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NABL NATIONAL ACCREDITATION BOARD FOR TESTING AND CALIBRATION LABORATORIES

NABL 103

SPECIFIC GUIDELINES for CHEMICAL TESTING

LABORATORIES

ISSUE NO : 03 AMENDMENT NO : 00 ISSUE DATE: 25.03.2008 AMENDMENT DATE: --

National Accreditation Board for Testing and Calibration Laboratories Doc. No: NABL 103 Specific Guidelines for Chemical Testing Laboratories Issue No: 03 Issue Date: 25.03.2008 Last Amend No: 00 Amend Date: -- Page No: i

AMENDMENT SHEET

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National Accreditation Board for Testing and Calibration Laboratories Doc. No: NABL 103 Specific Guidelines for Chemical Testing Laboratories Issue No: 03 Issue Date: 25.03.2008 Last Amend No: 00 Amend Date: -- Page No: ii

ABBREVIATIONS AOAC : Association of Official Analytical Chemists

APHA : American Public Health Association

APLAC : Asia Pacific Laboratory Accreditation Cooperation

AS : American Standard

ASTM : American Society for Testing and Materials

BIS : Bureau of Indian Standards

BIPM : Bureau International des Poids et Measure (International Bureau of Weights and Measures)

BS : British Standard

CRM : Certified Reference Material

ISO : International Organization for Standardization

EA : European Cooperation of Testing Authorities

FTIR : Fourier Transform Infrared

GFAAS : Graphite Furnace Atomic Absorption Spectrometer

e.g. : For Example

GUM : Guide to the Expression of Uncertainty in Measurement

ICPAES : Inductively Coupled Plasma Atomic Emission Spectrometer

ICP-MS : Inductively Coupled Plasma – Mass Spectrometer

IEC : International Electrotechnical Committee

ILAC : International Laboratory Accreditation Cooperation

IUPAC : International Union of Pure and Applied Chemists

NABL : National Accreditation Board for Testing and Calibration Laboratories

NATA : National Association of Testing Authorities

NIST : National Institute of Standards and Technology

NMR : Nuclear Magnetic Resonance

QC : Quality Control

w.r.t. : With Respect To

National Accreditation Board for Testing and Calibration Laboratories Doc. No: NABL 103 Specific Guidelines for Chemical Testing Laboratories Issue No: 03 Issue Date: 25.03.2008 Last Amend No: 00 Amend Date: -- Page No: iii

CONTENTS

Sl Title Page Amendment Sheet i

Abbreviations ii

Contents iii

1. Introduction 1

2. References 2

3. Terms and Definitions 3

4. Scope 7

5. Technical Requirements 9

6. Groupwise Codification for Chemicals Tests 28

Annexure – A 37

Annexure – B 40

Annexure – C 78

National Accreditation Board for Testing and Calibration Laboratories Doc. No: NABL 103 Specific Guidelines for Chemical Testing Laboratories Issue No: 03 Issue Date: 25.03.2008 Last Amend No: 00 Amend Date: -- Page No: 1/ 88

1. INTRODUCTION 1.1 The requirements for accreditation are laid down in the International Standard ISO/IEC

17025: 2005 (General requirements for the competence of calibration and testing

laboratories). These requirements apply to all types of objective testing but in certain

instances additional guidance is necessary to take account of the type of testing and the

technologies involved. 1.2 This document has been produced by a TECHNICAL COMMITTEE constituted by NABL

for the purpose. It supplements ISO/ IEC 17025: 2005 standard and provides specific

guidance on the accreditation of chemical laboratories for both assessors and

laboratories preparing for accreditation. It gives detailed guidance for those undertaking

quantitative and qualitative examination of the composition, nature and properties of

materials, products and substances. 1.3 Laboratories conducting tests on food should also consult NABL specific criteria on

biology (NABL – 102) and the NABL guidance document on Food (NABL – 114).


2. REFERENCES

ISO/ IEC 17025: 2005 General Requirements for the Competence of Testing and

Calibration Laboratories

ISO/ IEC 17025 Application Document : 2000 Version 1, NATA, Australia

ISO Guide 30 Terms and Definitions used in connection with reference materials. UKAS: LAB 27 Accreditation for Chemical Laboratories


3. TERMS AND DEFINITIONS 3.1 Selectivity

Selectivity of a method refers to the extent to which it can determine particular analyte(s)

in a complex mixture without interference from the other components in the mixture. A

method which is perfectly selective for an analyte or group of analytes is said to be

specific. The applicability of the method should be studied using various samples,

ranging from pure standards to mixtures with complex matrices. In each case the

recovery of the analyte(s) of interest should be determined and the influences of

suspected interferences duly stated. Any restrictions in the applicability of the technique

should be documented in the method.

