Answers and Analysis
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Questions matching UMC Chapter 4
9 results
UMC 2006 403.7, see also Table 4-4
UMC 2009 403.7, see also Table 4-4
UMC 2012 403.7, see also T403.7
Topic: Exhaust Ventilation
Per Section 403.7 Exhaust Ventilation "Exhaust airflow shall be provided in accordance with the requirements in Table 4-4. Exhaust makeup air shall be permitted to be any combination of outdoor air, recirculated air, and transfer air." Per Table 4-4, Parking garages are to be exhausted at a rate of 0.75 cfm/ft2. Can parking garage exhaust rate be modulated below the listed 0.75 cfm/ft2, if a CO monitoring system is installed in the parking garage?
No, systems for removal of vapors, gases, and smoke shall be designed by the constant velocity or equal friction methods prescribed by Section 505.2 (2006/2009/2012) of the code. The Authority Having Jurisdiction may approve a design that incorporates a variable system if it is determined by the AHJ to be equivalent to the code.
UMC 2009 403.1.1, Table 4-1
UMC 2012 Section 403.2.1, Table 402.1
UMC 2015 Section 403.2.1, Table 402.1
Topic: Ventilation air requirements
When determining the rate of breathing zone outdoor air using Table 402.1 should the calculation include cfm/person and cfm/sqft (area)?
Do we use the highest number or the total of both?
Do we use the highest number or the total of both?
Both values are required to derive an answer.
The breathing zone outdoor airflow shall be not less than the value determined in accordance with Equation 403.2.1.
The breathing zone outdoor airflow shall be not less than the value determined in accordance with Equation 403.2.1.
UMC 2015 402.1.3
UMC 2018 402.1.3
Topic: Ventilation in Health Care Facilities
Where can if find a definition for what is considered a Health Care Facility under the UMC?
A Health Care Facility is not defined in the Uniform Mechanical code. A health care facility will be classified by the local Authority Having Jurisdiction in terms of occupant density, activities and building construction.
The ventilation requirements for a Health Care Facility are within the scope of the UMC Section 402.1.3 and will be in accordance with ASHRAE 170.
The ventilation requirements for a Health Care Facility are within the scope of the UMC Section 402.1.3 and will be in accordance with ASHRAE 170.
UMC 2012 402.3
UMC 2015 402.3
UMC 2018 402.3
UMC 2021 402.3
Topic: Ventilation Air, Dwellings
1. Section 402.3 of the UMC indicates that mechanical ventilation systems be enabled when spaces are occupied. If a dwelling unit is provided with a ductless split system heat pump which recirculates air within a space, will an interlock with an exhaust fan (or a continuously operating exhaust fan) serving that space still qualify as a mechanically ventilated space?
1.Yes.
UMC 2012 403.7
UMC 2015 403.7
UMC 2018 403.7
UMC 2021 403.7
Topic: Exhaust Ventilation
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)?
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).+
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).+
UMC 2012 403.7 504.1
UMC 2015 403.7 504.1
UMC 2018 504.1
UMC 2021 403.7 504.1
Topic: Residential Kitchen Exhaust
1. Is UMC 403.7 /Table 403.7 a separate requirement from environmental air duct requirement per 504.1?
2. If a ductless range hood is installed, then exhaust is not required in kitchens?
2. If a ductless range hood is installed, then exhaust is not required in kitchens?
1. Yes, they are separate applicable requirements of the 2018 Uniform Mechanical Code. UMC section 403.7 and table 403.7 establish the proscribed exhaust rates so that the proper amount of make up air can be provided to the said space, whereas UMC section 504.1 is a general requirement that states what material is required and how it is to be installed. Section 504.1 does not give direction on the amount of air that needs to be exhausted by the duct. Additionally, Chapter 6 provides ducts shall be airtight.
2. No that is not correct. Section 504.1 (1) exception applies to the construction of the duct. This would exempt a ductless range hood construction, since there is no duct in this application. UMC section 405.4 states in part: ‘A mechanical exhaust directly to the outdoors shall be provided in each kitchen…’ UMC section 403.7 does state that exhaust make up air shall be permitted to be combination of outdoor air, recirculated air, and transfer air. Even though a ductless range hood is a recirculating exhaust it is still considered exhaust, but it does not satisfy the requirements of UMC section 405.4. Jurisdictions also have different indoor air quality requirements based on the building occupancy and adopted energy code.
