provide excess sections for walk through servicing, maintenance, and
shall ensure that the piping connections and electrical conduits are
fully enclosed within the units. The designer shall ensure close
coordination with the architecture and structural disciplines for
aesthetics, operating weight, shaft locations, etc., while selecting
the roof top units.
1.7.3 COORDINATION
Coordinate and make provisions for all necessary stairs, cat walks,
platforms, steps over roof mounted piping and ducts, etc., that will be
required for access, operation and maintenance. Access to roofs by
portable ladder is not acceptable.
1.7.4 COOLING TOWERS
Select and locate cooling towers to avoid problems with aesthetics,
noise, vibrations, air recirculation or drift. Include a noise analysis
of the proposed cooling tower relative to adjacent occupancies and
consider alternative cooling tower selections, if necessary, to meet
noise level of 60 dB(A) at 15 m (50 feet) which may be lowered for
critical locations. Consider provisions for security and maintenance
lights and receptacles. Provide a permanent service platform and
ladders for access to cooling tower basin access doors.
1.7.5 AIR COMPRESSORS
Large control air compressors can be a source of objectionable noise
and vibration. They should be mounted on vibration isolators and should
be located to avoid noise problems in occupied areas, including shops
and the engineering control center. Compressors may require an
enclosure or acoustical treatment.
1.7.6 SCREENS AND FILTERS FOR AIR
At medical centers where cottonwood trees, or similar types, are likely
to interfere with operation of air intakes for air handling units,
cooling towers, or air cooled condensers, provide easily cleanable
screens or roughing filters at the air inlets.
1.8
LOCATIONS OF OUTSIDE AIR INTAKES AND EXHAUST AIR OUTLETS
1.8.1 GENERAL
Outside air intake and exhaust air outlets shall be located to avoid
health hazards, nuisance odors and reduction in capacity of air
conditioning equipment and corrosion of equipment caused by re-entry of
exhaust air from laboratories, transportation systems, cooling towers
and air cooled condensers, etc.
1.8.2 MINIMUM REQUIREMENTS
1.8.2.1 The bottom of all outdoor intakes shall be located as high as
practical but not less than three feet above ground level or, if
installed through the roof, one meter (three feet) above the roof
level.
1.8.2.2 Operating Room system air intakes shall be at least 9 m (30 ft)
above the ground.
highest point of the building (NFPA 99, 5-3.3.4).
HVAC DESIGN MANUAL
1-25
GENERAL REQUIREMENTS
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