Answers and Analysis
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Questions matching UMC Chapter 9
22 results
UMC 2003 904.1.1
UMC 2006 904.1.1
UMC 2009 904.1.1
UMC 2012 904.1.1
Topic: Combustion Air
Is the removal of a door from a mechanical room in a single family dwelling acceptable in accordance with Section 701.3 of the 2006 UMC, to achieve proper combustion air requirements for combing spaces on the same story.
No. Simply removing the door is not adequate. The intent of the code is to provide a permanent opening when combining communicating spaces. In addition to removing the door, the casing and door hardware would also need to be removed and the opening should be finished to provide a permanent opening so that the door cannot be readily installed. If the door to the mechanical room is in a bedroom or bathroom the door cannot be removed and combustion air shall be provided from outdoors as required in Section 904.1 of the UMC (2003/2006/2009).
UMC 2003 904.2
UMC 2006 904.2
UMC 2009 904.2
UMC 2012 904.1.1
Topic: Prohibited Installation
Is other equipment, such as a water heater, considered part of the enclosure? In other words, is it true that other equipment cannot be inside the “enclosing space”?
No. Other equipment, such as water heaters, are not considered to be an integral part of the enclosure. The intent of this section is to provide “clear working space” requirements and not to prohibit other appliances from occupying the same enclosure.
Although a fuel burning appliance must be installed with proper clearance according to its listing, this does not eliminate the requirement of this section for clear working space. The furnace room is still required to be at least 12 inches wider than the furnace. Note: The exception allows a replacement furnace to be installed with lesser clearances as long as it is installed per the listing, proper combustion air is provided per Chapter 7 (2003/2006/2009), and it is first approved by the Authority Having Jurisdiction.
Although a fuel burning appliance must be installed with proper clearance according to its listing, this does not eliminate the requirement of this section for clear working space. The furnace room is still required to be at least 12 inches wider than the furnace. Note: The exception allows a replacement furnace to be installed with lesser clearances as long as it is installed per the listing, proper combustion air is provided per Chapter 7 (2003/2006/2009), and it is first approved by the Authority Having Jurisdiction.
UMC 2003 904.7
UMC 2006 904.7
UMC 2009 904.7
UMC 2012 314.3
Topic: Prohibited Sources
In the 2000 UMC Section 906.6.2 required that an outside or return air for a heating system not be taken where it will pick up objectionable odors, fumes, or flammable vapors, or where it is less than 10 feet above the surface of any abutting public driveway; or where it is in a horizontal position in a sidewalk, street, alley, or driveway. I am unable to locate this requirement in the 2006 UMC. Where is this requirement located in the 2006 UMC?
The provisions of Section 906.6 of the 2000 UMC are not included in the 2006 UMC. However, Section 904.7 states in part “Furnace plenums and air ducts shall be installed in accordance with … NFPA 90B, Standard for the Installation of Warm-Air Heating and Air-Conditioning Systems.” NFPA 90B Section 4.2.3 Continuous Ducts is quoted as: 4.2.3 Continuous Ducts. (A) Return air shall be conducted to the appliance through continuous ducts, except as permitted in 4.2.3(B) through 4.2.3(E). (B) Underfloor spaces shall be permitted to be used as plenums for return of air from rooms directly above, provided that such spaces are cleaned of all combustible material, are tightly enclosed, and are not used for storage or occupancy. (C) Furnaces, boilers, and other heat-producing appliances shall not be installed in a return plenum. (D) Accessible abandoned materials shall be deemed to be storage and shall not be permitted to remain. (E) In a single-story residence, the return air shall be permitted to travel through the first floor living space to the return air inlet on the furnace (see 6.3.3).
Additionally, UMC Section 904.3 (2003/2006/2009) requires that a furnace shall be installed in accordance with the manufacturer’s instructions.
Additionally, UMC Section 904.3 (2003/2006/2009) requires that a furnace shall be installed in accordance with the manufacturer’s instructions.
