UNFORM CODES QUESTIONS & ANSWERS

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

Does the UPC exception for shower receptors of 30 x 60” include a 1-piece shower enclosures of the same dimension?
- Yes. Section 408.6 of the 2018 UPC, Exception (2) permits the installation of a shower receptor having dimensions of not less than 30 inches in width and 60 inches in length. This allows the replacement of a bathtub with a walk in shower without meeting the minimum shower requirements found in Section 408.6. Listed one piece shower receptors meeting the dimensions found in Exception (2) would be acceptable.
If a furnace compartment does not have a ceiling and is open to a ventilated attic, do we still need to bring in lower combustion air into the furnace compartment?
- Yes. The purpose of the upper and lower openings is to vent the appliance compartment. The hot air will rise and be replaced by the cooler lower combustion air opening. Furthermore, the code has a provision for the one opening method and the lower combustion opening would not be required so long as the provisions of Section 701.4.2 are met.
Please explain IAPMO’s acceptance of a vacuum breaker as adequate protection against backflow on commercial garbage grinders with the water supply connected directly to the sewer. We are considering that an airgap be required for this installation in this area.
- Section 603.3.5 (2003/2006/2009) 603.4.4 (2012/2015/2018) prohibits direct connection of the potable water supply to sewer connected waste piping under any circumstances. The section later differentiates between a direct connection to drainage piping and the necessary introduction of a supply of flushing water to an open plumbing fixture or trap by means of a submerged inlet when protected by a properly placed vacuum breaker. A directly flushed siphon jet water closet is a common example. Here, a vacuum breaker protected flushometer valve delivers water to both the bowl flushing rim and the siphon jet in the bottom of the trap. IAPMO listed open hopper commercial food waste disposers require a continuous water supply while operating. The water usually enters the hopper through one or more strategically placed low inlets which, are properly located on the inlet side of the appliance trap when these inlets are protected by an approved vacuum breaker installed at a suitable height above the flood level rim of the hopper or scrap table, the garbage disposer meets the cross-connection control and water supply safety requirements of the UPC.
Scenario: Commercial kitchen hood exhaust system, treated by a grease removal system or pollution control unit (scrubber).
Question:
Is the duct leaving the grease removal system or pollution control unit (scrubber) classified as grease exhaust or can it be treated as an environmental air exhaust or general exhaust?
- The duct leaving the pollution control unit is classified as grease exhaust even after being scrubbed, the exhaust would still fall under the requirements of “Grease Exhaust”. Pollution Control Units are generally listed to UL1978 and considered part of the exhaust duct system and not the exhaust termination. Section 209 of the 2012 Uniform Mechanical Code defines a grease duct as a containment system for the transportation of air and grease vapors that is designed and installed to reduce the possibility of the accumulation of combustible condensation and the occurrence of damage if a fire occurs within the system; while the definition of environmental air duct as found in Section 207 states that other than heating or air conditioning systems for human use would be considered environmental air.
The Uniform Plumbing Code requires water heaters generating a glow or spark or flame capable of igniting flammable vapors to be installed in a garage, provided that the pilots and burners or heating elements and switches are at least 18 inches above the floor level in residential garages. The Code further states, “when such water heaters installed within a garage are enclosed in a separate, approved compartment having access only from outside of the garage, such water heaters may be installed at floor level, provided the required combustion air is also taken from the exterior of the garage.” Would the requirements of the Code apply to a water heater located in a room adjacent to a residential garage if the door of this room opens directly into the garage?
- The intent of the Code is to separate all sources of ignition from potential fuel sources. A door or opening which would permit the flow of fuel or vapors into the space where the water heater is installed would defeat this objective and be in violation of the Code.
1. Are we to assume that furnaces shall no longer be installed in underfloor spaces for new construction? We are a little confused on the reasoning for deleting these requirements when replacing or installing furnaces in crawl spaces. If underfloor furnaces are still allowed, what code requirements do we use? 2. Is there a particular reason(s) that IAPMO does not recognize factory-built, listed, wood-burning fireplaces? 3. If the 2006 UMC does not address the past requirements of "return air," especially prohibited locations, what resource does IAPMO rely on for these requirements?
- 1. No. Furnaces are not specifically prohibited from being installed in under floor spaces. The applicable code sections for furnaces installed under floor are: a. Sections 304.1 (303.1, 2009) & 902.0(A) requires appliances to be installed according to their listing; b. Sections 305.0 & 305.1 (304.0 & 304.1, 2009; 904.10, 2012/2015/2018) specifies requirements for access; c. Section 604.0 (2003/2006/2009/2012/2015/2018) applies to ducts in crawl spaces; d. Chapter 7 (2003/2006/2009/2012/2015/2018) specifies combustion air and ventilation requirements; and e. Sections 904.2 and 904.7 (2003/2006/2009/2012/2015/2018) (904.3.1, 2012/2015/2018) also have provisions for furnace installation. 2. Typically, factory-built wood-burning fireplaces are regulated by the Building code. Chapter 17 of the UMC does recognize wood-burning fire-places by referencing NFPA 211-03 (NFPA 211-06). 3. Furnaces shall be installed per the manufacturer’s installation instructions in regards to prohibited locations.
What is the reason for the UPC Section 1014.3.4.2, that states each business establishment for which a gravity grease interceptor is required shall have an interceptor that serves that establishment?
- The language found in Section 1014.3.4.2 of the 2012 Uniform Plumbing Code (UPC), was first introduced into the Code in 1982 as part of newly adopted Appendix H - Recommended Procedures for Sizing Commercial Kitchen Grease Interceptors. The proponent of that code change stated the following as the substantiation for that code change; “Without this code change, it would be very difficult to locate the source of oils, fats and grease that are draining into the sanitary drainage system where more than one establishment utilizes the same interceptor.” That language was subsequently moved into the body of the code in the 2006 edition of the UPC.
Do you know where the requirements are located, that allow ventless (or ductless) clothes dryers?
- The UMC does not specifically allow ventless or ductless clothes dryers. All dryer exhaust ducts shall terminate on the outside of the building unless approved by the AHJ as an alternate method.
Is a gas-fired water heater allowed to be installed in a half bath which has no shower or bathtub?
- Section 505.1 prohibits installation of a gas-fired water heater in a bathroom. However, Section 204.0 (2015/2018) defines bathroom as a room equipped with a shower or bathtub. A room equipped with neither a tub or shower is considered to be a toilet room (as opposed to being a bathroom) and is not prohibited by Code from containing a gas-fired water heater.
Please clarify the intent of UMC Section 931.1 (904.11/2009, 904.10/2012, 304.4/2015, 2018) regarding access openings and passageways.
- The code prescribes a minimum opening to the attic equipment of 30 inches x 30 inches but allows 22 inches x 30 inches opening when the equipment may be removed through such an opening. (This allows access penetrations into attics without requiring a joist to be cut when framed on 24 inch centers). The distance from the opening to the equipment shall not be further than 20 feet when measured along the center of the passageway and should have a minimum 24 inch wide solid floor to walk on. (This is also helpful when joists are spaced on 24 inch centers to allow standard 4 foot deck material to be halved and attached to the 24 inch center joist.) The passageway shall have clear space of 30 inches x 30 inches. This is an invisible clear space from the opening to the equipment that shall be maintained while traveling on the 24 inch wide solid floor.