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Micro/Hood Combo duct in Fire Partition

S

Shawn Ridenhour

Registered User
Joined
Aug 5, 2019
Messages
3
Location
California
I am working through a plan check comment regarding duct penetration (membrane) into a double stud fire partition between two apartments from a Micro/Hood combination exhaust. The duct continues up through the one hour horizontal fire assembly continuing up the fire partition on the next floor up then up and out the roof.

The plan checker wants a code path on how this is allowable. The hangup I am having is regarding the requirement of a damper per 717.5.4 for Group R occupancies requiring ducts that penetrate fire partitions needing to have a damper. The other question is whether or not dampers are allowed in Micro/hood ducts?

717.5.4 Exception 2.
Items 2.1 is ok, duct is 7" dia.
Item 2.2 requires approx. 60 ga duct which could be done.
Item 2.3 is ok, duct does not communicate w/ other rooms.
Item 2.4, duct is not above ceiling......potential issue here. Duct would need to go up into floor/ceiling first or create a soffit above cabinet?
Item 2.5 is ok duct does not terminate at a wall register in fire-resistance rated wall.
Item 2.6 through penetration system could possibly meet the requirements.
​

Penetration at Fire Partition Detail: https://arris.egnyte.com/dl/rlSVcrKBZK
Detail at Duct/Fire Partition/Floor/Ceiling: https://arris.egnyte.com/dl/rlSVcrKBZK
 
It is in the code only H occupancies require a fire damper. All other occupancies there are exceptions that can be met which would eliminate the fire damper requirement

2018 IBC
717.5.4 Fire partitions.
Ducts and air transfer openings that penetrate fire partitions shall be protected with listed fire dampers installed in accordance with their listing.
Exceptions: In occupancies other than Group H, fire dampers are not required where any of the following apply:
1. Corridor walls in buildings equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1 or 903.3.1.2 and the duct is protected as a through penetration in accordance with Section 714.
2. Tenant partitions in covered and open mall buildings where the walls are not required by provisions elsewhere in the code to extend to the underside of the floor or roof sheathing, slab or deck above.
3. The duct system is constructed of approved materials in accordance with the International Mechanical Code and the duct penetrating the wall complies with all of the following requirements:
3.1. The duct shall not exceed 100 square inches (0.06 m2).
3.2. The duct shall be constructed of steel not less than 0.0217 inch (0.55 mm) in thickness.
3.3. The duct shall not have openings that communicate the corridor with adjacent spaces or rooms.
3.4. The duct shall be installed above a ceiling.
3.5. The duct shall not terminate at a wall register in the fire-resistance-rated wall.
3.6. A minimum 12-inch-long (305 mm) by 0.060-inch-thick (1.52 mm) steel sleeve shall be centered in each duct opening. The sleeve shall be secured to both sides of the wall and all four sides of the sleeve with minimum 11/2-inch by 11/2-inch by 0.060-inch (38 mm by 38 mm by 1.52 mm) steel retaining angles. The retaining angles shall be secured to the sleeve and the wall with No. 10 (M5) screws. The annular space between the steel sleeve and the wall opening shall be filled with mineral wool batting on all sides.
4. Such walls are penetrated by ducted HVAC systems, have a required fire-resistance rating of 1 hour or less, and are in buildings equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1 or 903.3.1.2. For the purposes of this exception, a ducted HVAC system shall be a duct system for conveying supply, return or exhaust air as part of the structure’s HVAC system. Such a duct system shall be constructed of sheet steel not less than No. 26 gage thickness and shall be continuous from the air-handling appliance or equipment to the air outlet and inlet terminals.
 