UMC 2003 904.7
UMC 2006 904.7, see also 312.0
UMC 2009 904.7, see also 311.3(5)
UMC 2012 304.3(5)
Topic: Prohibited Sources
Section 906.6 on prohibited locations of return air from the 2000 UMC seems to have been removed from the 2006 UMC. Has this section been removed from the UMC? Do the restrictions on having return air in the bathroom, kitchen, etc. still apply and if so where can that section be found in the 2006 UMC?
The provisions of Section 906.6 of the 2000 UMC are not included in the 2006 UMC. However, Section 904.7 states in part “Furnace plenums and air ducts shall be installed in accordance with … NFPA 90B, Standard for the Installation of Warm-Air Heating and Air-Conditioning Systems.” NFPA 90B Section 4.2.3 Continuous Ducts is quoted as: 4.2.3 Continuous Ducts. (A) Return air shall be conducted to the appliance through continuous ducts, except as permitted in 4.2.3(B) through 4.2.3(E). (B) Underfloor spaces shall be permitted to be used as plenums for return of air from rooms directly above, provided that such spaces are cleaned of all combustible material, are tightly enclosed, and are not used for storage or occupancy. (C) Furnaces, boilers, and other heat-producing appliances shall not be installed in a return plenum. (D) Accessible abandoned materials shall be deemed to be storage and shall not be permitted to remain. (E) In a single-story residence, the return air shall be permitted to travel through the first floor living space to the return air inlet on the furnace (see 6.3.3).
Additionally, UMC Section 904.3 (2003/2006/2009) requires that a furnace shall be installed in accordance with the manufacturer’s instructions.
Additionally, UMC Section 904.3 (2003/2006/2009) requires that a furnace shall be installed in accordance with the manufacturer’s instructions.
UMC 2003 904.8(C)
UMC 2006 904.8(C)
UMC 2009 904.8(C)
UMC 2012 904.8(3)
Topic: Cooling Coils
Does the UMC prohibit cooling coils (such as DX systems with refrigerant) upstream of the furnace?
The UMC prohibited the installation of a cooling coil upstream of a furnace unless the furnace is specifically listed for such use. Section 904.8(C), 908.8(3)/2012, of the UMC also prohibits refrigeration coils from being installed upstream of a furnace unless the furnace is listed for downstream installation.
UMC 2003 904.10.2.2
UMC 2006 904.10.2.2
UMC 2009 904.10.3
UMC 2012 303.9.3
Topic: Installation of Rooftop Equipment
The UMC appears silent on the length of the guardrail. How long should the guardrail be? I propose it should extend at least 6 feet from any part of the rooftop equipment. What guidance can you give concerning the length of the guardrail?
Although the code is silent on the length of the rail, it would seem reasonable that the guardrail extend the entire length of the equipment as a minimum; although, extending it further would provide additional protection. The Authority Having Jurisdiction should have the final decision on what would be acceptable.
UMC 2003 904.10.2.2
UMC 2006 904.10.2.2
Topic: Installation of Equipment on Roofs
1. Was the intent that each piece of equipment have its own service outlet?
2. Can a single service outlet serve more than one piece of equipment?
3. If the answer to #1 is "no," and the answer to #2 is "yes," is less than 25 feet too far away to be considered adjacent?
4. If the answer to #1 is "no," and the answer to #2 is "yes," is more than 25 feet too far away to be considered adjacent?
2. Can a single service outlet serve more than one piece of equipment?
3. If the answer to #1 is "no," and the answer to #2 is "yes," is less than 25 feet too far away to be considered adjacent?
4. If the answer to #1 is "no," and the answer to #2 is "yes," is more than 25 feet too far away to be considered adjacent?
1. No
2. Yes
3. No
4. Yes
Sections 309.0 (2003), 308.0 (2006), and 309.0 (2009) requires that all equipment regulated by the code shall have a receptacle located within 25 feet of the equipment. This requirement is consistent with Section 210.63 of the 2005 National Electrical Code.
2. Yes
3. No
4. Yes
Sections 309.0 (2003), 308.0 (2006), and 309.0 (2009) requires that all equipment regulated by the code shall have a receptacle located within 25 feet of the equipment. This requirement is consistent with Section 210.63 of the 2005 National Electrical Code.
