Statutes, codes, and regulations
District Of Columbia Administrative Code
Title 12 - CONSTRUCTION CODES SUPPLEMENT OF 2017Subtitle 12-E - MECHANICAL CODE SUPPLEMENT OF 2017
Chapter 12-E6 - DUCT SYSTEMS
Rule 12-E607 - DUCT AND TRANSFER OPENINGS

D.C. Mun. Regs. tit. 12, r. 12-E607

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Current through Register Vol. 71, No. 49, December 6, 2024
Rule 12-E607 - DUCT AND TRANSFER OPENINGS

Strike Sections 607.5.4 and 607.5.4.1 of the International Mechanical Code in its entirety and insert new Sections 607.5.4, 607.5.4.1, 607.5.4.2 and 607.5.4.3 in the Mechanical Code in their place to read as follows:

607.5.4

Corridors/smoke barriers.Corridor dampers, ceiling radiation dampers and smoke dampers in corridors and smoke barriers shall be provided as required in Sections 607.5.4.1 and 607.5.4.2. Smoke dampers and smoke damper actuation methods shall comply with Section 607.5.4.3.

607.5.4.1

Corridors. Duct and air transfer openings that penetrate corridors shall be protected with dampers as follows:

1. A corridor damper shall be provided where corridor ceilings, constructed as required for the corridor walls as permitted in Section 708.4, Exception 3 of the Building Code, are penetrated.
2. A ceiling radiation damper shall be provided where the ceiling membrane of a fire-resistance-rated floor-ceiling or roof-ceiling assembly, constructed as permitted in Section 708.4, Exception 2 of the Building Code, is penetrated.
3. A listed smoke damper designed to resist the passage of smoke shall be provided at each point a duct or air transfer opening penetrates a corridor enclosure required to have smoke and draft control doors in accordance with Section 716.5.3 of the Building Code.

Exceptions:

1.Corridor dampers, ceiling radiation dampers and smoke dampers are not required in corridor penetrations where:
(a) the building is equipped throughout with an approved smoke control system in accordance with Section 513 and
(b)smoke dampers are not necessary for the operation and control of the system.
2.Corridor dampers, ceiling radiation dampers and smoke dampers are not required in corridor penetrations where:
(a) the duct is constructed of steel not less than 0.019 inch (0.48 mm) in thickness and
(b) there are no openings serving the corridor.
3.Smoke dampers are not required in ducted corridor penetrations where:
a. The building is equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1 or 903.3.1.2 of the Building Code;
b. The duct is constructed of steel no t less than 0.019 inches (0.48 mm) in thickness;
c. The ducted system supplies outdoor air only to the corridor and to air-handling units that serve spaces adjoining the corridor through ducted connections; and
d. The outdoor air supply fan is designed to provide a continuous airflow.
607.5.4.2

Smoke barriers. A listed smoke damper designed to resist the passage of smoke shall be provided at each point a duct or air transfer opening penetrates a smoke barrier. Smoke dampers and smoke damper actuation methods shall comply with Section 607.5.4.3.

Exceptions:

1.Smoke dampers are not required where the openings in ducts are limited to a single smoke compartment and the ducts are constructed of steel.
2.Smoke dampers are not required in smoke barriers required by Section 407.5 of the Building Code for Group I-2, Condition 2, where the HVAC system is fully ducted in accordance with Section 603 and where the building is equipped throughout with (a) an automatic sprinkler system in accordance with Section 903.3.1.1 of the Building Code and with (b) quick-response sprinklers in accordance with Section 903.3.2 of the Building Code.
607.5.4.3

Smoke damper actuation. Smoke dampers shall close as required by Section 607.3.3.2.

Strike Section 607.5.5 of the International Mechanical Code in its entirety and insert new Section 607.5.5 to the Mechanical Code in its place to read as follows:

607.5.5

Shaft enclosures. Shaft enclosures that are permitted to be penetrated by ducts and air transfer openings shall be protected with listed fire and smoke dampers installed in accordance with their listing.

Exceptions:

1. Fire and smoke dampers are not required at penetrations of exhaust shafts where steel exhaust subducts extend at least 22 inches (559 mm) vertically in exhaust shafts provided there is a continuous airflow upward to the outside and the fan is provided with backup standby power.
2. Fire dampers are not required where penetrations are tested in accordance with ASTM E 119 or UL 263 as part of the fire-resistance-rated assembly.
3. Fire and smoke dampers are not required where ducts are used as part of an approved smoke control system in accordance with Section 909 of the Building Code.
4. Fire and smoke dampers are not required where the penetrations are in dedicated parking garage exhaust or supply shafts that are separated from other building shafts by not less than two (2)-hour fire- resistance-rated construction.
5. Smoke dampers are not required at penetrations of shafts where the building is equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1 or 903.3.1.2 of the Building Code.
6. Fire dampers and combination fire/smoke dampers are not required in kitchens and clothes dryer exhaust systems installed in accordance with this code.

D.C. Mun. Regs. tit. 12, r. 12-E607

Final Rulemaking published at 67 DCR 5679 (5/29/2020)