Every week we will be including additional questions and informal UPC and UMC interpretations
- Does the scope of UMC Chapter 11 include cooling systems used for human comfort? For example would a chilled water air handler, refrigeration system, split system DX fan coil or heat pump apply?
- Yes, comfort air is within the scope of Chapter 11 (2003/2006/2009/2012/2015/2018/2021).
- Is an anodeless type gas transition riser the only type that can be used for installation of plastic gas piping? Comment: Transition gas riser companies make a compression type gas riser that is used for connecting plastic underground and then terminating to the surface. Are these acceptable to the UPC?
- Anodeless risers shall be permitted in accordance with section 1211.1.7(2003/2006/2009) 1210.1.7(2012) 1126.96.36.199 (2015) 1208.6.7 (2018/2021) provided they meet all applicable listing and product approval criteria. Specifically, connections that transition between metallic & plastic piping shall conform to ASTM D2513, ASTM F1973 or ASTM 2509. If the riser is appropriately listed with compliant connections it may be approved.
- In Chapter 4 of the UMC, is there a requirement for the location of outside or ventilation intake?
- No, although there are sections in the code that refer to the termination of other items to an intake. For example, Section 504.5 (2003/2006/2009/2012/2015/2018/2021) for environmental air duct limitation, Sections 510.8.2.1 and 510.8.3 (2003/2006/2009/2012/2015/2018/2021) for commercial kitchen grease duct exhaust, and Sections 802.6 and 802.8 (2003/2006/2009/2012/2015/2018/2021) for gas vent limitations.
- Is a right/left nipple/coupling allowed to be concealed in the UPC?
- No, Section 1211.3.2 of the UPC (starting in 2009) specifically prohibits the use of right and left couplings in concealed locations. When NFPA 54 was inserted into the code in 2003, it changed a number of things we had always done under the UPC, the use of right and left hand couplings being one of them. The 2012/2015/2018/2021 UPC Section 1210.3.1 has been revised to now include the use of right/left nipple/couplings and to no longer permit the use of ground joint unions in concealed spaces.
- Is the removal of a door from a mechanical room in a single family dwelling acceptable in accordance with Section 701.5 of the 2021 UMC, to achieve proper combustion air requirements for combining spaces on the same story?
- No. Simply removing the door is not adequate. The intent of the code is to provide a permanent opening when combining communicating spaces. In addition to removing the door, the casing and door hardware would also need to be removed and the opening should be finished to provide a permanent opening so that the door cannot be readily installed. If the door to the mechanical room is in a bedroom or bathroom the door cannot be removed and combustion air shall be provided from outdoors as required in Section 904.1 of the UMC (2003/2006/2009/2012/2015/2018/2021).
- Can a gas shut-off valve be located behind a range or stove, or must it be located in an adjacent cabinet in order for it to be "accessible"?
- Yes. The shut-off valve may be located in, under, or behind the appliance, as long as the appliance can be removed without removing the shut-off valve. Appliance flexible connectors are manufactured to provide for the removal of an appliance (range, dryer, etc.) for access to the shut-off valve.
- If the vent connector is required to be "installed within the space or area in which the appliance is located and shall be connected to a chimney or vent" and "connectors shall be short and straight as possible," then that portion of a pipe that leaves the "space or area" of the appliance might be considered a vent and not vent connector, therefore needs to meet vent requirements? If required to be as short as possible, would the length at this vent connector be contrary to that requirement?
- Yes. The code allows a vent connector from a listed gas appliance with a draft hood to pass through walls or partitions if they are Type B or L vents installed according their listings. In addition, single wall metal pipe may be used when installed with a ventilated thimble. The code also allows the horizontal portion of the vent system to equal the vertical height. Note: The UMC limits single-wall penetrations to exterior walls only.
- In a commercial building with regularly scheduled restroom mop downs, would the floor drains in those restrooms be considered as having their trap seals adequately protected?
- Regular scheduled mop downs with water may be considered acceptable, provided that adequate water enters the drain and the area is not cleaned with dry chemicals only.
- Do I consider fumes from an underground parking garage with a fan-forced exhaust vent as flammable and utilize UMC Section 506.9 for vent termination? Or can you direct me to the correct code section?
- Yes. Garage ventilation systems in Group S, Division 3 parking garages should terminate in accordance with the provisions of Section 506.9.1, since ducts routinely convey exhaust products containing carbon monoxide, smoke, soot, water vapor, and particles of rubber from tires. Because garage ventilation systems may also be required to dissipate fumes from vehicular fuel spills, it is recommended that they should be regarded as ducts conveying flammable vapors.
- What constitutes an over-temperature safety protection device? Must the device be a pressure and temperature relief valve or can it be some other type of electrical device?
- An over-temperature safety protection device is installed directly on the water heater by the manufacturer. When the temperature reaches 210°F or higher, this built-in safety device opens and shuts off the fuel supply to the heater. When the temperature falls below 210°F, the built-in safety device closes and allows the fuel supply to flow to the heater. Water heaters that have these devices are labeled to indicate that such a device is included in the water heater design. Standards for the construction of water heaters require this built-in over-temperature device. In addition to this fuel supply cut-off device installed by the manufacturer, the Code requires the additional installation of a temperature and pressure relief valve. Note: This requirement is also applicable to electric water heaters. See also 505.6, 608.0 (2003/2006/2009) 504.6, 608.0 (2012) 505.2 (2015/2018/2021)
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