DRAFT ANSI N323C-200x
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AMERICAN NATIONAL STANDARD
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American National Standard
Radiation Protection Instrumentation
Test and Calibration –
Air Monitoring Instruments
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FINAL DRAFT – July 2008
N42 Comment Resolution Copy
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Sponsor
National Committee on Radiation Instrumentation, N42
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Accredited by the
American National Standards Institute
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Secretariat
Institute of Electrical and Electronics Engineers, Inc.
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Approved (date to be determined)
American National Standards Institute
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Abstract- This standard establishes test and calibration requirements for air
monitoring instruments used for the detection and measurement of airborne
radioactive substances.
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Key words: radioactive air monitoring, calibration and tests.
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Participants
At the time it approved this standard, the Accredited Standards Committee on Radiation
Instrumentation, N42, had the following membership:
Michael P. Unterweger, Chair
Louis Costrell, Deputy Chair
William Ash, Administrative Secretary
Organization Represented .......................................................................... Name of Representative
Canberra ..................................................................................................................Markku Koskelo
Chew, M.H. ................................................................................................................. Jack M. Selby
Commerce Dept, U.S. NIST ............................................................................. Michael Unterweger
........................................................................................................................... Louis Costrell (Alt.)
Department of Homeland Security............................................................................... Peter Shebell
Entergy-ANO .............................................................................................................. Ron Schwartz
Health Physics Society. .................................................................................................. Sandy Perle
Institute of Electrical & Electronics Engineers, Inc. ................................................... Louis Costrell
............................................................................................................................ Julian Forster (Alt.)
...................................................................................................................... Anthony Spurgin (Alt.)
................................................................................................................. Michael Unterweger (Alt.)
International Medcom .......................................................................................................Don Sythe
Lawrence Berkeley National Laboratory .............................................................. Edward J. Lampo
Lawrence Livermore National Laboratory ...................................................................Gary Johnson
NASA, GSFC ................................................................................................ R. Sachidananda Babu
U. S. Nuclear Regulatory Commission ....................................................................... Cynthia Jones
Nuclear Standards Unlimited .................................................................................. Al N. Tschaeche
Oak Ridge National Laboratory ............................................................................ Peter J. Chiaro, Jr
......................................................................................................................... Charles Britton (Alt.)
Ortec Corp. ........................................................................................................... Ronald M. Keyser
Pacific Northwest National Laboratory.................................................................... Richard Kouzes
Swinth Associates ............................................................................................... Kenneth L. Swinth
U.S. Army ............................................................................................................... Edward Groeber
U. S. Nuclear Regulatory Commission ....................................................................... Cynthia Jones
Members-At-Large........................................................................................................ Morgan Cox
.................................................................................................................................. Frank X. Masse
.......................................................................................................................... Joseph C. McDonald
.................................................................................................................................... Paul L. Phelps
.................................................................................................................................... Joseph Stencel
.................................................................................................................................... Lee J. Wagner
.................................................................................................................................... Ernesto. Corte
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At the time this standard was approved, Subcommittee N42.RPI had the following membership:
Morgan Cox, Co-Chair
Jack M. Selby, Co-Chair
Dru Carson
Peter J. Chiaro, Jr.
Jack Cooley
Leo Faust
Edward Groeber
Jerry Hiatt
Mark D. Hoover
Ron Keyser
J. C. McDonald
Robert Murphy
Cheryl Olson
Scott Rogers
Michael P. Unterweger
Ed Walker
Chuan-Fu Wu
At the time this standard was approved, the ANSI N323C Working Group had the following
members:
Michelle L. Johnson, Co-Chair
Mark D. Hoover, Co-Chair
L. Bryan Belvin
Brent Blunt
Morgan Cox
Stephen A. Epperson
Michael S. Ford
Robert J. Ford
John A. Glissmeyer
Robert A. Kellner
Timothy Martinson
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George J. Newton
John C. Rodgers
Johnafred M. Thomas
James T. Voss
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CONTENTS1.0
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SCOPE
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1.1
Applications of this standard
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1.2
Special word usage
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2.0
DEFINITIONS
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3.0
PROGRAM ELEMENTS
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3.1
Type testing
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3.2
Acceptance testing
3.2.1
Physical inspection
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General operations test
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Radiological response tests
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3.3
Initial calibration
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3.4
Functional checks
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3.5
Maintenance and recalibration
3.5.1
Maintenance
3.5.2
Recalibration
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3.6
Performance tests
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4.0
AIR FLOW RATE CALIBRATIONS
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5.0
INSTRUMENT CALIBRATIONS
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5.1
Pre-calibration inspection
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5.2
As-found readings
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5.3
Electronic calibration
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5.4
Meters and chart recorders
5.4.1
Analog linear readout instruments
5.4.2
Analog logarithmic readout instruments
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Digital readout instruments
5.4.4
Microprocessor-based instruments
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5.5
Background response verification
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5.6
Calibration of background subtraction
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5.7
Alarm circuit verification
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Radiological calibration
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6.0 ADDITIONAL CALIBRATION REQUIREMENTS FOR PARTICULATE AND
NOBLE GAS MONITORS
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6.1
Alpha and beta particulate monitors
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6.2
Keep-alive sources
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6.3
Noble gas monitors
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Pre-calibration
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Electronic calibration
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Radiological calibration
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7.0
CALIBRATION FOR SPECIAL CONDITIONS
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8.0
FACILITIES, CONDITIONS, AND EQUIPMENT
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8.1
Calibration facility
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8.2
Test and calibration conditions
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8.3
Calibration standards
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8.4
Maintenance of standards
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8.5
Check sources
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9.0
DOCUMENTATION
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9.1
Facility documentation
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9.2
Instrument Documentation
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10.0
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APPENDIX A - SUMMARY OF A LIFE-CYCLE APPROACH TO INSTRUMENT
DEVELOPMENT AND APPLICATION
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APPENDIX B - FLOW RATE METER CALIBRATIONS
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REFERENCES
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AMERICAN NATIONAL STANDARD
RADIATION PROTECTION INSTRUMENTATION
TEST AND CALIBRATION –
AIR MONITORING INSTRUMENTS
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1.0
Scope
This standard establishes test and calibration requirements for air monitoring
instruments used for detection and measurement of airborne radioactive substances.
The appendices of this standard provides reference information.
The standard covers the following topics:
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Test and calibration elements of a comprehensive air monitoring instrument
program;
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Test and calibration requirements for all types of air monitoring instruments;
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Additional requirements for specialized monitors;
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Calibration for special conditions;
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Required conditions, facilities, and equipment, and
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Documentation.
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1.1
Applications of this standard
This standard applies to the calibration of installed, portable, and personal air
monitoring instruments used for regulatory compliance, including continuous air
monitors for effluent, work place, and environmental applications. It may not be
universally applicable to all programs, especially those with more limited objectives
such as process control. When calibrating instrumentation used for objectives other
than regulatory compliance, the user of this standard should exercise judgment in the
application of these requirements and should document the monitoring objectives and
the reasons for any exceptions to the requirements of this standard. Relationship to
other standards
This standard shall be used in conjunction with ANSI N42.17B-1989 listed below. Many
items herein are identical to those in N42.17B, for example, the standard test conditions
of Table 2 in section 8.2.
