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Uniform Codes Questions & Answers 

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

1. In the UMC, does "direct exit" imply a separate exterior door from every room in the building? 2. Does "direct exit" imply a direct route of exit with maximum distance to the exterior of the building?

1. Yes. 2. Yes, a direct route would be assumed in the same room or open area within 100 feet of such an exterior door.

Are brass plated closet bolts acceptable?

The Product Certification Committee maintains that closet tank or bowl accessories shall be manufactured of a non-ferrous metal. This excludes the use of brass plated steel bolts or any other type of plated ferrous metal. The terms equally corrosion resistant material in UPC Section 408.3 (2003) 407.3 (2006/2009) 402.6.2 (2012/2015) and noncorrosive in Section 408.4 (2003) 407.4 (2006/2009) 402.4 (2012/2015) are used as general terms. It was never the intent of the Code to establish parameters of acceptable corrosion resistance for copper versus copper alloy, versus stainless steel, etc. By eliminating the use of ferrous metal (plated or not) for closet bolts, nuts, and washers, a reasonably long service life can be expected.

Is aluminum an acceptable material to be used in construction of commercial kitchen hood? If it is acceptable, what is minimum thickness?

Aluminum is not an approved material for the construction of a commercial hood unless it meets the exception for listed hoods or it is determined by the AHJ to be equivalent in strength, fire and corrosion resistance.

Is it acceptable to vent a one-bathroom house with a single 2 inch vent? Is the requirement for aggregate cross-sectional area (Section 904.0) based on the required building sewer size as determined by fixture units or the footnote to Table 7-5 (2003/2006/2009) Table 703.2 (2012) 703.2 (2015) that requires a minimum 3 inch wasteline for a toilet?

The required aggregate cross-sectional vent area is based on Table 7-5 (2003/2006/2009) Table 703.2 (2012/2015) and all footnotes. A single bathroom house containing a water closet requires a 3 inch building sewer and would, therefore, require single or multiple venting equal in area.

1. Does the Uniform Mechanical Code section 606 require access panels in walls or ceilings to identify that a smoke or fire damper is behind them? 2. Also, if the ceiling is T-bar, does it require that the closest panel be identified for access?

1. Yes. Section 606.5 (605.5/ 2012) requires dampers to be provided with an approved means of access that is large enough to permit inspection and maintenance of the damper and its operating parts. Access points shall be permanently identified on the exterior with labels that read "Smoke Damper." The code section provides for easy identification of the location of dampers for maintenance purposes by workers without access to original plans or as-built. 2. Yes, if you are using a T-bar ceiling panel as access, you must identify that panel.

1. Do plumbing vents require a minimum separation dimension from each other? 2. Does Section 906.0 permit a plumbing vent to terminate beneath the overhang of a higher roof?

1. No specific dimension is quoted, but separation should be at least adequate to permit flashing space as required by Section 906.5. 2. When the basic clearances required by Section 906.0 are observed and the vent opening properly clears the overhang, code requirements should be adequately met, providing there are no other limiting factors.

Is it within the Uniform Mechanical Code’s intent to consider the roof as an approved disposal site?

No, the roof is not an approved disposal site. One of the basic tenets of the UMC is that no operation of a mechanical system must cause injury to people or damage the building that contains it. The passage of water over any surface (including roofs) will cause erosion. Condensate allowed to pool anywhere could stagnate and allow algae growth that could be a slip hazard. This is one reason why UMC Section 310.1 (309.1, 2009) (312.1, 2012) prohibits draining condensate over a public way. In areas with intense sunshine, water magnifies the damaging effect of the sun, deteriorating the roofing material more rapidly. Condensate from fuel-efficient condensing appliances may be acidic and be deleterious to the roofing material. Any of these problems would preclude the Authority Having Jurisdiction from approving the roof as a disposal area for condensate. Even a landscaped area may not be an approved location if the area is too small and condensate flow from a large building would overwhelm the landscaped area’s ability to absorb it. The code's intent is that condensate be directed to plumbing fixtures or to a disposal area capable of containing and absorbing whatever flow rate may occur without any danger to people or damage to the building.

Where the fixture unit loading necessitates a 2 inch vent and structural features require an initial horizontal vent section that is 120 feet long and followed by a vertical vent section that is 60 feet long and then terminates above the roof, what are the minimum sizes and lengths of the vent pipes that are permitted by the UPC?

The note at the bottom of Table 7-5 (2003/2006/2009) Table 703.2 (2012/2015) limits horizontal vent sections to 1/3 of the total length permitted by the Table . This limitation may be waived, provided that vent pipe is increased one pipe size or more for its entire length. For this example, a 2 1/2 inch vent would be required.

In accordance with UMC Section 310.1 condensate drainage states "discharged to an approved plumbing fixture or disposal area". Does a drywell constitute as an approved area?

Section 814.3 of the 2009 Uniform Plumbing Code does recognize a drywell as an approved receptor for condensate waste, although the Authority Having Jurisdiction would have the final approval factoring in the geographical, topographical and climatic conditions in addition to the amount and composition of the condensate being discharged.

UPC Section 215.0 defines the beginning of a mobile home park sewer as a point “two feet downstream of the last mobile home site.” Which end of the system is the last site located?

The site furthest upstream on the common piping system is the last site. This section includes both trunklines and branches that begin two feet downstream of the most remote mobile home site as measured from the ultimate point of disposal.

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