ASTM E2120-00

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Designation:E2120–00
Standard Practice for
the Performance Evaluation of the Portable X-Ray
Fluorescence Spectrometer for the Measurement of Lead in
Paint Films
This standard is issued under the fixed designation E 2120; 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 2.2 ANSI Standards:
American National Standard N538–1979, “Classification of
1.1 This practice covers portable x-ray fluorescence (XRF)
Industrial Ionizing Radiation Gauging Devices”
instruments intended for the measurement of lead in paint. It is
American National Standard N542–1977, “Sealed Radioac-
intended that manufacturers apply this practice to one unit of a
tive Sources, Classification”
particular model of an instrument when that model is initially
2.3 Underwriters Laboratory Standards:
available. Replicate tests on additional units of the same model
Underwriters Laboratory Standard 544, “Medical and Den-
of an instrument are to be performed at the discretion of the
tal Equipment”
manufacturer. This practice also is intended for use by third
Underwriters Laboratory Standard 3101–1, “ChemicalAna-
parties performing independent evaluation of portable x-ray
lyzers”
fluorescence instruments.
1.2 All performance evaluation data are to be in Interna-
3. Terminology
tional System of Units (SI) units.
3.1 Definitions:
1.3 Tests of performance are based on replicate measure-
3.1.1 accuracy, n—the theoretical maximum error of a
mentsofcertifiedreferencepaintfilmsonavarietyofsubstrate
measurement, expressed as the proportion of the amount being
materials. Tests are performed to determine: bias, precision,
measured without regard for the direction of the error, that is
linearity, limit of detection, interferences, substrate affects, and
achieved with a given probability (typically 0.95) by the
stability.
method.
1.4 This standard does not purport to address all of the
3.1.2 bias, n—the discrepancy between the mean of the
safety concerns, if any, associated with its use. It is the
distribution of measurements from a method and the true
responsibility of the user of this standard to establish appro-
concentration being measured.
priate safety and health practices and determine the applica-
3.1.3 limit of detection, n—the smallest (true) signal that
bility of regulatory limitations prior to use.
will be detected with a probability 1 – b (b is the probability
2. Referenced Documents ofanerrorofthesecondkind,failingtodecidethatasubstance
is present when it is), where the a posteriori decision mecha-
2.1 ASTM Standards:
nism has a built-in protection level, a (a is the probability of
D 3332 Test Methods for Mechanical Shock Fragility of
an error of the first kind, deciding that the substance is present
Products, Using Shock Machines
when it is not), against falsely concluding that a blank
E 344 Terminology Relating to Thermometry and Hydrom-
observation represents a “real” signal. The b and a terms
etry
4 typically are 5 % or 1 %, depending on the requirements of the
E 456 Terminology Relating to Quality and Statistics
testing program.
E 1605 Terminology Relating to Abatement of Hazards
3.1.4 precision, n—the closeness of agreement between
from Lead-Based Paint in Buildings and Related Struc-
repetitive test results obtained under prescribed conditions (see
tures
1 6
This practice is under the jurisdiction of ASTM Committee E06 on Perfor- Available from American National Standards Institute, 11 W. 42nd St., 13th
mance of Buildings and is the direct responsibility of Subcommittee E06.23 on Floor, new York, NY 10036.
Abatement of Hazards from Lead in Buildings and Related Structures. Available from Underwriters Laboratories, Inc., Research Triangle Park, NC.
Current edition approved Nov. 10, 2000. Published March 2001. Originally Kennedy, E.R., T.J. Fischbach, R. Song, P.M. Miller, and S.A. Shulman,
published as PS 116 – 99. Last previous edition PS 116 – 99. Guidelines for Air Sampling and Analytical Method Development and Evaluation
Annual Book of ASTM Standards, Vol 15.09. DHHS(NIOSH)PublicationNo.95–117.NationalInstituteforOccupationalSafety
Annual Book of ASTM Standards, Vol 14.03. and Health, Cincinnati, OH 45226, May 1995.
4 9
Annual Book of ASTM Standards, Vol 14.02. Currie, L.A., “Limits for Qualitative Detection and Quantitative Determina-
Annual Book of ASTM Standards, Vol 04.11. tion,” Anal. Chem., 40 (3), pp. 586–593, 1968.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
E2120–00
TerminologyE 456).Theprecisionofasingleinstrumentisthe 3.3.8.1 Discussion—An example CRM in use is the NIST
random component of its accuracy and is usually indicated by Standard Reference Material (SRM) 2579, which consists of
the value of the standard deviation. five films at <0.0001, 0.29, 1.02, 1.63 and 3.53 mg Pb/cm ,
respectively.
