3.1.1.3
Oil Charging
Except for factory sealed units, two complete charges of lubricating oil
for each compressor crankcase shall be furnished. One charge shall be used
during the performance testing period, and upon the satisfactory completion
of the tests, the oil shall be drained and replaced with the second charge.
3.1.2
Mechanical Room Ventilation
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For mechanical rooms which are intended to house
refrigeration equipment, designers will use ASHRAE
15 to determine applicable design criteria. Delete
this paragraph if a mechanical room is not
applicable to the design.
In summary, ASHRAE 15 allows the use of either
natural or mechanical ventilation systems, however
natural ventilation is allowed only in certain
limited applications. Natural ventilation is
allowed only when "a refrigerant system is located
outdoors more than 6.1 m (20 feet) 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.
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SECTION 15620A
Page 51
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