Taken from the Online Editions of the UPC & UMC Answers & Analysis
SUBJECT: Solvent Cement
SECTION: 301.2 (2024 UPC)
Question:
Are one-step solvent cements acceptable for PVC joints?
Answer:
No. One-step PVC solvent cement does not meet the requirements found in Chapter 7 of the Uniform Plumbing Code. Per Section 705.6.2, joints for PVC-DWV pipe and fittings are made using a two-step process. The first step is to apply purple primer to the pipe and fittings, which is listed to the standard ASTM F656 followed by the application of a solvent cement listed to ASTM D2564.
SUBJECT: Independent Systems
SECTION: 311.0 (2024 UPC)
Question:
- Would this section apply to new detached accessory dwelling units requiring a separate drainage system.
- Could the building drain of the main dwelling unit extend to serve a new detached accessory dwelling unit if a side yard, driveway, or court is available for constructing the building sewer.
Answer:
- Yes. Section 311.1 of the Uniform Plumbing Code specifically requires drainage systems from new buildings and/or new work in existing buildings to connect separately and independently to a public or private sewer*.
- No. The exception to Section 311.1 permits the extension of a building drain to another building on the same lot, only if a private sewer is not accessible by means of an adjoining court, yard or driveway. *Private Sewer: A building sewer that receives the discharge from more than one building drain and conveys it to a public sewer, private sewage disposal system, or another point of disposal.
SUBJECT: Access to Toilet Facilities
SECTION: 422.4.1 (2024 UPC)
Question:
In a multi-story building is it permissible to group required bathroom facilities on alternating floors as long as the total occupant load for both floors is used to determine the required fixture type and quantity?
Answer:
Yes. The minimum number of fixtures required shall be determined by applying the requirements found in Section 422.1 and Table 422.1 of the Uniform Plumbing Code. Section 422.4.1 states that “in multi-story buildings, accessibility to the required toilet facilities shall not exceed one vertical story.” Additionally, Section 422.4 requires toilet facilities for employees and customers in other than shopping malls or centers shall have a maximum travel distance not to exceed 500 feet.
SUBJECT: Definition of Environmental Air Duct
SECTION: 207.0 (2024 UMC)
Question:
- Does the electrical room exhaust, as described in the comments, meet the definition of environmental air duct as defined in Chapter 2?
- If so, is the termination required to comply with Section 502.2.1 for environmental air ducts? The electrical room is provided with exhaust duct system for heat removal only. The exhaust is discharged into the adjacent area which is an occupied area.
Answer:
- No, electrical rooms are not a generally considered to be an occupied space of an occupancy as defined in the Uniform Mechanical Code section 217.0.
- As long as the temperature of the electrical room is less than 250º Fahrenheit and is categorized as Class 1 Air under provisions of Chapter 4 Ventilation Air, the electrical room exhaust is permitted to convey to occupied areas as long as that occupied area exhaust air is terminated to the outdoors in accordance with section 502.2.1 of the UMC.
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Last modified: February 19, 2026