3.2 Range

For quantitative analysis the working range for a method is determined by examining

samples with different analyte concentrations and determining the concentration range

for which acceptable accuracy and precision can be achieved. The working range is

generally more extensive than the linear range, which is determined by the analysis of a

number of samples of varying analyte concentrations and calculating the regression from

the results, usually using the method of least squares. The relationship of analyte

response to concentration does not have to be perfectly linear for a method to be

effective. For methods showing good linearity 5 different standards (plus a blank) are

usually sufficient for producing calibration curves. More standards will be required where

linearity is poor. In qualitative analysis, it is commonplace to examine replicate samples

and standards over a range of concentrations to establish at what concentration a

reliable cut-off point can be drawn between detection and non-detection.

3.3 Linearity

Linearity is determined by the analysis of samples with analyte concentrations spanning

the claimed range of the method. The results are used to calculate a regression line

against analyte calculation using the least squares method. It is convenient if a method

is linear over a particular range but it is not an absolute requirement. Where linearity is

unattainable for a particular procedure, a suitable algorithm for calculations should be

determined


3.4 Sensitivity

Sensitivity is the difference in analyte concentration corresponding to the smallest

difference in the response of the method that can be detected. It is represented by the

slope of the calibration curve and can be determined by a least squares procedure, or

experimentally, using samples containing various concentrations of the analyte.

3.5 Limit of Detection

Limit of detection of an analyte is determined by repeat analysis of a blank test portion

and is the analyte concentration whose response is equivalent to the mean blank

response plus 3 standard deviations. Its value is likely to be different for different types

of sample 3.6 Limit of Quantitation

Limit of quantitation is the lowest concentration of analyte that can be determined with

an acceptable level of accuracy and precision. It should be established using an

appropriate standard or sample, i.e. it is usually the lowest point on the calibration curve

(excluding the blank). It should not be determined by extrapolation 3.7 Ruggedness

Sometimes also called robustness. Where different laboratories use the same method

they inevitably introduce small variations in the procedure, which may or may not have a

significant influence on the performance of the method. The ruggedness of a method is

tested by deliberately introducing small changes to the method and examining the

consequences. A large number of factors may need to be considered, but because most

of these will have a negligible effect, it will normally be possible to vary several at once.

The technique is covered in detail by the AOAC (8). Ruggedness is normally evaluated

by the originating laboratory, before other laboratories collaborate


3.8 Accuracy

The accuracy of a method is the closeness of the obtained analyte value to the true

value. It can be established by analysing a suitable reference material. Where a suitable

reference material is not available, an estimation of accuracy can be obtained by spiking

test portions with chemical standards. The value of spiking is limited; it can only be used

to determine the accuracy of those stages of the method following the spiking. Accuracy

can also be established by comparison with results obtained by a definitive method or

other alternative procedures and via intercomparison studies 3.9 Precision

Precision of a method is a statement of the closeness of agreement between mutually

independent test results and is usually stated in terms of standard deviation. It is

generally dependent on analyte concentration, and this dependence should be

determined and documented. It may be stated in different ways depending on the

conditions in which it is calculated. Repeatability is a type of precision relating to

measurements made under repeatable conditions, i.e. same method; same material;

same operator; same laboratory; narrow time period. Reproducibility is a concept of

precision relating to measurements made under reproducibility conditions, i.e. same

method; different operator, different laboratories; different equipment; long time period.

3.10 Reference Material

A reference material (RM) is a material or substance one or more properties of which are

sufficiently established to be used for the calibration of an apparatus, the assessment of

a measurement method, or for assigning values to materials. 3.11 Certified Reference Material

A certified reference material (CRM) is a reference material one or more of whose

property values are certified by a technically valid procedure, accompanied by, or

traceable to a certificate or other documentation which is issued by a certifying body. 3.12 Sample

A portion of material selected to represent a larger body of material.


3.13 Sample handling

This refers to the manipulation to which samples are exposed during the sampling

process, from the selection from the original material through to the disposal of all

samples and test portions.

