Acoustic measurements to ascertain compliance with these
Regulations shall be in substantial conformity with standards and Recommended
Practices established by professional organizations such as ANSI and
(a) Personnel conducting sound
measurements shall be trained and experienced in the current techniques and
principles of sound measuring equipment and instrumentation. The Commissioner
shall establish sufficiently detailed measurement procedure guidelines
specifying, but not necessarily being limited to, the following: The
appropriate utilization of fast or slow sound level meter dampening when making
sound level measurements, the rise time specified in microseconds for measuring
impulse noise, the need for a whole circuit in such measurements, and the
proper weighting to be used in measuring impulse noise.
Instruments shall conform to the
following standards of their latest revisions:
(i) ANSI S1.4-1971, "Specifications for Sound
Level Meters," Type 1 or 2.
ANSI S1.11-1966, "Specifications for Octave, One-Half Octave and One-Third
Octave Band Filter Sets," Type E, Class II.
(iii) If a magnetic tape recorder or a
graphic level recorder or other indicating device is used, the system shall
meet the applicable requirements of SAE Recommended Practice J184, "Qualifying
a Sound Data Acquisition System."
(c) Instruments shall be set up to conform to
ANSI S1.13-1971, "Methods for the Measurement of Sound Pressure
manufacturer's instructions for use of the instruments shall be followed,
including acoustical calibration of equipment used.
(e) The determination of
L90 to ascertain
background levels requires a statistical analysis. A graphic level recording
and visual interpretation of the chart recording to determine the levels is an
acceptable method. Instruments designed to determine the cumulative
distribution of noise levels are also acceptable used either in the field or in
the laboratory to analyze a tape recording. Dynamic visual estimations from a
sound level meter are not an acceptable method for determining such levels.
Sound level sampling techniques are acceptable and will often be the most
practical to employ. Such a technique using Connecticut Noise Survey Data Form
#101 with accompanying instructions is acceptable.
In measuring compliance with Noise Zone
Standards, the following short-term noise level excursions over the noise level
standards established by these Regulations shall be allowed, and measurements
within these ranges of established standards shall constitute compliance
Allowable Levels above standards (dBA)
Time period of such levels (minutes/hour)
Measurements taken to determine compliance with Section 3 shall be taken at
about one foot beyond the boundary of the Emitter Noise Zone within the
receptors's Noise Zone. The Emitter's Noise Zone includes his/her individual
unit of land or group of contiguous parcels under the same ownership as
indicated by public land records. The Emitter's Noise Zone also includes
contiguous publicly dedicated street and highway rights-of-way, railroads
rights-of-way and waters of the State.