outdoors more than 6.1 m (20 ft) from building
openings and is enclosed by a penthouse, lean-to or
other open structure", otherwise mechanical
ventilation is required.
The amount of ventilation air required for a
mechanical room will be determined based upon the
ventilation equations in ASHRAE 15. In order to use
these equations, a designer must approximate the
mass of refrigerant (kgs or lbs) expected in the
largest system located in the mechanical room.
Refrigerant quantities will be determined based upon
a minimum of 2 different system manufacturers.
a. For a natural ventilation system, ASHRAE 15
provides an equation for sizing the amount of free
opening area required.
b. For a mechanical ventilation system, ASHRAE
15 requires both normal and alarm ventilation.
Normal ventilation will be sized to cover personnel
ventilation requirements (2.5 1/s/m2 or 0.5 cfm/ft2)
and heat buildup requirements if applicable. Alarm
ventilation will be sized based upon the equations
in ASHRAE 15. Both the normal and alarm ventilation
rates can be achieved using the same ventilation
system (e.g., multi-speed exhaust fans), however,
individual systems are preferred. For the alarm
ventilation, exhaust intakes will be located near
the equipment and close to the finished floor. Most
commonly used refrigerants are heavier-than-air and
subsequently sink to the floor. Also per ASHRAE 15,
air supply and exhaust ducts to the mechanical room
will serve no other area within a facility.
Discharge air from a mechanical ventilation system
will be to the outdoors.
**************************************************************************
Mechanical ventilation systems shall be in accordance with Section 15895
AIR SUPPLY, DISTRIBUTION, VENTILATION, AND EXHAUST SYSTEM.
3.1.3
Building Surface Penetrations
Sleeves in nonload bearing surfaces shall be galvanized sheet metal,
conforming to ASTM A 653/A 653M, Coating Class G-90, 1 mm (20 gauge) 20
gauge. Sleeves in load bearing surfaces shall be uncoated carbon steel
pipe, conforming to ASTM A 53/A 53M, [Schedule 30] [Schedule 20] [Standard
weight]. Sealants shall be applied to moisture and oil-free surfaces and
elastomers to not less than 13 mm 1/2 inch depth. Sleeves shall not be
installed in structural members.
3.1.3.1
Refrigerated Space
Refrigerated space building surface penetrations shall be fitted with
sleeves fabricated from hand-lay-up or helically wound, fibrous glass
reinforced polyester or epoxy resin with a minimum thickness equal to
equivalent size Schedule 40 steel pipe. Sleeves shall be constructed with
integral collar or cold side shall be fitted with a bonded slip-on flange
or extended collar. In the case of masonry penetrations where sleeve is
SECTION 15652A
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