ASTM D6327-98
(Test Method)Standard Test Method for Determination of Radon Decay Product Concentration and Working Level in Indoor Atmospheres by Active Sampling on a Filter
Standard Test Method for Determination of Radon Decay Product Concentration and Working Level in Indoor Atmospheres by Active Sampling on a Filter
SCOPE
1.1 This test method provides instruction for using the grab sampling filter technique to determine accurate and reproducible measurements of indoor radon decay product (RDP) concentrations and of the working level value corresponding to those concentrations.
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Designation: D 6327 – 98
Standard Test Method for
Determination of Radon Decay Product Concentration and
Working Level in Indoor Atmospheres by Active Sampling
on a Filter
This standard is issued under the fixed designation D 6327; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope bility of regulatory limitations prior to use. See Section 9 for
additional precautions.
1.1 This test method provides instruction for using the grab
sampling filter technique to determine accurate and reproduc-
2. Referenced Documents
ible measurements of indoor radon decay product (RDP)
2.1 ASTM Standards:
concentrations and of the working level value corresponding to
D 1356 Terminology Relating to Sampling and Analysis of
those concentrations.
Atmospheres
1.2 Measurements made in accordance with this test method
D 1605 Practices for Sampling Atmospheres for Analysis of
will produce RDP concentrations representative of closed-
Gases and Vapors
building conditions. Results of measurements made under
D 3631 Test Methods for Measuring Surface Atmospheric
closed-building conditions will have a smaller variability and
Pressure
are more reproducible than measurements obtained when
E 1 Specification for ASTM Thermometers
building conditions are not controlled. This test method may be
utilized under non-controlled conditions, but a greater degree
3. Terminology
of variability in the results will occur. Variability in the results
3.1 Definitions— For definitions of terms used in this test
may also be an indication of temporal variability present at the
method, refer to Terminology D 1356.
sampling site.
3.2 Definitions of Terms Specific to This Standard:
1.3 This test method utilizes a short sampling period and the
3.2.1 radon—the particular isotope Radon-222.
results are indicative of the conditions only at the place and
3.2.2 radon decay products (RDP)—any or all of the
time of sampling. The results obtained by this test method are
particular isotopes polonium-218, bismuth-214, lead-214, and
not necessarily indicative of longer terms of sampling and
polonium-214.
should not be confused with such results. The averaging of
3.2.3 grab sampling—the act and all procedures involved
multiple measurements over hours and days can, however,
with obtaining a short term sample through the use of an
provide useful screening information. Individual measure-
operating air pump.
ments are generally obtained for diagnostic purposes.
3.2.4 working level—quantity of short-lived decay products
1.4 The range of the test method may be considered from
that will result in 1.3 3 10 MeV of potential alpha energy per
0.0005 WL to unlimited working levels (WL), and from 40
liter of air. The working level is the common unit for
Bq/m3 to unlimited for each individual randon decay product.
expressing environmental RDP exposure.
1.5 This test method provides information on equipment,
procedures, and quality control. It provides for measurements
4. Summary of Test Method
within typical residential or building environments and may
4.1 Grab sampling measurements of RDP concentrations in
not necessarily apply to specialized circumstances, for ex-
air are performed by collecting the RDP from a known volume
ample, clean rooms.
of air on a filter and subsequently counting the activity on the
1.6 This standard does not purport to address all of the
filter following collection. The counting is performed at
safety concerns, if any, associated with its use. It is the
specified times for specified periods. The energy from radio-
responsibility of the user of this standard to establish appro-
active decay of the particles collected on the filter is converted
priate safety and health practices and determine the applica-
Annual Book of ASTM Standards, Vol 11.03.
1 3
This test method is under the jurisdiction of ASTM Committee D22 on Annual Book of ASTM Standards, Vol 14.03.
Sampling and Analysis of Atmospheres and is the direct responsibility of Subcom- Annual Book of ASTM Standards, Vol 14.03.
mittee D22.05 on Indoor Air. Thomas, J.W. “Measurement of Radon Daughters in Air,” Health Physics, Vol
Current edition approved Oct. 10, 1998. Published December 1998. 23, 1972, p. 783.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D 6327
to light pulses by a zinc sulfide phosphor in contact with the 7.2.3 High voltage power supply.
filter. The light pulses are detected and converted to counts. 7.3 Thermometer, (See Specification E 1).
