Section Saf-C 1625.04 - Vibration Limits(a) Blasting shall be conducted so that vibrations adjacent to any structure, not controlled by the blaster, or for which the blaster has received the owner's written permission as described in Saf-C 1607.05, do not exceed the limits cited in Table 1625.1 or (e) below: Table 1625.1 Vibration Limits When Using Instrumentation
Frequency of ground vibration in cycles per second | Maximum amplitude of ground motion in inches |
Up to 10 | 0.0305 |
20 | 0.0153 |
30 | 0.0102 |
40 | 0.0076 |
50 | 0.0061 |
60 | 0.0051 |
70 | 0.0043 |
80 | 0.0038 |
(b) A peak particle velocity of 2.0 inches per second shall be the maximum of any one of the 3 mutually perpendicular ground motion velocity components of a vibration. These components shall be measured in directions vertical, longitudinal, and transverse to the vibration Source. Any ground vibration over peak particle velocity of 2.0 inches per second shall be reported to the director within 24 hours.(c) The instrument used to monitor the ground vibrations produced by each blast shall produce printed seismograms of vibrations that are recorded in units of particle velocity in inches/seconds, occurring along 3 mutually perpendicular axes at ground level. The monitoring device shall be placed between the blast location and the nearest structure.(d) The printed measurements of the blast ground vibrations, as required in (c) above, shall be retained by the blasting contractor for a period of at least 6 months, and shall be made available to the director upon request.(e) When instrumentation for the measurement of blasting ground vibration is not used, the maximum weight of explosive to be used on a single delay shall be in accordance with the guidelines of the United States bureau of mines bulletin number 656 as outlined below: (1) For the purposes of this rule "distance" means distance in feet from the nearest structure;(2) For the purposes of this rule "weight" means the weight of the explosives in pounds per delay period or 8 milliseconds or greater.(3) Table 1625.2 below shall set forth the requirements of the sample scaled distance: Table 1625.2 Sample Scaled Distance
DISTANCE IN FEET | WEIGHT SCALED 50 |
10 | .04 |
15 | .09 |
20 | .16 |
25 | .25 |
30 | .36 |
40 | .64 |
50 | 1.00 |
60 | 1.44 |
70 | 1.96 |
80 | 2.56 |
90 | 3.24 |
100 | 4.00 |
110 | 4.84 |
130 | 6.76 |
150 | 9.00 |
170 | 11.6 |
190 | 14.40 |
210 | 17.60 |
230 | 21.20 |
250 | 25.00 |
270 | 29.00 |
290 | 33.60 |
400 | 64 |
500 | 100 |
600 | 144 |
700 | 196 |
800 | 256 |
900 | 324 |
1000 | 400 |
1100 | 484 |
1200 | 576 |
1300 | 676 |
1400 | 784 |
1500 | 900 |
1600 | 1024 |
1700 | 1156 |
1800 | 1296 |
1900 | 1444 |
2000 | 1600 |
2500 | 2500 |
3000 | 3600 |
3500 | 4900 |
4000 | 6400 |
5000 | 10000 |
WEIGHT = (DISTANCE)2 / 50)
(4) At less than 5 feet, the total amount of explosive used shall not exceed one-eighth of a pound.(5) For distances not in the table, the formula, weight = (distance/50) X (distance/50), shall be used to determine maximum explosive weight.(6) The graph for the scaled distance table shall be a nomograph as illustrated in Figure 1625.1 below: Figure 1625.1
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N.H. Admin. Code § Saf-C 1625.04
#2220, eff 12-31-82; ss by #2837, eff 8-27-84; ss by #4584, eff 3-3-89; ss by #5996, INTERIM, eff 3-3-95, EXPIRES, 7-1-95; ss by #6054, eff 7-1-95, EXPIRED: 7-1-03
New. #8116, INTERIM, eff 7-14-04, EXPIRES: 1-10-05; ss by #8231, eff 12-20-04; ss by #10396, eff 8-15-13
Amended by Volume XXXIII Number 37, Filed September 12, 2013, Proposed by #10396, Effective 8/15/2013, Expires 8/15/2023.