N.H. Code Admin. R. 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. (1) For the purposes of this rule "distance" means distance in feet from the nearest structure;
2. (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. (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. (4) At less than 5 feet, the total amount of explosive used shall not exceed one-eighth of a pound.
5. (5) For distances not in the table, the formula, weight = (distance/50) X (distance/50), shall be used to determine maximum explosive weight.
6. (6) The graph for the scaled distance table shall be a nomograph as illustrated in Figure 1625.1 below:
  Figure 1625.1

Source. #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