Orifice testing of compressors.

  1. Law
  2. CFR 49
  3. Transportation
  4. Other Regulations Relating to Transportation
  5. Federal Railroad Administration, Department of Transportation
  6. Steam Locomotive Inspection and Maintenance Standards
  7. Steam Locomotives and Tenders
  8. Brake and Signal Equipment
  9. Orifice testing of compressors.

Checkout our iOS App for a better way to browser and research.

§ 230.71 Orifice testing of compressors.

(a) Frequency of testing. The compressor or compressors shall be tested for capacity by orifice test as often as conditions may require, but not less frequently than once every 92 service days.

(b) Orifice testing criteria.

(1) Compressors in common use, as listed in the following table, shall have orifice test criteria as follows:

Expand Table
Make Compressor size Single strokes per minute Diameter of orifice
(in inches) 		Air pressure maintained
(in pounds)
Westinghouse 91⁄2 120 11⁄64 60
Westinghouse 11 100 3⁄16 60
Westinghouse 150 CFM 81⁄2 CC 100 9⁄32 60
Westinghouse 120 CFM 81⁄2 100 15⁄64 60
New York 2a 120 5⁄32 60
New York 6a 100 13⁄64 60
New York 5b 100 15⁄64 60

Note: This table shall be used for altitudes to and including 1,000 feet. For altitudes over 1,000 feet the speed of compressor may be increased 5 single strokes per minute for each 1,000 feet increase in altitude.

(2) For compressors not listed in the table in paragraph (b)(1) of this section, the air pressure to be maintained shall be no less than 80 percent of the manufacturer's rated capacity for the compressor.


Download our app to see the most-to-date content.