2. No that is not correct. Section 504.1 (1) exception applies to the construction of the duct. This would exempt a ductless range hood construction, since there is no duct in this application. UMC section 405.4 states in part: ‘A mechanical exhaust directly to the outdoors shall be provided in each kitchen…’ UMC section 403.7 does state that exhaust make up air shall be permitted to be combination of outdoor air, recirculated air, and transfer air. Even though a ductless range hood is a recirculating exhaust it is still considered exhaust, but it does not satisfy the requirements of UMC section 405.4. Jurisdictions also have different indoor air quality requirements based on the building occupancy and adopted energy code.
UMC 2015 402.1.3
UMC 2018 402.1.3
UMC 2021 404.1.2
Topic: Ventilation in Health Care Facilities
Is section 402.1.3 the correct code section to use for obtaining the minimum ventilation outdoor air rates in dental offices, outpatient walk-in clinics and medical offices?
Yes, this section is correct as occupancies listed in table 402.1 of the (2015/2018/2021) Uniform Mechanical Code are the most common addressed in construction and ASHRAE Standard 170 specifically addresses ventilation in Health Care occupancies. This standard applies to patient care areas and related support areas within health care facilities, including hospitals, nursing facilities, and outpatient facilities as defined under “SCOPE” in Standard 170.
However, although section 402.1.3 of the 2018 UMC states that mechanical ventilation shall be designed and installed in accordance with this code for health care facilities, Table 402.1 does not list minimum ventilation rates for Health Care Facilities or similar occupancies. Please refer to ASHRAE 170 and The Health Care Facilities Code for the design and installation of the mechanical ventilation for health care facilities. Ventilation requirements for healthcare facilities are more complex than requiring a certain amount of ventilation in a space. ASHRAE has published a standard that sets requirements. ANSI/ASHRAE standard 170 has more comprehensive requirements for ventilation, including design parameter requirements. The Facility Guidelines Institute has also incorporated ASHRAE 170 into the design requirements for health care facilities. Minimum ventilation rates for spaces not specified in ASHRAE 170 shall be obtained in ASHRAE 62.1 per ASHRAE 170 7.1.a.2.
However, although section 402.1.3 of the 2018 UMC states that mechanical ventilation shall be designed and installed in accordance with this code for health care facilities, Table 402.1 does not list minimum ventilation rates for Health Care Facilities or similar occupancies. Please refer to ASHRAE 170 and The Health Care Facilities Code for the design and installation of the mechanical ventilation for health care facilities. Ventilation requirements for healthcare facilities are more complex than requiring a certain amount of ventilation in a space. ASHRAE has published a standard that sets requirements. ANSI/ASHRAE standard 170 has more comprehensive requirements for ventilation, including design parameter requirements. The Facility Guidelines Institute has also incorporated ASHRAE 170 into the design requirements for health care facilities. Minimum ventilation rates for spaces not specified in ASHRAE 170 shall be obtained in ASHRAE 62.1 per ASHRAE 170 7.1.a.2.
UMC 2015 N/A
UMC 2018 N/A
UMC 2021 403.7.2
Topic: Enclosed Parking Garages
In regards to 2018 UMC section 403.7.2 are both carbon monoxide and nitrogen dioxide detectors required?
Yes, both are required under the provisions of the 2021 Uniform Mechanical Code section 403.7.2. Mechanical ventilation systems for enclosed parking garages shall operate continuously, unless exception (2) is followed. Both approved automatic carbon monoxide sensing device and a nitrogen dioxide detector shall be used to modulate the ventilation system.
Most newer diesel vehicle exhaust cannot be detected by carbon monoxide detectors. Nitrogen dioxide detectors have been developed which will detect diesel emissions which will solve the concern about diesel vehicle emissions in enclosed parking garages.
Additionally, when an underground parking structure doubles as a loading zone for deliveries, carbon monoxide exposure is the greatest concern when it comes to life safety and health, so it is the principal detector usually applied in the design. These sections of the 2021 UMC address emissions from gasoline powered vehicles and other gases such as nitrogen dioxide that is generated from diesel-fueled delivery vehicles.
The carbon monoxide sensing devices, and nitrogen dioxide detectors may be installed in parallel or as a combined unit.
Most newer diesel vehicle exhaust cannot be detected by carbon monoxide detectors. Nitrogen dioxide detectors have been developed which will detect diesel emissions which will solve the concern about diesel vehicle emissions in enclosed parking garages.
