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ASTM E1647-98a

(Practice)

Standard Practice for Determining Contrast Sensitivity in Radioscopy

Standard Practice for Determining Contrast Sensitivity in Radioscopy

SCOPE
1.1 This practice covers the design and material selection of a contrast sensitivity measuring gage used to determine the minimum material thickness or density that may be imaged without regard to spatial resolution limitations.
1.2 This practice is applicable to transmitted-beam radioscopic imaging systems utilizing X-ray and gamma ray radiation sources.
1.3 The values stated in inch-pound units are to be regarded as standard.
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific safety statements, see NIST/ANSI Handbook 114 Section 8, Code of Federal Regulations 21 CFR 1020.40 and 29 CFR 1910.96.

General Information

Status
Historical
Publication Date
09-May-1998
ICS
11.040.50 - Radiographic equipment
Technical Committee
E07 - Nondestructive Testing
Drafting Committee
E07.01 - Radiology (X and Gamma) Method
Current Stage
Ref Project

Relations

Replaced By
ASTM E1647-03 - Standard Practice for Determining Contrast Sensitivity in Radioscopy
Effective Date
10-Aug-2003
Referred By
ASTM E1411-16 - Standard Practice for Qualification of Radioscopic Systems
Effective Date
10-May-1998
Referred By
ASTM E2445/E2445M-20 - Standard Practice for Performance Evaluation and Long-Term Stability of Computed Radiography Systems
Effective Date
10-May-1998
Referred By
ASTM E2533-21 - Standard Guide for Nondestructive Examination of Polymer Matrix Composites Used in Aerospace Applications
Effective Date
10-May-1998
Referred By
ASTM E1416-23 - Standard Practice for Radioscopic Examination of Weldments
Effective Date
10-May-1998
Referred By
ASTM E1931-16(2022) - Standard Guide for Non-computed X-Ray Compton Scatter Tomography
Effective Date
10-May-1998
Referred By
ASTM E3398-23 - Standard Guide for Digital Neutron Radiography
Effective Date
10-May-1998
Referred By
ASTM E2033-17 - Standard Practice for Radiographic Examination Using Computed Radiography (Photostimulable Luminescence Method)
Effective Date
10-May-1998