3.2 The definitions given in Terminologies E 344 and
E 1605 shall apply to this practice.
NOTE 1—The supply of NIST SRM 2579 standard paint films is now
(r1998) exhausted, though it is likely that this SRM will be replaced with
3.3 Definitions of Terms Specific to This Standard:
a new SRM. CRMs from NIST or commercial vendors may be used in
3.3.1 battery charger, n—a means for recharging a portable
place of NIST SRM 2579, provided the action level of concern, for
instrument’s self-contained battery pack, usually converting 2
example, HUD action level of 1.0 mg/cm , is represented by one of the
110 V AC to low level DC power.
new films.
3.3.2 cycle or reading time, n—a period of x-ray data
3.3.9 stray radiation, n—the sum of leakage and scattered
collection (counting) performed automatically by some instru-
radiation as measured according to 7.1.8.
ments. Such time may be established by a standardization
3.3.10 useful beam, n—radiation that passes through the
procedure that would adjust for variation in the strength of the
window aperture, cone, or other collimating device of the
radioactive source. Also, it might be adjustable on some
source housing; sometimes called primary beam.
instruments to achieve different levels of measurement preci-
3.3.11 X ray detector, n—a device that generates an elec-
sion. Depending on the instrument model, one “cycle time”
tronic signal as a result of the interception of an X ray.
may be equivalent to one “measurement time” or several
Examples include gas proportional counters, for example, Xe,
“cycles” may be automatically or manually averaged to equal
solid scintillation counters, for example, CsI, and semiconduc-
one “measurement time.” The time begins with the opening of
tor devices of elemental, for example, Si or Ge, or compound,
the XRF instrument shutter to expose the paint film surface to
for example, HgI , CdTe, or CdZnTe, composition.
the source radiation and is concluded when the source shutter
4. Summary of Practice
is closed.
4.1 The x-ray instrument is evaluated with respect to a
3.3.3 display unit, n—an electronic device that presents the
series of manufacturer’s requirements for bias, precision,
results of the measurement to the user. Other parameters such
effects of environment, data display, battery operation, con-
as total measurement time also may be presented.
struction, markings, and documentation. The performance of
3.3.4 measurement time, n—the duration of a single mea-
the instrument is evaluated in the laboratory by measuring a
surement observed in real time.Ameasurement may comprise
series of standard lead-containing paint films placed on a wide
several individual readings or cycles.
variety of different substrate materials. Data from replicate
3.3.5 measurement value, n—the readout of a lead concen-
measurements and comparison of measured and expected
tration in mg/cm obtained at the end of one cycle time (or
values are then used to determine bias, precision, limit of
several cycle times if multiple readings are averaged) or at the
detection, linearity, interferences, substrate effects, and stabil-
end of one measurement time.
ity; radiation safety is evaluated, as well.
3.3.6 probe, n—a hand-held device containing the radioac-
5. Significance and Use
tive source, x-ray detector, and associated mechanical and
5.1 The XRF instrument is used to measure the lead content
electrical components that is placed against the test sample to
in paint films in buildings and related structures in order to
perform the measurement. The probe may constitute a part or
determine the potential lead hazard and the possible need for
all of the XRF instrument.
in-place control or abatement, or both.
3.3.7 radioactive source, n—a radioactive material (for
57 109 241
5.2 This practice also is to be used for the laboratory
example, Co, Cd, and Am) that emits X rays or gamma
evaluation of the performance of portable x-ray fluorescence
rays that serve to cause ionization of the lead atoms in the
instrumentation.
sample, and subsequently a cascade of higher energy electrons
5.3 This practice is to be used as a guide for determining
intothevacatedlowerenergyshells.Astheseelectronsfallinto
thatthemanufacturerofportablex-rayinstrumentationhasmet
the lower energy orbitals, they emit energy in the form of X
certain requirements, most of which deal with instrument
rays that are characteristic of lead.
construction.
