Answers and Analysis
This knowledge base, updated to include the analyses from the 2003 through the most recent editions of the Uniform Plumbing and Mechanical Codes, continues to be a premier source for engineers, inspectors, students, contractors and tradesmen. Questions come from a broad base of users, and answers are informal interpretations of the Codes provided by a committee of code officials and special experts - they are clearly stated and to the point. This updated site combines the most pertinent analyses from the previous manual and presents them together with those based on the most recent publications of the Uniform Codes. This makes the Answers and Analysis database one of the most valuable tools you as a member can access wherever you have an internet connection.
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Questions matching UMC Chapter 11
33 results
UMC 2003 1104.1
UMC 2006 1104.1
UMC 2009 1104.1
UMC 2012 1104.1
Topic: Machinery Room Requirements
Assume a system with a 750 ton water-cooled centrifugal chiller (evaporator, compressor and condenser) with 1085 lbs of R-123 refrigerant charge, chilled and condenser water pumps are located in an enclosed room isolating it from any occupied space. Is this considered a low probability system? If it is, does the system have to comply with only Section 1106.0 and Sections 1110.0 through 1125.0 only? The quantity of refrigerants listed in Table 11-1 are for high probability systems, does not apply to refrigerant machinery rooms (footnote 8) and the example has a B1 safety class refrigerant, a refrigerant machine room is not required. Is this correct?
Although the term “normally occupied space” is not specifically defined in the Uniform Mechanical Code, it has been interpreted by the building code as, “Normally occupied space, which would include all areas of a building that may be occupied and for this purpose, includes those areas which may be occupied on an infrequent basis such as storage rooms and restrooms. “The basis for this is that refrigerant released in a small confined space could overcome an individual entering the room without warning.”
Taking into consideration the definition provided, the space in question would be considered a normally occupied space. Therefore, since the quantity of refrigerant in a single, independent circuit shall not exceed the amounts shown in Table 11-1 (2003/2006/2009) and T1102.2 (2012), it would be considered a high probability system. A refrigeration machinery room would be required per Section 1107.1.1 (2003/2006/2009/2012).
As this is not specifically defined in the UMC, it would be practical to address this with the local Authority Having Jurisdiction
Taking into consideration the definition provided, the space in question would be considered a normally occupied space. Therefore, since the quantity of refrigerant in a single, independent circuit shall not exceed the amounts shown in Table 11-1 (2003/2006/2009) and T1102.2 (2012), it would be considered a high probability system. A refrigeration machinery room would be required per Section 1107.1.1 (2003/2006/2009/2012).
As this is not specifically defined in the UMC, it would be practical to address this with the local Authority Having Jurisdiction
UMC 2003 1105.2
UMC 2006 1105.2
UMC 2009 1105.2
UMC 2012 1105.2
Topic: Volume of Occupied Space
If a packaged rooftop air conditioning unit is serving several small offices, can the total volume of all spaces served be included in the calculation of permissible refrigerant quantities?
Yes, as long as the dampers have a permanent stop allowing not less than one quarter of the area to be closed off.
UMC 2003 1105.2, see also Table 11-1
UMC 2006 1105.2, see also Table 11-1
UMC 2009 1105.2, see also Table 11-1
UMC 2012 1105.2, see also T1102.2
Topic: Volume of Occupied Space
In regards to Section 1105.2, how do we determine compliance for these refrigerants in an air conditioner system and what values do we use for these refrigerants?
Table 11-1, “Refrigerant Groups, Properties and Allowable Quantities,” (T1102.2 (2012)) 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) direct the code user to the proper standard for refrigerants. ASHRAE 34 is a referenced standard and should be used as appropriate.
Note: The 2009 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 standards located in Chapter 17, Part II, UMC (2003/2006/2009/2012) direct the code user to the proper standard for refrigerants. ASHRAE 34 is a referenced standard and should be used as appropriate.
Note: The 2009 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.
UMC 2003 1106.9
UMC 2006 1106.9
UMC 2009 1106.9
UMC 2012 1106.9
Topic: Condensation Control
Does the code require the installation of insulation on refrigerant lines outside of a structure used for condensing units located either at ground level or on the roof?
No. The code does not require insulation on refrigerant lines outside the structure.
UMC 2003 1107.1, see also Table 11-1
UMC 2006 1107.1, see also Table 11-1
UMC 2009 1107.1, see also Table 11-1
UMC 2012 1107.1, see also T1102.2
Topic: Refrigeration Machinery Rooms
Regarding a room containing the refrigerant compressors for a large grocery store:
1. When the refrigerant quantities in a single system exceed the amounts in Table 11-1 for a single system, which would otherwise require a refrigeration machinery room, can the room be designed so that it is open to either the main floor or other areas that are large enough to meet the allowable quantities as shown in Table 11-1 to eliminate the need for the refrigeration machinery room?
2. Does footnote 7 of Table 11-1 indicate that this table, pounds per 1000 cubic feet of occupied space, is not applicable for determining when a refrigeration machinery room is necessary?
1. When the refrigerant quantities in a single system exceed the amounts in Table 11-1 for a single system, which would otherwise require a refrigeration machinery room, can the room be designed so that it is open to either the main floor or other areas that are large enough to meet the allowable quantities as shown in Table 11-1 to eliminate the need for the refrigeration machinery room?
2. Does footnote 7 of Table 11-1 indicate that this table, pounds per 1000 cubic feet of occupied space, is not applicable for determining when a refrigeration machinery room is necessary?
1. Anytime the amount of refrigerant in a system exceeds the allowable amount in Table 11-1, a machinery room is required. Additionally, if an A1 system having an aggregate combined compressor horsepower of 100 (73.55 kW) or more, a machinery room is required. Since the table is based on cubic volume of space, all areas that freely communicate with the space could be used to calculate the volume. The concern would be the size and location of the communicating opening which would have to be determined and approved by the AHJ.
2. No. Footnote 7 clarifies that refrigeration machinery rooms and cooling systems used for human comfort are not subject to being sized based on pounds of refrigerant per cubic foot of space.
2. No. Footnote 7 clarifies that refrigeration machinery rooms and cooling systems used for human comfort are not subject to being sized based on pounds of refrigerant per cubic foot of space.
UMC 2003 1107.1
UMC 2006 1107.1
UMC 2009 1107.1
UMC 2012 1107.1
Topic: Refrigeration Machinery Rooms
The 2006 UMC Section 1107.1 requires a refrigeration machinery room when any of the following conditions exist. Section 1107.1.3 requires an A1 system having an aggregate combined compressor horsepower of 100 (73.55 kW) or more is used.