The following national and international standards specify design and performance
issues, including when, where, and how air monitoring instruments shall, should, or may
be used to sample or monitor airborne radioactive substances. Such issues are
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addressed in this standard to the extent that they influence the ability to achieve proper
calibration.
ANSI N42.17B-1989, Performance Specifications for Health Physics Instrumentation –
Occupational Airborne Radioactivity Monitoring Instrumentation, specifies performance
criteria and testing procedures for instruments and instrument systems designed to
continuously sample and quantify concentrations of radioactivity in ambient air in the
workplace. It does not specify which instruments or systems are required, nor does it
address the specific locations or applications of such instruments.
ANSI N42.18-1974 (Reaffirmed 2004), Specification and Performance of On-Site
Instrumentation for Continuously Monitoring Radioactivity in Effluents, provides
recommendations for the selection of continuous monitors specific to the continuous
monitoring and quantification of radioactivity in effluents released to the environment
from nuclear facilities under normal operating conditions. It applies to continuous
monitors that measure normal releases, detect inadvertent releases, show general
trends, and annunciate radiation levels that have exceeded predetermined levels. It
does not cover emergency situations, sample extraction, laboratory analyses,
environmental monitoring, or process control.
ANSI N13.1-1999, Sampling and Monitoring Releases of Airborne Radioactive
Substances from the Stacks and Ducts of Nuclear Facilities, presents a comprehensive
approach to achieving an unbiased, representative sample from air streams by meeting
rigorous criteria for obtaining a well-mixed sample.
ANSI N320-1979 (Reaffirmed 2003), Performance Specifications for Reactor
Emergency Radiological Monitoring Instrumentation, addresses the essential
performance parameters of monitoring instruments used during an accident at nuclear
reactors. The instrument operating environment, operational characteristics, lower and
upper detection limits are also addressed. The general instrument locations inside the
reactor plant, at release points, and in the plant environs are addressed.
ANSI N42.22-1995 (Reaffirmed 2002), Traceability of Radioactive Sources to the
National Institute of Standards and Technology (NIST) and Associated Instrument
Quality Control, provides a description of the criteria necessary for manufacturers to
maintain and assure measurement traceability of radionuclides to NIST.
ANSI N42.23-1996 (Reaffirmed 2004), Measurement and Associated Instrumentation
Quality Assurance for Radioassay Laboratories, provides the framework to create a
national or an organizational NIST-traceable measurement quality assurance (MQA)
program.
ANSI N42.30-1999, Performance Specification for Tritium Monitors, provides
performance requirements for tritium monitors used for monitoring airborne tritium
radioactivity. It also provides set methods that can be used to establish performance
characteristics of a monitor.
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IEC 60761-1 (2002) Equipment for Continuously Monitoring Radioactivity in Gaseous
Effluents-Part 1: General requirements. These five standards are self explanatory
based on their titles.
IEC 60761-2 (2002) Equipment for Continuously Monitoring Radioactivity in Gaseous
Effluents- Part 2: Specific requirements for radioactive aerosol monitors including
transuranic aerosols.
IEC 60761-3 (2002) Equipment for Continuously Monitoring Radioactivity in Gaseous
Effluents-Part 3: Specific requirements for radioactive noble gas monitors.
IEC 60761-4 (2002) Equipment for Continuously Monitoring Radioactivity in Gaseous
Effluents-Part 4: Specific requirements for radioactive iodine monitors.
IEC 60761-5 (2002) Equipment for Continuously Monitoring Radioactivity in Gaseous
Effluents-Part 5: Specific requirements for tritium monitors.
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1.2
Special word usage
Throughout this standard, three verbs have been used to indicate the degree of rigor
intended for each specific criterion. The word shall denotes a requirement, the word
should denotes a recommendation, and the word may denotes permission.
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2.0
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Definitions
Acceptance Test: Evaluation or measurement of performance characteristics to verify
that certain stated specifications and contractual requirements are met as agreed
between the manufacturer and the purchaser/user. (ANSI N323A-1997; ANSI N42.332003)
Accredited Calibration Laboratory: A calibration laboratory that has been accredited
by an authoritative body (e.g., Health Physics Society, American Association of
Physicists in Medicine, National Institute of Science and Technology), with respect to its
qualifications to perform calibrations on the type of instruments covered by this
standard. (ANSI N323A-1997)
Accuracy: The degree of agreement of the observed value with the conventionally true
value of the quantity being measured. (ANSI N323A-1997; ANSI N42.33-2003)
Adjust: To alter the response by means of hardware or software control. (ANSI N323A1997; ANSI N42.33-2003)
Air Sampler: Device designed to trap the radioactive contamination contained in a
known volume of air passing through a filter or around an impaction surface in a pre-set
time interval. For example, continuous moving filter type, intermittent moving type, fixed
filter type. (IEC 50(394)
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Air Monitoring Instrument: Radiation monitor for the continuous measurement of the
radioactive emission rate of the airborne materials. (IEC 50 (394)) Note: These are also
termed Continuous Air Monitors or CAMs.
Calibrate: (A) To adjust and or determine the response or reading of a device relative
to a series of conventionally true values for radiation sources. (B) To determine the
strength of a radiation source relative to a standard or conventionally true value (ANSI
N323A-1997).
Calibration: A set of operations that establishes the relationship between values
indicated by a measuring instrument or measuring system, and the conventionally true
values of the measurand under specified conditions. (ANSI N42.33-2003)
Check Source: A not necessarily calibrated radioactive source that is used to confirm
the continuing functionality of an instrument. (ANSI N42.33-2003)
Conventionally True Value (CTV) of a Quantity: The commonly accepted estimate of
the value of that quantity. This and the associated uncertainty will preferably be
determined by a national or transfer standard, or by a reference instrument that has
been calibrated against a national or transfer standard, or by a measurement quality
assurance (MQA) interaction with the National Institute of Standards and Technology
(NIST) or an accredited calibration laboratory. Refer to ANSI N42.22-1995 (reaffirmed
2002) and ANSI N42.23-1996 (Reaffirmed 2004).
Decade: A range of values for which the upper value is a power of ten above the lower
value (ANSI N323A-1997; ANSI N42.33-2003).
Detection Limits: Refer to Range.
Detection Threshold (Lower limit of detection): Value of the indication of the
measurement for which the relative random uncertainty equals +/-100% at the
probability of 95%. (IEC 394-40-20)
Detector: A device or component designed to produce a quantifiable response to
ionizing radiation normally measured electronically. (ANSI N323A-1997; ANSI N42.332003)
Effective Center: For a given set of irradiation conditions, the point within a detector
where the response is equivalent to that which would be produced if the entire detector
were located at the point. (ANSI N42.33-2003)
Energy Dependence: Variation in instrument response as a function of radiation
energy for a constant radiation type and exposure rate referenced to air. (ANSI N42.332003)
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Functional Check: A frequently used qualitative check to determine that an instrument
is operational and capable of performing its intended function. Note: Such checks may
include, for example, a battery check, zero setting, or source response check. (ANSI
N42.33-2003)
Indicated Value: (A) A scale or decade reading. (B) The displayed value of the
readout. See also: reading (ANSI N323A-1997; ANSI N42.33-2003).
