2.13.2.9 MISCELLANEOUS REQUIREMENTS
2.13.2.9.1 Smoke dampers are not required in the interstitial deck
penetrations.
2.13.2.9.2 Smoke detectors shall be located on the upstream side of the duct-
mounted humidifiers. Where the smoke detectors have to be located on the
downstream side of the humidifiers, maximum possible distance shall be
maintained between them.
straight duct run for at least six duct widths to ensure fairly uniform
airflow and homogenous air/smoke mixing.
2.13.3 PENETRATIONS OF FIRE AND SMOKE BARRIERS
Penetrations of fire walls, fire partitions, shafts, ceilings, and floors
shall be protected as required by NFPA 90A, and NFPA 101 with the following
amplifications:
2.13.3.1 Fire dampers are required in the duct penetrations of the fire walls
and fire partitions with a fire resistance rating of 2 hours or greater.
2.13.3.2 Fire dampers are not required in duct penetrations of the corridor
walls rated less than 2 hours. Note that in a fully sprinklered building, the
corridor walls are not fire rated except when used as means of egress.
Transfer grilles shall not be installed in the corridor walls of the health
care facilities even if they are equipped with fusible link fire dampers,
with the exception of toilets, bathrooms, and janitor closets (HAC), which
open to the corridor.
2.13.3.3 FIRE DAMPERS IN LABORATORY FUME HOOD EXHAUST SYSTEMS: NFPA 45, does
not permit fire dampers in laboratory fume hood exhaust systems. The exhaust
from laboratory fume hoods shall be limited to a single fire zone. Provide a
separate fire rated shaft from each fire zone for laboratory fume hood
exhaust to reach the top of the building. When the quantity of laboratory
hoods prohibits a separate shaft from each fire zone, one shaft may be used
for the laboratory hood exhaust ducts without fire dampers based on NFPA 90A.
2.13.3.4 PENTHOUSE FLOOR DUCT PENETRATIONS: Provide fire dampers only if the
penthouse is, or will in the future be, considered a story of the building. A
story is defined as either exceeding 90 Sq M (1000 Sq Ft) or one-third of the
roof area.
2.13.3.5 For the wood-framed attics used for mechanical rooms in the existing
buildings, fire dampers are not required in floor penetrations. The metal
duct provides the required 1-hour separation.
2.13.3.6 VA HOSPITAL BUILDING SYSTEMS: Fire dampers are only required where
the interstitial deck penetrations are located over an exit passageway
(corridor serving as a two hour passageway no space) and/or where the
interstitial deck penetration openings exceed 0.1450 Sq M (225 Sq Inches).
This means a duct of 325 mm x 325 mm (13-inch x 13-inch). Seal openings per
VA Standard Detail 15840-14.
HVAC DESIGN MANUAL
2-52
HVAC SYSTEMS AND EQUIPMENT
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