1. Is it the intent of Section 1107.1.3 to disallow a chiller of 100 horsepower or more using an A1 refrigerant from being located outside the building?
2. Is it the intent of Section 1107.1.3 to require an A1 system of 100 horsepower or more to be located in a refrigeration machinery room only if located inside the building?
1. Is it the intent of Section 1107.1.3 to disallow a chiller of 100 horsepower or more using an A1 refrigerant from being located outside the building?
2. Is it the intent of Section 1107.1.3 to require an A1 system of 100 horsepower or more to be located in a refrigeration machinery room only if located inside the building?
1. Yes. A chiller of 100 horsepower or more shall be provided with a refrigeration machinery room. Section 1107.1.4 states, “Refrigeration machinery rooms shall house all refrigerant-containing portions of the system other than the piping and evaporators permitted by Section 1105.3.”
2. No. Refer to answer 1.
2. No. Refer to answer 1.
UMC 2003 1107.1.1
UMC 2006 1107.1.1
UMC 2009 1107.1.1
UMC 2012 1107.1.1
Topic: Refrigeration Machinery Rooms
Do receivers and accumulators have to be located in a refrigeration machinery room for a refrigeration system using ammonia as the refrigerant where the system contains 35 pounds or more of refrigerant?
Yes. Receivers and accumulators for ammonia systems are considered to be part of the refrigeration system and should be placed in a refrigeration machinery room. The condition that triggers this requirement is the amount of refrigerant in pounds per 1,000 cubic feet of space as outlined in Table 11-1 (T1102.2 (2012)).
UMC 2003 1108.2.3
UMC 2006 1108.2.3
UMC 2009 1108.2.3
UMC 2012 1108.2.3
Topic: Refrigeration Machinery Rooms
Does the code allow you to provide cooling to a refrigeration machinery room in a climate where the outside air may be 105°F or higher?
Yes. The intent of the code is to limit the temperature rise within the machinery room to 104°F and does not specifically preclude the use of a cooling unit to satisfy the requirement.
UMC 2003 1106.12
UMC 2006 1106.12
UMC 2009 1106.12
UMC 2012 1106.12
Topic: Overflows
This section requires provisions for overflow in attics or furred spaces.
1. Does this include units located in closets or on a stand serving as a return air or supply air in the garage, equipment room, or closet located on either the first or second any other floor?
2. Does the structural damage refer to the stand used for return or supply air and does this mean we need to pipe the secondary to a noticed location?
3. Do we need to open a second non trapped opening into the coil section in these locations or should we leave them closed?
Comment
This seems to be a local opinion that needs clarity due to the confusion being spread by various interpretations.
1. Does this include units located in closets or on a stand serving as a return air or supply air in the garage, equipment room, or closet located on either the first or second any other floor?
2. Does the structural damage refer to the stand used for return or supply air and does this mean we need to pipe the secondary to a noticed location?
3. Do we need to open a second non trapped opening into the coil section in these locations or should we leave them closed?
Comment
This seems to be a local opinion that needs clarity due to the confusion being spread by various interpretations.
1. Yes. All interior installations including attics and furred spaces require a secondary drain pan drained to a proper location or approved fixture. The section requires overflow protection for all equipment that produces condensation that would create damage. A “furred space” is to be either an attic/ceiling assembly, floor/ceiling assembly, or a floor/subfloor assembly requiring protection from structural damage.
2. No. Structural damage means any damage to the building. Generally the support system would be noncombustible under section 1106.2 of the 2009 UMC. Section 309.2 (2009), 310.2 (2003/2006), 312.2 (2012) requires a secondary drain line to be ran and discharge at a point that can be readily observed.
3. No. It is not necessary to open the secondary opening, the two openings are used depending on the installation of the AHU, rather it is installed in the vertical or horizontal position. The secondary pan will catch the overflow. If you open the second opening the unit may not drain properly. A standing overflow may be used and the MFG of the equipment may require the secondary drain line to be trapped. The Authority Having Jurisdiction can approve alternate materials and methods as long as they meet the requirements of section 105.0.
2. No. Structural damage means any damage to the building. Generally the support system would be noncombustible under section 1106.2 of the 2009 UMC. Section 309.2 (2009), 310.2 (2003/2006), 312.2 (2012) requires a secondary drain line to be ran and discharge at a point that can be readily observed.
3. No. It is not necessary to open the secondary opening, the two openings are used depending on the installation of the AHU, rather it is installed in the vertical or horizontal position. The secondary pan will catch the overflow. If you open the second opening the unit may not drain properly. A standing overflow may be used and the MFG of the equipment may require the secondary drain line to be trapped. The Authority Having Jurisdiction can approve alternate materials and methods as long as they meet the requirements of section 105.0.
UMC 2012 1109.4
Topic: Emergency Control
Section 1109.4 of the Uniform Mechanical Code states "The switch shall be automatically shutoff where the refrigerant vapor concentration in the machinery room exceeds the vapor detector’s upper detection limit or 25 percent of the LFL, whichever is lower.” This is in regards to the emergency power off switch.
What is the "vapor detector's upper detection limit"?
Is it the highest concentration the detector can sense?
Is it the highest setpoint on the refrigerant monitor?
Or is it something different? If so, what?
What is the "vapor detector's upper detection limit"?
Is it the highest concentration the detector can sense?
Is it the highest setpoint on the refrigerant monitor?
Or is it something different? If so, what?
1. Section 1107.4 of the 2012 Uniform Mechanical Code specifies refrigerant-vapor alarm activation limits, thereby defining the vapor detector’s “upper detection limit ” as the point that the alarms shall be activated where the value not greater than one-half or fifty percent (50%) of the immediately dangerous to life or health (IDLH) level has been detected as per the values listed in Table 11-1 per type of refrigerant, or a measurement consistent therewith; or the permissible exposure level (PEL), or measurement consistent therewith; or 25 percent of the LFL, whichever is less.
PEL, TWA and IDLH are commonly understood as:
PEL- is the 8-hour TWA PEL is the level of exposure established as the highest level of exposure an individual may be exposed to without incurring the risk of adverse health effects.
TWA-Time-Weighted Average for concentrations.
IDLH-Immediately Dangerous to Life and Health (set by the U.S. National Institute of Occupational Safety and Health, NIOSH), the maximum concentration of airborne contaminants, normally expressed as parts per million (ppm), from which one could escape within 30 minutes without a respirator and without experiencing any escape impairing (e.g., severe eye irritation) or irreversible health effects.