Instrument: A complete system consisting of one or more assemblies designed to
quantify one or more characteristics of ionizing radiation or radioactive material. (ANSI
N323A-1997, ANSI N42.33-2003)
Keep-alive Source: A radioactive source, typically with a disintegration rate of a few
Bq, mounted on or near the detector to assure that the detector is operational at all
times by providing a continuous positive signal.
Monitoring: Real time measurement of radioactivity or radiation level. (ANSI N42.332003)
Overload Response (or Over-range Response): The response of an instrument
when exposed to radiation intensities greater than the upper measurement limit. (ANSI
N323A-1997; ANSI N42.33-2003)
Performance Test: An evaluation of the performance of an instrument in response to a
given influence quantity. (ANSI N323A-1997; ANSI N42.33-2003)
Personal air sampler: Air sampler worn on the person (e.g., lapel air sampler).
Portable Air Monitoring Instrument: A readily transportable instrument that meets
the definition of “air monitoring instrument,” and that is not considered to be “installed.”
Range: All values lying between the detection threshold and the upper measurement
limit. (ANSI N323A-1997, ANSI N42.33-2003)
Reading: The indicated value of the readout. (ANSI N323A-1997, ANSI N42.33-2003)
Readout: The portion of the instrument that provides a visual display of the instrument
response. (ANSI N323A-1997, ANSI N42.33-2003)
Response: Ratio, under specified conditions, of the value of quantity measured by the
equipment or assembly under test and the conventionally true value of this quantity.
(IEC 50(394))
Sampling: The process of collecting a sample from a volume of air.
Standard (instrument or source): (A) National standard – a standard determined by a
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nationally recognized competent authority to serve as the basis for assigning values to
other standards of the quantity concerned. In the U.S., this is an instrument, source, or
other system or device maintained and promulgated by the National Institute of
Standards and Technology (NIST). (ANSI N42.33-2004) (B) Primary standard – a
standard that is designated or widely acknowledged as having the highest metrological
qualities and whose value is accepted without reference to other standards of the same
quantity. (ISO 1993; ANSI N42.33-2004) (C) Secondary Standard - a standard whose
value is assigned by comparison with a primary standard of the same quantity. (ISO
1993; ANSI N42.33-2004) (D) Reference Standard - a standard, generally having the
highest metrological quality available at a given location or in a given organization, from
which measurements made there are derived. (ISO 1993; ANSI N42.33-2004) (E)
Transfer Standard: A standard used as an intermediary to compare standards. (Note:
If the intermediary is not a standard, the term transfer device should be used. (ISO
1993) (F) Working Standard - a standard that is used routinely to calibrate or check
material measures, measuring instruments, or reference materials. A working standard
is usually traceable to NIST. (ISO 1993; ANSI N42.33-2003)
Test: A procedure whereby the instrument, circuit, or component is evaluated. (ANSI
N42.33-2004)
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3.0 Program Elements
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Type Testing: Initial test of two or more production instruments made to a specific
design to show that the design meets defined specifications. (ANSI N42.33-2004)
Uncertainty: The estimated bounds of the deviation from the conventionally true value,
generally expressed as a percent of the mean, and ordinarily taken as the square root
of the sum of the square of the two components (ANSI N323A-1997; ANSI N42.332003):
a) Those components that are evaluated by statistical means; and
b) Those components that are evaluated by other means. (see NIST Special
Publication 1297).
Upper Measurement Limit: The upper measurement limit is the maximum
level at which the instrument meets the required accuracy. (ANSI N323A1997; ANSI N42.33-2003)
The test and calibration elements of a comprehensive air monitoring instrument
program include tests that are performed once (typically on new instruments), such as
type testing and acceptance testing, as well as elements that are performed repeatedly,
such as functional checks, periodic maintenance and recalibration, and performance
testing. Each of these elements is discussed further in the following sections.
Appendix A summarizes a life-cycle approach to the development and application of
instrumentation. It lists additional development and prototype steps that may be
performed when developing and applying an instrument. These additional tests are not
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discussed further in this standard but are included in Appendix A to provide a
comprehensive outline of a complete program for instrument development, testing, and
application.
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3.1
Type testing
The accuracy of operational measurements can be affected by instrument stability and
by variation in influence quantities such as radiation energy and radiation direction,
temperature, pressure, humidity, and electromagnetic and electrostatic conditions. The
instrument performance characteristics, as defined by the type testing, will indicate how
accurately the instrument can be expected to measure the airborne radioactive material
under variable operating conditions.
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Type testing shall be performed for each instrument model. Type testing shall be
performed on two or more production units to fully characterize the performance and
limitations of the instrument. Users shall match operational requirements with the
conditions of type testing that demonstrate an instrument is capable of meeting those
requirements. The results of type testing shall be documented.
Type testing shall be repeated:
1. When modifications are made to the instrument design that may affect instrument
performance, or
2. When changes occur in operational conditions that may affect instrument
performance
3.2
Acceptance testing
Acceptance testing shall be performed on each new instrument before initial use. For
large numbers of instruments, it shall be considered acceptable to establish statistical
criteria for testing and accepting instruments.
Acceptance testing should evaluate each instrument against specific characteristics
identified during the type testing as critical or indicative of overall instrument
performance. The purpose of acceptance testing is to demonstrate that the instrument
meets certain stated specifications and/or contractual requirements.
An acceptance test should consist of:
a) physical inspection,
b) general operations tests, and
c) radiological response tests.
The acceptance testing protocol should be agreed upon between the manufacturer and
the purchaser/user. The results of acceptance testing should be documented.
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3.2.1 Physical inspection
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A physical inspection identifies any physical abnormalities that may effect instrument
operation (for example, broken parts; improperly operating moving parts; loose or
missing screws; unsecured circuit boards; loose wires, connectors, or components;
loose or misaligned knobs, and misaligned calibration potentiometer access holes).
Physical inspections shall be performed on each instrument.
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3.2.2 General operations test
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A general operations test is a determination of non-radiological operating functions (for
example, checking battery condition, verifying mechanical zero, testing the meter zero
potentiometer, or checking visual display elements, if applicable). General operations
tests shall be performed on each instrument.
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3.2.3 Radiological response tests
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When greater than 40 instruments are involved, the radiological response tests should
be performed on a random selection of 10% of the instrument batch. When fewer than
40 instruments are involved, no fewer than 4 instruments should be tested, or 100% of
the batch if fewer than 4 instruments. The instruments should be tested under the
range of anticipated operating conditions. If one instrument in a sample of a large
quantity fails the test, an additional 10% should be tested. An additional failure would
result in the need to test the entire batch.
