Every week we will be including additional questions and informal UPC and UMC interpretations
- What is the reason behind the 5 feet above the floor requirement for a vacuum breaker for a bedpan washer, and 6 feet above the floor requirement for the hose connection? Doesn’t the vacuum breaker have to be higher than the hose connection?
- UPC Section 603.4.17 (2009), 603.5.16 (2012), 603.5.15 (2015/2018/2021) is referring to two separate installations; however, the reasoning behind the height requirements is similar. Atmospheric vacuum breakers must be located at least 6 inches above any and all downstream piping. When a hose is attached to these outlets as with a bed-pan washer, maintaining that height requirement becomes more difficult, which is a major factor in the height requirement for both the bed-pan washer and for the hose connection. These applications can be considered a high risk or health hazard. So ensuring that the AVB is at a proper height and not subjected to backpressure is critical.
- Is the reference to “other exhaust systems” referring to Product Conveying Exhaust systems?
- No, the Term/Phrase “Other exhaust systems” would not refer to Product Conveying Exhaust systems. Any system that falls outside the listed category of “Environmental Air Duct” in section 504.0 would be covered elsewhere in Chapter 5 of the 2021 Uniform Mechanical Code. Section 505.0 of the 2021 Uniform Mechanical Code is specifically applicable Product Conveying Exhaust Systems; Section 506.0 is specifically applicable Product Conveying Exhaust Ducts; and the balance of the Chapter is devoted to Commercial Kitchens Ventilation.
- 1. Is a brass or PVC compression fitting that uses a compression nut, friction ring, and rubber compression washer considered a rigid joint or a slip joint?
2. Can these fittings be used in a concealed location or be buried in the ground for water piping?
- 1. The joints on the compression fitting as described are slip joints
2. In water piping, slip joints may be used only on the exposed fixture supply line (see Section 606.2.3 (2003/2006/2009) 605.15 (2012),605.14 (2015/2018/2021).
- Would the installation of a plastic gas line under an ocean pier be a code violation?
- No. Section 1310.7.1 of the 2021 UMC states, "plastic pipe, tubing and fittings shall be used outside, underground only."
- What type of backflow preventer is required by the UPC for domestic water lines serving water cooled ice machines with fractional horse power compressors?
- If there is a chance of back-pressure, and the protection required is against contamination, a reduced pressure principle device would be the correct device to install. A pressure type vacuum breaker could be used if there is no possibility of back-pressure. Double check valve assemblies are designed to be used for pollution protection against food or drink materials that cause a change in color, odor, or taste, but otherwise are not harmful or hazardous.
- UMC Section 502.2.2 states ducts conveying explosive or flammable vapors shall have the termination point for exhaust ducts discharging to the atmosphere shall be 30 feet from property line, 10 feet from openings into building, 6 feet from exterior walls or roofs, 30 feet from combustible walls or openings into the building that are in the direction of the exhaust discharge and 10 feet above adjoining grade. Does the section apply to the vent discharge (outlet) of an underground storage tank of flammable and combustible liquids in a motor fuel dispensing facility? There is a distance of 5 feet to property line for this application in the Fire Code, however, it is less stringent.
- No. Section 502.2.2 applies to duct termination only. The Uniform Mechanical Code does not regulate underground gasoline storage tanks. Provisions for underground storage tanks are typically found in the Fire Code.
- Can single wall metal pipe be used in dwellings and residential occupancies as a vent connector? In an attached U Occupancy?
- The code prohibits the use of single wall metal pipe as a vent material in residential occupancies, but does allow Galvanized sheet steel at least 0.018 inches (0.46 mm) thick, (28 Ga) single wall vent connectors to be used to connect the appliance to the type B vent in residential water heater applications. Water heaters installed in Group U Occupancies, which includes but is not limited to water towers, barns and towers may utilize 28 Ga. single wall vent connectors when installed per Section 510.10 of the 2021 UPC. Note: Venting requirements for other gas burning appliances, please refer to the Uniform Mechanical Code.
- When is the appropriate time for the inspector to inspect the closet flange on a water closet installation in relation to the phase of construction?
- The appropriate time for the inspector to inspect the closet ring or flange for a water closet installation is at the “roughing in” phase (see Section 220.0, 2003/2006/2009/2012/2015/2018/0221) of a plumbing system, which is prior to the installation of the fixtures. Section 316.3.2 (2003/2006/2009), 402.6.1 (2012/2015/2018/2021) requires that closet bends or stubs shall be cut so as to present a smooth surface with the top of the closet ring before rough inspection is called. The local Authority Having Jurisdiction sets the policies regarding partial rough-in plumbing inspections.
- Project restaurant is located on 5th story of 52-story high rise in Las Vegas, Clark County, NV. Project has no accessible roof and requires solid-fuel system to exhaust out the side of the building. 1. Does the 2021 UMC Section 517.4 "Exhaust Systems for Solid-Fuel Cooking" only apply to systems without exhaust hoods (i.e. directly vented appliances)? 2. Is the intent of the 2021 UMC Section 517.5.1 to prevent embers/sparks from a solid-fuel appliance contacting a combustible building structure?
- 1. No. Section 517.4 addresses all solid fuel cooking systems. 2. Per Section 517.5.1 (2003/2006/2009/2012/2015/2018/2021), the intent of the code is to minimize the entrance of sparks and embers into the grease control device and into the hood and duct system.
- Can the venting system for three water heaters be sized using the alternate method of the area of the largest connector, plus 50 percent of the area of the smaller connector?
- Section 510.10.3.4 (2003/2006/2009) 509.10.2.3 (2012/2015/2018/2021) limits the use of the alternate method for sizing common vent to applications where there are only two draft hood equipped appliances. When there are more than two fuel-burning appliances connected to a common vent connector, sizing should be completed using the appropriate tables in Chapter 5 (2003/2006/2009/2012) or by other methods approved by the Authority Having Jurisdiction.
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