06-06
detection, the duct detector (through its auxiliary contacts)
shall:
a. Stop the supply and associated return air fan; the building
exhaust air fan(s) shall continue to run.
b. Sound an alarm at the fire alarm system.
c. Sound an audible alarm and print an alarm message at the
central engineering control center (ECC).
2. SMOKE DAMPERS: In addition to the supply air duct detector listed
in Paragraph 1, for air handling units with capacities larger than
420 m3/min (15,000 CFM) and serving more than one floor, the
following shall be provided:
a. Smoke dampers shall be provided in the supply and return air
ducts to isolate the air handling unit as shown in Supplement,
ATTACHMENT No. 1.
b. Smoke detectors shall be provided at each main branch return
air duct, at each floor, as it connects to the vertical return
air main duct at shaft.
c. Upon smoke detection by any duct detector, in addition to the
sequence of operation listed in paragraph 1, the smoke dampers
shall close. The arrangement is shown in Supplement, ATTACHMENT
No. 1.
3. SMOKE BARRIERS: For a fully sprinklered building using quick
response sprinkler heads, duct mounted smoke detectors and/or
dampers are not required at the smoke barrier crossing of the HVAC
ducts. If the building is not fully sprinklered with quick
response sprinklers, smoke dampers and detectors shall be required
in each duct as each barrier penetration. Upon activation of any
detector, the sequence of operation listed in paragraphs 1 and 2
shall take place.
B. FIRE DAMPERS: Fire dampers are required at the duct penetrations of
the two hour rated fire walls, fire partitions, shafts, ceiling, and
floors. Exception: Vertical separation; where the fire dampers are
required even in one hour rated wall. Fire dampers are not required
in duct penetration of exterior walls and roof.
C. MISCELLANEOUS REQUIREMENTS:
1. Stairs Pressurization: VA does not require ressurization of
stairwells.
2. Elevators Smoke Venting: To comply with Rule 100.4 of ANSI.1,
Elevator Safety Code, provide smoke venting control as shown in VA
Standard Detail No. 15900-18.
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