) for forced circulation systems and 40F (4.44C) for gravity circulation systems. Such piping may be of the upfeed system, downfeed system or the combination upfeed and downfeed systems and shall be installed as follows:
For upfeed systems, the return circulation pipe shall connect so the supply risers below the top-most supply branch to fixtures and not more than 12 inches (300 mm) below.
- For downfeed systems and combination upfeed and downfeed systems, the return circulation pipe shall connect to the base of each downfeed riser.
- For inverted downfeed systems, the return circulation pipe shall connect to the supply risers above the lowest supply branch to fixtures and not more than 12 inches (300 mm) above.
- For inverted upfeed systems and inverted combination downfeed and upfeed systems, the return circulation pipe shall connect to the top of the riser above the highest fixture.
- Return circulation pipes shall connect to the water heater or storage tank. Each return circulation riser branch shall be provided with a shutoff valve and check valve. Where more than one return circulation riser connects to a return main, each return circulation riser branch shall be provided with a shutoff valve, check valve and balancing valve or a check valve and combination shutoff balancing valve. All trapped piping shall be provided with an automatic air vent at the highest point.
§ 18-29-607.2.1 Piping insulation.*
Piping in required return circulation systems shall be insulated to provide a thermal resistance, R, excluding film resistances, of
For SI: R = [t1 - t0(0.0304)K x m2]/W
where t1 - t0 is the design temperature differential between the water in the pipe and the surrounding air in degrees Fahrenheit (F).
Exception: Pipe insulation is not required where t1 - t0 is 25F (14C) or less.
*Note As set forth in Coun. J. 3-28-01, p. 55444, 1; section numbering duplicates that of the immediately preceding section.
§ 18-29-607.2.2 Pump operation.
Where a circulating pump is installed on a return circulation hot water system, the pump shall be arranged to shut off automatically or to allow manual shut off when the hot water system is not in operation.
§ 18-29-607.3 Thermal expansion control.
A means of controlling increased pressure caused by thermal expansion shall be provided where required in accordance with Sections § 18-29-607.3 and § 18-29-607.3.2.
§ 18-29-607.3.1 Pressure reducing valve.
For water service system sizes up to and including 2 inches (50 mm), a device for controlling pressure shall be installed where thermal expansion has caused the pressure on the downstream side of a pressure reducing valve to exceed the main supply pressure. A pressure reducing valve with an integral bypass check valve or other device shall be installed to satisfy this requirement.
§ 18-29-607.3.2 Backflow prevention device or check valve.
Where a backflow prevention device, check valve or other device is installed on a water supply system utilizing storage water heating equipment such that thermal expansion causes an increase in pressure, a device for controlling pressure shall be installed.
§ 18-29-607.4 Hot water supply to fixtures.
The hot water supply to any fixture requiring hot water shall be installed on left side of the fixture.
§ 18-29-607.5 Expansion joints.
Mechanical expansion joints shall be accessible and may be used where necessary to provide for expansion and contraction of the pipes. For hot water piping, the expansion function shall be provided by the flexing of the piping material with expansion loops or swing joints. The piping shall be properly anchored and installed as follows:
- Each hot water riser shall be provided with anchors at a maximum distance of 100 feet (30.5 m) or less with an expansion loop of required length provided between such anchors.
- Each hot water main shall be provided with anchors at a maximum distance of 100 feet (30.5 m) or less with an expansion loop of required length provided between such anchors. Offsets of 90 degrees in a horizontal main shall be of required length to absorb expansion by flexure.
- Branches from mains connected to risers shall be provided with a swing joint of required length unless the branch is of adequate length to absorb expansion by flexure.
- Branches from risers to fixtures shall be provided with a swing joint of required length unless the branch is of adequate length to absorb expansion by flexture.
§ 18-29-607.6 Prohibited connections.
Any water pipe connection to any pump or other appliance through which any vibration, shock, strain, stress, or pulsation may effectuate a water hammer is prohibited. Any excess noises or sounds in the water supply system of any building or structure that may be communicated through such connection or service pipe of the Chicago Waterworks System is also prohibited.