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ASTM E1647-98a - Standard Practice for Determining Contrast Sensitivity in RadioscopyASTM E1647-98a - Standard Practice for Determining Contrast Sensitivity in Radioscopy
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ASTM E1647-98a - Standard Practice for Determining Contrast Sensitivity in Radioscopy
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NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
Designation: E 1647 – 98a
Standard Practice for
Determining Contrast Sensitivity in Radioscopy
This standard is issued under the fixed designation E 1647; 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 Used for Radiography
E 1411 Practice for Qualification of Radioscopic Systems
1.1 This practice covers the design and material selection of
2.2 Federal Standards:
a contrast sensitivity measuring gage used to determine the
21 CFR 1020.40 Safety Requirements for Cabinet X-ray
minimum change in material thickness or density that may be
Systems
imaged without regard to spatial resolution limitations.
29 CFR 1910.96 Ionizing Radiation
1.2 This practice is applicable to transmitted-beam radio-
2.3 NIST/ANSI Standards:
scopic imaging systems utilizing X-ray and gamma ray radia-
NIST/ANSI Handbook 114 General Safety Standard for
tion sources.
Installations Using Non-Medical X-ray and Sealed
1.3 The values stated in inch-pound units are to be regarded
Gamma Ray Sources, Energies to 10 MeV
as standard.
2.4 Other Standard:
1.4 This standard does not purport to address all of the
EN 462 – 5 Duplex Wire Image Quality Indicator
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
3. Terminology
priate safety and health practices and determine the applica-
3.1 Definitions—Definitions of terms applicable to this test
bility of regulatory limitations prior to use. For specific safety
method may be found in Terminology E 1316.
statements, see NIST/ANSI Handbook 114 Section 8, Code of
Federal Regulations 21 CFR 1020.40 and 29 CFR 1910.96.
4. Summary of Practice
4.1 It is often useful to evaluate the contrast sensitivity of a
2. Referenced Documents
penetrating radiation imaging system separate and apart from
2.1 ASTM Standards:
spatial resolution measurements. Conventional image quality
B 139 Specification for Phosphor Bronze Rod, Bar, and
indicators (IQI’s), such as Test Method E 747 wire and Practice
Shapes
E 1025 plaque IQIs, combine the contrast sensitivity and
B 150 Specification for Aluminum Bronze Rod, Bar, and
resolution measurements into an overall performance figure of
Shapes
3 merit. Such figures of merit are often not adequate to detect
B 161 Specification for Nickel Seamless Pipe and Tube
subtle changes in imaging system performance. For example,
B 164 Specification for Nickel-Copper Alloy Rod, Bar, and
3 in a high contrast image, spatial resolution can degrade with
Wire
almost no noticeable effect upon overall image quality. Simi-
B 166 Specification for Nickel-Chromium-Iron Alloys
larly, in an application in which the imaging system provides a
(UNS N06600, N06601, and N06690) and Nickel-
very sharp image, contrast can fade with little noticeable effect
Chromium-Cobalt-Molybdenum Alloy (UNS N06617)
3 upon the overall image quality. These situations often develop
Rod, Bar, and Wire
and may go unnoticed until the system performance deterio-
E 747 Practice for the Design Manufacture and Material
rates below acceptable image quality limits.
Grouping Classification of Wire Image Quality Indicators
(IQI) Used For Radiology
5. Significance and Use
E 1316 Terminology for Nondestructive Examination
5.1 The contrast sensitivity gage measures contrast sensitiv-
E 1025 Practice for Hole-Type Image Quality Indicators
ity independent of the imaging system spatial resolution
limitations. The thickness recess dimensions of the contrast
This practice is under the jurisdiction of ASTM Committee E-7 on Nonde-
structive Testing and is the direct responsibility of Subcommittee E07.01 on
Radiology (X and Gamma) Method. Available from the Superintendent of Documents, U.S. Government Printing
Current edition approved May 10, 1998. Published September 1998. Originally Office, Washington, DC 20402.
published as E 1647 – 94. Last previous edition E 1647 – 98. Available from American Society for Nondestructive Testing, 1711 Arlingate
Annual Book of ASTM Standards, Vol 02.01. Plaza, P.O. Box 28518, Columbus, OH 43228-0518.
3 7
Annual Book of ASTM Standards, Vol 02.04. Available from British Standards Institute, 2 Park Street, London, England
Annual Book of ASTM Standards, Vol 03.03. W1A2B5.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
E 1647 – 98a
TABLE 1 Design of the Contrast Sensitivity Gage
sensitivity gage are large with respect to the spatial resolution
limitations of most imaging systems. Four levels of contrast Gage Thickness J Recess K Recess L Recess M Recess
T 1 % of T 2 % of T 3 % of T 4 % of T
sensitivity are measured: 4 %, 3 %, 2 %, and 1 %.
5.2 The contrast sensitivity gage is intended for use in
conjunction with a high-contrast resolution measuring gage,
TABLE 2 Contrast Sensitivity Gage Dimensions
such as the EN 462 – 5 Duplex Wire Image Quality Indicator.
Gage
Such gages measure spatial resolution essentially independent B DIM. C DIM. D DIM. E DIM. F,G DIM.
Size
of the imaging system’s contrast sensitivity. Such measure-
1 0.750 in. 3.000 in. 0.250 in. 0.625 in. 0.250 in.
ments are appropriate for the qualification and performance
19.05 mm 76.20 mm 6.35 mm 15.88 mm 6.35 mm
monitoring of radiographic and radioscopic imaging systems.
2 1.500 in. 6.000 in. 0.500 in. 1.250 in. 0.500 in.
38.10 mm 152.40 mm 12.70 mm 31.75 mm 12.7 mm
5.3 Radioscopic system performance may be specified by
3 2.250 in. 9.000 in. 0.750 in. 1.875 in. 0.750 in.
combining the measured contrast sensitivity expressed as a
57.15 mm 228.60 mm 19.05 mm 47.63 mm 19.05 mm
percentage with the spatial resolution expressed in millimeters 4 3.000 in. 12.000 in. 1.000 in. 2.500 in. 1.000 in.
76.20 mm 304.80 mm 25.40 mm 63.50 mm 25.4 mm
of unsharpness. For the EN 462 – 5 spatial resolution gage, the
unsharpness is equal to twice the wire diameter. For the line
pair gage, the unsharpness is equal to the reciprocal of the
TABLE 3 Contrast Sensitivity Gage Application
line-pair/mm value. As an example, an imaging system that
Gage Size Use on Thicknesses
exhibits 2 % contrast sensitivity and images the 0.1 mm
1 Up to 1.5 in. (38.1 mm)
EN 462 – 5 paired wires (equivalent to imaging 5 line-pairs/
2 Over 1.5 in. (38.1 mm) to 3.0 in. (76.2 mm)
millimeter resolution on a line-pair gage) performs at a
3 Over 3.0 in. (76.2 mm) to 6.0 in. (152.4 mm)
2 %–0.2 mm sensitivity level. A standard method of evaluating
4 Over 6.0 in. (152.4 mm)
overall radioscopic system performance is given in Practice
E 1411.
6. Contrast Sensitivity Gage Construction and Material
6.2.4 Common trade names or alloy designations have been
Selection
used for clarification of pertinent materials.
6.1 Contrast sensitivity gages shall be fabricated in accor-
6.3 The materials from which the contrast sensitivity gage is
dance with Fig. 1, using the dimensions given in Table 1, Table
to be made is designated by group number. The gage is
2, and Table 3.
applicable to all materials in that group. Material groupings are
6.2 The gage shall preferably be fabricated from the test
as follows:
object material. Otherwise, the following material selection
6.3.1 Material Group 03:
guidelines are to be used:
6.3.1.1 The gage shall be made of magnesium or a magne-
6.2.1 Materials are designated in eight groupings, in accor-
sium alloy, provided it is no more radio-opaque than unalloyed
dance with their penetrating radiation absorption characteris-
magnesium, as determined by the method outlined in 6.4.
tics: groups 03, 02, and 01 for light metals and groups 1
6.3.1.2 Use for all alloys where magnesium is the predomi-
through 5 for heavy metals.
nant alloying constituent.
6.2.2 The light metal groups, magnesium (Mg), aluminum
6.3.2 Materials Group 02:
(Al), and titanium (Ti) are identified 03, 02, and 01, respec-
6.3.2.1 The gage shall be made of aluminum or an alumi-
tively, for their predominant constituent. The materials are
num alloy, provided it is no more radio-opaque than unalloyed
listed in order of increasing radiation absorption.
aluminum, as determined by the method outlined in 6.4.
6.2.3 The heavy metals group, steel, copper base, nickel
6.3.2.2 Use for all alloys where aluminum is the predomi-
base, and other alloys are identified 1 through 5. The materials
nant alloying
...

