Yes, a sediment trap is required on all gas appliances, including water heaters, where one is “not incorporated as part of the gas utilization equipment.” Sediment traps are not required on appliances such as “illuminating appliances, ranges, clothes dryers, decorative vented appliances for installation in vented fireplaces, gas fireplaces, and outdoor grills.” For some reason Code language is sometimes written in the negative declaration. 1212.9 (2021) states which appliances do not require sediment traps at installation. Water heaters and furnaces are not included in that list; consequently, a sediment trap is required for residential water heaters.
Table 1102.3, “Refrigerant Groups, Properties and Allowable Quantities,” is appropriate for determining compliance with the maximum quantities allowed in a refrigeration system. When the code is silent in its clarification of a particular requirement, the Administrative Authority must be responsible for the enforcement and clarification. Proper research and information collection is of utmost importance when variances in code provisions are required. The standards located in Chapter 17, Part II, UMC (2003/2006/2009/2012/2015/2018/2021) direct the code user to the proper standard for refrigerants. ASHRAE 34 is a referenced standard and should be used as appropriate. Note: The 2021 Uniform Mechanical Code includes the most current refrigerant tables from ASHRAE 34 and includes many of the new refrigerants. At the time of printing, the safety group designation is listed but the quantitative values for the refrigerants used in your example were not available and not included. Due to the constant and rapid development of new refrigerants, it will not contain all of the maximum quantity values; therefore, the standard should be addressed when they are not shown.
The sections are as follows 310.6 Dissimilar Metals, 605.16 Dielectric unions, 605.17 Joints Between Various Materials and 1210.1.3 Protection Against Corrosion. These sections are requirements for several different types of installations.
No, this requirement is specifically applicable to section 1005.2 of the 2021 Uniform Mechanical Code which pertains to boilers and pressure vessels and the termination of their listed pressure relief valves. Safety and relief valves shall not discharge so as to be a hazard, a potential cause of damage or otherwise a nuisance. High pressure must be vented to the outside of the structure. Low pressure can discharge to the drainage system; the installation must conform to the Uniform Plumbing Code. The termination of pressure steam valves should be consistent with UMC 1005.4 due to the hazard potential created by discharge of steam or as specified by the manufacturer of the valve and or boiler. Additionally sections 904.6 and 904.6.1 of the 2021 UMC also deal with relief valve termination. Section 904.6.1 when applied, should be cross referenced with section 1005.3 (Splash Shield) that states any operating temperature exceeding 212º F the discharge piping needs to be installed with a splash shield or centrifugal separator.
1. Yes, an electric water heater could be installed in a dwelling unit plenum under Exception 1, Section 602.2. 2. Yes, wiring and connections in a plenum would be allowed under Exception 5, Section 602.2 assuming compliance with applicable listings, installation instructions, and the National Electrical Code.
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.
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. 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).