Every week we will be including additional questions and informal UPC and UMC interpretations
- Is it the intent of UPC Section 704.3 to allow the dishwasher to flow out of the floor drain if there is an obstruction downstream of the dishwasher’s connection to the sanitary sewer?
- Yes, the adjacent floor drain required as part of the installation requirements for pot sinks, scullery sinks, commercial dishwashers and silverware washing machines is a “safety” outlet, intended to aid in the prevention of waste water backing into the fixture or appliance in the event of a stoppage downstream.
- In the UMC: 1. Does the supply air being supplied into a compensating hood need to be shut down when the fire-extinguishing system is discharged? 2. For this same hood, would the 20 percent makeup air being supplied to the room need to be shut down when the fire-extinguishing systems discharges? 3. Would the makeup air on a non-compensating hood need to be shutdown when the fire-extinguishing system discharges?
- 1. Yes. Section 511.3, exception #1 clearly states, “when the fire extinguishing system discharges, makeup air supplied to the hood shall be shut off.” 2. Yes, same as answer #1. 3. Yes. The code does not distinguish between compensating and non-compensating hoods.
- Is it the intent of UPC Section 609.1 to prohibit the use of “saddle taps”?
- The use of a “saddle tap” is limited to a product which is listed or labeled by a listing agency acceptable to the Authority Having Jurisdiction, and is installed in accordance with the condition(s) of its listing. Note: Installation standards only apply if they are adopted and these two are for PVC yard piping and Asbestos cement pipe only.
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UMC Section 506.9, it states that Ducts conveying explosive or flammable vapors must be 6 ft from exterior walls or roofs, and other product conveying outlets must terminate 3 ft from exterior walls or roofs.
Does this code apply to the wall that the duct is terminating on?
In other words, is it okay to have a product conveying duct terminate flush to a wall?
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Yes, the termination requirements of Section 506.9 (2) apply to the wall the duct terminates on. It is not acceptable to have the product conveying duct to terminate flush to the wall. Section 506.9(2) of the 2012 Uniform Mechanical Code would apply to the termination of other product conveying ducts.
- Is the foot valve in a well considered to be a device requiring an expansion tank?
- No, although a foot valve is a device that could prevent pressure relief through the building supply, private water well systems are normally designed to pump water through a storage tank which stabilizes the pressure and operates the same as an expansion tank. An expansion tank, as required by Section 608.3, is not necessary in a private well water system which has a storage pressure tank between the foot valve and the building piping system.
- UPC Section 601.3 (2003/2006/2009), 417.5 (2012/2015/2018/2021) states that “faucets and diverters shall be connected to the water distribution system so that hot water corresponds to the left side of the fittings.” There is no mention of where the person stands in relation to the fittings. If I were standing on the outside of an island tub, where should the hot be? I can operate the faucet from outside or inside the tub.
- The left side of a faucet is determined when the operator is positioned inside of the fixture (tub, shower, etc.) facing the control valves.
- I would like to know what is the minimum distance from windows of a residential building to the point where the exhaust air from commercial clothes dryers is discharged to the atmosphere.
- Commercial dryer exhaust meets the definition of environmental air. The termination for commercial dryers must be in compliance with Section 504.5 (2003/2006/2009/2012) 504.4 (2015/2018/2021) or in accordance with the listing and the manufacturer’s installation instructions, whichever is more restrictive. Section 504.5 requires that environmental air duct exhaust terminate a minimum of 3 feet from property lines and openings into buildings.
- Would the size of the water supply system be able to control thermal expansion without installing a thermal expansion tank?
- There is no provision in UPC Section 608.3 which allows thermal expansion to be controlled by the size of the water system.
- In the UMC, is the correct spacing between combustion air openings and environmental duct openings 4 feet?
- No, 3 feet from building openings is the correct minimum spacing per UMC Section 504.5.
- Does a cleanout, located inside a cabinet and which requires opening the hinged cabinet door and removing a drawer, meet the accessibility requirements of UPC Section 707.9 (2003/2006) 707.8 (2009/2012/2015/2018/2021)?
- Yes, as defined in Section 203.0 of the UPC, “Readily accessible means direct access without the necessity of removing any panel, door, or similar obstruction”. Opening a cabinet door is considered readily accessible. See also 707.10 (2003/2006), 707.9 (2009/2012/2015/2018/2021)
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