Sound Level

{
  "id": "MLC-T-ENV-026168",
  "term": "Sound Level",
  "field": "Environment",
  "definition": "1. Level, in decibels, measured by instrumentation which satisfies the requirements of American National Standard Specification for Sound Level Meters S1.4-1971 Type 1 (or S1A) or Type 2 if adjusted as shown in Table 1. This publication is available from the American National Standards Institute, Inc., 1430 Broadway, New York, New York 10018. For the purpose of these procedures the sound level is to be measured using the weighting of spectrum and either the FAST or SLOW dynamic averaging characteristics, as designated. It is abbreviated as LA.\n\n2. Quantity in decibles measured by a sound level meter satisfying the requirements of American National Standards Specification for Sound Level Meters S1.4-1971. This publication is available from the American National Standards Institute, Inc., 1430 Broadway, New York, New York 10018. Sound level is the frequency-weighted sound pressure level obtained with the standardized dynamic characteristic “fast” or “slow” and weighting A, B, or C; unless indicated otherwise, the A-weighting is understood.\n\n3. Weighted sound pressure level measured by the use of a metering characteristic and weighing A, B, or C as specified in American National Standard Specification for Sound Level Meters S1.4-1971 or subsequent approved revision. The weighting employed must be specified, otherwise A-weighting is understood.\n\n4. 20 times the logarithm to base 10 of the ratio of pressure of a sound to the reference pressure. The reference pressure is 20 micropascals (20 micronewtons per square meter). NOTE: Unless otherwise explicitly stated, it is to be understood that the sound pressure is the effective (rms) sound pressure, per American National Standards Institute, Inc., 1430 Broadway, New York, New York 10018.",
  "references": [
    "40 CFR 201.1 (2013 CFR)",
    "40 CFR 202.10 (2013 CFR)",
    "40 CFR 204.2 (2013 CFR)",
    "40 CFR 205.2 (2013 CFR)"
  ],
  "url": "https://mlchart.com/terminology/environment/sound-level/"
}