2. Refrigerant monitor typically have two or more alarm settings. The first is set at an appropriate level based on the type of refrigerant to detect a concentration low enough to provide early detection in order to minimize refrigerant loss. The upper stage alarm is set at an appropriate level based on the type of refrigerant in order to activate devices such as strobes and horns, activate mechanical room ventilation along with shut down of the chiller.
3. No, it is an activation point of the detector.
4. Yes. See answer 3.
PEL, TWA and IDLH are commonly understood as:
PEL- is the 8-hour TWA PEL is the level of exposure established as the highest level of exposure an individual may be exposed to without incurring the risk of adverse health effects.
TWA-Time-Weighted Average for concentrations.
IDLH-Immediately Dangerous to Life and Health (set by the U.S. National Institute of Occupational Safety and Health, NIOSH), the maximum concentration of airborne contaminants, normally expressed as parts per million (ppm), from which one could escape within 30 minutes without a respirator and without experiencing any escape impairing (e.g., severe eye irritation) or irreversible health effects.
2. Refrigerant monitor typically have two or more alarm settings. The first is set at an appropriate level based on the type of refrigerant to detect a concentration low enough to provide early detection in order to minimize refrigerant loss. The upper stage alarm is set at an appropriate level based on the type of refrigerant in order to activate devices such as strobes and horns, activate mechanical room ventilation along with shut down of the chiller.
3. No, it is an activation point of the detector.
4. Yes. See answer 3.
UMC 2006 1107.1
UMC 2009 1107.1
UMC 2012 1107.1
Topic: Refrigeration Machinery Rooms
Section 1107.1 addresses when a Refrigeration Machinery Room is required. 1107.4.1 states that if the refrigerant used is other than group A1 than a Refrigeration Machinery Room is required. However, it does not clearly address whether or not an outdoor installation of a refrigeration system with a non-type A1 refrigerant would also be acceptable.
Is an outdoor installation of non-A1 refrigerant acceptable as long as the other provisions of the code are met?
Is an outdoor installation of non-A1 refrigerant acceptable as long as the other provisions of the code are met?
No, section 1107.1.4 of the Uniform Mechanical Code states that a refrigeration room is required when the system contains a refrigerant other than a group A1 refrigerant. A refrigeration room is not required if the systems containing a refrigerant other than a group A1 refrigerant meets 1 of the 4 exceptions listed in 1107.1.4.
UMC 2006 1108.8
UMC 2009 1108.8
UMC 2012 1108.8
UMC 2015 1107.8
Topic: Fans
Is Section 1108.8 (2006/2009/2012); 1107.8 (2015) meant to address only fan motors, conduit, and switchgear?
Does this exclude any equipment that remains energized in the event of an emergency stop triggered by ammonia detector per paragraph 1109.4 from conforming with requirements for a Class I, Division I hazardous location? This would include exhaust fan motors if located in the airstream, refrigerant detectors, manual reset switches in the machine room, audible and visual alarms in the machine room, conduit serving these components in the machine room, etc.
Does this exclude any equipment that remains energized in the event of an emergency stop triggered by ammonia detector per paragraph 1109.4 from conforming with requirements for a Class I, Division I hazardous location? This would include exhaust fan motors if located in the airstream, refrigerant detectors, manual reset switches in the machine room, audible and visual alarms in the machine room, conduit serving these components in the machine room, etc.
No. The intent of Section 1108.8 (2006/2009/2012); 1107.8 (2015) is to have all “fans and associated” electrical equipment conform with requirements for a Class I, Division I hazardous location, not limit this section to fan motors, conduit, and switchgear.
UMC 2009 1101.0; 1105.3; 217.0
UMC 2012 1101.1; 1105.3; 217.0
Topic: Volume of Occupied Space
Section 1105.2 (2009/2012) limits the quantity of refrigerant in a single independent refrigerant system.
Section 1105.3 (2009/2012) refers to a Refrigerated Process and Storage Area. There does not appear to be a definition in the code of what these rooms are.
I have a vvt fan coil in a small data room which is served from a large refrigerant system. The volume of refrigerant gas in the system exceeds the allowable limits for that room. Would the exception 1105.3.1 (2009/2012) apply for this room, thereby allowing us to incorporate a refrigerant vapor detection system in lieu of relocating the unit or modifying the space volume?
Section 1105.3 (2009/2012) refers to a Refrigerated Process and Storage Area. There does not appear to be a definition in the code of what these rooms are.
I have a vvt fan coil in a small data room which is served from a large refrigerant system. The volume of refrigerant gas in the system exceeds the allowable limits for that room. Would the exception 1105.3.1 (2009/2012) apply for this room, thereby allowing us to incorporate a refrigerant vapor detection system in lieu of relocating the unit or modifying the space volume?
No. Section 1105.3 (2009/2012) only applies to refrigerated process and storage areas. Section 1101.0 (2009); 1101.1 (2012) states occupied spaces shall be in accordance with Chapter 11; the data room is an occupied space as defined in Section 217.0.
UMC 2009 1102
UMC 2012 1102.1
Topic: Refrigeration Systems
Section 1102.0 (2009); 1102.1 (2012) states that "Except as modified by this code, refrigeration systems shall comply with ASHRAE 15." Under ASHRAE 15, chillers that exceed the thresholds of Section 1107.1 (2009/2012) must be installed in a refrigeration room or OUTDOORS. The uniform mechanical code does not include the word outdoors. Are air-cooled chillers considered an A1 system having an aggregate combined compressor horsepower of 100 (74.6kW) or more allow to be installed outdoors without a refrigeration room so long as they are installed not less than 20 feet from building openings or intakes?
No. The intent of Section 1102.0 (2009); 1102.1 (2012) is that an A1 system having an aggregate combined compressor horsepower of 100 or more shall be provided with a refrigeration machinery room.
Section 103.2 (2009); 101.3.1 (2012) states “Where, in a specific case, different sections of this code or referenced standards specify different materials, methods of construction, or other requirements, the most restrictive shall govern as determined by the Authority having Jurisdiction…” Section 1107.1 (2009/2012) requires machinery rooms to house all refrigerant containing portions of the system except piping and evaporators permitted by Section 1105.3 (2009/2012), discharge piping required by chapter 11 and cooling towers along with their essential piping. Therefore, while ASHRAE 15 is referenced in Section 1102.0 (2009); 1102.1 (2012), the specific code language reads in part: “Except as modified by this code, refrigeration systems shall comply with ASHRAE15….” And the more restrictive provisions of the UMC shall prevail.
