Skip navigation links
Code Development
Education, Training and Certification
About Us
Industry Links
Contact Us
What's New
Skip navigation links
Members Only
Why Become a Member
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:

When installing a floor sink, which an indirect waste from a commercial sink drains into, should the floor rim flange of the sink be placed on top of the finished floor or set flush with the finished floor?

The UPC does not require elevation of receptors to prevent the tops of their flanges from being flush with the finished floor. Nonetheless, specific conditions may justify local authorities requiring receptors to be installed as to prevent unintended waste collection from other than the intended primary fixture. See also 408.1 and 408.2 (2003) 407.1 and 407.2 (2006/2009) 402.0 (2012/2015)

Section 510.5.2.2 does not permit the use of a flanged with edge weld or flanged with filled weld. Would this method be allowed in the UMC as Figures 5-6 a, b, c, d clearly allow the use of a flanged connection that is no different than the welded flange?

No. The 2006 UMC only allows overlapping duct connections of either telescoping or bell type for welded field joints. The examples used in UMC Figure 5-6 (2003/2006/2009) are to be used only in a duct-to-fan connection. The reason for the limitation is to prevent pocketing of grease in the duct that could result in excessive accumulation of grease.

Do the standards listed in Table 14-1 of Chapter 14 constitute mandatory code requirements of jurisdictions adopting the UPC, or is their application optional at the discretion of the local Authority Having Jurisdiction?

The UPC formerly required that all plumbing components be submitted to the local Authority Having Jurisdiction for approval. Plumbing products also had to conform to the applicable standards of Table 14-1, Table 1401.1 (2012) Table 1701.1 (2015) To make the UPC eligible for local adoption by reference in many areas, three copies of each standard cited had to be made available to the adopting agency for its files. This became impractical because of the mass of supporting documents that was required to be submitted. Although these standards were being applied and met nationally, they were often unavailable and were commonly cross-referenced to other complementary standards. Section 301.1.1 (2003/2006/2009/2012) 301.2 (2015) requires that all plumbing materials “shall be submitted to the Authority Having Jurisdiction for approval and shall conform to approved applicable recognized standards and shall be free from defects.” This leaves the final acceptance of plumbing materials and the choice of standards strictly up to the local enforcement agency. The standards in Table 14-1, Table 1401.1 (2012) Table 1701.1 (2015) are, in most instances, the only nationally-recognized standards covering the subject item. They have been painstakingly developed by the plumbing industry and most of the plumbing components now in general use conform to one or more of these standards. The standards listed in Table 14-1, Table 1401.1 (2012) provide adequate guidelines by which to judge the acceptability of plumbing materials.

Does the UMC have jurisdiction over compressed air systems and compressed air piping? Or does ASME B31.1 have jurisdiction over pressure vessels and compressed air systems?

The UMC in conjunction with ASME B31.3 would apply. Chapter 14 (Process Piping), provides the provisions for piping conveying gases, while ASME B31.3 would provide the requirements for the remaining portion of a compressed air system. Since air is a gas, Chapter 14 would apply. If any conflicts arose the UMC would take precedence. The appropriate standard for pressure vessels would be ASME Boiler & Pressure Vessel Code Part VIII, Division 1, 2 or 3 based on the operating pressures.

In a gas piping system in a restaurant, is the ansul valve considered an appliance?

No. This valve would be more correctly defined as an appurtenance

Do all metal ducts buried in the ground need to be encased in concrete? There are no exceptions listed in Section 604.0 therefore should it be encased in concrete? Is the intent of this requirement to encase the pipe in concrete?

Yes, metal ducts when installed in or under concrete slab shall be encased in at least 2 inches of concrete. There are products approved for direct bury such as fiberglass, reinforced products and PVC coated metal ducts that do not have to be encased in concrete.

What guidelines, if any, limit the discretionary powers granted by UPC Section 301.2?

Section 301.2 (301.3 2015) grants authority to code administrators to approve materials or products at their discretion. However, Section 301.2 (301.3 2015) places an obligation on the administrator to approve only those alternate materials or products which comply “with the intent of this code,” and which are “at least the equivalent of that prescribed in this code.” In theory, an administrator could approve cardboard pipe, but only if it could be shown to have a performance expectation equivalent to that of other approved piping materials. In summary, it is the intent of UPC, Chapter 3 to avoid limiting the use of alternative products which are equivalent or superior quality, strength, fire-resistance, effectiveness, durability, and safety over those prescribed by this code. However, it is not intended that indiscriminate approval be encouraged when such products fail to comply with code intent of this code or with good engineering practices. Product approval incurs a serious burden of liability and an implied responsibility for public health and safety.

The ceiling space in a nonresidential building is used as a return air plenum. It has exposed wood framing members. Although it is combustible material and cannot meet flame and smoke requirements, the space is protected with a metallic fire sprinkler system with sprinklers in the plenum. It also has smoke detectors in the plenum. Is this an allowable installation per the code?

No. Section 602.2 clearly states that material exposed within ducts or plenums shall meet minimum flame-spread index and smoke-developed rating requirements. There are no exceptions that would allow exposed wood within the plenum by adding a fire sprinkler system or smoke detectors.

Is the color coding that is required by Section 601.2 (2330/2006/2009/2012) 601.3 (2015) for potable and nonpotable water systems to be applied by the manufacturer or in the field by the installer?

The identification that is required by Section 301.1.2 (2003/2006/2009) 301.1.1 (2012), 301.2.1 (2015) is applied by the manufacturer. The identification that is required by Section 601.2 (2003/2006/2009/2012) 601.3 (2015)is applied by the installer.

Is Manual D the only approved and authorized method of sizing ductwork per the code?

No. Manual D is not the only approved method of sizing ductwork. ACCA Manual Q may be used for commercial applications. In addition, Section 601.2 states that other approved methods may be used. The Authority Having Jurisdiction would have to determine if the alternate method of sizing would be equivalent to the provisions set forth in the UMC.

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