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SCOPE
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5.1 Principal Advantage of Compton Scatter Tomography—The principal advantage of CST is the ability to perform three-dimensional X-ray examination without the requirement for access to the back side of the examination object. CST offers the possibility to perform X-ray examination that is not possible by any other method. The CST sub-surface slice image is minimally affected by examination object features outside the plane of examination. The result is a radioscopic image that contains information primarily from the slice plane. Scattered radiation limits image quality in normal radiographic and radioscopic imaging. Scatter radiation does not have the same detrimental effect upon CST because scatter radiation is used to form the image. In fact, the more radiation the examination object scatters, the better the CST result. Low subject contrast materials that cannot be imaged well by conventional radiographic and radioscopic means are often excellent candidates for CST. Very high contrast sensitivities and excellent spatial resolution are possible with CST tomography.  
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SIGNIFICANCE AND USE
4.1 This practice provides a means to compare DDAs on a common set of technical measurements, realizing that in practice, adjustments can be made to achieve similar results even with disparate DDAs, given geometric magnification, or other industrial radiologic settings that may compensate for one shortcoming of a device.  
4.2 A user should understand the definitions and corresponding performance parameters used in this practice in order to make an informed decision on how a given DDA can be used in the target application.  
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4.4.1 For iSRbdetector, see 5.1, 7.7, 8.2.  
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4.4.5 For ISO-MTL, see 5.2 (or 7.9, if already completed), 7.10, 8.6.  
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1.1 This practice describes the evaluation of Digital Detector Arrays (DDAs), and assures that one common standard exists for quantitative comparison of DDAs so that an appropriate DDA is selected to meet NDT requirements.  
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1.3 The results reported based on this practice should be based on a group of at least three individual detectors for a particular model number.  
1.4 Units—The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system are not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used independently of the other, and values from the two systems shall not be combined.  
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  • Standard
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ASTM
ASTM E1672-12(2020)(Guide)
Standard Guide for Computed Tomography (CT) System Selection

