# 204.51 Definitions.
(a) *Portable air compressor* or *compressor* means any wheel, skid, truck, or railroad car mounted, but not self-propelled, equipment designed to activate pneumatic tools. This consists of an air compressor (air end), and a reciprocating rotary or turbine engine rigidly connected in permanent alignment and mounted on a common frame. Also included are all cooling, lubricating, regulating, starting, and fuel systems, and all equipment necessary to constitute a complete, self-contained unit with a rated capacity of 75 cfm or greater which delivers air at pressures greater than 50 psig, but does not include any pneumatic tools themselves.
(b) *Maximum Rated Capacity* means that the portable air compressor, operating at the design full speed with the compressor on load, delivers its rated cfm output and pressure, as defined by the manufacturer.
(c) *Model year* means the manufacturer's annual production period which includes January 1 of such calendar year; Provided, that if the manufacturer has no annual production period, the term “model year” shall mean the calendar year.
(d) *Compressor configuration* means the basic classification unit of a manufacturer's product line and is comprised of compressor lines, models or series which are identical in all material respects with regard to the parameters listed in § 204.55-3.
(e) *Category* means a group of compressor configurations which are identical in all aspects with respect to the parameters listed in paragraph (c)(1)(i) of § 204.55-2.
(f) [Reserved]
(g) *Noise emission test* means a test conducted pursuant to the measurement methodology specified in § 204.54.
(h) *Inspection Criteria* means the rejection and acceptance numbers associated with a particular sampling plan.
(i) *Acceptable Quality Level (AQL)* means the maximum percentage of failing compressors that, for purposes of sampling inspection can be considered satisfactory as a process average.
(j) *Batch* means the collection of compressors of the same category or configuration, as designated by the Administrator in a test request, from which a batch sample is to be randomly drawn and inspected to determine conformance with the acceptability criteria.
(k) *Batch sample* means the collection of compressors that are drawn from a batch.
(l) *Batch sample size* means the number of compressors of the same category or configuration which is randomly drawn from the batch sample and which will receive emissions tests.
(m) *Test sample* means the collection of compressors from the same category or configuration which is randomly drawn from the batch sample and which will receive emissions tests.
(n) *Batch size* means the number, as designated by the Administrator in the test request, of compressors of the same category or configuration in a batch.
(o) *Test sample size* means the number of compressors of the same configuration in a test sample.
(p) *Acceptable of a batch* means that the number of non-complying compressors in the batch sample is less than or equal to the acceptance number as determined by the appropriate sampling plan.
(q) *Rejection of a batch* means that the number of non-complying compressors in the batch sample is greater than or equal to the rejection number as determined by the appropriate sampling plan.
(r) *Acceptance of a batch sequence* means that the number of rejected batches in the sequence is less than or equal to the sequence acceptable number as determined by the appropriate sampling plan.
(s) *Rejection of a batch sequence* means that the number of rejected batches in a sequence is greater than or equal to the sequence rejection number as determined by the appropriate sampling plan.
(t) *Shift* means the regular production work period for one group of workers.
(u) *Failing compressor* means that the measured noise emissions of the compressor, when measured in accordance with the applicable procedure, exceeds the applicable standard.
(v) *Acceptance of a compressor* means that the measured noise emissions of the compressor, when measured in accordance with the applicable procedure, conforms to the applicable standard.
(w) *Test Compressor* means a compressor used to demonstrate compliance with the applicable noise emissions standard.
(x) *Tampering* means those acts prohibited by section 10(a)(2) of the Act.
(Secs. 6 and 13, Noise Control Act, Pub. L. 92-574, 86 Stat. 1244; (42 U.S.C. 4912))
[41 FR 2172, Jan. 14, 1976, as amended at 42 FR 41635, Aug. 18, 1977; 47 FR 57711, Dec. 28, 1982]