UMC 2003 904.10.3
UMC 2006 904.10.3
UMC 2009 904.1
UMC 2012 304.2
Topic: Access to Equipment on Roofs
Is there a section in the 2006 Uniform Mechanical Code that requires buildings constructed before its adoption to be brought in compliance? In particular, I am interested in Section 904.10.3 Access to Equipment on Roofs.
No. Section 104.2(2003/2006/2009) and 102.2 (2012) in the UMC states “Mechanical systems lawfully in existence at the time of the adoption of this code may have their use, maintenance, or repair continued if the use, maintenance, or repair is in accordance with the original design and location and no hazard to life, health, or property has been created by such mechanical systems.”
UMC 2003 904.10.3
UMC 2006 904.10.3
UMC 2009 904.1
UMC 2012 304.2.1
Topic: Access to Equipment on Roofs
The 2000 UMC Section 910.8 "Access" requirements and ladder specifications has been removed. Section 904.10.3 (904.10, 2009) "Access to Equipment on Roofs" does not address ladder specifications or requirements except for "shall be accessible" (15 foot rule and clearances from the roof edge is mentioned). Where in the code can I justify a ladder on a building with roof equipment if less than 15 feet?
There are no requirements for permanent access on buildings less than 15 feet in height. The Uniform Mechanical Code only addresses buildings greater than 15 feet. The local AHJ would have to determine what is considered “accessible” in their respective jurisdiction.
UMC 2003 904.10.3.4
UMC 2006 904.10.3.4
UMC 2009 304.1.3
UMC 2012 304.2.2
Topic: Permanent Lighting
In Section 904.10.3.4 (304.1.3, 2009), the light at the roof access, is this to be installed on the interior or exterior of the building?
The light should be installed on the interior of the building to provide adequate lighting for the access means leading to the roof and for the hatch itself. Some hatches have locks that may be difficult to open without proper lighting.
UMC 2006 904.11
UMC 2009 904.11
UMC 2012 904.1
Topic: Dryer Booster Fans
Does the access, outlet and illumination requirements of the UMC for attic equipment extend to dryer booster fans?
Section 904.11 is specific to attic furnaces and would not pertain to a dryer booster fan. Section 503.1 (2003/2006/2009) states that motors and fans must be accessible for servicing. Therefore, adequate access must be determined by the Authority Having Jurisdiction and the manufacturers' installation instructions. Section 309.0 (2003/2006), (308.0, 2009), (310.0, 2012) states that equipment having electrical connections must have a means of disconnect adjacent to and within sight of the equipment served and have a receptacle within 25 feet of the equipment for service and maintenance purposes. Illumination is not specifically addressed for equipment.
UMC 2003 916.1
UMC 2006 916.1
UMC 2009 916.1
UMC 2012 916.1
Topic: Floor-Mounted Appliance Clearance
Section 916.1(b) states that the clearance to metal cabinets above a range can be a minimum of 24 inches if a ventilating hood is installed under the cabinet.
1. Does that mean that the clearance to the range hood can be less than 24 inches?
2. Section 916.1(b) #3 states that a listed microwave can be installed over the range if it conforms to the terms of the manufacturers' instructions. Does that mean that the clearance to the bottom of the microwave must be a minimum of 24 inches?
3. If the manufacturers' instructions allow the microwave to have less than a minimum of 24 inches clearance above the range, is that permissible?
1. Does that mean that the clearance to the range hood can be less than 24 inches?
2. Section 916.1(b) #3 states that a listed microwave can be installed over the range if it conforms to the terms of the manufacturers' instructions. Does that mean that the clearance to the bottom of the microwave must be a minimum of 24 inches?
3. If the manufacturers' instructions allow the microwave to have less than a minimum of 24 inches clearance above the range, is that permissible?
1. No, Section 916.1(B), #2 (916.1.2#2/2012) would require a minimum 24 inches clearance between the cooking surface and the bottom of the hood if the hood meets the requirements of Section 916.1(B), #2.