3.3.8 standard paint films, n—free-standing, certified refer-
5.4 The evaluation may be performed by the manufacturer,
ence paint films, that is, certified reference materials (CRMs),
or an independent party. The results may be presented to
that are acquired from the National Institute of Standards and
various government agencies and, upon request, potential
Technology (NIST) or a commercial vendor. The lead levels in
purchasers and users of the instrumentation.All or parts of this
the standard paint films (CRMs) shall be based on “x” level for
practice also may be performed by an x-ray instrument
leadwhere“x”isequaltotheappropriatelocal,state,orfederal
owner/user to determine the acceptability of an instrument or
action level for lead in coatings (in mg/cm of lead coating).
whether the performance of an instrument continues to be
The paint films shall be as follows:
acceptable, or both.
(Film 1) <0.2x
5.5 This practice may be used by field testers for quality
(Film 2) 0.2x to 0.5x
control by performing selected activities described in the
(Film 3) 0.7x to 1.3x
(Film 4) 1.5x to 2x)
document on a regular and recurring basis in a manner similar
(Film 5) >2x
to those protocols followed by users of laboratory instruments.
E2120–00
5.6 Limitation—Bias and precision, as determined in the (b) Storage outside the manufacturer’s stated temperature
laboratorybythispractice,togetherprovideonlyanestimateof and humidity range.
the accuracy that may be achieved in the field.Accuracy in the
(c) Mechanical shock equivalent to hitting the probe or
field will depend upon the instrument calibration, the form and display unit against a door frame or similar object, or dropping
composition of the substrate, the structure of the paint film
either more than a distance of 30 cm (1 ft).
being analyzed, as well as other factors.
NOTE 2—The critical velocity, V , which is the velocity at which
c
product failure just begins to occur, may be determined using Test
6. Requirements
Methods D 3332. (Formal procedure for testing for failure due to rapid
6.1 Unless otherwise specified, the following requirements
change in the velocity occurring from collision.)
are to be met by the manufacturer of the x-ray instrument.
6.1.5 Data Display Resolution—The digital data display
6.1.1 Bias—The manufacturer shall provide a value or
shall have incremental steps not greater than 0.1 mg/cm ; that
valuesforthebiasoftheinstrumentmodelthathas[have]been
is, a resolution of at least 6 0.1 mg/cm .
determined using the procedure presented in Section 7 of this
6.1.6 Battery Condition—When the instrument is battery
practice. This value shall be made available to potential users,
operated, the bias, precision, and other operational parameters
and also to interested parties, for example, the U. S. Environ-
such as calibration stability shall not be affected by battery
mental Protection Agency and the U. S. Department of
condition, unless a continuous automatic indication of unreli-
Housing and Urban Development.
able battery condition is provided. The indication of unreliable
6.1.2 Precision—The manufacturer shall provide a value or
battery condition must be presented until the battery condition
values for the precision of the instrument model that has been
is corrected. When an instrument uses a rechargeable battery,
determined using the procedure presented in Section 7 of this
some indication shall be provided by the instrument system to
practice. This value shall be made available to potential users,
indicate that the battery is charging.
and also to interested parties, for example, the U. S. Environ-
6.1.7 Construction:
mental Protection Agency and the U. S. Department of
6.1.7.1 Electrical—The instrument and accessories (such as
Housing and Urban Development.
battery chargers) shall meet the electrical safety requirements
6.1.3 Limit of Detection—The manufacturer shall provide a
of UL 544 and UL 3101-1.
value or values for the limit of detection of the instrument that
6.1.7.2 The surface of the instrument including the probe,
has been determined using the procedure presented in Section
controlconsole,andaccessoriesshallwithstandphysicalclean-
7 of this practice. This value shall be made available to
ing using a damp cloth, HEPA vacuum, or manufacturer’s
potential users, and also to interested parties, for example, the
recommended procedures without performance degradation.
U. S. Environmental Protection Agency and the U. S. Depart-
6.1.7.3 The instrument shall withstand a free fall of3m(10
ment of Housing and Urban Development.
ft) onto a flat concrete surface at 25°C (77°F) without evidence
6.1.4 Environment:
of mechanical or electronic failure that could present a radia-
6.1.4.1 Operating Environment—The instrument shall be
tion, or electrical safety hazard, or both. The essential criteria
capable of meeting the manufacturer’s performance specifica-
for passing such a test are that there shall be no external
tions for bias and precision when operating in an environment
dispersal of radioactive material and that the source capsule
of2to35°C(35to95°F)andarelativehumidityof15to95 %,
shall remain captive in its protective source housing. Dumm
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