3.14 Sub-sample

This refers to a portion of the sample obtained by selection or division; an individual unit

of the lot taken as part of the sample or; the final unit of multistage sampling 3.15 Sample preparation

This describes the procedures followed to select the test portion from the sample (or

subsample) and includes: in-laboratory processing; mixing; reducing; coning and

quartering; riffling; and milling and grinding.

3.16 Test portion This refers to the actual material weighed or measured for the analysis.


4. SCOPE 4.1 The Scope of accreditation of a laboratory is the formal statement of the range of

activities for which the laboratory has been accredited; the scope is recorded in detail on

a laboratory’s accreditation certificate. A laboratory’s scope should be defined as

precisely as possible so that all parties concerned know accurately and unambiguously

the range of tests and/or analyses covered by that particular laboratory’s accreditation.

The schedule format should typically define the laboratory’s accreditation in terms of: (i) The range of products, materials or sample types tested or analysed;

(ii) Types of tests or analysis carried out;

(iii) The specification or method/technique used;

(iv) The concentration range and accuracy/precision

4.2 Where non-routine testing is carried out, it is recognised that a more flexible approach to

scope may be necessary, but the scope must be as specific as is feasible and the quality

assurance system maintained by the laboratory must ensure that the quality of the

results is under control. Frequently, a single measurement technique may be used for

different analytes in a wide variety of samples. This measurement stage may be covered

by a single method. However, the methods used to prepare the samples for subsequent

analysis may vary considerably according to the nature of the analyte and sample

matrix. Thus several methods may be required to cover each different analyte matrix

combination. This is illustrated by gas chromatography, a technique applicable to a wide

variety of analytes. Depending on the matrix, a diverse range of methods may be used

to prepare analytes for gas chromatographic analysis; however, the procedures involved

in the final analytical stage vary little. 4.3 Where a laboratory uses analytical tools such as mass spectrometry, NMR or FTIR, it

may be appropriate to use the terms qualitative and/or quantitative chemical analysis

under the type of test heading. However, the onus will be on the laboratory to

demonstrate to the assessors that in using these techniques, it is meeting all of the

criteria for accreditation. In particular, the experience, expertise and training of the staff

carrying out the tests and those interpreting the data involved will be a major factor in

determining whether or not such analyses can be accredited.


It is accepted that sometimes it is not practicable for laboratories to use a (fully

documented) standard method in the conventional sense, which specifies each sample

type and determinant. In this case, the laboratory must have its own method or

procedure for the use of the instrument in question, which includes a protocol defining

the approach to be adopted when different sample types are analysed. Full details of the

procedures, including instrument parameters, used must be recorded at the time of each

analysis such as to enable the procedure to be repeated in precisely the same manner

at a later date. Where a particular analysis subsequently becomes routine, a full method

as required by NABL must be written and followed. The statement in the column of the

methods schedule will normally take the form of “Documented In-House Methods” using

GC-coupled mass spectrometry/NMR/FTIR, ICP-MS, etc. (Refer ISO/IEC 17025: 2005

para 5.4.2, 5.4.3, 5.4.4 and 5.4.5). Whenever there is deviations from standard method

or inadequate clarification in Standard Method, the laboratory needs to develop effective

procedure for ensuring the quality of results.

4.4 The approach to extending or amending the scope of accreditation should be as flexible

as possible. Normally the laboratory will give written notice to NABL of the tests, which it

wishes to add to its scope, quoting Standard method references (where applicable) and

providing copies of documented validated in-house methods before surveillance and re-

assessment.


5. TECHNICAL REQUIREMENTS 5.2 Personnel 5.2.1 The chemical testing laboratory shall be headed by a person preferably having a post

graduate degree in chemistry or equivalent or Bachelor degree in chemical engineering /

technology or equivalent with adequate experience in the relevant area especially in the

analysis of testing of relevant products.

The minimum qualification for the technical staff in a chemical testing laboratory shall be

Graduate in Science with chemistry as one of the subjects or Diploma in chemical

engineering / technology or equivalent or specialization in relevant fields like Textile,

Polymer etc. The staff shall have sufficient training and exposure in analytical chemistry

and in analysis and testing of appropriate products.

The laboratory technicians or equivalent shall have higher secondary certificate in

science / ITI and at least one year experience or training in a relevant laboratory. 5.2.2 The minimum requirement for an Authorized Signatory shall be a Graduate in Science

with chemistry as one of the subjects / Diploma in Chemical engineering / technology or

equivalent from a recognized university with at least 5 years experience in relevant field,

or Post-graduate in chemistry / specialization in relevant subject / Degree in Chemical

engineering / technology or equivalent from a recognized university with at least 2 years

experience in relevant field.

