Current through Register Vol. 49, No. 13, September 23, 2024
Subpart 1.
Applicability.
As part of every project, indoor air monitoring must be
performed as specified in this part except that indoor air monitoring is not
required:
A. when a project is
performed in preparation for demolition of a facility and the facility will not
be entered or occupied by any individual not involved with asbestos-related
work during and after the project; or
B. if a domiciled owner of a single-family
residence conducts a project in the single-family residence.
Subp. 2.
General.
Indoor air monitoring must be conducted outside the
containment area during all asbestos-related work including preparation and
cleanup from the time disturbance of asbestos-containing material occurs until
the results of clearance air sampling indicate fiber levels in the air within
the containment do not exceed the clearance standard or alternative clearance
standard.
A. For each containment, two
air samples must be collected simultaneously no less than once during every
zero to five-hour period while abatement personnel are performing
asbestos-related work.
B. One of
the two indoor air monitoring samples required in item A must be collected
within ten feet of the entrance to the decontamination unit. The other air
sampling location must be selected to detect failures in the
containment.
C. Sample collection
must be performed within ten feet of the containment.
D. Sample collection and analysis must comply
with this part and part 4620.3597, subparts 2 to 4.
Subp. 3.
Evacuation and corrective
measures.
If, during the project, the fiber concentration in air
measured outside the containment exceeds the indoor air standard, or the
alternative indoor air standard, or one or more samples are too heavily loaded
to allow for quantitative analysis, the steps in items A and B must take
place.
A. Except as noted in subpart
4, the occupied area immediately adjacent to the asbestos work area must be
evacuated.
B. Evacuated areas must
not be reoccupied until:
(1) the containment
barriers are examined by the site supervisor for holes or separations in the
barriers and any holes or separations are repaired;
(2) the negative pressure of the containment
is checked by the site supervisor and if not in compliance with part 4620.3570,
is brought into compliance;
(3) the
areas adjacent to the containment are cleaned using HEPA-filter vacuum
cleaning, wet wiping methods, or both;
(4) following completion of subitems (1) to
(3), five air samples have been collected simultaneously according to parts
4620.3596 and 4620.3597 in the area where elevated fiber levels occurred;
and
(5) analysis indicates that the
fiber concentration in all air samples collected under subitem (4) does not
exceed the indoor air standard or the alternative indoor air
standard.
Subp.
4.
Suspected nonasbestos dust.
When elevated fiber concentrations in the air outside the
containment are suspected to be from nonasbestos dust in the air, evacuation of
the occupied areas immediately adjacent to the asbestos work area may be
delayed, provided the actions in this subpart are taken immediately.
A. The indoor air monitoring samples which
indicate elevated fiber concentrations must be reanalyzed by transmission
electron microscopy to distinguish between asbestos and nonasbestos fibers
greater than five microns in length with an aspect ratio of three-to-one.
Repeat analysis under this item must meet the requirements of "Mandatory
Transmission Electron Microscopy Method," Code of Federal Regulations, title
40, chapter I, subchapter R, part 763, subpart E, appendix A, section II, Parts
A, E, F, H, I, and J, amended through October 30, 1987, and as qualified in
subitems (1) and (2).
(1) Code of Federal
Regulations, title 40, chapter I, subchapter R, part 763, subpart E, appendix
A, section II, part A, is modified as follows:
(a) The definition of "aspect ratio" is
modified to read:
"3. "Aspect ratio" -- a ratio of the length to the width of a
particle. Minimum aspect ratio as defined by this method is equal to or greater
than 3:1."
(b) The
definition of "fiber" is modified to read:
"9. "Fiber" -- a structure greater than or equal to five
microns in length with an aspect ratio (length to width) of 3:1 or greater and
having substantially parallel sides."
