New Hampshire Code of Administrative Rules
Saf - Department of Safety
Subtitle Saf-C - Commissioner, Department of Safety
Chapter Saf-C 1600 - EXPLOSIVES
Part Saf-C 1625 - LOADING OF EXPLOSIVE MATERIALS IN BLAST HOLES
Section Saf-C 1625.04 - Vibration Limits

Universal Citation: NH Admin Rules Saf-C 1625.04

Current through Register No. 40, October 3, 2024

(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

Click here to view

#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

Disclaimer: These regulations may not be the most recent version. New Hampshire may have more current or accurate information. We make no warranties or guarantees about the accuracy, completeness, or adequacy of the information contained on this site or the information linked to on the state site. Please check official sources.
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.