SIGNIFICANCE AND USE
5.1 This guide will aid the purchaser in generating a CT system specification. This guide covers the conversion of purchaser's requirements to system components that must occur for a useful CT system specification to be prepared.  
5.2 Additional information can be gained in discussions with potential suppliers or with independent consultants.  
5.3 This guide is applicable to purchasers seeking scan services.  
5.4 This guide is applicable to purchasers needing to procure a CT system for a specific examination application.
SCOPE
1.1 This guide covers guidelines for translating application requirements into computed tomography (CT) system requirements/specifications and establishes a common terminology to guide both purchaser and supplier in the CT system selection process. This guide is applicable to the purchaser of both CT systems and scan services. Computed tomography systems are complex instruments, consisting of many components that must correctly interact in order to yield images that repeatedly reproduce satisfactory examination results. Computed tomography system purchasers are generally concerned with application requirements. Computed tomography system suppliers are generally concerned with the system component selection to meet the purchaser's performance requirements. This guide is not intended to be limiting or restrictive, but rather to address the relationships between application requirements and performance specifications that must be understood and considered for proper CT system selection.  
1.2 Computed tomography (CT) may be used for new applications or in place of radiography or radioscopy, provided that the capability to disclose physical features or indications that form the acceptance/rejection criteria is fully documented and available for review. In general, CT has lower spatial resolution than film radiography and is of comparable spatial resolution with digital radiography or radioscopy unless magnification is used. Magnification can be used in CT or radiography/radioscopy to increase spatial resolution but concurrently with loss of field of view.  
1.3 Computed tomography (CT) systems use a set of transmission measurements made along a set of paths projected through the object from many different directions. Each of the transmission measurements within these views is digitized and stored in a computer, where they are subsequently conditioned (for example, normalized and corrected) and reconstructed, typically into slices of the object normal to the set of projection paths by one of a variety of techniques. If many slices are reconstructed, a three dimensional representation of the object is obtained. An in-depth treatment of CT principles is given in Guide E1441.  
1.4 Computed tomography (CT), as with conventional radiography and radioscopic examinations, is broadly applicable to any material or object through which a beam of penetrating radiation may be passed and detected, including metals, plastics, ceramics, metallic/nonmetallic composite material and assemblies. The principal advantage of CT is that it has the potential to provide densitometric (that is, radiological density and geometry) images of thin cross sections through an object. In many newer systems the cross-sections are now combined into 3D data volumes for additional interpretation. Because of the absence of structural superposition, images may be much easier to interpret than conventional radiological images. The new purchaser can quickly learn to read CT data because images correspond more closely to the way the human mind visualizes 3D structures than conventional projection radiology. Further, because CT images are digital, the images may be enhanced, analyzed, compressed, archived, input as data into performance calculations, compared with digital data from other nondestructive evaluation modalities, or transmitted to other locations for remote viewing. 3D data sets can be rendered ...

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ASTM
ASTM E1695-20e1(Test Method)
Standard Test Method for Measurement of Computed Tomography (CT) System Performance

SIGNIFICANCE AND USE
4.1 The major factors affecting the quality of a CT image are total image unsharpness (UTimage), contrast (Δµ), and random noise (σ). Geometrical and detector unsharpness limit the spatial resolution of a CT system, that is, its ability to image fine structural detail in an object. Random noise and contrast response limit the contrast sensitivity of a CT system, that is, its ability to detect the presence or absence of features in an object. Spatial resolution and contrast sensitivity may be measured in various ways. In this test method, spatial resolution is quantified in terms of the modulation transfer function (MTF), and contrast sensitivity is quantified in terms of the contrast discrimination function (CDF). The relationship between contrast sensitivity and spatial resolution describing the resolving and detecting capabilities is given by the contrast-detail-diagram (CDD metric, see also Guide E1441 and Practice E1570). This test method allows the purchaser or the provider of CT systems or services, or both, to measure and specify spatial resolution and contrast sensitivity and is a measure for system stability over time and performance acceptability.
SCOPE
1.1 This test method provides instruction for determining the spatial resolution and contrast sensitivity in X-ray and γ-ray computed tomography (CT) volumes. The determination is based on examination of the CT volume of a uniform cylinder of material. The spatial resolution measurement (Modulation Transfer Function) is derived from an image analysis of the sharpness at the edges of the reconstructed cylinder slices. The contrast sensitivity measurement (Contrast Discrimination Function) is derived from an image analysis of the contrast and the statistical noise at the center of the cylinder slices.  
1.2 This test method is more quantitative and less susceptible to interpretation than alternative approaches because the required cylinder is easy to fabricate and the analysis easy to perform.  
1.3 This test method is not to predict the detectability of specific object features or flaws in a specific application. This is subject of IQI and RQI standards and standard practices.  
1.4 This method tests and describes overall CT system performance. Performance tests of systems components such as X-ray tubes, gamma sources, and detectors are covered by separate documents, namely Guide E1000, Practice E2737, and Practice E2002; c.f. 2.1, which should be consulted for further system analysis.  
1.5 Units—The values stated in SI units are to be regarded as standard. The values given in parentheses after SI units are provided for information only and are not considered standard.  
1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.7 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

