UNFORM CODES QUESTIONS & ANSWERS

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

Would piping installed downstream from an approved backflow prevention device be required to be buried or protected in any specified manner?
- No. However, Section 603.4.12 (2003) 603.4.11 (2006/2009) 603.5.11 (2012/2015/2018/2021) specifies that in cases where it is impractical to correct individual cross-connections on the domestic water line, the line supplying such outlets is considered a non-potable water line. No drinking or domestic water outlets are permitted to connect to the nonpotable water line. Whenever possible, all portions of the nonpotable water line must be exposed and all exposed portions must be properly identified in a manner satisfactory to the Authority Having Jurisdiction. Each outlet on the nonpotable water line which may be used for drinking or domestic purposes must be posted: “CAUTION: NONPOTABLE WATER, DO NOT DRINK.
Does the UMC require a residential gas range to have an exhaust hood?
- No, Section 501.0 of the 2021 Uniform Mechanical Code does not require any residential range to have an exhaust hood. Hood is defined in Section 210.0 in UMC to be applicable to commercial food processing equipment, it does not apply to domestic kitchens. Domestic exhaust ventilation is required in residential kitchens under Chapter 4 of the UMC as per Table 403.7. Part II of Chapter 5 expressly applies to commercial kitchens, where in addition to the exhaust hood and grease duct, a fire suppression system is required.
Are compression repair couplings exempt from the requirements of the UPC?
- A compression repair coupling must be constructed to applicable standards, tested and listed, and then installed per the listing limitations and applicable code requirements.
In a multifamily apartment project, where the building is owned and maintained by the developer, may the condensate drain serving the HVAC units that supply the common corridors be connected to a lavatory tailpiece or bathtub overflow inlet?
- No, as required by Section 310.5 of the 2021 Uniform Mechanical Code, in order for that condensate drain line to be attached to that tailpiece the occupant of that unit must be the one in control of that unit.
  The controlling person would be the end user who would have access. The intent of the UMC is that the condensate wastes connection shall be located in the area controlled by the same person controlling the air-conditioned space.
Does an existing gas water heater in a bathroom have to be relocated if a new yard line is installed, or if for any reason the gas meter is relocated or new gas piping is installed?
- Existing work in accordance with the law in effect prior to the effective date of this Code may not be required to be changed unless the Authority Having Jurisdiction determines that the installation is dangerous, unsafe, and a menace to life, health, or property (see Section 101.5.1 (2003/2006/2009) 101.8 (2012) 101.2 (2015/2018/2021). If the water heater complied with the adopted code in effect when installed, it is the responsibility of the local Authority Having Jurisdiction to determine if an existing installation is safe or not, and establish their own requirements regarding changes to comply with the current code.
1. Is the definition intent of a "dwelling" or "dwelling unit" to refer to a residential home or residential townhome?
2. Does the definition of "dwelling or dwelling unit" apply to high-rise condos or high-rise apts in a non-residential application?
- 1. Yes, a dwelling as defined within the 2021 Uniform Mechanical Code is a single-family, duplex or townhome with no more than two dwelling units in the building.
  2. Yes, a dwelling unit, as defined within the 2021 Uniform Mechanical Code, could apply to high-rise condominium or apartment building. The UMC also defines Residential Building as one or ‘…portion thereof that is used for human habitation.’
  
  Both the definition intent of a dwelling or dwelling unit as defined within the 2021 Uniform Mechanical Code are only applicable to the UMC and not to any other code standards.
Are water closet flanges with a 2" offset acceptable to the UPC?
- Offset closet flanges may obstruct flow if it does not comply with the applicable standard required by the UPC. Table 7-1 (2009), Table 701.1 (2012), Table 701.2 (2015/2018/2021) requires PVC fittings to comply with ASTM D2665. In that standard it references ASTM D3311, which is the standard for DWV plastic fittings patterns. The pattern for an offset closet flange has to be free of ledges and corners that would obstruct flow. Section 311.5 (2009), 310.5 (2012/2015/2018/2021) states “no fitting, fixture, and piping connection, appliance, device, or method of installation that obstructs or retards the flow of water, wastes, sewage, or air into the drainage or venting system, in an amount exceeding the normal frictional resistance to flow, shall be use.”
Although individual units are not interconnected by ducts, they share a common plenum or space. Is an automatic shutoff required for each of the referenced individual air-handling units?
- Yes. Since the units are working together and are moving more than 2,000 cubic feet per minute, Section 609.0 requires that each unit in the system shall have an automatic shutoff.
When are “existing, non-compliant” materials, equipment, or plumbing systems required to be replaced with currently compliant products or installation requirements?
- Existing systems may remain in service, when maintained in accordance with the law in effect prior to the effective date of this Code, provided that no hazard to life, health, or property exists, or would be created by such ongoing utilization. If an existing system is replaced or additions are made to the system the new work and materials shall meet the current code requirements.