Analysis of the number of counts in each counting interval 7.4 Barometer, (See Test Methods D 3631).
determines the concentrations of the RDP. The two counting
8. Reagents and Materials
methods which have found the most general use are the
8.1 National Institute of Standards and Technology (NIST)
Kusnetz and the modified Tsivoglou procedures.
traceable alpha calibration source, typically americium-241, to
8,9
5. Significance and Use
determine counter efficiency.
5.1 The test method provides a relatively simple method for
9. Hazards
determination of the concentration of RDP without the need for
9.1 Since radioactive material is being utilized, both in the
specialty equipment built expressly for such purposes.
form of calibration standards and particles collected on sample
5.2 Using this test method will afford investigators of radon
filters, wear disposable gloves during handling of these items.
in dwellings a technique by which the RDP can be determined.
9.2 If the atmospheres being measured are known to contain
The use of the results of this test method are generally for
high concentrations of RDP, wear an HEPA half-mask respi-
diagnostic purposes and are not necessarily indicative of results
rator during sampling.
that might be obtained by longer term measurement methods.
9.3 The calibration source from NIST must be shielded
5.3 An improved understanding of the frequency of elevated
when not being used for calibration. Shield the source by
radon in buildings and the health effect of exposure has
returning the source to the original NIST storage container and
increased the importance of knowledge of actual exposures.
placing the source in the original storage geometry within the
The measurement of RDP, which are the direct cause of
container.
potential adverse health effects, should be conducted in a
manner that is uniform and reproducible; it is to this end that
10. Preparation of Apparatus
this test method is addressed.
10.1 Verify proper operation of the equipment prior to
collection of the sample. Refer to equipment manuals for
6. Interferences
information.
6.1 Interferences may be caused by any alpha-emitting
10.1.1 Operate each counting system at the high-voltage
particle capable of inducing a light pulse in the phosphor
(HV) and threshold settings that combines maximum stability,
screen used for alpha-counting. In general, the only significant
good counting efficiency, and low background counts. Each
interference source is that of the decay products of radon-220,
manufacturer’s counting systems have different set-up require-
thoron, which may be considerable in certain geographical
ments and optimization procedures. A general similar proce-
regions. The direction of the interference is always positive.
dure is available.
The extent to which thoron decay products interfere can be
10.2 Determine the counter efficiency and background for
estimated or measured through alpha-spectroscopy or serial
the sampling filter and phosphor screen pair prior to collection
type measurements.
of the sample (see Section 11).
6.2 Some depth penetration to the filter may occur. The
10.3 The air pump, filter assembly, and connecting tubing
extent of the penetration may be estimated using membrane
shall not leak.
filter types not suggested within this test method. The direction
10.4 A volume meter is needed for measuring total sample
of interferences is always negative.
flow. A calibrated dry gas test meter is the most satisfactory
total volume meter available for source test work. Calibrate the
7. Apparatus
meter in the laboratory prior to use with a positive displace-
7.1 Collection Apparatus:
ment liquid meter or a cylinder and piston flow calibrator, and
7.1.1 Air pump capable of 10 to 12 L/min flow rate.
determine a meter correction factor, C , as necessary.
M
7.1.2 Bubble tube airflow calibration cell, 1 L or larger.
10.5 Locate the scintillation counter to provide rapid access
7.1.3 Calibrated dry gas meter.
from the sampling site when the modified Tsivoglou counting
7.1.4 Flow meter (optional).
procedure is utilized. This process is necessary due to the short
7.1.5 Open-faced filter holder, 25 or 47-mm diameter.
time period between sampling and the start of counting.
7.1.6 Membrane filters, mixed cellulose ester, 25 or 47-mm
diameter, 0.8-μm pore size.
11. Procedure
7.1.7 Sharpened forceps, for removal of sample filters.
11.1 Calibration of Scintillation Counter:
7.1.8 Stopwatch, accurate to 1 s.
7.2 Decay Counting Apparatus:
Interlaboratory Radon-Daughter Measurement Comparison Workshop: 9-12
7.2.1 Zinc sulfide phosphor discs, 51-mm diameter.
September 1985, GJ/TMC-25 UC-70A, United States Department of Energy,
7.2.2 Scintillation Counter, scaler and photomultiplier tube.
Washington D.C. [Available through: NIST, National Technical Information Ser-
vice, United States Department of Commerce, Springfield, VA 22161].
Available from: NIST Standard Reference Materials Catalog, NIST Special
Indoor Radon and Randon Decay Product Measurement Protocols, EPA Publication 260, U.S. Department of Commerce, Nation Institute of Standards and
402–R–92–004, July 1992, United States Environmental Agency, Washington D.C. Technology 1990-1991, Issued January 1990, as Catalog SRM No. 4904NG.