2. No. The clearance can be less if it is installed per the microwave manufacturer’s listed minimum clearances.
3. Yes
2. No. The clearance can be less if it is installed per the microwave manufacturer’s listed minimum clearances.
3. Yes
UMC 2003 928.3
UMC 2006 928.3
UMC 2009 928.3
UMC 2012 928.3
Topic: Air Supply
Can combustion air for a vented wall furnace be supplied from inside a new single-family structure which is built to meet unusually tight construction requirements?
Yes, only if the combustion air provisions of Section 701.1 (2003/2006/2009/2012) are met.
UMC 2006 931
UMC 2009 904.11
UMC 2012 904.1
Topic: Required Access Openings
Are the openings 30 inches x 30 inches or 30 inches x 22 inches suppose to indicate the “free” area or the “framed” opening? (The “free” area is usually 1/2 inch smaller due to molding or drywall.)
Section 931.0 (904.11, 2009/ 904.10, 2012) of the code requires specific minimum openings which must be maintained after all trim and moldings have been installed for doors and passageways. Note: For the purpose of answering this question, Section 931.0 (904.11, 2009/ 904.10, 2012) was found to contain identical wording as that in Section 319.3 of the 1994 edition.
UMC 2006 931.1
UMC 2009 904.11
UMC 2012 904.1
Topic: Attic Access and Passageway Requirements
1. Does a passageway need 30 inches x 30 inches unobstructed clearance from the attic opening to the mechanical equipment?
2. Does “unobstructed” mean without any box outs or vertical offsets in the passageway and catwalk?
3. Are there any size exceptions to the above questions?
2. Does “unobstructed” mean without any box outs or vertical offsets in the passageway and catwalk?
3. Are there any size exceptions to the above questions?
1. Yes, see Section 931.1 (904.11/2009, 904.10/2012).
2. Yes. The passageway must maintain the above stated dimensions but it could make horizontal or vertical offsets.
3. Yes. The largest piece of equipment in question must be able to be removed through this passageway.
2. Yes. The passageway must maintain the above stated dimensions but it could make horizontal or vertical offsets.
3. Yes. The largest piece of equipment in question must be able to be removed through this passageway.
UMC 2006 931.1
UMC 2009 904.11
UMC 2012 904.1
Topic: Attic Furnaces (Clearances)
Please clarify the intent of Section 931.1 (904.11/2009, 904.10/2012) regarding access openings and passageways.
The code prescribes a minimum opening to the attic equipment of 30 inches x 30 inches but allows 22 inches x 30 inches opening when the equipment may be removed through such an opening. (This allows access penetrations into attics without requiring a joist to be cut when framed on 24 inch centers).
The distance from the opening to the equipment shall not be further than 20 feet when measured along the center of the passageway and should have a minimum 24 inch wide solid floor to walk on. (This is also helpful when joists are spaced on 24 inch centers to allow standard 4 foot deck material to be halved and attached to the 24 inch center joist.)
The passageway shall have clear space of 30 inches x 30 inches. This is an invisible clear space from the opening to the equipment that shall be maintained while traveling on the 24 inch wide solid floor.
The distance from the opening to the equipment shall not be further than 20 feet when measured along the center of the passageway and should have a minimum 24 inch wide solid floor to walk on. (This is also helpful when joists are spaced on 24 inch centers to allow standard 4 foot deck material to be halved and attached to the 24 inch center joist.)
The passageway shall have clear space of 30 inches x 30 inches. This is an invisible clear space from the opening to the equipment that shall be maintained while traveling on the 24 inch wide solid floor.
UMC 2006 904.11
UMC 2009 904.11
UMC 2012 904.1
Topic: Appliances in Attics and Under-floor Spaces
A furnace suspended above a suspended acoustic ceiling. The ceiling is eight feet above the floor. Do all of the requirements of Section 904.11 apply to this type of application?
Comment
I don't think that the intent of the code would allow a service person to work off a ladder.
Comment
I don't think that the intent of the code would allow a service person to work off a ladder.
The area above a suspended acoustic ceiling is considered accessible by the UMC, but not an attic. Equipment can be serviced using ladders or other means. Attic is defined in the Building code.
