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Part 453: Measurement Of Noise Emission; Stationary Test

[page 1 of 1]

Contents:

Sec.

§453.1 Scope of the Rules in this Part

(a) The rules in this Part specify conditions and procedures for measuring the sound level generated by a vehicle when the vehicle's engine is rapidly accelerated from idle to governed speed at wide-open throttle with the vehicle stationary, its transmission in neutral and its clutch engaged, for the purpose of ascertaining whether the motor vehicle conforms to the sound level limit set forth in section 386(3)(b) of the New York State Vehicle and Traffic Law.

(b) The rules in this Part apply only to a motor vehicle that is equipped with an engine speed governor.

(c) Tests conducted in accordance with the rules of this Part may be made on either side of the vehicle.

§453.2 Site Characteristics; Stationary Test

(a)

(1) The motor vehicle to be tested shall be parked on the test site. A microphone target point shall be established on the ground surface of the site, on the centerline of the lane in which the motor vehicle is parked, at a point that is within three feet (0.9 m) of the longitudinal position of the vehicle's exhaust system outlet(s). A microphone location point shall be established on the ground surface not less than 35 feet (10.7 m) and not more than 83 feet (25.3 m) from the microphone target point. Within the test site is a triangular measurement area. A plan view diagram of a standard test site, having an open site within a 50-foot (15.2 m) radius of both the microphone target point and the microphone location point, is shown in Figure 2 below.

(2) Measurements may be made at a test site having smaller or greater dimensions in accordance with the rules in Part 454 of this Title.

TABULAR OR GRAPHIC MATERIAL SET FORTH AT THIS POINT IS NOT DISPLAYABLE

Figure 2--STANDARD TEST SITE STATIONARY TEST

(b) The test site must be an open site, essentially free of large sound-reflecting objects. However, the following objects may be within the test site, including the triangular measurement area:

(1) Small cylindrical objects such as fire hydrants or telephone or utility poles.

(2) Rural mailboxes.

(3) Traffic railings of any type of construction except solid concrete barriers (see section 450.2[s]).

(4) One or more curbs having a height of one foot (0.3 m) or less.

(c) The following objects may be within the test site if they are outside of the triangular measurement area of the site:

(1) Any vertical surface, regardless of size (such as a billboard), having a lower edge more than 15 feet (4.6 m) above the ground.

(2) Any uniformly smooth surface slanting away from the vehicle with a slope that is less than 45 degrees above the horizontal.

(3) Any surface slanting away from the vehicle that is 45 degrees or more and not more than 90 degrees above the horizontal, if all points on the surface are more than 15 feet (4.6 m) above the surface of the ground in the test site.

(d) The surface of the ground within the measurement area must be relatively flat. (See section 450.2[o]). The site shall be a "hard" site. However, if the site is determined to be "soft", the correction factor specified in section 454.3(b) of this Title shall be applied to the measurement.

§453.3 Ambient Conditions; Stationary Test

(a)

(1) Sound. The ambient A-weighted sound level at the microphone location point shall be measured, in the absence of motor vehicle noise emanating from within the clear zone, with fast meter response using a sound level measurement system that conforms to section 451.2 of this Title.

(2) The measured ambient level must be 10 dB(A) or more below that level specified in section 450.3 of this Title, Table 1, which corresponds to the maximum permissible sound level reading which is applicable at the test site at the time of testing.

(b) Wind. The wind velocity at the test site shall be measured at the beginning of each series of noise measurements and at intervals of five to 15 minutes thereafter until it has been established that the wind velocity is essentially constant. Once this fact has been established, wind velocity measurements may be made at intervals of once every hour. Noise measurements may only be made if the measured wind velocity is 12 mph (19.3 kph) or less. Gust wind measurements of up to 20 mph (33.2 kph) are allowed.

(c) Precipitation. Measurements are prohibited under any conditions of precipitation; however, measurements may be made with snow on the ground. The ground within the measurement area must be free of standing water.

§453.4 Location and Operation of Sound Level Measurement System; Stationary Test

(a) The microphone of a sound level measurement system that conforms to section 451.2 of this Title shall be located at a height of not less than two feet (0.6 m) nor more than six feet (1.8 m) above the plane of the roadway surface and not less than 3 1/2 feet (1.1 m) above the surface on which the microphone stands. The preferred microphone height on flat terrain is four feet (1.2 m).

(b) When the sound level measurement system is hand-held or otherwise monitored by a person located near its microphone, the holder must orient himself relative to the highway in a manner consistent with the recommendation of the manufacturer of the sound level measurement system. In no case shall the holder or observer be closer than two feet (0.6 m) from the system's microphone, nor shall he locate himself between the microphone and the vehicle being measured.

(c) The microphone of the sound level measurement system shall be oriented toward the vehicle at an angle that is consistent with the recommendation of the system's manufacturer. If the manufacturer of the system does not recommend an angle of orientation for its microphone, the microphone shall be oriented at an angle of not less than 70 degrees and not more than perpendicular to the horizontal plane of the test site at the microphone target point.

(d) The sound level measurement system shall be set to the A-weighting network and "fast" meter response mode.

§453.5 Measurement Procedure; Stationary Test

In accordance with the rules in this Part, a measurement shall be made of the sound level generated by a stationary motor vehicle as follows:

(a) Park the motor vehicle on the test site as specified in section 453.2 of this Part. If the motor vehicle is a combination of vehicles, park the combination so that the longitudinal centerlines of the towing vehicle and the towed vehicle or vehicles are in substantial alignment.

(b) Turn off all auxiliary equipment which is installed on the motor vehicle and which is designed to operate under normal conditions only when the vehicle is operating at a speed of five mph (eight kph) or less. Examples of such equipment include cranes, asphalt spreaders, liquid or slurry pumps, auxiliary air compressors, welders and trash compactors.

(c) If the motor vehicle's engine radiator fan drive is equipped with a clutch or similar device that automatically either reduces the rotational speed of the fan or completely disengages the fan from its power source in response to reduced engine cooling loads, park the vehicle before testing, with its engine running at high idle or any other speed the operator may choose, for sufficient time, but not more than 10 minutes, to permit the engine radiator fan to automatically disengage when the vehicle's noise emissions are measured under stationary test.

(d) With the motor vehicle's transmission in neutral and its clutch engaged, rapidly accelerate the vehicle's engine from idle to its maximum governed speed with wide-open throttle. Return the engine's speed to idle.

(e) Observe the maximum reading on the sound level measurement system during the time the procedures specified in subdivision (d) of this section are followed. Record that reading, if the reading has not been influenced by extraneous noise sources such as motor vehicles operating on adjacent roadways.

(f) Repeat the procedures specified in subdivisions (d) and (e) of this section until the first two maximum sound level readings that are within two dB(A) of each other are recorded. Numerically average those two maximum sound level readings. When appropriate, correct the average figure in accordance with Part 454 of this Title.

(g) The average figure, corrected as appropriate, contained in accordance with subdivision (f) of this section, is the sound level generated by the motor vehicle for the purpose of determining whether it conforms to the sound level limit set forth in section 38(3)(b) of the New York State Vehicle and Traffic Law. (Table 1 in section 450.3 lists the range of maximum permissible sound level readings for various test conditions.)