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ASTM
ASTM E1570-19(Practice)
Standard Practice for Fan Beam Computed Tomographic (CT) Examination

SIGNIFICANCE AND USE
5.1 This practice establishes the basic parameters for the application and control of fan-beam CT examinations. This practice is written so it can be specified on the engineering drawing, specification, or contract. It will require a detailed procedure delineating the technique or procedure requirements and shall be approved by the Cognizant Engineering Organization (CEO).  
5.2 The requirements in this practice shall be used when placing a CT system into NDT service and establishing a baseline of system performance measures. Monitoring the system performance over time shall be performed, including calibration procedures, performance measurements, and system maintenance in accordance with Section 9.
SCOPE
1.1 This practice establishes the minimum requirements for computed tomography (CT) examination of test objects using fan beam systems (systems that generate one or a few CT cross sectional slices at a time). The examination may be used to nondestructively disclose physical features or anomalies within a test object by providing radiological density and geometric measurements. This practice implicitly assumes the use of penetrating radiation, specifically X-ray and γ-ray.  
1.2 CT is broadly applicable to any material or test object through which a beam of penetrating radiation passes. The principal advantage of CT is that it provides densitometric (that is, radiological density and geometry) images of thin cross sections through an object without the structural superposition in projection radiography.  
1.3 There are areas in this practice that may require agreement between the purchaser and the supplier, or specific direction from the cognizant engineering organization. These items should be addressed in the purchase order or the contract. Generally, the items are application specific or performance related, or both.  
1.4 Techniques and applications employed with CT are diverse. This practice is not intended to be limiting or restrictive. Refer to Guides E1441 and E1672 that provide additional information and guidance on CT fundamentals and tradeoffs in designing or purchasing a CT system, or both.  
1.5 Units—The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.7 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

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  • Standard
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ASTM
ASTM E2903-18(Test Method)
Standard Test Method for Measurement of the Effective Focal Spot Size of Mini and Micro Focus X-ray Tubes

SIGNIFICANCE AND USE
5.1 One of the factors affecting the image quality of a radiographic image is geometric unsharpness. The degree of geometric unsharpness is dependent upon the focal spot size of the radiation source, the distance between the source and the object to be radiographed, the distance between the object to be radiographed and the image plane (film, imaging plate, Digital Detector Array (DDA), or radioscopic detector). This test method allows the user to determine the effective focal spot size (dimensions) of the X-ray source. This result can then be used to establish source to object and object to image detector distances appropriate for maintaining the desired degree of geometric unsharpness or maximum magnification possible, or both, for a given radiographic imaging application. The accuracy of this method is dependent upon the spatial resolution of the imaging system, magnification, and signal-to-noise of the resultant images.
SCOPE
1.1 The image quality and the resolution of X-ray images highly depend on the characteristics of the focal spot. The imaging qualities of the focal spot are based on its two dimensional intensity distribution as seen from the imaging place.  
1.2 This test method provides instructions for determining the effecting size (dimensions) of mini and micro focal spots of industrial X-ray tubes. It is based on the European standard, EN 12543–5, Non-destructive testing - Characteristics of focal spots in industrial X-ray systems for use in non-destructive testing - Part 5: Measurement of the effective focal spot size of mini and micro focus X-ray tubes.  
1.3 This standard specifies a method for the measurement of effective focal spot dimensions from 5 up to 300 μm of X-ray systems up to and including 225 kV tube voltage, by means of radiographs of edges. Larger focal spots should be measured using Test Method E1165 Standard Test Method for Measurement of Focal Spots of Industrial X-Ray Tubes by Pinhole Imaging.  
1.4 The same procedure can be used at higher kilovoltages by agreement, but the accuracy of the measurement may be poorer.  
1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.7 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

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  • Standard
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