The Uniform Mechanical Code does not address procedures for safely setting up and utilizing ladders; see the appropriate state and federal regulations.
The Uniform Mechanical Code does not address procedures for safely setting up and utilizing ladders; see the appropriate state and federal regulations.
UMC 2012 919.4
UMC 2015 927.4
Topic: Combustion and Ventilation Air
In the situation of an infra red heater installed in an outdoor patio cover which has a solid roof and in which the side of the patio cover is open on 2 and 3 sides:
1. The heater is installed with the correct distance of 16" from any combustibles. Is a vent required over the heater as described in 919.4(2)?
2. Is there any venting required at all in this situation as the heater is already located in an outdoor area (not livable space).
1. The heater is installed with the correct distance of 16" from any combustibles. Is a vent required over the heater as described in 919.4(2)?
2. Is there any venting required at all in this situation as the heater is already located in an outdoor area (not livable space).
Yes, section 919.4(2) of the Uniform Mechanical Code states that exhaust openings for removing flue products shall be above the level of the heaters, if the openings for natural ventilation are at a level above heater (open walls) then a vent above is not required. Listed infrared outdoor heaters can be ventless in accordance with installation instructions and their listing that is designed to be in an outdoor environment. In an outdoor environment they gather combustion air and expel flue gas exhaust directly into the outdoor environment. If the area can be closed in a way that would cause the accumulation of exhaust fumes from gathering then a vented model would be required.
UMC 2009 905.5(3)
UMC 2012 905.5(3)
UMC 2015 504.4.3.1(3)
UMC 2018 504.4.3.1(3)
Topic: Exhaust Ducts, Type 2 Clothes Dryer
Condition: Multi-family project consisting of 4 levels of apartments and a laundry facility on each level.
Each laundry room contains three Type 2 dryers that are adjacent to exterior wall. The dryer ducts are 24
ga and shall terminate at the exterior wall independently with a backdraft damper.
The noted section states, "Type 2 clothes dryers shall be equipped or installed with lint-controlling
means."
Does a Type 2 dryer equipped with an internal lint filter satisfy the code requirement?
Each laundry room contains three Type 2 dryers that are adjacent to exterior wall. The dryer ducts are 24
ga and shall terminate at the exterior wall independently with a backdraft damper.
The noted section states, "Type 2 clothes dryers shall be equipped or installed with lint-controlling
means."
Does a Type 2 dryer equipped with an internal lint filter satisfy the code requirement?
Yes, a listed Type 2 dryer equipped with a lint filtering system would meet the minimum standards of Section 504.4.3.1 (3) of the 2015 Uniform Mechanical Code.
The manufacturers listing of the equipment might require other means for lint control such as an exhaust fan interlocked with dryer operation and include cleanouts within the exhaust piping.
The manufacturers listing of the equipment might require other means for lint control such as an exhaust fan interlocked with dryer operation and include cleanouts within the exhaust piping.
UMC 2012 924.1.1
UMC 2015 916.2.1.1
UMC 2018 907.1, 907.1.1
UMC 2021 916.2.1.1
Topic: Vent-Free Wall Heaters
Are gas fired, vent-free wall heaters permitted per the UMC?
Yes, unvented wall heaters may be installed in accordance with the manufacturers installation instructions, the terms of their listing requirements, and the strict requirements of section 916.2.1.1 Unvented Room Heaters, and its noted exceptions. Wall heaters shall not be installed in or attached to walls of combustible material unless listed for such installation. Combustion air shall be provided in accordance with Section 701.0.
UMC 2012 905.5
UMC 2015 504.4.3.1
UMC 2018 504.4.3.1
UMC 2021 504.4.3.1
Topic: Exhaust Ducts for Type 2 Clothes Dryers
Since we can't add a damper on a clothes dryer exhaust, is there a specific requirement for clothes dryer exhaust duct (type 2/commercial) that we need to meet?
