ANSI/ASHRAE Standard 15-1994, Safety Code For Mechanical Refrigeration

Request from: Earvin V. Henderson, Principal Engineer, Engineering Department, Building 705-K, Westinghouse Savannah River Company, Aiken, SC 29808.

Reference: This request refers to a requirement for overpressure protection of a packaged chiller system as covered in ANSI/ASHRAE 15-1994, Subclauses 2.4 and 9.7.1.

Background: A packaged chiller system incorporating an air cooled refrigerant condenser coil with a chilled water evaporator is listed by a nationally recognized testing laboratory as conforming to UL Standard 1995, thus complying with Subclause 2.4 of ASHRAE 15-1994. This system, however, lacks the overpressure protection required by Subclause 9.7.2 of ASHRAE 15. There are two possible interpretations of Subclauses 2.4 and 9.7.1, taken together.

Westinghouse Interpretation No.1. In order to qualify, listings referenced in 2.4 must certify compliance with the design, manufacture, and factory test requirements of Standard 15. Therefore, the listing of conformance to UL Standard 1995 does not apply to Subclause 2.4, both a) on a prima facia basis, and b) specifically because the overpressure protection required by 9.7.1 is lacking in the example cited.

Westinghouse Interpretation No.2. Listing by an approved, nationally recognized testing laboratory qualifies the listed equipment as complying with Standard 15, even if a) the listing does not reference ASHRAE 15, or b) the equipment does not comply with one or more of the design, manufacture, or factory test requirements of ASHRAE 15, specifically 9.7.1.

Question 1. Mr. Henderson’s letter opines that Westinghouse Interpretation No. 1 is correct. Is this correct?

Answer: Yes.