Section 103.2 (2009); 101.3.1 (2012) states “Where, in a specific case, different sections of this code or referenced standards specify different materials, methods of construction, or other requirements, the most restrictive shall govern as determined by the Authority having Jurisdiction…” Section 1107.1 (2009/2012) requires machinery rooms to house all refrigerant containing portions of the system except piping and evaporators permitted by Section 1105.3 (2009/2012), discharge piping required by chapter 11 and cooling towers along with their essential piping. Therefore, while ASHRAE 15 is referenced in Section 1102.0 (2009); 1102.1 (2012), the specific code language reads in part: “Except as modified by this code, refrigeration systems shall comply with ASHRAE15….” And the more restrictive provisions of the UMC shall prevail.
UMC 2006 1132.0
UMC 2009 1132.0
UMC 2012 1132.0
UMC 2015 1124
Topic: Electrical
Regarding Section 1132.0 (2003/2006/2009/2012); 1124.0 (2015) Electrical :
1. What is the objective definition of “excessive” in this context?
2. Does shutoff mean stopping a fan through a control signal or safely disconnecting the fan motor from power?
3. Background on the intent of this requirement.
1. What is the objective definition of “excessive” in this context?
2. Does shutoff mean stopping a fan through a control signal or safely disconnecting the fan motor from power?
3. Background on the intent of this requirement.
1. Excessive in this context would mean vibration above and beyond the normal operation of the equipment or system that could have potential effect on the equipment or its performance. Any vibration that would cause a disturbance of any type throughout said piece of equipment includes but is not limited to noise. An example of such a situation would be a fan blade that may be out of balance due to a loose connection or damage.
2. Shutoff would mean active control switch through which the fan would disengage from the power and stop working upon sensing excessive vibration.
3. This section of the Uniform Mechanical Code was originally adopted into the 1994 edition of the UMC. The original intent was to provide fans with vibration detector switches to shut down out of balance wheels.
2. Shutoff would mean active control switch through which the fan would disengage from the power and stop working upon sensing excessive vibration.
3. This section of the Uniform Mechanical Code was originally adopted into the 1994 edition of the UMC. The original intent was to provide fans with vibration detector switches to shut down out of balance wheels.
UMC 2015 1106.1.4
Topic: Refrigerant Machinery Rooms
Is there an exception for small quantities of non-A1 refrigerants, so that a refrigeration machinery room is not required?
No, there is no exception for small quantities.
UMC 2009 1106.8
UMC 2012 1106.8
UMC 2015 1105.6
UMC 2018 1105.6
Topic: Prohibited Locations
Why are refrigeration systems or parts thereof prohibited from being located within required exit enclosure?
Required exit enclosures provide a means of safe egress for occupants from a building to the outside in case of an emergency. This section of the Uniform Mechanical Code also provides for the protection of equipment and piping that may be subject to damage located within the path of travel. Leaking refrigerants can be flammable and toxic to occupants. The building code also proscribes specific requirements for ventilation within an exit enclosure. Refrigeration is comfort cooling and not ventilation for smokeproof enclosures.
UMC 2006 1107.5
UMC 2015 1106.5
UMC 2018 1106.5
Topic: Separation
Why is a ‘refrigeration machinery room’ required to be separated from other portions of the building?
This requirement under section 1107.5 of the 2006 Uniform Mechanical Code provides for a measure of safety based on the potential level of hazard created by the toxicity or flammability of refrigerants used in the equipment within the machinery room as required by the building code.
UMC 2009 1111.3
UMC 2012 1111.3
UMC 2015 1109.7
UMC 2018 1109.7
Topic: Pipe Enclosure
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.
UMC 2012 1107.1.3
UMC 2015 1106.1.3
UMC 2018 1106.1.3
Topic: A1 System
Does UMC Section 1106.1.3 apply if the compressor horsepower connected to the independent refrigerant circuit when the refrigerant quantity referenced in Section 1106.1.1 is under 100 HP?
To meet the condition of exception as outlined in 1106.1, the A-1 system would be required to have an aggregate combined compressor horsepower of under 100. The horsepower of a refrigeration system is determined as defined under Section 220.0 of the 2015 Uniform Mechanical Code. The reason for the requirement for an enclosure in a machinery room is to limit the amount of refrigerant that could escape into occupied areas from a single break.
UMC 2015 1104.2.2, 1104.2.3.1
UMC 2018 1104.2.2, 1104.2.3.1
Topic: Non Connecting Spaces, Closures
1. Is a door that can be closed considered a permanent opening for compliance with 1104.2.1 Volume Calculations?
2. How should the size and location of a permanent opening or duct be calculated?
2. How should the size and location of a permanent opening or duct be calculated?
(1) No, the door could be closed at any time and therefore would not be considered a permanent opening.
(2) By calculating the volume of the permanent opening or the duct.
Section 1104.2.2 of the 2015 Uniform Mechanical Code states calculations are based on the volume of the occupied spaces through permanent openings. Additionally, sections 1104.2.3.1, 1104.2.3.2, and section 1104.2.3.3 provides that the volume of supply, return ducts and plenums can be used if smoke dampers, fire dampers, and combination smoke and fire dampers only close in an emergency not associated with a refrigerant leak.
(2) By calculating the volume of the permanent opening or the duct.
Section 1104.2.2 of the 2015 Uniform Mechanical Code states calculations are based on the volume of the occupied spaces through permanent openings. Additionally, sections 1104.2.3.1, 1104.2.3.2, and section 1104.2.3.3 provides that the volume of supply, return ducts and plenums can be used if smoke dampers, fire dampers, and combination smoke and fire dampers only close in an emergency not associated with a refrigerant leak.
UMC 2012 1109.1
UMC 2015 1108.1
UMC 2018 1108.1
UMC 2021 1108.1
Topic: Refrigeration Machinery Room Equipment and Controls
Is the intent of this code specifically geared toward reducing the hazard present due to flammable refrigerants?
The intent of this code is to reduce the hazard due to toxicity and flammable refrigerants. It is not just flammable refrigerants. It is also because of the toxicity and corrosiveness of the (some) refrigerants. Also, to keep any material or other people that would not need to be in that room out. Additional equipment or appurtenances in a machinery room can increase the potential for a safety hazard for an individual needing safe entrance and exit while occupying and working in a refrigerant machinery room. The code currently does not take exception to non-toxic and non-flammable refrigerants.