Well

If he does not know if allowed or not,

Must be allowed till a code section is provided from plan reviewer
 
mtlogcabin said:
It is in the code only H occupancies require a fire damper. All other occupancies there are exceptions that can be met which would eliminate the fire damper requirement

2018 IBC
717.5.4 Fire partitions.
Ducts and air transfer openings that penetrate fire partitions shall be protected with listed fire dampers installed in accordance with their listing.
Exceptions: In occupancies other than Group H, fire dampers are not required where any of the following apply:
1. Corridor walls in buildings equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1 or 903.3.1.2 and the duct is protected as a through penetration in accordance with Section 714.
2. Tenant partitions in covered and open mall buildings where the walls are not required by provisions elsewhere in the code to extend to the underside of the floor or roof sheathing, slab or deck above.
3. The duct system is constructed of approved materials in accordance with the International Mechanical Code and the duct penetrating the wall complies with all of the following requirements:
3.1. The duct shall not exceed 100 square inches (0.06 m2).
3.2. The duct shall be constructed of steel not less than 0.0217 inch (0.55 mm) in thickness.
3.3. The duct shall not have openings that communicate the corridor with adjacent spaces or rooms.
3.4. The duct shall be installed above a ceiling.
3.5. The duct shall not terminate at a wall register in the fire-resistance-rated wall.
3.6. A minimum 12-inch-long (305 mm) by 0.060-inch-thick (1.52 mm) steel sleeve shall be centered in each duct opening. The sleeve shall be secured to both sides of the wall and all four sides of the sleeve with minimum 11/2-inch by 11/2-inch by 0.060-inch (38 mm by 38 mm by 1.52 mm) steel retaining angles. The retaining angles shall be secured to the sleeve and the wall with No. 10 (M5) screws. The annular space between the steel sleeve and the wall opening shall be filled with mineral wool batting on all sides.
4. Such walls are penetrated by ducted HVAC systems, have a required fire-resistance rating of 1 hour or less, and are in buildings equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1 or 903.3.1.2. For the purposes of this exception, a ducted HVAC system shall be a duct system for conveying supply, return or exhaust air as part of the structure’s HVAC system. Such a duct system shall be constructed of sheet steel not less than No. 26 gage thickness and shall be continuous from the air-handling appliance or equipment to the air outlet and inlet terminals.
Click to expand...

Thank you for your response. The CBC differs slightly:

For Group A, E, I and R occupancies, high-rise buildings, and other applications listed in Section 1.11 regulated by the Office of the State Fire Marshal, ducts and air transfer openings that penetrate fire partitions shall be protected with listed fire danlpers iI/stalled in accordance \vith their listings.
Exceptions:
1. Fire dampers are not required in corridor penetrations where the duct is constructed ofsteell1ot less than 0.019 inch (0.48 mm) in thickness, protected as a through penetration in accordance with Section 713 and there are no openings serving the corridor.
2. Fire dampers are not required where the duct system is constructed of approved materials in and the duct penetrating the wall complies with all of the following requirements:
2.1. For other than corridors in Group /-2 occupancies the duct shall not exceed 100 square inches (0.6 1Il2).
2.'? The duct shall be constructed of steel (l mini· mum (If OJ)2 17 inch (0.55 117m) ill thickness.
2.3. The duct shall not have openings that communicate the corridor with adjacent spaces or rooms.
2.4. The duct shall be installed above a ceiling,
2,5. The duct shall not terminate at a wall register in the fire-resistance rated wall.
2,6. The duct shall be protected as a through penetration in accordance with Section 714 or shall comply with the all of the following:
I. A minimum J 2-inch-long (305 111111) by OJ)60·inch-thick (1.52 117m) steel sleeve shall he centered in each duct opening.
2. The sleeve shall be secured to both sides of the wall and for all four sides of the sleeve with minimum 1'12-inch by tlr inch by 0.060-inch (38 mm by 38 mm by 1.52 mm) steel retaining angles.
3. The retaining angles shall be secured to the sleeve and the wall with No, 10 (M5) screws.
4. The annular space between the steel sleeve and the wall opening shall be filled with mineral wool batting on all sides.​

In our case, the duct penetrates the fire partition below the ceiling and I do not think I can get the 12" long sleeve to fit in the opening. Also, is this duct technically part of the HVAC system? For number 4, how does the No 26 gage
 
Once in the rated assembly, does it ever exit the rated assembly, till it gets out of the building?
 
cda said:
Once in the rated assembly, does it ever exit the rated assembly, till it gets out of the building?
Click to expand...
The duct starts at the ground floor, into the fire partition, up through the second floor floor/ceiling, up through the second floor fire partition, then through the roof attic and through the roof. At the roof it does not continue through the fire partition in the attic because of the trusses at the double wall.

See detail: https://arris.egnyte.com/dl/3O4hCMFTxF.
 
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