Radiological response characteristics that may be tested during acceptance testing
include detection efficiency, energy dependence, overload response, measurement
range, and stability.
These tests shall be performed on calibrated instruments.
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3.3
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Each instrument shall be calibrated prior to deployment. Initial calibration shall be
performed as described in Sections 4, 5 and 6.
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Initial calibration
Functional checks
Functional checks shall be performed in the field prior to putting the instrument into
service and periodically during use to ensure:
(1) that the instrument is operating properly, and
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(2) that the instrument alarms on an appropriate level of detected radioactivity.
The frequency of functional checks should be commensurate with the overall reliability
of the instrument, the degree to which the instrument monitors itself for failures, and the
hazard potential of the material to be monitored.
The manufacturer should provide an appropriate method to verify:
a.
b.
c.
d.
Proper audible and visual alarms,
Detector operation using a radioactive source or natural background,
Flow rate, and
Calibration.
If the functional check includes the use of a check source to verify radiological
response, the radiological response of the instrument should be within ±20% of the
reference response. The reference response should be obtained for each instrument
when exposed to a source in a constant and reproducible manner, either at the time
that the instrument is received in the field or before its first use. Where it is shown that
readings for a specific model of instrument fall within ±20%, it shall be permissible to
obtain generic reference responses for a given source. Alpha monitoring instruments
shall use a long-lived alpha emitter such as thorium or uranium for functional checks.
Functional checks shall be documented. Appropriate data from the functional checks
should be recorded and reviewed for adverse trends indicating the need for changes in
component replacement frequency, component design, recalibration frequency, or
facility-related interfaces.
3.5
Maintenance and recalibration
Maintenance and recalibration shall be performed periodically on all instruments to
assure that the instruments continue to meet the required accuracy for field
measurements. This is required even when the functional check requirements are met.
Recalibration frequency shall be documented.
The frequency of maintenance and recalibration should typically be set at one year and
shall be based on the following:
 Documented functional check procedures and results,
 Documented maintenance histories including failure rates for the same model
instruments in the same environment,
 Manufacturer specifications,
 Design specifications, and
 Performance history.
If the performance history of the instrument(s) indicates that the instrument is
sufficiently reliable (i.e., recalibration as-found data is within tolerance > 95% of the
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time), less frequent recalibrations may be performed, provided the recalibration
frequency does not exceed 3 years. An example motivation for less frequent
recalibrations is if the monitor is not routinely accessible (i.e. during periods of reactor
operation).
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3.5.1 Maintenance
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Where instruments are subjected to extreme operational conditions, hard usage, or
corrosive environments, more frequent maintenance and recalibration should be
scheduled. As found readings shall be documented to demonstrate that few (e.g., less
than 15%) instruments are out-of-calibration with the selected recalibration frequency.
If large numbers (e.g., more than 15%) of instruments are out-of-calibration at the end
of the selected recalibration interval, the maintenance and recalibration frequency
should be increased. NCSL RP-1, Establishment and Adjustment of Calibration
Intervals, provides additional information on a statistically based, technically defensible,
method of determining the appropriate recalibration intervals.
Maintenance shall be performed using components that affect performance, electronic
and/or electrical and mechanical, which are at least equivalent to those specified by the
manufacturer. If the manufacturer does not provide maintenance instructions, a
maintenance instruction should be written and approved by persons in the organization
responsible for performing the maintenance and/or recalibration. Where the
manufacturer does provide written instructions, the organization responsible for
maintenance and/or recalibration may document acceptance of the instructions.
Repairs made using unapproved instructions or components that may affect instrument
performance constitute an instrument modification, and shall render invalid any type
tests made on the instrument model as applied to the specific instrument. Modified
instruments shall have their performance tested and documented prior to issuance for
field use. If the user can document that the modifications will not affect the instrument
performance, additional testing is not required.
3.5.2 Recalibration
Recalibration is different from a functional check or simple evaluation with a check
source. It includes a pre-calibration check followed by adjustment and recalibration.
Recalibration shall be scheduled after any maintenance or repair that can affect
instrument performance. For this requirement, adjusting the air flow rate, adjusting
alarm set points, or changing batteries or filters is not normally considered
maintenance.
During the pre-calibration check the instrument shall be tested to ensure that certain
electronic operating requirements, specified by the manufacturer, are met. This
ensures that the instrument is in proper working order prior to recalibration.
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Recalibration shall be performed as described in Sections 4, 5 and 6.
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Performance tests
Over the life of an instrument, the instruments should be periodically performance
tested to verify that component aging and/or replacement components have not
affected the ability of the instrument to meet operational requirements. For large
numbers of instruments, it shall be considered acceptable to establish statistical criteria
for performance testing.
Whenever modifications are made to the instruments that affect their response,
performance tests shall be conducted to evaluate the response characteristic that may
have been impacted. Modifications include altering the instrument firmware or software
or replacing instrument parts with spare parts other than those recommended by the
manufacturer.
Whenever changes that may affect instrument performance occur in the operational
environment, performance tests shall be conducted to evaluate how the instrument
performance may have been impacted. Such tests may be conducted as an extension
of the original type testing.
All or a subset of the performance tests may be conducted as part of the maintenance
and recalibration procedures. Performance testing may include range, detection
efficiency, linearity, detection limit, and response to overload conditions.
Performance tests shall be documented and documentation of any changes in the
performance characteristics of the instrument shall be provided to the user.
4.0
Air flow rate calibrations
All flow meters shall be calibrated against devices that are traceable to NIST or another
National/International Standards Laboratory. Before calibrating the air flow-rate sensor,
the air in-leakage should be verified to be less than 5% (ANSI N13.1-1999) of the
nominal flow rate. Flow meters shall be calibrated with a filter or device installed that
produces a pressure drop equivalent to the pressure drop of the filter type to be used
during normal operations.
During calibration, the standard flow meter should be upstream of, and inline with, the
filter so that it measures air going through the filter. This will prevent measuring air that
has entered the system from leakage paths around or after the filter.
Rotameters and mass flow meters shall be calibrated at the average flow rate
anticipated during use, and should also be calibrated at one point above and one point
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below the anticipated sampling flow rate (e.g., 75% and 125% of the anticipated
sampling flow rate).
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5.0
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This section provides general instructions applicable to all air monitors. Additional
instructions for specific types of air monitors are provided in the Section 6.
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5.1
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Critical venturi flow meters shall be calibrated with a sufficient pressure differential
across the meter to ensure that the velocity at the throat of the meter is sonic. The
absolute pressure at the entrance of the critical flow meter should be within 
the average absolute pressure anticipated at that location. The temperature at the
entrance of the critical flow meter during calibration should be within 5C of the
average temperature anticipated at the entrance to the critical flow meter during
sampling.
Air flow meter readings should be within ±15% of the conventionally true value of the
actual flow rate. Note that if the instrument uses a mass flow meter, appropriate
corrections for ambient pressure and temperature are required. The air flow reading
shall correspond to actual volumetric flow, not standard flow at standard temperature
and pressure.
Additional information on calculating uncertainty for flow meter calibrations is provided
in Appendix B.