UMC 2018 1107.1.7.2
UMC 2021 1107.1.7.2
Topic: Refrigeration Detectors
What is meant by "upper detection limit of the refrigerant detector"?? is this the highest concentration the detector can accurately detect, or does it mean something else?
Yes, the definition is correct. The upper detection limit is the highest concentration that the refrigerant detector can reliably detect, which should be determine by the manufacturer of the unit.
At either 25% of the LFL or the upper detection limit, whichever value is lower would cause de-energizing of the listed equipment in the machinery room.
For example, if the maximum limit of the detector is 30% you would need to use 25% of LFL. If the maximum limit of the detector is 22% you would use 22% of the LFL. It is the maximum limit SET POINT of the detector.
At either 25% of the LFL or the upper detection limit, whichever value is lower would cause de-energizing of the listed equipment in the machinery room.
For example, if the maximum limit of the detector is 30% you would need to use 25% of LFL. If the maximum limit of the detector is 22% you would use 22% of the LFL. It is the maximum limit SET POINT of the detector.
UMC 2018 1106.8
UMC 2021 1106.8
Topic: Maximum Temperature
1. Why is the temperature in machinery rooms limited to 104°F?
2. Are there alternates means to achieve compliance?
3. Isn't 1106.3(2) at 122°F contradictory to 1106.8?
2. Are there alternates means to achieve compliance?
3. Isn't 1106.3(2) at 122°F contradictory to 1106.8?
1. Because of the heat generated by the refrigeration equipment, the room temperature needs to remain at a temperature limited to 104°F. This prescriptive requirement is for the machinery to operate at its optimum, as latent heat loads may affect the design of refrigerants and oils used for lubrication of the equipment the temperature is limited.
2. The code does not offer any exceptions to this. This is to be addressed by the design of the machinery room ventilation to maintain a safe temperature and where natural ventilation cannot provide the required temperature, then mechanical ventilation is required.
3. No, this is a total of the 104°F limit addressed earlier plus and the limit of 18°F d temperature rise allowed by incoming air introduced into the machinery room for the entry of authorized personnel.
2. The code does not offer any exceptions to this. This is to be addressed by the design of the machinery room ventilation to maintain a safe temperature and where natural ventilation cannot provide the required temperature, then mechanical ventilation is required.
3. No, this is a total of the 104°F limit addressed earlier plus and the limit of 18°F d temperature rise allowed by incoming air introduced into the machinery room for the entry of authorized personnel.
UMC 2012 1109.1, 1109.2
UMC 2015 1108.1
UMC 2018 1108.1
UMC 2021 1108.1
Topic: Refrigeration Machinery Room Equipment and Controls General
In regard to a Chiller Refrigeration Machinery Room, may Electrical Equipment that serves the Chiller and also other Equipment in the building reside in the same room as the chiller?
Comment:
We have a Chiller Refrigeration Machinery Room with a Natural Gas Fired Water Cooled Chiller that uses R-134A (Safety Group A1. The room also contains various Electrical Equipment for the building, including the main breaker, Automatic Transfer Switch, and the
460 Volt to 120 Volt Transformer that then serves the Chiller. Per UMC 1109.2 the Electrical Equipment install meets the Electrical Code. However, the State Inspector is citing 1109.1
and has indicated that extra electrical equipment may not be in the same room as the Chiller. The City Building inspector is completely fine with the install.
Comment:
We have a Chiller Refrigeration Machinery Room with a Natural Gas Fired Water Cooled Chiller that uses R-134A (Safety Group A1. The room also contains various Electrical Equipment for the building, including the main breaker, Automatic Transfer Switch, and the
460 Volt to 120 Volt Transformer that then serves the Chiller. Per UMC 1109.2 the Electrical Equipment install meets the Electrical Code. However, the State Inspector is citing 1109.1
and has indicated that extra electrical equipment may not be in the same room as the Chiller. The City Building inspector is completely fine with the install.
Yes, Electrical Equipment that serves the Chiller and also other Equipment in the building may reside in the same room as the chiller, provided the refrigerant is Group A1. The electrical equipment that serve the chiller room needs to meet section 1109.2 of the 2012 Uniform Mechanical Code.
Electrical equipment that is essential for the refrigeration process, maintenance of the equipment, or for the illumination of the room can be placed in the machinery room as long as the electrical equipment complies with the electrical code, whereas electrical equipment that serves solely other parts of a building cannot be placed in a machinery room. As stated in the comment the chiller uses a safe refrigerant classed A-1 and most of the equipment listed serves the refrigeration process in one way or another therefore the Authority Having Jurisdiction deemed them safe and essential to the process, Exclusion would be applied to equipment, piping, ducts, vents, or similar devices that are not essential for the refrigeration process. If it is not essential for the chiller room it clearly states that it shall not be in the chiller room under the provisions of section 1109.1 of the 2012 Uniform Mechanical Code. In describing this specific Refrigeration Machinery Room the equipment serves both the chiller and other equipment in the building.
Sections 1108.8, 1109.1 and 1109.2 of the 2012 Uniform Mechanical Code state that the machinery rooms with Safety Group A1 or B1 refrigerants are not required to be classified as a Class1, Division1 hazardous location; and when other refrigerants are used, instances the machinery room would be considered either a Class1, Division1 or Class1, Division 2 hazardous location for the fans and associated equipment to operate the emergency purge of the machinery room.
The flammability ratings increase in Safety Group A2 and A3, or B2 refrigerants; while both the flammability along with the toxicity increase in the Safety Group B3 refrigerants. The intent of the UMC is to recognize the use of certain refrigerants if properly treated are not necessarily any more dangerous to work in than other locations. In those machinery rooms where other than Safety Group A1 or B1 refrigerants are used, the electrical components of the fans and associated equipment to operate the emergency purge of the machinery room would need to intrinsically safe.
Electrical equipment that is essential for the refrigeration process, maintenance of the equipment, or for the illumination of the room can be placed in the machinery room as long as the electrical equipment complies with the electrical code, whereas electrical equipment that serves solely other parts of a building cannot be placed in a machinery room. As stated in the comment the chiller uses a safe refrigerant classed A-1 and most of the equipment listed serves the refrigeration process in one way or another therefore the Authority Having Jurisdiction deemed them safe and essential to the process, Exclusion would be applied to equipment, piping, ducts, vents, or similar devices that are not essential for the refrigeration process. If it is not essential for the chiller room it clearly states that it shall not be in the chiller room under the provisions of section 1109.1 of the 2012 Uniform Mechanical Code. In describing this specific Refrigeration Machinery Room the equipment serves both the chiller and other equipment in the building.
