Current through Register Vol. 56, No. 18, September 16, 2024
(a) This section shall
apply to ground vibrations on a construction closest to the nearest loaded blast
hole to be detonated that are neither owned nor leased by the person conducting or
contracting for the blasting operation.
(b) In planning any blast, precautions shall be
taken to protect construction from damage.
(c) The limits for ground vibration when blasting
shall be in accordance with Table 7.26(e) or (f) below. In no case shall the peak
particle velocity at a construction exceed two inches per second except when
permitted by N.J.A.C. 12:190-1.6.
(d) If the ground vibrations are not within the
blasting criteria of (e) below due to either blast design or geological conditions,
the Commissioner may require a modified control method for the blast site.
(e) This subsection shall apply to ground
vibration limits for blasting operations.
1. The
blasting shall be conducted so that the low frequency ground vibration does not
exceed the limits of Figure 7.26(e).
Data in
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(f)
This subsection shall apply to ground vibration limits for blasting operations
utilizing a modified scaled distance established by petition.
1. At any site where blasting is of continuing
nature with the blast design unchanged and geological conditions unchanging, the
commissioner may be petitioned to set a modified scaled distance equation which
would be less restrictive than (d), (e) or (f) above.
2. The petition shall include:
i. A written statement of the reasons for the
request,
ii. A map showing residences
within a radius of 3,000 feet of the blast site,
iii. A proposed method of establishing a modified
scaled distance,
iv. An outline of the
test procedures including monitoring of at least three blasts with approved
instrumentation,
v. A map showing the
exact placement of one instrument at the nearest building, the placement of one
instrument at a distance of 2,000 feet from the blast, and the placement of a third
instrument at some distance between the first two instruments,
vi. A proposed schedule for the test runs which
shall be observed by the commissioner.
3. The instrumentation data shall be interpreted
by a competent person. The modified scaled distance equation shall be based on the
criteria established in (f) above. The modified scaled distance equation shall be
prepared by a competent person and submitted to the commissioner for
approval.
4. Upon approval by the
Commissioner, the modified scaled distance equation may be used at the specific
blast site in place of (e) above provided:
i. The
conditions under which the testing was performed do not change,
ii. The procedure established is verified every
six months,
iii. The modified scaled
distance equation is not willfully disregarded.
(g) This subsection shall apply to instrumentation
used in monitoring ground vibration limits.
(h) Instrumentation used in this section shall
comply with the following:
1. All instruments used
shall be operated by a competent person, and the recordings shall be interpreted by
a competent person.
2. All instruments
and instrumentation systems shall be considered approved only if the instrument
meets the following criteria:
i. The instrument
shall be calibrated in accordance with the manufacturer's recommendations but not
less than once a year by a competent person;
ii. The instrument shall be capable of measuring
and recording particle velocity displacement, or acceleration in three mutual
perpendicular directions;
iii. The
instrument shall have a seismic range from .005 to 10 inches per second (254 mm/s);
and
iv. The instrument shall have a
frequency response range from 2 to 300 hertz.
3. All instruments transducers shall be firmly
coupled to the ground or be used in accordance with the manufacturer's
recommendations.
4. The instrument shall
be placed between a construction closest to the nearest blast hole to be detonated
that is neither owned nor leased by the person conducting or contracting for the
blasting operations. The instrument shall be set up as close to the construction as
possible to comply with (h)3 above.Chapter Notes