Instrument calibrations
Pre-calibration inspection
Prior to calibrating the instrument, inspect the instrument for obvious damage. After
determining that there is no obvious damage, establish the following conditions prior to
exposing the air monitor to a radioactive source for adjustment and calibration:
1. Instrument contamination levels shall be low enough that contamination does not
interfere with calibration. The detector and sample chamber should be as free of
radioactive contamination as possible to prevent cross contaminating calibration
sources.
2. If the instrument is zeroed as part of normal operation, the meter or display shall be
adjusted to zero or the point specified by the manufacturer using the adjustment or
adjustments provided.
3. The batteries and/or power supply shall comply with the instrument manufacturer's
specification.
4. The instrument shall be turned on and allowed to stabilize as appropriate.
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5.2
As-found readings
Prior to adjusting the instrument, as-found readings shall be taken and recorded. The
as-found readings should include:
1. determining the system background and verifying that it is within the userestablished limits, and
2. determining the response of the instrument to a source of known radioactivity and
verifying that it is within the user established limits.
If separate calibration controls are used for each range or decade, as-found readings
shall be taken on each range or decade. If only one calibration control is used for all
ranges or decades, only one as-found reading needs to be recorded.
As-found readings shall also be recorded for the flow sensor.
5.3
Electronic calibration
Electronic calibration shall be performed to verify meter/display linearity. Linearity shall
be checked at several points within the range of the instrument. If the instrument has a
single calibration adjustment for the meter or display, electronic calibration need be
performed at only two points; one near the lower limit of detection and one near the
upper limit of measurement. If multiple calibration adjustments are provided, two points
within the range of each adjustment shall be checked.
The signal used to perform electronic calibration should mimic the pertinent
characteristics of the detector signal (e.g., pulse width, pulse height).
In addition to verifying/adjusting linearity, the electronic calibration may include adjusting
pulse width, obtaining high voltage (HV) plateaus, and setting detector operating
voltage, amplifier gain, thresholds, and windows.
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5.4
Meters and chart recorders
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Both local and remote monitor recorders, if supplied, should be verified to provide
readouts within ±10% of the meter indication. This verification should be made at a
minimum of three points covering the range of the instrument.
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5.4.1 Analog linear readout instruments
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Analog, linear readout instruments with a single calibration control for all scales shall be
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adjusted either at the point recommended by the manufacturer or at a point within the
normal range of use. Instruments with calibration controls for each scale shall be
adjusted on each scale.
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5.4.2 Analog logarithmic readout instruments
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If instruments have ranges that are not calibrated, a limited calibration tag that notes
the limits of calibration shall be attached to the instrument.
After adjustment the response of the instrument shall be checked near the end points of
each scale (approximately 20% and 80% of full scale).
Instrument readings shall be within 15% of the conventionally true values (CTV) for the
lower point and 10% of the CTV for the upper point. Readings within 20% shall be
acceptable if a calibration chart or graph is prepared and provided with the instruments.
Analog, logarithmic readout instruments that commonly have a single readout scale
spanning several decades, normally have two or more adjustments. The instrument
shall be adjusted for each scale according to the site specifications or the
manufacturer’s specifications. Alternatively, it shall be permissible to calibrate at points
of importance to the user if the impact on accuracy is justified and documented.
If instruments have ranges or decades that are not calibrated, a limited calibration tag
that notes the limits of calibration shall be attached to the instrument. The same
principles should be applied to microprocessor-controlled instruments.
After adjustment, calibration shall be checked at a minimum of one point on each
decade. Instrument readings shall have a maximum deviation from the CTV of no more
than 10% of the full decade value. If the display is not marked at intervals
corresponding to 10% of the point (i.e., a display calibrated at a decade mark
frequently does not have graduations to 10% in the next decade), it is permissible to
use the spacing on the low side of the calibration point to estimate the calibration limit
on the high side of the calibration point.
5.4.3 Digital readout instruments
Digital readout instruments shall be calibrated as in 5.4.1.
If the instrument is designed to auto scale, the calibration point should be selected far
enough from the auto scaling point that auto scaling will not affect the reading.
The instrument should be cycled through a complete test of all display segments or
indicators, either electronically or radiologically.
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If the instrument has both digital and analog readouts, both readouts shall be
calibrated.
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5.4.4 Microprocessor-based instruments
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If the instrument uses multiple algorithms or if the influence of calibration factors varies
over the range of application, the calibration or test points selected for the instrument
shall include at least one point within each algorithm and transition points between
algorithms.
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Verify that background count rate due to electronic noise, instrument contamination, or
external radiation sources is within limits. If the instrument uses a filter, background
readings should be taken with the filter in place. Air flow should be off to prevent the
accumulation of radon progeny on the filter during the performance of this test.
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Background response verification
Calibration of background subtraction
Proper functioning of background subtraction capability shall be verified. If the
instrument corrects for interference from radon progeny collected on a filter, a filter shall
be installed and air flow shall be on during the performance of this test.
If the instrument responded to interfering external radiation fields during type testing,
calibration adjustments for background subtraction should be performed in appropriate
interfering external radiation fields equivalent to the radiation fields expected during
use.
Calibration of the background subtraction capability may be performed electronically
using pulse generators or other electronic calibration devices.
The manufacturer’s recommendation should be followed for calibration of monitors that
have background subtract capabilities.
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5.7
Alarm circuit verification
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Calibration shall include verification of radiation and failure alarms, alarm delay time,
and alarm relays. Operability of audible and visual alarms may be verified electronically
or by using a radioactive source to actuate the alarm. Alarm set points shall be set and
verified during the electronic calibration and should actuate at ±10% of the expected
value. If monitors have adjustable alarm set points that may be adjusted during use,
this alarm setting mechanism shall also be verified to function properly.
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5.8
Radiological calibration
Real-time air monitoring instruments should be calibrated with radioactive sources that
exhibit the radiation type and energies of the airborne radioactivity to be monitored.
Table 2 identifies a selection of sources that should be used for calibration.
Table 2 - Reference sources for calibration of continuous air monitors
Radiation type
Gamma
Alpha
Beta
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Reference source
137
Cs filtered to remove ≥ 90% of
the betas and associated 137Ba
x-rays
241
Am, 230Th, 239Pu, NatU
90
Sr-90Y in equilibrium, filtered
through 50 mg/cm2 of material
with atomic number (Z) ≤ 13
Efficiency measurements should be performed in accordance with the manufacturer's
recommendations. Radiation sources of sufficient strength to provide a count rate of at
least one-quarter full scale should be used to determine efficiency.
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6.0 Additional calibration requirements for particulate and noble
gas monitors
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In addition to the requirements of Section 5.0, the following requirements apply to the
calibration of specific types of air monitoring instruments.
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6.1
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Alpha and beta particulate monitors
Calibration of alpha and beta air monitoring instruments using single or multi channel
analyzers shall include steps to verify or adjust linearity, pulse width, gains, windows,
and thresholds. These steps may be performed electronically using a pulse generator
or similar electronic calibration devices that provide periodic and variable amplitude
signals or they may be performed using radioactive materials. These steps shall be
performed prior to performing the radiological calibration.