Sections 1108.8, 1109.1 and 1109.2 of the 2012 Uniform Mechanical Code state that the machinery rooms with Safety Group A1 or B1 refrigerants are not required to be classified as a Class1, Division1 hazardous location; and when other refrigerants are used, instances the machinery room would be considered either a Class1, Division1 or Class1, Division 2 hazardous location for the fans and associated equipment to operate the emergency purge of the machinery room.
The flammability ratings increase in Safety Group A2 and A3, or B2 refrigerants; while both the flammability along with the toxicity increase in the Safety Group B3 refrigerants. The intent of the UMC is to recognize the use of certain refrigerants if properly treated are not necessarily any more dangerous to work in than other locations. In those machinery rooms where other than Safety Group A1 or B1 refrigerants are used, the electrical components of the fans and associated equipment to operate the emergency purge of the machinery room would need to intrinsically safe.
UMC 2021 1106.1
Topic: Refrigeration Machinery Room
Can you please provide an explanation of why a refrigeration machinery room is required when all of the following conditions exist?
1. 1106.1.1 Exceed Quantities of table 1102.3
2. 1106.1.2 Equipment: Direct and indirect fire absorption
3. 1106.1.3 Horsepower compressor in excess of 100
4. 1106.1.4 Refrigerant system contains other than Group A1 refrigerant
If only one condition exist, such as only exceeding the quantities of table 1102.3 does a refrigeration machinery room is or not required?
1. 1106.1.1 Exceed Quantities of table 1102.3
2. 1106.1.2 Equipment: Direct and indirect fire absorption
3. 1106.1.3 Horsepower compressor in excess of 100
4. 1106.1.4 Refrigerant system contains other than Group A1 refrigerant
If only one condition exist, such as only exceeding the quantities of table 1102.3 does a refrigeration machinery room is or not required?
1. Refrigeration systems located indoors are required to be in a machinery room if any of the conditions in the 2021 Uniform Mechanical Code sections 1106.1.1 thru 1106.1.4 exist. The exception being located outdoors. This requirement is for containment, evacuation, proper alarming, and safe handling of refrigerants.
This requirements provide for a measure of safety based on the potential level of hazard created by the toxicity or flammability of refrigerants used in the equipment within the machinery room as required by the building code.
Anytime the amount of refrigerant in a system exceeds the allowable amount in Table 1102.3 a machinery room is required. Since the Table is based on cubic volume of space, all areas that freely communicate with the space could be used to calculate the volume.
The reason for the requirement for an enclosure in a machinery room when the aggregate combined compressor horsepower is over 100, is to limit the amount of refrigerant that could escape into occupied areas from a single break.
Section 1106.1.4 of the 2021 UPC states that a refrigeration room is required when the system contains a refrigerant other than a group A1 refrigerant. A refrigeration room is not required if the systems containing a refrigerant other than a group A1 refrigerant meets 1 of the 2 exceptions listed in 1106.1.4.
2. If any one, or a combination of conditions outlined in this section would require a machinery room for the equipment.
This requirements provide for a measure of safety based on the potential level of hazard created by the toxicity or flammability of refrigerants used in the equipment within the machinery room as required by the building code.
Anytime the amount of refrigerant in a system exceeds the allowable amount in Table 1102.3 a machinery room is required. Since the Table is based on cubic volume of space, all areas that freely communicate with the space could be used to calculate the volume.
The reason for the requirement for an enclosure in a machinery room when the aggregate combined compressor horsepower is over 100, is to limit the amount of refrigerant that could escape into occupied areas from a single break.
Section 1106.1.4 of the 2021 UPC states that a refrigeration room is required when the system contains a refrigerant other than a group A1 refrigerant. A refrigeration room is not required if the systems containing a refrigerant other than a group A1 refrigerant meets 1 of the 2 exceptions listed in 1106.1.4.
2. If any one, or a combination of conditions outlined in this section would require a machinery room for the equipment.
UMC 2018 1106.2
Topic: Refrigeration Machinery Room Ventilation
Does the requirement for a machinery room mean that "ALL" four specified conditions must exist or just "ANY" one specified condition must exists?
Comment: For example I have a chiller that does not exceed the quantity of refrigerant allowed on Table 1102.2 but the chiller is 300HP. As you will see there is a difference from 2000 UMC verbiage and 2012 & 2015 verbiage. This does throw us a curve since the 2000 UMC clearly indicates as long as one of the conditions exists the machinery room is required but the 2012 & 2015 code leads to the conclusion that conditions 1107.1.1 through 1107.1.4 must exist. If the machinery room is large enough as per Table 1102.2 to allow the refrigerant to dissipate without requiring a vapor alarm does that mean that no alarm has to be installed? If alarm is not required then is the Emergency ventilation and emergency controls required? Emergency equipment is triggered by vapor alarm system. 2012 & 2015 UMC 1107.1
Where Required. Refrigeration systems shall be provided with a refrigeration machinery room where the "CONDITIONS" as outlined in Section 1107.1.1 through Section 1107.1.4 exist. 1107.1.1 Quantity. The quantity of refrigerant in a single, independent refrigerant circuit of a system exceeds the amounts of Table 1102.2. 1107.1.2 Equipment. Direct- and indirect-fired absorption equipment is used. Exceptions: Direct and indirect-fired lithium bromide absorption systems using water as the refrigerant. 1107.1.3 A1 System. An A1 system having an aggregate combined compressor horsepower of 100 (74.6 kW) or more is used. 1107.1.4 A1 Refrigerant. The system contains other than a Group A1 refrigerant. Exceptions: (1) Lithium bromide absorption systems using water as the refrigerant. (2) Ammonia-water absorption unit systems installed outdoors, provided that the quantity of refrigerant in a single system does not exceed Table 1102.2 amounts and the discharge is shielded and dispersed. (3) Systems containing less than 300 pounds (136.1 kg) of refrigerant R-123 and located in an approved exterior location. (4) Systems containing less than 35 pounds (15.9 kg) of refrigerant R-717 and located in an approved exterior location. Refrigeration machinery rooms shall house refrigerant containing portions of the system other than the piping and evaporators permitted by Section 1105.3, discharge piping required of this chapter, and cooling towers regulated by Part II of this chapter, and their essential piping.