Additionally, when an underground parking structure doubles as a loading zone for deliveries, carbon monoxide exposure is the greatest concern when it comes to life safety and health, so it is the principal detector usually applied in the design. These sections of the 2021 UMC address emissions from gasoline powered vehicles and other gases such as nitrogen dioxide that is generated from diesel-fueled delivery vehicles.
The carbon monoxide sensing devices, and nitrogen dioxide detectors may be installed in parallel or as a combined unit.
UMC 2021 405.4, 405.4.1
Topic: Indoor Air Quality for Residential Occupancies
Can I install an unvented kitchen range hood for my Junior accessory dwelling unit (JADU) based on the following kitchen exhaust code?
405.4 Kitchen Exhaust. A mechanical exhaust directly to the outdoors shall be provided in each kitchen. The fan shall run intermittently (on demand) or continuously. A readily accessible manual control designed to be operated as needed or an automatic control shall be provided for intermittent operations.
405.4.1 Exhaust Rate. For intermittent-controlled operations, the exhaust rate shall be not less than 100 ft3/min (0.047 m3/s) for range hoods or 300 ft3/min (0.141 m3/s) for mechanical exhaust fans including downdraft appliances. and shall be rated for sound at a maximum of 3 sone at greater than or equal to 100 cfm. For continuous operated ventilation, the exhaust rate shall be not less than 5 air changes per hour based on kitchen volume for enclosed kitchens and shall be rated for sound at a maximum of 1.0 sone.
Exception: A vented range hood shall not be required in dwelling unit kitchens equipped with a local mechanical exhaust system installed in accordance with ASHRAE 62.2.
Comment: ASHRAE 62.22 Alternative Compliance Path (for "existing dwelling" = my garage) -I plan to add to two (2) vented (non-fixed) shaded (to reduce direct sunlight and heat) skylights to make it less cavernous and light up the JADU. The tool found in the website below appears to take this extra (skylight) ventilation into account, which could help my case for an unvented kitchen range:
https://www.redcalc.com/ashrae-62-2-alternative-compliance-path/
405.4 Kitchen Exhaust. A mechanical exhaust directly to the outdoors shall be provided in each kitchen. The fan shall run intermittently (on demand) or continuously. A readily accessible manual control designed to be operated as needed or an automatic control shall be provided for intermittent operations.
405.4.1 Exhaust Rate. For intermittent-controlled operations, the exhaust rate shall be not less than 100 ft3/min (0.047 m3/s) for range hoods or 300 ft3/min (0.141 m3/s) for mechanical exhaust fans including downdraft appliances. and shall be rated for sound at a maximum of 3 sone at greater than or equal to 100 cfm. For continuous operated ventilation, the exhaust rate shall be not less than 5 air changes per hour based on kitchen volume for enclosed kitchens and shall be rated for sound at a maximum of 1.0 sone.
Exception: A vented range hood shall not be required in dwelling unit kitchens equipped with a local mechanical exhaust system installed in accordance with ASHRAE 62.2.
Comment: ASHRAE 62.22 Alternative Compliance Path (for "existing dwelling" = my garage) -I plan to add to two (2) vented (non-fixed) shaded (to reduce direct sunlight and heat) skylights to make it less cavernous and light up the JADU. The tool found in the website below appears to take this extra (skylight) ventilation into account, which could help my case for an unvented kitchen range:
https://www.redcalc.com/ashrae-62-2-alternative-compliance-path/
No, section 405.1 if of the 2021 Uniform Mechanical Code is a general regulation and applies to the dwelling unit, however two specific subsections (405.3 Bathrooms and 405.4 Kitchen) require mechanical exhaust at a specified exhaust rate. Refer to section 102.1 which states in part: ‘… Where there is a conflict between a general requirement and a specific requirement, the specific requirement shall prevail’.
The exception in section 405.4.1 the 2021 UMC section 405.4.1 is also limited in that it allows a local mechanical exhaust system installed in accordance with ASHRAE 62.2. A vented non-fixed skylight does not meet this exception by definition or by listing. This exception or consideration may require approval from the local AHJ as they may approve the passive ventilation from the open skylights to meet the intent as stated in ASHRAE 62.2.
The exception in section 405.4.1 the 2021 UMC section 405.4.1 is also limited in that it allows a local mechanical exhaust system installed in accordance with ASHRAE 62.2. A vented non-fixed skylight does not meet this exception by definition or by listing. This exception or consideration may require approval from the local AHJ as they may approve the passive ventilation from the open skylights to meet the intent as stated in ASHRAE 62.2.