MECHANICAL EQUIPMENT PERFORMANCE
ISSUE:
The effects of altitude on mechanical equipment performance.
BACKGROUND:
Selecting equipment using unadjusted catalog data can result in undersized
equipment. For instance, the American Gas Association recommends that for
altitudes above 2,000 feet, reduce equipment ratings 4% for each 1,000 feet
above sea level. Below an elevation of 2,000 feet, the errors are considered
insignificant.
RECOMMENDATIONS:
1. According to weather stations listed in the 1997 American Society of Heating,
Refrigerating, and Air-Conditioning Engineers (ASHRAE) Handbook of
Fundamentals, following 20 VA medical centers have altitudes above 2,000 feet
and would be affected when selecting equipment:
Prescott, AZ; Tucson, AZ; Denver, CO; Ft. Lyon, CO; Grand Junction, CO;
Boise, ID; Ft. Harrison, MT; Miles City, MT; Reno, NV; Albuquerque, NM;
Asheville, NC; Ft. Meade, SD; Hot Springs, SD; Amarillo, TX; Big Spring, TX;
Salt Lake City, UT; Spokane, WA; Beckley, WV; Cheyenne, WY; and Sheridan,
WY.
2. Apply correction factors for altitudes as per manufacturer's data to avoid
undersized equipment. Altitude affects not only pressure drops and motor HP, but
also the heating and cooling capacities of heat exchangers.
FOR ADDITIONAL INFOR MATION:
Contact Satish Sehgal at 202-565-5032, Kurt Knight at 202-565-4980, or Sat
Gupta at 202-565-5268.
22 December 1997
FM-187C-DA80
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