Energy calibration of alpha monitors that use multi-channel analyzers should be based
on radon progeny peaks (radon progeny collected on a filter) to ensure that the solid
source characteristics don’t influence the energy calibration. Response to a plated
source should then be adjusted (as appropriate) to compensate for differences between
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the response to a plated source and the response to a filter source.
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Keep-alive sources
The absence of significant quantities of alpha emitting radon progeny may cause
detector low count alarms on an alpha continuous air monitor (CAM) placed
downstream of a High Efficiency Particulate Air (HEPA) filter. Keep-alive sources may
be used to prevent spurious alarms. For example, a small amount of thorium (a few
tenths of a Bq generating around 2 to 3 cpm, depending on instrument efficiency) may
be mounted on or near the detector.
When this technique is used the outside of the instrument should be labeled to indicate
that a source is present, and appropriate adjustments to the background subtraction
circuit should be made.
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6.3
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Although radon is a natural radioactive noble gas, its measurement is not included in
this standard. Note, however, that the presence of radon, or its decay products, may
interfere with the measurement of other radioactive gases.
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6.3.1 Pre-calibration
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Pre-calibration should include verifying that pre-filters or absorbants are in place to
remove particulates and radioiodines.
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6.3.2 Electronic calibration
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Noble gas monitors
To prevent the need for several sources of different activities, the measuring assembly
alone may be tested by injection of an appropriate electronic signal at the normal
detector input.
Electronic set up of the noble gas monitor should be consistent with the electronic set
up used during initial calibration.
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6.3.3 Radiological calibration
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Gaseous sources should be used for calibration. If solid sources are used, type testing
shall establish the response of the instrument to the gas of concern. In addition,
response of the unit to solid sources shall be established by cross calibration against
gaseous sources during type testing.
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Gaseous sources may consist of bottles of pressurized air or gas containing the
radioactive gas with which the unit is to be tested. This may be the radioactive gas for
which the unit is designed or some other radioactive gas of interest.
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6.3.3.1
Solid sources may be used in lieu of radioactive gas sources for subsequent calibration.
Such sources shall be of physical form appropriate for the unit being calibrated, to allow
location of the source relative to the detector to be accurately fixed and repeatable.
Initial Calibration with Gaseous Sources
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Gaseous sources shall be used for the type testing of noble gas monitors. The type
testing may also include the initial calibration. The gas used should be the gas intended
to be monitored. Depending on the application and the type of detector in use with the
instrument, calibration with a gas not to be monitored, may be used provided that
corrections for the difference in energies are made. The calibration gas used shall be
traceable to NIST or another National/International Standards Laboratory except in the
case where the calibration laboratory has the capability to perform a traceable analysis.
Tests using the calibration gas shall be corrected as needed for temperature, pressure,
radioactive decay, time and chamber or system volume. The calibration will determine
the value of the measured gas vs. the instruments response.
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Calibration with solid sources
Calibration of noble gas monitors with solid sources is allowed only after an initial
calibration with gaseous sources during type testing has determined the instrumental
efficiency. Solid sources used in the calibration of gaseous monitors shall be traceable
to NIST or another National/International Standards Laboratory. The sources shall be
presented to the detector under test in a documented and reproducible geometry. Initial
testing with solid source(s) shall be done to determine the correlation of the solid source
efficiencies to those determined during the initial calibration performed with gas. An
Initial evaluation with solid source(s) shall determine the value of the measured
source(s) vs. the instruments response. The efficiency determined for the solid source
shall be compared with the value determined from the gaseous source calibration to
produce the response factor to be used in all subsequent calibrations utilizing the solid
sources. All subsequent calibrations using the solid sources shall, at a minimum, test
two points of the operating range of the detector. One point within the first two decades
above the background level of the system and the other within the upper two decades
of the system shall be tested to insure system linearity.
All solid source calibrations shall be corrected for radioactive decay and use the solid
source / gaseous source ratio for the determination of the noble gas detector efficiency.
7.0
Calibration for special conditions
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An instrument should be used within the operating limits and for the types of radiation
for which it was designed and type tested.
If the instrument will be used under environmental conditions that are outside the
operating limits of the instrument as identified by the manufacturer or during type
testing, a calibration for special conditions shall be performed.
If an instrument will be used to measure activity from a source other than for which it
was designed (i.e., using a tritium monitor to measure krypton gas or using a
transuranic alpha particulate monitor to measure radon progeny), a special calibration
shall be performed with a radioactive source similar in geometry and physical properties
to the source the instrument will be used to monitor.
The calibration for special conditions needs to be performed only once and a correction
factor established to use in later calibrations, unless:
1. The instrument is modified or physically altered, or
2. The normal calibration suggests a change or deterioration has occurred in
instrument performance, or
3. The special conditions change.
Instruments calibrated for special conditions shall be labeled with the conditions under
which the calibration is valid.
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8.0
Facilities, conditions, and equipment
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8.1
Calibration facility
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The photon radiation background at the calibration facility should be low, known, and
stable and shall be accounted for and documented during calibration.
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Test and calibration conditions
Testing and calibration of instruments should be performed under a group of controlled
conditions called standard test conditions, Table 3. This is recommended to ensure that
performance variations are eliminated in the calibrations and that performance
characteristics can be related to the calibrated instrument. Temperature, relative
humidity, and atmospheric pressure shall be noted at the time of instrument
calibrations.
Table 3 – Standard test conditions
25
Influence quantities
Acceptable range for standard test conditions
Warm up time
> 1 minute or manufacturer’s specification
Relative humidity
Ambient ±10%, not to exceed 75%
Ambient temperature
20C to 24C
Atmospheric pressure
70 to 101.3 kPa
Line voltage(a)
Nominal ± 1%
Frequency(a)
60 Hz ± 0.5 Hz
Background ambient photon
radiation (external)
2.5% of full scale of the range or decade under
test, but nominally should not exceed 0.5 μGy/h
(50 μrad/h), referenced to air.
Non-ionizing electromagnetic field
of external origin
Less than 50% of the lowest value that causes
interference
Magnetic induction of external
origin
Less than twice the induction due to the earth's
magnetic field
Residual radionuclide
contamination
Contamination shall be low and should be less
than limits for total activity listed in NRC Reg Guide
1.86.
(a) Applicable only to AC powered instruments.
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8.3
Calibration standards
Instruments shall be calibrated with appropriate standards of known hierarchy derived
from national standards. Working standards, when used, shall be compared at least
annually to a higher level standard. Refer to ANSI N42.22 and ANSI N42.23.
Calibrations of the reference radiation fields or sources shall be obtained in one of the
following ways:
1. Comparison of the radiation field from a user's reference source with the radiation
field from a national or secondary standard source in the same geometry, using a
"transfer instrument" with a reproducibility of ±2 percent. The transfer calibration
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shall use a calibration curve for the transfer instrument taken with the national or
secondary source over a range that covers both the national or secondary source
measurement and the user source measurement. (Such a curve reduces to a single
point if the transfer calibration procedure is such that the transfer instrument
readings are identical for both measurements.)