(2) Code of Federal Regulations, title 40,
part 763, subpart E, appendix A, section II, part F, is modified as follows:
(a) Paragraph 9(a) is modified to read:
"9. Recording Rules.
a. Any continuous grouping of particles in which an asbestos
fiber with an aspect ratio greater than or equal to 3:1 and a length greater
than or equal to 5.0 microns is detected shall be recorded on the count sheet.
These will be designated asbestos structures and will be classified as fibers,
bundles, clusters, or matrices. Record as individual fibers any contiguous
grouping having 0, 1, or 2 definable intersections. Groupings having more than
2 intersections are to be described as cluster or matrix. An intersection is a
nonparallel touching or crossing of fibers, with the projection having an
aspect ratio of 3:1 or greater. See the following Figure 2:"
(b) Paragraph 9(a), figure 2, the portion
entitled "DO NOT COUNT AS STRUCTURES," is modified by changing the aspect ratio
from "5:1" to "3:1" and the micrometer length from "0.5" to "5.0."
(c) Paragraph 9(a)(i) is modified to read:
"i. Fiber. A structure having minimum length greater than or
equal to five microns and an aspect ratio (length to width) of 3:1 or greater
and substantially parallel sides. Note the appearance of the end of the fiber,
i.e., whether it is flat, rounded, or dovetailed."
(d) Paragraph 10(a) is modified to read:
"a. Fiber. A structure having minimum length greater than or
equal to 5 microns and an aspect ratio (length to width) of 3:1 or greater and
substantially parallel sides. Note the appearance of the end of the fiber, i.e,
whether it is flat, rounded, or dovetailed."
B. If the analysis results
obtained according to item A indicate the concentration of asbestos fibers in
the air exceeds 0.01 fibers per cubic centimeter of air, the occupied area
immediately adjacent to the asbestos work area must be evacuated and not
reoccupied until the corrective measures of subpart 3, item B, have been
performed and documented.
Subp.
5.
Indoor air monitoring during glove bag or
mini-containment procedures.
When the glove bag or mini-containment procedures in parts
4620.3580 and 4620.3581 are used, indoor air monitoring must be performed
according to this subpart.
A. At least
two indoor air samples per room must be collected continuously from the time of
initial disturbance of the asbestos-containing material until the time all
glove bags or mini-containments have been removed in the room.
B. Indoor air samples during glove bag or
mini-containment procedures must be collected within ten feet of the glove bag
or mini-containment operation.
C.
Sample collection and analysis must be completed according to subpart 4, item
A, or part 4620.3597, subparts 2 to 4.
D. The glove bag or mini-containment
operation is not complete and the asbestos work area must not be reoccupied
until each of the indoor air samples has been analyzed and the result of each
sample indicates a fiber level below the indoor air standard or the alternative
indoor air standard.
E. Except as
noted in item F, if any indoor air sample result exceeds the indoor air
standard or the alternative indoor air standard, or if any indoor air sample is
too heavily loaded to be quantitatively analyzed, subitems (1) to (3) must be
followed.
(1) The area where the glove bag or
mini-containment operation was performed must be recleaned and reinspected
according to part 4620.3575, subpart 4.
(2) After recleaning and reinspection, at
least two indoor air samples must be collected according to item C within ten
feet of the area where the glove bag or mini-containment operation was
performed.
(3) If any air sample
result exceeds the indoor air standard or alternative indoor air standard,
subitems (1) and (2) must be repeated.
F. When elevated fiber concentrations in the
asbestos work area are suspected to be from nonasbestos dust in the air, the
asbestos work area may be reoccupied if the following actions are taken:
(1) the actions required in subpart 4, item
A, must be performed immediately; and
(2) if the analysis results obtained
according to subpart 4, item A, indicate the concentration of asbestos fibers
in the air exceeds 0.01 fibers per cubic centimeter of air, or if any indoor
air sample is too heavily loaded to be quantitatively analyzed, the asbestos
work area must be evacuated and the actions required in item E must be taken
immediately.
Statutory Authority: MS s
144.05;
326.70 to
326.81
