Section 431.344 - Test procedure for measuring and determining energy efficiency of compressors(a)Scope. This section is a test procedure that is applicable to a compressor that meets the following criteria:(1) Is an air compressor;(2) Is a rotary compressor;(3) Is not a liquid ring compressor;(4) Is driven by a brushless electric motor;(5) Is a lubricated compressor;(6) Has a full-load operating pressure greater than or equal to 75 pounds per square inch gauge (psig) and less than or equal to 200 psig;(7) Is not designed and tested to the requirements of the American Petroleum Institute Standard 619, "Rotary-Type Positive-Displacement Compressors for Petroleum, Petrochemical, and Natural Gas Industries;"(8) Has full-load actual volume flow rate greater than or equal to 35 cubic feet per minute (cfm), or is distributed in commerce with a compressor motor nominal horsepower greater than or equal to 10 horsepower (hp); and(9) Has a full-load actual volume flow rate less than or equal to 1,250 cfm, or is distributed in commerce with a compressor motor nominal horsepower less than or equal to 200 hp.(b)Testing and calculations. Determine the applicable full-load package isentropic efficiency ([ETA]isen,FL), part-load package isentropic efficiency ([ETA]isen,PL), package specific power, maximum full-flow operating pressure, full-load operating pressure, full-load actual volume flow rate, and pressure ratio at full-load operating pressure using the test procedure set forth in appendix A of this subpart. 82 FR 1102 , Jan. 4, 2017