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Uniform Codes Questions & Answers
Uniform Codes Questions & Answers 

Every week we will be including additional questions and informal UPC and UMC interpretations:

When replacing the water distribution system of an existing apartment complex, would it be required to replace the shower valve with pressure balancing tub/shower valves?

Pressure balancing shower valves became a code requirement in the 1997 edition of the UPC. Section 101.5.3 (2009), 101.11.2 (2012), 102.2 (2015) does not require fixtures, such as the shower valves in your question, to the current standards unless the valves are being replaced. Replacement valves would need to meet current codes and standards per sections 418.0 (2009); 408.3 (2012/2015).

Is it permissible for concealed, unprotected gas piping with screwed joints to be installed in walls or floor/ceiling assemblies that are "framed and rocked" without the use of recesses, channels, or access panels? What about welded joints?

Yes. It is permissible for concealed, unprotected gas piping to be installed in walls or floor/ceiling assemblies that are framed and rocked. In addition, this would include welded joints as well as screwed joints.

When a combination tub/shower valve, listed to ASSE 1016, and installed only as tub filler, does this comply with UPC Section 414.5?

Temperature limiting valves for bathtubs and whirlpool tubs shall meet the requirements of ASSE 1070 or CSA B125.3 as prescribed in Section 414.5 of the (2006/2009) 409.4 (2012/2015) UPC. The difference between the two devices is; a 1016 device can be a pressure balance, thermostatic mixing or combination pressure balance and thermostatic mixing valve. A 1070 device is thermostatic mixing valve only. A 1016 device is required on shower or tub/shower combination valves to prevent thermal shock when standing in the water under the showerhead. A 1070 device is allowed in section 414.5 because the thermal shock issue is eliminated when the water from the tub filler mixes with the water in the tub. A person is not standing directly under the water coming from a tub spout and is not subject to thermal shock. Please consult the AHJ in your jurisdiction to see if they would allow the installation described.

Are galvanized fittings allowed in a gas piping system?

Yes. Section 1309.5.2.2 (2003) (1309.5.8.4(2), 2006/2009), (1308.5.10.4, 2012) allows for the use of galvanized pipe and, therefore, allows the use of galvanized fittings.

Does an emergency shower and/or eyewash located inside of a building require a drain to the sanitary system?

Yes. Section 304.0 requires liquid waste from all plumbing fixtures, appurtenances, and appliances to be properly connected to the drainage system of the building. In 2012 Section 416.5 was added and allows emergency showers and eyewashes to be install without a drain. If a drain is installed it must comply with Section 811.0 (Chemical Waste).

Is it possible that the requirements for combustion air into a boiler room be different for a forced draft boiler/burner that pulls in combustion air to the burner via its own motor and fan versus that of a natural draft-type burner that does not?

Yes. Sections 1021.0 (2003), 1020.0 (2006) and 1019.0 (2009/2012) refers you to Chapter 7 for combustion air requirements. Section 701.1.1 states “Gas utilization equipment of other than natural draft and Category I vented appliances shall be provided with combustion, ventilation, and dilution air in accordance with the equipment manufacturer’s instructions.” If the manufacturer’s instructions do not address combustion air, than the provisions of Sections 701.6 or 701.7 (2003/2006/2009/2012) must be followed.

We have a proposal before us to split the lot and building to allow for a townhouse or zero lot line construction. However, the duplex shares common utilities. According to the UPC, is each unit required to have independent utilities?

Yes, each dwelling unit shall have all utilities (sewer, water, and gas lines) located on the specific lot dedicated to the townhouse unit per Sections 308.0 and 721.0 (2003/2006/2009) 307.0 and 721.0 (2012/2015) A townhouse configuration would demand that all interior piping which serves either half of the converted duplex be totally independent of the other half.

These questions are related to Section 701.1.1 in regards to combustion air evaluations in existing homes (i.e., built 5 to 50 years ago). 1. When calculating indoor volume for combustion air in a residence, are the Btu/h input ratings of cooking appliances and clothes dryers excluded the way they were in the 2000 UMC? 2. When calculating room volume for a natural draft wall furnace in the living room, must the Btu/h input of the pre-existing gas range in the kitchen (manufacturer's instructions not known) be added to that of the wall furnace?

1. No. Section 701.1.1 provides exceptions for direct vent appliances and Type I clothes dryers that are provided with makeup air in accordance with Section 504.3.2. Gas appliances other than natural draft design and other than Category 1 appliances shall be provided with combustion, ventilation and dilution air in accordance with the appliance manufacturer’s instructions. If the cooking appliance is a natural draft type, the total Btu/h input shall be included when calculating the indoor room volume. 2. Yes, if the two rooms freely communicate without doors.

Should the restroom facilities in a private day-care center be classified as private or public use?

According to the definition of public use in Section 218.0, the plumbing fixtures installed in a private daycare center are classified as public use. See also Private or Private Use

If a building or part of a building is served by multiple air-handling units, is it required that all air-handling units shut down when one senses smoke? Note, the units serve a common area or use a common plenum with an aggregate exceeding 2,000 cubic feet per minute.

Yes. The key to the code section is the definition of air-moving systems. This definition states that an air moving system comprises one or more air-handling units used to supply a common space. Section 609.0 states that qualifying air-moving systems shall be equipped with an automatic shutoff. Detection of smoke in the supply side of any of the equipment should interrupt the power to the air-moving system of one or more units. This is supported by Exception 1, which allows a total coverage smoke-detection system to take the place of individual detectors to accomplish the required shutdown. Clearly, a system-wide shutdown should be the end result of an alarm from either an individual or total-coverage smoke detector.

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