Comment:
The clothes dryer (Type 2) has a steel exhaust duct, going to the main exhaust shaft as a subduct. The main exhaust shaft is 22-gauge steel. Main exhaust fan up the roof running continuously with pressure sensor. We know we can’t have dampers in a clothes dryer exhaust, so in terms of fire safety concern, is there a specific fire wrap or insulation that we need to add in our exhaust duct? What I can see from UMC 504.4.3.1 we need to have at least 6 inches clearance from the next combustible material, if less, the adjacent combustible material shall be protected, but we only have concrete next to the duct, and the wall penetration going to the main exhaust shaft is also concrete. Per UMC 604.1, we need to insulate our ducts. But are there specific insulation criteria we need to meet and do we need to add protection on the wall penetration, and the concrete wall before the penetration in case the exhaust duct have less than 6 inches clearance.
Comment:
The clothes dryer (Type 2) has a steel exhaust duct, going to the main exhaust shaft as a subduct. The main exhaust shaft is 22-gauge steel. Main exhaust fan up the roof running continuously with pressure sensor. We know we can’t have dampers in a clothes dryer exhaust, so in terms of fire safety concern, is there a specific fire wrap or insulation that we need to add in our exhaust duct? What I can see from UMC 504.4.3.1 we need to have at least 6 inches clearance from the next combustible material, if less, the adjacent combustible material shall be protected, but we only have concrete next to the duct, and the wall penetration going to the main exhaust shaft is also concrete. Per UMC 604.1, we need to insulate our ducts. But are there specific insulation criteria we need to meet and do we need to add protection on the wall penetration, and the concrete wall before the penetration in case the exhaust duct have less than 6 inches clearance.
Yes, section 504.4.3.1 of the 2021 Uniform Mechanical Code states that where ducts pass through walls, floors, or partitions, the space around the duct shall be sealed with a noncombustible material and section 504.4.4 states the common exhaust duct shall be of rigid metal and be installed in a fire-resistant rated enclosure In accordance with the building code. The duct material shall be of rigid metal with a thickness of 0.020 of an inch (24 gauge). The duct enclosure shall be provided with a cleanout opening of not less than 12 inches x 12 inches. Duct wrap is not required and a six inch clearance from adjacent combustible material is only required if The Type II Dryer is unlisted. Ducts that pass through firewalls or fire separations are required to have smoke/fire dampers and cannot pass through corridors, but these ducts do not include dryer exhaust. Committee Response to Comment:
The type of system described in the comment meets the requirements of Section 504.4.4 of the 2021 UMC. Please note that Section 604.1 refers to Furnace Plenums and Air Duct, not exhaust duct for clothes dryers. Any fire protection requirements would be in the Building or Fire Codes. If a fire or fire/smoke damper is required by these codes, any alternative means/methods to their requirements must also be found in the respective codes. The Authority Having Jurisdiction can interpret the building, fire, and mechanical codes, resolve conflicts between codes, and allow alternative materials and methods that are equivalent in safety and fire resistance.
The type of system described in the comment meets the requirements of Section 504.4.4 of the 2021 UMC. Please note that Section 604.1 refers to Furnace Plenums and Air Duct, not exhaust duct for clothes dryers. Any fire protection requirements would be in the Building or Fire Codes. If a fire or fire/smoke damper is required by these codes, any alternative means/methods to their requirements must also be found in the respective codes. The Authority Having Jurisdiction can interpret the building, fire, and mechanical codes, resolve conflicts between codes, and allow alternative materials and methods that are equivalent in safety and fire resistance.
UMC 2015 926.2
UMC 2018 925.1
UMC 2021 925.1
Topic: Factory Built Commercial Crematories
1. Is a factory built commercial crematory, listed in accordance with UL 2790, considered a Class B furnace?
No, this is not considered a Class B furnace. It would be classified as a Class A. An incinerator must comply with UL 2790 and NFPA 86 Standard for Ovens and Furnaces. Based on scope language of NFPA 86, which defines a Class B oven or furnace as, “Class B Furnace: An oven or furnace that has heat utilization equipment wherein there are no flammable volatiles or combustible materials being heated.” Crematory furnaces are used to process the combustible box (coffin) in which a dead body is cremated and turn the organic tissue into ash through the combustion process.