Skip navigation links
Code Development
Membership
Education, Training and Certification
Publications
Events
About Us
Industry Links
Contact Us
What's New
Skip navigation links
Members Only
Why Become a Member
Join IAPMO
How We Help You:Expand How We Help You:
Contact Field Manager
Field Services Assistance
Ask A Code Question
IAPMO Certified Professionals Search
Government Relations
Drought ToolkitExpand Drought Toolkit
Accredited Green Plumbers Training
Career Center
Uniform Codes Questions & Answers
Uniform Codes Questions & Answers 

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

Does Section 416.0 (2003) 415.0 (2006/2009) 417.5 (2012/2015) require the hot water supply piping to be on the left side of the fixtures, or does this section apply solely to the required placement of the hot water control valve?

Section 416.0 (2003) 415.0 (2006/2009) 417.5 (2012/2015) requires that the hot water be connected to the left side of the faucet or diverter; there is no orientation requirement for piping, existing walls, floors, or ceilings.

1. Regarding the interlocking of electrical equipment to the dust collection system, a tenant states that only his sanding equipment generates “dust”, therefore, are the only machines that need to be interlocked with the dust collection system. Does this meet the provisions of Section 503.1? 2. He further claims that some of his equipment, table saws and related equipment do not generate airborne dust but rather they produce chips and small fragments of wood not regulated by Section 503.1. Is this assumption correct? 3. Would a piece of equipment such as a planer, which produces combustible shavings or “curls” of wood still require the interlock with dust collection equipment?

1. Section 503.1 - All equipment that produces dust must be interlocked. 2. Section 505.1 - The building or fire code determines when ventilation equipment is required. 3. Section 503.1 - Yes. A planer is considered dust-producing equipment.

Does the plumbing code require that the entire combustion air openings be located within 12 inches of the floor and within 12 inches of the ceiling of the heater enclosure or does the code permit that a portion of the combustion air opening be located within 12 inches of the floor or ceiling with the balance of the opening permitted to be more than 12 inches above the floor (or more than 12 inches below the ceiling)?

Plumbing code language has never required combustion air openings to be entirely within the upper or lower 12 inches of an enclosure. Combustion air openings are required to be located at least partly within the 12 inch space above the floor and partly within the 12 inch space below the ceiling. This rule applies to louvered walls and doors as well as to individual combustion air openings.

There is a discrepancy between UMC Section 310.3 (309.3, 2009) and UPC Table 8-2 regarding condensate pipe sizing. Which is correct? If both are applicable, please explain.

Section 101.4.1.4 (2003/2006/2009/2012) of the UPC states in part, "when the requirements within the jurisdiction of this plumbing code conflict with the requirements of the mechanical code, this code shall prevail," meaning Table 8-2 (2003/2006/2009) of the UPC would prevail. However, it should be noted that UPC Table 8-2 was revised in the 2003 edition to match the UMC requirements.

Can a gas water heater be located in a hallway closet where the hallway opens into bedrooms? The door on the closet has louvers.

Yes. so long as the opening is not directly into the bedroom or bathroom and the intent and objectives of the Code have not been violated.

Should we require our contractors to use metal tape to put their dryer ducts together?

No. The language in Sections 504.3.1 and 504.3.2.1 is prescriptive because of the nature of the exhaust content, thus the restriction about screening and the use of connectors (screws) that would obstruct the flow. The understanding is that a lint buildup could occur. Section 504.0 is referenced for direction on the general provisions that say, among other things, “ducts should be substantially airtight” and then refers you to Chapter 6. Section 602.4 (2003/2006/2009) says, “Joints of duct systems shall be made substantially airtight by the means of tapes, mastics, gasketing, or other means.” The committee sees these code sections as allowing quite a range of materials for sealing dryer exhaust ducts. Metal tape is certainly an option, but it would not be required. Careful examination of the manufacturer’s instructions and listings of its sealing products would indicate those suitable for the prolonged heat of a dryer exhaust.

I understand that for corrosion (electrolysis) to occur, dissimilar metals must be joined together and exposed to wet or damp conditions. The water is the catalyst for the corrosion process. Without the touching of water, steel and copper, there could not be a problem. Is it required to isolate copper piping from the steel hanger?

There is a possibility of either corrosion or electrolysis when a difference in potential exists between metals. Abrasive action caused by expansion, contraction, vibration, and the possibility of condensate generation, may result in a condition requiring some means of isolating the copper pipe from the steel hanger to prevent premature failure. For these reasons, Section 314.4 (2003/2006/2009) 313.4 (2012) 313.2 (2015) states, in part, "Piping shall be isolated from incompatible materials.

Can you clarify for us if a gas-fired steam table requires ventilation via a Type II hood?

Section 508.1 requires hoods above all commercial-type deep fat fryers, broilers, fry grills, steam-jacketed kettles, hot-top ranges, ovens, barbecues, rotisseries, dishwashing machines and similar equipment which produce comparable amounts of steam, smoke, grease or heat in food-processing establishments. The Authority Having Jurisdiction (AHJ) would have to determine if the piece of equipment produces a comparable amount of steam to warrant the installation of a Type II hood. There are several pieces of kitchen equipment available that produce varying amounts of steam. It would be difficult to say that all steam tables require a Type II hood, when there may not be enough steam escaping to be concerned. Additionally, most kitchen and restaurants move a tremendous amount of air that may be enough to compensate for small steam producing units. The decision to require a Type II hood would have to be made by the AHJ taking into account the amount of steam being produced by the equipment and the design of the air moving system serving the space.

Does Section 311.4 (2003/2006/2009),310.4 (2012/2015)expressly prohibit Single Stack Drainage and Venting Systems?

Section 311.4 (2003/2006/2009), 310.4 (2012/2015) prohibits the installation of "single stack drainage and venting systems with unvented branch lines " Section 301.2.2 (2003) 301.2 (2006/2009/2012) 301.3 (2015) states, "The Authority Having Jurisdiction may approve any such alternate provided that the Authority Having Jurisdiction finds that the proposed design is satisfactory and complies with the intent of this Code." It is the intent of this code that every trap be protected by a vent to guard "against siphonage and to ensure air circulation" throughout all parts of the drainage Section 1004.0 (2003/2006/2009/2012/2015) prohibits the use of "S" traps. None of these basic plumbing design provisions are possible when "unvented branch lines" are installed. In summary, modern waste and vent systems have evolved from the one pipe systems of the late 1800's because science and empirical evidence have shown what works and does not work well. Meeting the intent of the UPC and modern plumbing system design cannot be achieved by installing oversized, unvented "S" traps as an "alternative" system. Opting for such systems simply ignores standard plumbing concepts which have been developed and proven during the past 100 years.

Is the exhaust airstream from an enclosed parking garage to be considered “environmental air” or “product conveying air”?

The exhaust from an enclosed parking garage is considered product conveying air since these exhausts routinely convey exhaust products containing carbon monoxide and smoke. Additionally, since 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. See also UMC Answers and Analysis Section 506.9.1, Vent Termination.

If you have a code question you would like answered in this forum please click here to submit question

IAPMO members may view the complete online Answers & Analysis content here