2000 UMC 1107.1 When Required. Refrigeration systems shall be provided with a refrigeration machinery room when "ANY" of the following conditions exist: 2006 UMC Commentary Three (3) levels or types of physical exposure are of concern in regard to the hazards of refrigerants. The first of these is defined as "Permissible Exposure Limit" (PEL). This is the amount of an airborne refrigerant that may cause harmful effects when there is excessive exposure. The second level would include products that are "Immediately Dangerous to Life or Health" (IDLH). A refrigerant alarm system is required that will give both an audible and a visual indication when the concentration of a product identified as an IDLH nears the 50 percent concentration level. Third on the list are those refrigerants that have an explosive or flammability limit. Concentrations in excess of the "lower flammability limit" (LFL) are considered to be hazardous and are to be avoided. The code addresses each of the unique concerns associated with these products and stipulates a variety of remedial requirements, ranging from installation of signal alarms and automatic shutdowns to provision of continuous ventilation within the machinery room. NEW verbiage in the 2018 UMC 1106.2 Refrigeration Machinery Room, General Requirements. Where a refrigeration system is located indoors and a machinery room is required in accordance with Section 1106.1 , the machinery room shall be in accordance
with Section 1106.2.1 through Section 1106.2.5 .2.
Comment: For example I have a chiller that does not exceed the quantity of refrigerant allowed on Table 1102.2 but the chiller is 300HP. As you will see there is a difference from 2000 UMC verbiage and 2012 & 2015 verbiage. This does throw us a curve since the 2000 UMC clearly indicates as long as one of the conditions exists the machinery room is required but the 2012 & 2015 code leads to the conclusion that conditions 1107.1.1 through 1107.1.4 must exist. If the machinery room is large enough as per Table 1102.2 to allow the refrigerant to dissipate without requiring a vapor alarm does that mean that no alarm has to be installed? If alarm is not required then is the Emergency ventilation and emergency controls required? Emergency equipment is triggered by vapor alarm system. 2012 & 2015 UMC 1107.1
Where Required. Refrigeration systems shall be provided with a refrigeration machinery room where the "CONDITIONS" as outlined in Section 1107.1.1 through Section 1107.1.4 exist. 1107.1.1 Quantity. The quantity of refrigerant in a single, independent refrigerant circuit of a system exceeds the amounts of Table 1102.2. 1107.1.2 Equipment. Direct- and indirect-fired absorption equipment is used. Exceptions: Direct and indirect-fired lithium bromide absorption systems using water as the refrigerant. 1107.1.3 A1 System. An A1 system having an aggregate combined compressor horsepower of 100 (74.6 kW) or more is used. 1107.1.4 A1 Refrigerant. The system contains other than a Group A1 refrigerant. Exceptions: (1) Lithium bromide absorption systems using water as the refrigerant. (2) Ammonia-water absorption unit systems installed outdoors, provided that the quantity of refrigerant in a single system does not exceed Table 1102.2 amounts and the discharge is shielded and dispersed. (3) Systems containing less than 300 pounds (136.1 kg) of refrigerant R-123 and located in an approved exterior location. (4) Systems containing less than 35 pounds (15.9 kg) of refrigerant R-717 and located in an approved exterior location. Refrigeration machinery rooms shall house refrigerant containing portions of the system other than the piping and evaporators permitted by Section 1105.3, discharge piping required of this chapter, and cooling towers regulated by Part II of this chapter, and their essential piping.
2000 UMC 1107.1 When Required. Refrigeration systems shall be provided with a refrigeration machinery room when "ANY" of the following conditions exist: 2006 UMC Commentary Three (3) levels or types of physical exposure are of concern in regard to the hazards of refrigerants. The first of these is defined as "Permissible Exposure Limit" (PEL). This is the amount of an airborne refrigerant that may cause harmful effects when there is excessive exposure. The second level would include products that are "Immediately Dangerous to Life or Health" (IDLH). A refrigerant alarm system is required that will give both an audible and a visual indication when the concentration of a product identified as an IDLH nears the 50 percent concentration level. Third on the list are those refrigerants that have an explosive or flammability limit. Concentrations in excess of the "lower flammability limit" (LFL) are considered to be hazardous and are to be avoided. The code addresses each of the unique concerns associated with these products and stipulates a variety of remedial requirements, ranging from installation of signal alarms and automatic shutdowns to provision of continuous ventilation within the machinery room. NEW verbiage in the 2018 UMC 1106.2 Refrigeration Machinery Room, General Requirements. Where a refrigeration system is located indoors and a machinery room is required in accordance with Section 1106.1 , the machinery room shall be in accordance
with Section 1106.2.1 through Section 1106.2.5 .2.
Section 1106.0 of the 2018 Uniform Mechanical Code requires a machinery room when any of these four listed conditions exist with the exception of the equipment being outdoors or other specific exceptions listed under equipment and refrigerants in sections 1106.1.2, and 1106.1.4. This is spelled out in section 1106.1. If one of the items exist, you would need a dedicated machinery room.
Revisions to the UMC from the 2015 to the 2018 code did not substantively change the requirements of these sections; they are intended to make them clearer and easier to implement. The new exception in section 1106.1 of the 2018 UMC is consistent with section 7.4 of ANSI/ASHRAE Standard 15-2016, which states in part ‘All components containing refrigerant shall be located either in a machinery room or outdoors…’ with reference to sections 7.2 and 7.3 along with Table 7.4 of that standard.
Revisions to the UMC from the 2015 to the 2018 code did not substantively change the requirements of these sections; they are intended to make them clearer and easier to implement. The new exception in section 1106.1 of the 2018 UMC is consistent with section 7.4 of ANSI/ASHRAE Standard 15-2016, which states in part ‘All components containing refrigerant shall be located either in a machinery room or outdoors…’ with reference to sections 7.2 and 7.3 along with Table 7.4 of that standard.
UMC 2021 1104.2
Topic: Refrigerant Concentration Limit
If the provisions for exception 1 of section 1104.2 are met, does one need to comply with table 1102.3?
No, one does not need to comply with table 1102.3. However, the listed equipment shall contain no more than 6.6lbs of refrigerant. This would be complaint per section 1104.2, exception 1, of the 2021 Uniform Mechanical Code .Equipment which is installed in accordance with its listing and manufacturer’s installation instructions meeting the provision by capacity would be exempt provided its installation did not violate any other UMC requirements throughout the code.
UMC 2021 1104.6
Topic: Applications for Human Comfort and for Nonindustrial Occupancies.
Does section 1104.6 allow A2L refrigerants to be used on non-industrial occupancies including residential?
No, section 1104.6 of the 2021 Uniform Mechanical Code does not specifically prohibit the use of A2L Refrigerants in residential occupancies, but states they shall not be used in high-probability systems for human comfort.