2. Calibration of a user's transfer instrument with a national or secondary standard
source, followed by evaluation of user's reference source with the same transfer
instrument. The transfer instrument shall have a reproducibility of ±2 percent and
the procedure shall use a calibration curve as in Section 8.3 (1).
3. Where no national or secondary standard exists (as in the case of specific energies,
unusual sources, or unusual source configurations), by establishment of a standard
source or instrument with documented empirical and theoretical output or response
characteristics.
A calibration source or set of sources should be of sufficient activity to reach full scale
of any instrument to be calibrated. If the source is a radionuclide, the half-life should be
long, preferably greater than several years to minimize corrections and uncertainties.
Calibration sources should be from Table 2 and shall comply with applicable standards.
The activity or surface emission rate of calibration sources shall be known with an
accuracy of +/-10%.
Working standards shall be used only for routine calibrations or testing of instruments.
The source configuration and geometry should be comparable to the air sample
collector to detector configuration, and should be reproducible. The activity distribution
of working standards should mimic the collection media activity distribution. A
correction factor may be used to compensate for differences between the deposition
characteristics of the working standard and the collection media. Working standards
used to calibrate air monitoring instrumentation should approximate as closely as
possible the actual media and isotopic energy being monitored.
The energy spectrum for all calibration sources should be known and if absorbers,
collimators or high scatter geometries are employed, the effect shall be known on the
calibration accuracy relative to that from a low-scatter geometry. When shutters or
other source control devices are used, the effect of transit time on dose shall be known,
accounted for and documented.
The activity of calibration sources should be characterized and documented. Such
considerations as charged particle equilibrium, scattered or unwanted radiations from
the source, and ambient background radiation should be accounted for during
standardization of the calibration source.
8.4
Maintenance of standards
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Calibration standards shall be maintained through an ongoing measurement quality
assurance (MQA) program with NIST or an accredited calibration laboratory. Direct
comparison with national or secondary standards shall be undertaken when the MQA
program indicates an uncertainty in calibration greater than 4%. Quality control
procedures shall be in place to assure that the working and reference standards at a
facility maintain a known relationship.
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Check sources
Check sources should provide radiation of the same type or types as provided by those
sources used in instrument calibration. However, check sources may provide radiation
different from that used for calibration if:
(1)
The source-to-detector instrument geometry is well understood and easily
reproduced, or
(2)
The instrument response to this radiation is well understood and is not critically
dependent on instrument adjustment (e.g., the use of a photon source to check
instruments calibrated to detect to beta radiation may be acceptable; the use of a
photon source to check a detector utilizing a BF3 tube response to neutrons is not
acceptable). A reproducible source-to-detector geometry shall be established and
used for all functional check measurements.
Check sources do not need to be traceable to NIST. To avoid functional check failures
due to degradation of the check source; however, check sources should be compared
periodically with standards.
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9.0
Documentation
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9.1
Facility documentation
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A comprehensive and readily available record system shall be maintained by the
calibration facility. All records of data shall identify the individual who collected the data
on which the record is based. The facility records shall include at least the following:
1. The entire results of type testing
2. An inventory of all standards and calibration equipment.
3. A full history and calibration data, including certificates, for all standards and
applicable calibration equipment.
4. All procedures used for providing calibration services.
5. Routine quality control records.
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6. The results of all performance testing.
7. Records of instrumentation for which a calibration service was provided, and the
date that the calibration was performed including a description, sufficient for
identification of every item. The record system shall also include or reference a
detailed report for that specific calibration and the name of the person performing
that calibration.
8. Copies of all calibration reports issued and/or electronic records.
9. Information essential to the analysis and reconstruction of the calibration of a
specific item of instrumentation. We see little difference between this and 4.
10. Records detailing the education, experience, and training of all operating staff and
supervisory personnel.
11. A documented analysis of calibration uncertainty.
9.2
Instrument Documentation
Records shall be maintained of all calibration, maintenance, repair, and modification
data for each instrument. The record shall be dated and shall identify the individual
performing the work. The record shall be filed with previous records on the same
instrument and shall be readily retrievable. Additional information on calibration records
including recommended retention periods can be found in ANSI/HPS N13.6-1999.
Each instrument shall be labeled with the following information:
1.
2.
3.
4.
5.
Date of most recent calibration,
Initials or other specific identifying mark of the calibrator,
Date that calibration is again required,
Special-use or limited calibration label (if applicable), and
Serial number of instrument or other unique identification number used by the
facility to identify a specific instrument.
39
10.0 References
40
41
ANSI N1.1-1976, Glossary of Terms in Nuclear Science and Technology.1
1
ANSI publications are available from the Sales Department, American National
Standards Institute, 11 West 42nd Street, 13th Floor, New York, NY 10036, USA.
29
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
ANSI N13.1-1999, Sampling and Monitoring Releases of Airborne Radioactive
Substances from the Stacks and Ducts of Nuclear Facilities.
ANSI N13.2-1969 (Reaffirmed 1982), Administrative Practices in Radiation Monitoring.
ANSI N320-1979, Performance Specifications for Reactor Emergency Radiological
Monitoring Instrumentation.
ANSI N323A-1997, American National Standard Radiation Protection Instrumentation
Test and Calibration, Portable Survey Instruments.
ANSI N42.17A-1989 (Reaffirmed 1994), Performance Specifications for Health Physics
Instrumentation - Portable Instrumentation for Use in Normal Environmental Conditions.
ANSI N42.17B-1989, Performance Specifications for Health Physics Instrumentation –
Occupational Airborne Radioactivity Monitoring Instrumentation.
ANSI N42.18-1974 (Reaffirmed 1991), Specification and Performance of On-Site
Instrumentation for Continuously Monitoring Radioactivity in Effluents.
ANSI N42.30-2000, Performance Specifications for Tritium Monitors.
ANSI N42.33-2004, American National Standard for Portable Radiation Detection
Instrumentation for Homeland Security.
ANSI/HPS N13.6-1999, Practice for Occupational Radiation Exposure Records.2
ASTM C859-92B, Standard Terminology Relating to Nuclear Materials.3
ICRU Report 60-1998, Fundamental Quantities and Units for Ionizing Radiation.4
ICRU Report 39-1985, Determination of Dose Equivalents Resulting from External
Radiation Sources.
2
ANSI/HPS publications are available from the Health Physics Society, 1313 Dolley
Madison Blvd, Suite 402, McLean, VA, 22101, USA.
3
ASTM publications are available from ASTM International, 100 Barr Harbor Drive,
West Conshohocken, PA, 19428-2959 USA
4
ICRU publications are available from the National Council on Radiation Protection and
Measurements, 7910 Woodmont Avenue, Suite 800, Bethesda, MD 20814, USA.
