UFC 4-826-10
10 July 2002
2-6.1
Facility Design. Design new refrigerated facilities to meet the
considerations for building design that are provided in the refrigerated facility design
chapter of ASHRAE Handbook Refrigeration. Cold storage facilities held below freezing
can cause under floor ice formation, resulting in floor upheaval. Design sub-floor freeze
protection for facilities that are held below freezing, such as air duct systems, electrical
heating systems, or heated pipe grids. These systems are detailed in the above-
mentioned chapter. Comply with ASHRAE 15 criteria, including equipment placement,
ventilation design, door and passageway restrictions, refrigerant monitoring, open flame
devices, pressure relief and purge piping, refrigerant piping, signs, self contained
breathing apparatus (SCBA), and miscellaneous installation restrictions.
2-6.2
Refrigeration Load. Determine the refrigeration loads by the calculations
in the Refrigeration Load chapter of ASHRAE Handbook Refrigeration.
2-6.3
Refrigeration System Selection. The primary selection of a refrigeration
system, such as halocarbon or ammonia refrigerant, direct expansion or liquid
recirculation, should be determined by life cycle cost analysis. Should a system be
selected for a design because of other issues, such as safety, reliability, simplicity, the
preference of the owner, and the recommendations of the design engineer, then the
designer must clearly justify their selection in the project's design analysis, and include
concurrence from the user and the funding agency.
Perform the design of the entire system, including pipe sizes and
layout/slopes, based on guidance from ASHRAE. On the drawings, indicate that it will
be the Contractor's responsibility to coordinate the pipe sizes and layout/slopes with the
equipment and piping configurations to be provided. For small systems (systems with 1
or 2 compressors and 1 or 2 coolers; 1 compressor for each cooler), the designer may
elect to show only the individual components and their relative layout or schematic with
no pipe sizes or slopes. For these types of systems, it will be the Contractor's
responsibility to submit shop drawings and calculations to completely define the entire
system based on the equipment to be provided.
Refer to the ASHRAE Handbook Refrigeration, in the following chapters:
Liquid Overfeed Systems
System Practices of Halocarbon Refrigerants
System Practices for Ammonia Refrigerant
Secondary Coolants in Refrigeration Systems
2-6.3.1
Refrigerants. The selection of a refrigerant impacts the project
economics and safety. The selection, design, construction, and operation of a
refrigeration system must meet ASHRAE 15. Occupancy, and restrictions on refrigerant
quantity and usage are also detailed on the drawings. Product, occupancy, or other
criteria might require a "low-probability system" for the refrigeration system. Low-
probability systems are designed so that if a leak occurred, the refrigerant cannot enter
the occupied space. Most indirect systems are considered "low-probability systems".
2-3
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