7 10
Measurement of Radon and Radon Decay Products in Air, NCRP Report No. Standard Test Method for Radon Grab Sampling, Revision 02, March 31,
97, National Council on Radiation Protection and Measurements, Bethesda, MD 1992; GJ/TMC Technical Procedure RN-GRAB-U, United States Department of
20814, Nov. 15, 1988. Energy, Washington D.C.
D 6327
11.1.1 Determine the efficiency of the scintillation counter 11.2.5 Reassemble the filter holder with care to prevent
through use of the NIST-traceable alpha-emitting calibration tearing of the filter.
point source. 11.2.6 Obtain the initial dry gas meter reading.
11.1.2 Deactivate the photomultiplier tube. Exposure of an 11.2.7 Draw sample air through the filter for 5.00 min.
activated photomultiplier tube to light while connected to 11.2.8 Obtain the final dry gas meter reading and record the
power may permanently damage the photomultiplier tube. volume of air sampled in liters, V.
11.2.9 Disassemble the filter holder, and carefully transfer
NOTE 1—Although comments have been received indicating any light
the filter from the filter holder onto the phosphor disc with
incident on the deactivated photomultiplier tube, even though completely
which the background was just previously measured (exposed
disconnected from power, will result in spurious addition/deletions of light
pulses. Tests conducted with four photomultiplier tubes of two designs at sample filter side oriented toward the phosphor disc). During
the Grand Junction DOE Facility Radon Chamber indicated no variation
the transfer, inspect the filter for tears. If a tear is found, discard
in background counts from photomultiplier tubes kept in the dark versus
and begin again. Cover the filter with the cover plate. Cover
the same tubes with large mercury arc lamps over the tubes.
and reactivate the photomultiplier tube.
11.1.3 Place a fresh phosphor disc (phosphor side up) at the
11.3 Sample Counting— Two different counting techniques
center of the photomultiplier lens.
are described in this section, a modified Tsivoglou Technique
11.1.4 Cover and activate the photomultiplier tube. The
(see 11.3.1) and a Kusnetz Technique (see 11.3.2). Each
photomultiplier shall not be opened to light while activated or
technique requires a unique set of counting intervals. Addition-
the electronics will be shocked. It is very important that there
ally, each technique requires a separate set of calculations as
be no power to the opened photomultiplier.
listed in Section 12.
11.1.5 Activate the scintillation counter for a defined count-
11.3.1 Modified Tsivoglou Technique—Operate the scintil-
ing interval in minutes, C . The counting interval shall be long
I lation counter for the following time intervals. The intervals
enough to obtain at least 10 000 counts from the alpha-emitting
are measured from the time the 5.00 min sampling period has
source. The number of counts obtained from the phosphor is
ended.
the background count, B .
cal Count Designation, M Time Interval, T
(ab)
11.1.6 Deactivate the photomultiplier tube. M 2 to 5 min (3 min)
(2-5)
M 6 to 20 min (14 min)
(6-20)
11.1.7 Determine the calibration source count. Using for-
M 21 to 30 min (9 min)
(21-30)
ceps, place the calibration point source on top and in the center
Record the total number of counts during each time interval
of the same phosphor disc as used in 11.1.3.
M ,[M ,M , and M ].
11.1.8 Cover and then activate the photomultiplier tube. The ab (2-5) (6-20) (21-30)
photomultiplier shall not be opened to light while activated or
NOTE 2—Other counting techniques have been devised and are pres-
the electronics will be shocked. It is very important that there
ently in use. However, the most generally used counting technique is the
be no power to the opened photomultiplier.
one presented here.
11.1.9 Activate the scintillation counter for the counting
11.3.2 Modified Kusnetz Technique—Operate the scintilla-
interval, C , and the number counts obtained is the measured
I
tion counter over any 10 min interval between 40 and 90 min
calibration count, M .
cal
after the start of sampling. Record the total counts for the 10
11.1.10 Calculate the efficiency of the counter using the
min interval, K, and the time (in minutes after the end of
equation in 12.2.
sampling), t,atthe center of the 10 min interval.
11.2 Sample Measurement:
11.4 Obtain the temperature, s, and the ambient atmospheric
11.2.1 Deactivate the photomultiplier tube.
pressure, p, at the sampling site (See ASTM Standards in
11.2.2 Place a fresh phosphor disc at the center of the
Section 2.1).
photomultiplier lens. Select a sampling filter with the forceps,
and inspect the filter to determine if any tears are presen
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