UMC 2021 1105.3
Topic: Refrigeration Access
Where an indoor refrigerant fan coil (evaporator coil, txv, blower, filter) is installed in a non-rated attic, is it required to provide a minimum 30"x30"x30" accessible opening and passageway?
Yes, under the provisions of 2021 Uniform Mechanical Code Section 1105.3 Exception 2 access to the equipment is permitted through an unobstructed space not less than 30x30 inches with an unobstructed height of 30 inches for repair, service and replacement of air filters, brine control, stop valves, fan motors or drives, and remotely de-energized electrical connections. Additional accessiblity provisions can be found in chapter 3.
UMC 2021 1109.3
Topic: Penetration of Piping
According to section 1104.2 exception (1) states, “Listed equipment containing not more than 6.6 pounds (2.99 kg) of refrigerant, regardless of the refrigerant safety classification, provided the equipment is installed in accordance with the listing and with the manufacturer’s installation instructions.” removing the need to comply with table amounts listed in 1102.3, except as provided in section 1104.3 and 1104.4.
If a concentration limit meets the exceptions of section 1104.2 how does this apply to section 1109.3 exception (4)?
Comment: Section 1109.3 provides exceptions (4) states “Penetrations of a direct system where the refrigerant concentration does not exceed that listed in Table 1102.3 for the smallest occupied space through which the refrigerant piping passes.”
If a concentration limit meets the exceptions of section 1104.2 how does this apply to section 1109.3 exception (4)?
Comment: Section 1109.3 provides exceptions (4) states “Penetrations of a direct system where the refrigerant concentration does not exceed that listed in Table 1102.3 for the smallest occupied space through which the refrigerant piping passes.”
These are separate and distinct sections of the 2021 Uniform Mechanical Code. Section 1104.2 pertains to the actual equipment (chiller). UMC Section 1109.3 is referring the piping going through penetrations from the equipment. Both comments are correct for each use.
Small volume systems meet the exception to the prohibition of refrigerant piping penetrating floors, ceilings or roofs, which minimizes the risk to health and life safety in the event of a piping leak.
Piping penetrations of a direct system that do not exceed the limits listed in Table 1102.3 and meet manufacturer’s listing and installation requirements are compliant for the smallest occupied space through which the refrigerant piping passes through regardless of the refrigerant safety class as per section 1109.3 exception(4).
Small volume systems meet the exception to the prohibition of refrigerant piping penetrating floors, ceilings or roofs, which minimizes the risk to health and life safety in the event of a piping leak.
Piping penetrations of a direct system that do not exceed the limits listed in Table 1102.3 and meet manufacturer’s listing and installation requirements are compliant for the smallest occupied space through which the refrigerant piping passes through regardless of the refrigerant safety class as per section 1109.3 exception(4).
UMC 2021 1104.1
Topic: System Selection
Table 1104.1 indicates only A1 refrigerants are allowed for R-2 occupancies but the EPA will no longer allow A1 HFC refrigerants in about a year and a half. The industry is transitioning to A2L refrigerants for unitary products. Will IAPMO revise table adding more refrigerant classifications?
IAPMO employs a voluntary consensus development process accredited by the American National Standards Institute (ANSI), gathering the largest assembly of plumbing and mechanical experts in the world at its annual education and business conference and technical committee meetings, enabling anyone — members and non-members alike — to have a voice on proposed changes to the code.
On May 1, 2023 IAPMO published the 2024 edition of the UMC, which included new requirements for refrigeration machinery rooms where A2L and B2L refrigerants are used. IAPMO through its consensus process will continue to adapt to industry changes and update standards once they are approved and make them available in future code cycles or through issuance of TIAs
On May 1, 2023 IAPMO published the 2024 edition of the UMC, which included new requirements for refrigeration machinery rooms where A2L and B2L refrigerants are used. IAPMO through its consensus process will continue to adapt to industry changes and update standards once they are approved and make them available in future code cycles or through issuance of TIAs
UMC 2021 1109.4.1
Topic: Protection from mechanical damage
The code section says refrigerant piping shall not be installed in means of egress per ASHRAE 15:8.10.2. ASHRAE has amended and eliminated 15:8.10.2 such that now 15:9.12.1.3 governs prohibited locations for refrigerant piping under that ASHRAE 15 standard (see attachment). Will this be amended in the UMC?
Comment: The definition of a corridor under the 2021 IBC is an enclosed exit access component that defines and provides a path of egress travel. Following the definition of a corridor and ASHRAE 15:9.12.1.3, we can locate refrigerant piping within a corridor (means of egress) as long as its concealed.
Comment: The definition of a corridor under the 2021 IBC is an enclosed exit access component that defines and provides a path of egress travel. Following the definition of a corridor and ASHRAE 15:9.12.1.3, we can locate refrigerant piping within a corridor (means of egress) as long as its concealed.
The language in section 1109.4.1 of the 2021 Uniform Mechanical Code was extracted from the reference ASHRAE document during the code development process. IAPMO employs a voluntary consensus development process accredited by the American National Standards Institute (ANSI), gathering the largest assembly of plumbing and mechanical experts in the world at its annual education and business conference and technical committee meetings, enabling anyone — members and non-members alike — to have a voice on proposed changes to the code.
On May 1, 2023 IAPMO published the 2024 edition of the UMC, which included reference to ASHRAE 15-2019. IAPMO through its consensus process will continue to adapt to industry changes and update standards once they are approved and make them available in future code cycles or through issuance of TIAs.
2021 UMC section 1109.4.1 states that refrigerant piping shall not be installed in a means of egress and that passages shall not be obstructed by refrigerant piping. This language is specific and prescriptive. The building code defines and regulates corridors. The Authority Having Jurisdiction will approve the construction of the corridor based upon Chapters 7 and 10 of the building code. The AHJ may make the interpretation that if the refrigerant piping is concealed, it would no longer be considered within a corridor (means of egress).
On May 1, 2023 IAPMO published the 2024 edition of the UMC, which included reference to ASHRAE 15-2019. IAPMO through its consensus process will continue to adapt to industry changes and update standards once they are approved and make them available in future code cycles or through issuance of TIAs.
2021 UMC section 1109.4.1 states that refrigerant piping shall not be installed in a means of egress and that passages shall not be obstructed by refrigerant piping. This language is specific and prescriptive. The building code defines and regulates corridors. The Authority Having Jurisdiction will approve the construction of the corridor based upon Chapters 7 and 10 of the building code. The AHJ may make the interpretation that if the refrigerant piping is concealed, it would no longer be considered within a corridor (means of egress).