30
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
ISO 25-1990, General requirements for the competence of calibration and testing
laboratories5
IEC 50(394)-1995, International Electrotechnical Vocabulary, Chapter 394, Nuclear
Instrumentation, Instruments
ISO 4037-1 - 1996, X and Gamma Reference Radiations for Calibrating Dosimeters
and Dose Rate Meters and for Determining Their Response as a Function of Photon
Energy – Radiation Characteristics and Production Methods.
ISO 8769-1988, Reference sources for the calibration of surface contamination
monitors – beta-emitters (maximum beta energy greater than 0.15 MeV) and alphaemitters.
NBS Special Publication 250-1989, Calibration Services User's Guide. 6
NCSL RP-1-1996, National Conference of Standards Laboratories, Establishment and
Adjustment of Calibration Intervals.7
NIST-2001, NIST Handbook 150, 2001 Edition, Procedures and General Requirements
NIST Special Publication 1297-1993, Guideline for Evaluating and Expressing the
Uncertainty of NIST Measurement Results
NRC Regulatory Guide 1.86, Termination of Operating Licenses for Nuclear Plants. 8
NRC Regulatory Guide 8.25 (US NRC 1992)
ISO 1993, ISO Guide 99, International Vocabulary of Basic and General Terms in
Metrology (VIM), International Organization for Standardization, 1993
5
ISO publications are available from the ISO Central Secretariat, Case Postale 56, 1
rue de Varembé, CH-1211, Genève 20, Switzerland/Suisse. ISO publications are also
available in the United States from the Sales Department, American National Standards
Institute, 11 West 42nd Street, 13th Floor, New York, NY 10036, USA.
6
NBS and NIST publications are available from the Superintendent of Documents, U.S.
Government Printing Office, Washington, D.C. 20402.
7
NCSL publications are available from the National Conference of Standards
Laboratories, 1800 30th St. Suite 305B, Boulder, CO, 80301, USA.
8
NRC publications are available at www.nrc.gov.
31
1
2
3
4
Appendix A - Summary of a Life-Cycle Approach to Instrument Development and
Application
Life-Cycle Step
Mission
Evaluation a
Research and
Development a
Prototype Testing a
Type Testing b
Production Control
Testing a
Training a
Acceptance
Testing b
Initial Calibration b
Functional
Checks b
Purpose
To identify
mission
objectives and
conditions,
measurement
objectives,
performance
requirements,
and candidate
technologies
To aid in the
development of
a prototype that
is likely to meet
specifications
To demonstrate
that the design
of the
instrument is
likely to meet
certain
specifications
To demonstrate
that the design
of the
instrument as
manufactured
meets certain
specifications.
To control
production,
avoid defects,
and confirm
instrument
compliance with
specifications,
To ensure
proper execution
of all tests and
requirements
To demonstrate
compliance with
selected
specifications.
To establish a
traceable
calibration
relevant to
expected
conditions of
use.
To provide
indications that
the instrument is
operational.
Timing or frequency
Prior to initiation of the
development process, and
continuously throughout
the life cycle
Units to be tested
None (this step is
conceptual in nature)
Specifications
Definition of the
specifications that
will be evaluated in
the subsequent lifecycle steps
Responsibility
Responsible
officials, with input
from research,
development,
manufacturing, and
users
As needed
Individual
components and
assemblies.
As selected by the
manufacturer; or
requested by the
purchaser/user.
Manufacturer
As needed prior to start
of production
One or more
prototype units
As selected by the
manufacturer; or
requested by the
purchaser/user.
Manufacturer
(generally);
purchaser/user
(occasionally)
A minimum of once prior
to full production.
Two or more initial
production units.
All specifications
from the relevant
standard, or as
agreed upon between
manufacturer and
purchaser/user.
Generally the
manufacturer.
Occasionally the
purchaser/user
Depending on acceptable
failure rate agreed upon
between manufacturer
and purchaser/user.
As determined by the
manufacturer or as
agreed upon between
manufacturer and
purchaser/user.
As selected by
manufacturer, or
requested by the
purchaser/user.
Manufacturer
As appropriate to support
proper execution of each
step of the instrument life
cycle
After the units are
received and prior to their
initial use.
As needed to train
individuals to
properly carry out
life-cycle steps
As agreed upon
between
manufacturer and
purchaser/user.
Each unit.
As appropriate for
the instrument and
its use
All life cycle
participants
As selected by the
purchaser/user.
Purchaser/user.
Selected instrument
parameters and
responses.
Designated
calibration staff of
the users’
organization (or
selected vendor).
Each unit.
As appropriate for
the instrument being
used.
User.
Prior to initial use.
Before each use and
periodically during use.
32
Life-Cycle Step
Operational
Experience a
Purpose
Timing or frequency
Units to be tested
Specifications
Responsibility
To provide
During each operation
A representative
Selected instrument
User.
evidence of any
and during periodic
number of units
parameters and
operational
reviews of experience
responses
deficiencies
To provide
At a frequency, such as
Each unit.
As appropriate for
Designated
Maintenance and
preventive
annually, based on the
the instrument.
maintenance staff of
Recalibration b
maintenance,
design and reliability
the user’s
make necessary
history of the instrument.
organization (or
repairs, and
selected vendor).
reestablish a
traceable
calibration.
To verify that
As appropriate based on
A representative
Selected
As arranged by the
Periodic
the instrument
experience and
number of units.
specifications from
purchaser.
Performance
continues to
anticipated modes of
the type test.
Testing b
meet relevant
failure.
specifications.
a.
This step is included in the table to provide a complete overview of a comprehensive program for instrument development,
testing, and application. This step is not discussed further in this standard.
b. This step is part of a comprehensive instrument test and calibration program. This step is discussed in further detail
elsewhere in this standard.
(This table was adapted from Hoover, M.D. and Cox, M., A Life-Cycle Approach for Development and Use of Emergency Response and Health
Protection Instrumentation, in Public Protection from Nuclear, Chemical, and Biological Terrorism, Brodsky, A., Johnson, R.H. Jr., and Goans,
R.E., Eds., Medical Physics Publishing, Madison, WI, 2004.)
1
33
1
APPENDIX B - Flow Rate Meter Calibrations
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
The goal of the flow rate meter calibration is to help ensure that the uncertainty in the
measurement of the total volume of air sampled is  10%.
The following approach, described in U.S. Nuclear Regulatory Commission (NRC)
Guide 8.25 (US NRC 1992) can be employed to calculate the total uncertainty in the
volume of air (Uv):
2
2
2 1/2
UV = (Us + Uc + Ut )
where: Us is the uncertainty (dimensionless) in reading the flow rate meter scale. This
can be estimated by dividing one-half the value of the smallest scale division by
the indicated flow rate.
Uc is the error (dimensionless) associated with determining the calibration factor,
i.e., correcting the indicated flow. As an approximation, the error associated
with the calibration instrument may be used.
Ut is the error (dimensionless) associated with measurement of the sampling
time.
Note that Us can be multiplied by a fluctuation term Fs to account for fluctuation in the
steady-state reading of the meter. The fluctuation term is set at 1 for a meter whose
readings do not fluctuate. If there are fluctuations, the fluctuation term is taken to be
the average observed number of scale units above and below the mean indicated
value.
34