Current through Register Vol. 49, No. 13, September 23, 2024
Subpart 1.
Phase contrast microscopy air sample analysis.
Analysis by phase contrast microscopy must comply with
National Institute for Occupational Safety and Health (NIOSH) Method 7400,
revision number 3, titled "Fibers" published in the NIOSH Manual of Analytical
Methods, Third Edition, August 1994 supplement or equivalent methods. This
document is incorporated by reference, is not subject to frequent change, and
is available through the Minitex interlibrary loan system.
Subp. 2.
Procedures for establishing an
alternative indoor air standard.
When collecting air monitoring samples to establish an
alternative indoor air standard, the procedures in this part apply.
A. An alternative indoor air standard may be
established only if background fiber levels in the asbestos work area exceed
the indoor air standard before the start of abatement.
B. To establish an alternative indoor air
standard, five air monitoring samples must be collected simultaneously and
analyzed according to this part before the start of abatement including area
preparation.
C. The alternative
indoor air standard must be calculated as the upper bound of the range defined
by the 95 percent confidence interval from the average of the result of the
five indoor air monitoring samples.
D. Locations for air monitoring sample
collection must be selected to provide suitable data for comparison with indoor
air monitoring samples collected after abatement begins. Sample locations must
be indoors and within ten feet of where the containment will be
constructed.
E. The alternative
indoor air standard applies only to the containment area where the air samples
used to establish the alternative indoor air standard were collected.
Subp. 3.
Air monitoring
sample collection and analysis.
When phase contrast microscopy is used to analyze air
monitoring samples:
A. air volumes
drawn through the filter cassette must be sufficient to determine fiber
concentrations to 0.01 fibers per cubic centimeter of air;
B. a volume of 2,000 liters must be drawn
through the filter cassette, except as noted in item C; and
C. when a volume of 2,000 liters cannot be
drawn through the filter cassette, subitems (1) to (5) apply.
(1) More fields must be counted than the 100
microscope field maximum which is specified in NIOSH method 7400.
(2) The maximum number of fields to be
counted must be determined by dividing 2,000 liters by the volume filtered and
multiplying the result by 100 fields.
(3) Additional segments of the filter must be
used for counting.
(4) If the
cumulative fiber count reaches 100 fibers before the maximum number of fields
have been counted, the analysis must stop.
(5) The concentration must be calculated
based on the number of fibers and the number of fields counted.
Subp. 4.
Transitional air monitoring sample analysis.
Between July 1, 1996, and July 1, 1997, air monitoring
samples must be analyzed by:
A. a
laboratory that is accredited by the American Industrial Hygiene
Association;
B. an analyst
considered proficient by the American Industrial Hygiene Association's asbestos
analyst registry program; or
C. a
laboratory considered proficient in asbestos analysis by the American
Industrial Hygiene Association (AIHA) Proficiency Analytical Testing (PAT)
Program for phase contrast microscopy.
Subp. 5.
Air sample analysis.
Beginning July 1, 1997, air monitoring samples must be
analyzed by:
A. a laboratory that is
accredited by the American Industrial Hygiene Association; or
B. an analyst considered proficient by the
American Industrial Hygiene Association's asbestos analyst registry
program.
Statutory Authority: MS s
144.05;
326.70 to
326.81
