D.C. Mun. Regs. tit. 20, r. 20-2901

Current through Register Vol. 71, No. 44, November 1, 2024

Rule 20-2901 - EQUIPMENT

2901.1

Sound-level meters and microphones shall meet Type II specifications per ANSI S1.4-1971.

2901.2

Each sound-level meter shall be qualified annually.

2901.3

Each sound-level meter and microphone device shall meet the following specifications:

(a) External calibration devices with a known sound pressure level output at a single known frequency between two hundred (200) Hz and one thousand (1,000) Hz, as specified by the manufacturer;

(b) Windscreen with insertion loss less than five tenths (0.5) dB(A) below eight (8) kHz;

(c) Stopwatch, capable of cumulative operation and accurate to two percent (2%) or better;

(d) Wind speed indicator with at least twenty percent (20%) accuracy at twelve miles per hour (12 mph); and

(e) Earphones with impedance meeting the sound level meter manufacturer's specifications.

D.C. Mun. Regs. tit. 20, r. 20-2901

Final Rulemaking published at 26 DCR 1499, 1501 (September 28, 1979)