N.J. Admin. Code § 19:4-7.4
Current through Register Vol. 56, No. 11, June 3, 2024
Section 19:4-7.4 - Performance standards; vibrations(a) The following words and terms, when used in this section, shall have the following meanings, unless the context clearly indicates otherwise. "Amplitude" means the maximum displacement of the earth from the normal rest position. Amplitude is usually reported as inches or mils.
"Discrete impulses" means a ground transmitted vibration stemming from a source where specific pulses do not exceed 60 per minute or one per second.
"Frequency" means the number of times that a displacement completely repeats itself in one second of time. Frequency may be designated in cycles per second (cps) or hertz (Hz).
"Impact" means an earthborn vibration generally produced by two or more objects striking each other so as to cause separate and distinct pulses.
"Particle velocity" means a characteristic of vibration that depends on both displacement and frequency. If not directly measured, it can be computed by multiplying the frequency by the amplitude times the factor 6.28. The particle velocity will be in inches per second, when the frequency is expressed in cycles per second and the amplitude in inches.
"Steady state vibration" means a vibration which is continuous, as from a fan, compressor, or motor.
"Vibration" means a reciprocating movement transmitted through the earth, both in horizontal and vertical planes.
(b) Ground-transmitted vibration shall be measured with a seismograph or complement of instruments capable of recording vibration displacement and frequency, particle velocity, or acceleration simultaneously in three mutually perpendicular directions.(c) Table 7-2 below designates the maximum permitted particle velocities, except as otherwise designated. Where more than one set of vibration levels apply, the most restrictive shall govern. Measurements may be made at points of maximum vibration intensity. | TABLE 7-2 |
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| Vibration Level Restrictions |
|
| Performance | Maximum Peak |
| Standard | Particle Velocity, |
| Category | inches per second | Where Measured |
| A | 0.02 | On or beyond the subject property |
| | boundary line |
| B | 0.05 | On or beyond the subject property |
| | boundary line |
| C | 0.10 | On or beyond the zone boundaries |
(d) In any residential area, the peak particle velocity shall not exceed 0.02 inches per second during the hours of 7:00 A.M. to 9:00 P.M. and shall not exceed 0.01 inches per second during the hours of 9:00 P.M. to 7:00 A.M.(e) The maximum particle velocity shall be the maximum vector sum of three mutually perpendicular components recorded simultaneously. Particle velocity may also be expressed as 6.28 times the displacement in inches multiplied by frequency in cycles per second.(f) For the purpose of these regulations, steady state vibrations are vibrations which are continuous, or vibrations in discrete impulses more frequent than 60 per minute. Discrete impulses that do not exceed 60 per minute shall be considered impact vibrations. Impact vibrations are limited to values no more than twice as high as those specified in Table 7-2. N.J. Admin. Code § 19:4-7.4