Every week we will be including additional questions and informal UPC and UMC interpretations
- Are trap primers required for floor sinks: 1. Under a sink located in a meat cutting area of a small general store? 2. Located outside a freezer box for a drain for condensate from the freezer? 3. Under a long chest-type, frozen food container or a chest-type cooler for cheese and deli products?
- 1. Each jurisdiction has the option of how to enforce Section 1007.0. Trap primers are usually not required if the plumbing fixture in question receives an adequate supply of water to maintain the trap seal. 2. A floor sink that receives condensate discharge normally would not require a trap primer if the condensate flow is continuous year round. 3. See answer for #2.
- Is a UL listed tape required to seal ducts?
- Yes. Section 602.4 of the UMC states that "duct joints shall be made substantially airtight by means of tapes, mastics, gasketing, or other means." Closure systems for rigid air ducts and plenums shall be listed in accordance with UL 181A, Standard for Closure Systems for Use with Rigid Air Ducts and Air Connectors. Flexible air ducts shall be listed in accordance with UL 181B, Standard for Closure Systems for Use with Flexible Air Ducts and Air Connectors. (See Chapter 17, Part II.)
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Application:
A horizontal fan coil unit concealed in apartment bathroom ceiling with the condensate draining to a wye tailpiece above the lavatory trap.
1. Does this application require a fixed air-gap prior to the connection to the wye tailpiece?
2. Does the air break between the wye tailpiece inlet and the weir of the trap meet the code requirement of 814.3?
Comment:
The code sections read as follows:
814.3 Point of Discharge. Air-conditioning condensate waste pipes shall connect indirectly to the drainage system through an air gap or air break to properly trapped and vented receptors, dry wells, leach pits, or the tailpiece of plumbing fixtures.
203: Air Break. A physical separation which may be a low inlet into the indirect waste receptor from the fixture, appliance, or device indirectly connected.
211: Indirect Waste Pipe. A pipe that does not connect directly with the drainage system but conveys liquid wastes by discharging into a plumbing fixture, interceptor, or receptacle that is directly connected to the drainage system.
- 1) No, the connection of a condensate drain to the tailpiece of a lavatory described in Section 807.2 of the 2018 UPC is considered an airbreak. The lavatory is acting as an indirect waste receptor for the condensate waste line. (see definition of air break*)
2) The airbreak is the elevation difference between the pan for the air conditioning unit and the flood level rim of the lavatory.
*Section 203.0 Airbreak. A physical separation which may be a low inlet into the indirect waste receptor from the fixture, appliance, or device indirectly connected.
- Can soft annealed copper which is enclosed in a wall cavity or above a ceiling be considered to be in a raceway?
- No, a wall cavity or ceiling in a building is not considered a raceway. Walls and ceilings are always subject to cutting or penetrating in some shape or form. A raceway is an enclosed channel designed expressly for holding the annealed copper.
- How many total hangers would be required on a 100' straight run of 10' lengths of No Hub Cast Iron pipe?
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Per Table 313.3 of the 2018 Uniform Plumbing Code, Hubless Cast Iron, installed horizontally, shall be supported at every other joint unless over 4 feet, at which point it has to be supported at each joint. Additional requirements referenced in the footnotes include: 1) the adjacent joint must be supported within 18 inches of the joint; 2) a brace must be installed at least every 40ft. to prevent horizontal movement of the pipe; 3) a support must be installed at each horizontal branch connection and; 4) hangers may not be placed on the coupling.
A no-hub coupling, much like a threaded iron pipe coupling, consists of two joints. One half of the coupling creates a water tight seal for one piece of pipe or fitting while the other half serves a similar function for the connecting pipe or fitting. Per Table 313.3, a hanger for hubless cast iron needs to be installed within 18 inches of the joint. Since a no-hub coupling consists of two joints, a hanger would be required on both sides of the coupling.
- Does section UMC 510.1.3 Duct Installation, regarding sloping of exhaust ducts with "not less than 2 percent slope on horizontal runs up to 75 feet and not less than 8 percent slope on horizontal runs more than 75 feet", pertain only to the sloping of Type 1 grease exhaust ducts only, like it had in the previous edition of the code?
- No, Section 510.1.3 of the 2018 Uniform Mechanical Code does not pertain to Type 2 ducts. Section 510.1.7 of the 2018 UMC pertains to Type 2 duct systems. Type 2 exhaust duct used with a moisture related process such as a dishwasher would be required to drain back to the hood.
- Is it acceptable at any time to direct bury an "anode" style natural gas riser without an anode attached for cathodic protection?
- No. IAPMO lists “anode” type risers that meet DOT 192.281, 192.283, 192.375 and ASTM-D2513 CAT-1 specifications. Anode type risers not meeting those standards would need additional cathodic protection.
- Are flexible connectors allowed to be used in grease duct systems?
- Flexible connectors are not allowed in a grease duct in line exhaust fans inside the building. Additionally NFPA 96 sections 8.1.2.3 and 8.1.3.4 specifically prohibit the use of flexible connectors in grease duct systems. Sections 510.9.1.1 and 511.1.3.1 were previously added to the Uniform Mechanical Code in 2003 by the NFPA 96 task group.
- 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.
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