Written by 3:44 pm Answers and Analysis Q&A

Answers & Analysis | First Quarter 2023

Taken from the Online Editions of the UPC & UMC Answers & Analysis

SUBJECT: Temperature Limitation, Shower and Tub-Shower Control Valves SECTION: 406.3.2 (4) (2021 UPC) 

Question: 1. Why is this limited to a water heater conforming to ASSE 1084? 

2. Why isn’t ASSE 1082, Performance  requirements for water heaters with integral temperature control devices for hot water distribution systems also an option? 

Answer: 1. A water heater conforming to ASSE 1084, as found in Section 408.3.2 of the 2021 Uniform Plumbing Code (UPC), is a point of use water heater. Per Section 1.2.1 of ASSE 1084, “This water heater is intended to supply tempered water at point of use in order to reduce the risks of scalding”. These devices limit water temperature to a maximum of 120°F. 

2. A water heater listed to ASSE 1082, per Section 1.2 of the standard “is for water heaters that control the outlet temperature to specific limits and are installed within the hot water distribution system but not at point-of-use”. Water heaters listed to this standard limit water temperature to a maximum of 125°F, which exceeds the water temperatures permitted by Sections 407.3, 408.3.2, 409.4 and 410.3 of the 2021 UPC. 

SUBJECT: Drinking Fountain Alternatives 
SECTION: 415.2 (2018 UPC)

 Question: Are any of the following an approved “Water Station” that may be used as an alternative to drinking fountains? 

1. Water dispenser (portable units typically found in homes and offices with refillable water bottles but not connected to potable water distribution line). 

2. Soda fountains that also dispense water as one of the options (typically found in fast food restaurants). 

3. Bottle filling station. 

4. Is the statement in this code section, “where food is consumed indoors”, intended for restaurants only (A2) or can this be for other occupancies that have indoor eating like lunchrooms inside other types of occupancies like E, M, or B? 

Answer: 1. No. Section 206.0 of the 2018 UPC defines a drinking fountain as “A plumbing fixture connected to the potable water distribution system and sanitary drainage system that provides drinking water in a flowing steam so that the user can consume water directly from the fixture without use of accessories…”. 

2. Section 415.2 specifically states that “where food is consumed indoors, water stations shall be permitted to be substituted for drinking fountains.” Restaurant soda fountains in with water dispensers would fall into the category of a water station. 

3. Per Section 415.2, “… Bottle filling stations shall be permitted to be substituted for drinking fountains up to 50 percent of the requirement for drinking fountains.” 

4. Yes. Although other types of occupancies may have a sink for drinking water in their employee’s breakrooms, the public would not have access to its use. 

SUBJECT: Exhaust Ventilation 
SECTION: 403.7 (2021 UMC)

Question: Chapter 4, section 403.7 in Table 403.7 cites requirements for “Educational Science Laboratories”. 

1. Does this include Group B science laboratories outside of K-12 school applications? 

2. Does this include University research and teaching laboratories with quantities of hazardous materials below the Maximum Allowable Quantities stated in the Building Code Table 307.1(1)? 

Answer: 1. Yes, this would include any science laboratories used for educational purpose. Table 403.7 footnote # 8 in the 2018 Uniform Mechanical Code states that for unlisted occupancies for a proposed space not listed in table then the requirements for the listed occupancy that is most similar shall be used. 

The majority of UMC Chapter 4, Ventilation Air, is derived from ASHRAE 62.1. Table 403.7 is extracted from Table 6.5 of ASHRAE Standard 62.1 and is part of a prescriptive performance path. 

2. Yes, again this would include any science laboratories used for educational purpose. Science labs, due to their use, need exhaust air — this is a general requirement for any type of science lab. No distinction is made in Table 403.7 for the specific type of science lab or who may occupy it. Furthermore, when looking at other sections of Chapter 4, and a distinction is made for the types of labs, there is no difference in the requirements for “Science Laboratories” and “University/College Laboratories” (see Table 402.1, Minimum Ventilation Rates in Breathing Zone). 


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Last modified: March 28, 2023