Note: The Assessment team may however recommend Authorized Signatory who does

not meet the above specified minimum experience requirement with specific

recommendations to NABL, after adjudging the competence of the Authorized Signatory

during on-site assessment. 5.2.3 Chemical testing laboratory involved in testing variety of products shall have a group in-

charge for each area. The group in-charge shall have adequate relevant experience in

addition to the minimum qualification as specified in 5.2.1.


5.2.4 There shall be a system for imparting periodic, internal and external training to the

laboratory technical staff at different levels wherever required before assigning any

analytical and testing work. Internal Training alone is not considered adequate to make

the staff knowledgeable on the latest status of science and technology. The laboratory

should ensure the availability of necessary infrastructure either internally or access to

external, for training. Evidence of effective training in specific field should be available in

terms of performance in quality checks. All the technical staff working should be

sufficiently trained in all physical, chemical and instrumental methods of analysis of the

particular product under concern. 5.2.5 For meeting the requirement of internal audit, there should be at least one technical

personnel apart from the head with suitable qualification and experience, irrespective of

the size of the laboratory, who has received a formal training on internal audit.

The laboratory shall normally use personnel who are permanently employed by the

laboratory or appointed on long-term contract basis, provided laboratory ensures

availability of technical personnel with adequate experience. A laboratory is not expected

to be operated by trainees. Where additional personnel are required, the laboratory shall

ensure that such personnel are supervised and that their work does not put at risk of the

laboratory’s compliance.

5.2.6 Any testing conducted away from the base laboratory (such as in field laboratories, in a

mobile testing laboratory or in the field) must also be under adequate technical control.

This would normally require either the location of Authorized Signatory at each facility or

having an Authorized Signatory visit each facility at appropriate intervals commensurate

with the volume, complexity and range of such tests and the maintenance of a diary

recording the dates and relevant activities of each visit. An authorized signatory must be

involved in the setting up of field or site laboratory.


5.3 Environment and accommodational condition 5.3.1 Samples, reagents and standards should be stored so as to ensure their integrity. The

laboratory should guard against deterioration, contamination and loss of identity. 5.3.2 The Laboratory shall meet the safety requirements applicable to the test procedure

wherever the published standard specifications mention the requirements. 5.3.3 It may be necessary to restrict access to particular areas of laboratory because of the

nature of the work carried out there. Restrictions might be made because of security,

safety, or sensitivity to contamination. Typical examples might be work involving

explosives, radioactive materials, carcinogens, toxic materials and trace analysis. Where

such restrictions are in force, staff should be aware of:

i. the intended use of a particular area;

ii. the restrictions imposed on working within such areas;

iii. the reasons for imposing such restrictions

5.3.4 Frequently, it will be necessary to segregate certain types of work which are prone to

interferences from other work, or which present particular problems or hazards.

Examples are trace analysis (where physical separation from high-level is necessary)

and carcinogen analysis. When selecting designated areas for special work, account

must be taken of the previous use of the area. Before use, checks should be made to

ensure that the area is free of contamination. Once in use, access to such areas should

be restricted, and the type of work undertaken there carefully controlled. 5.3.5 The laboratory shall provide appropriate environmental conditions and controls

necessary for particular tests, including temperature, humidity, freedom from vibration,

freedom from airborne and dustborne microbiological contamination, special lighting,

radiation screening. Critical environmental conditions should be monitored. 5.3.6 One key responsibility of the laboratory management is to provide an adequate and safe

working environment. Laboratory facilities should reflect due consideration of space,

design, security, health and safety. It is recognised that laboratories will be required to

comply with Government building and safety legislation. The provisions of such

legislation shall be considered as additional essential requirements.


5.3.7 Space

Each employee must have adequate work space to accomplish assigned tasks.

Sufficient space must be provided for storage of supplies, equipment and tools.

Analysts/examiners must have space available for writing reports and other official

communications. Where possible, there must be a clear delineation of areas used for the

clerical aspects of laboratory work and the areas used for testing/examinations.

Adequate and appropriate space must be available for records, reference work and

other necessary documents. Sufficient space must be available for each instrument to

facilitate its operation.

Accessories should be preferably stored near each instrument to facilitate its use and

operation. (Labs in which usable space falls below adequate levels may experience

health and safety problems, compromised efficiency, adversely affected morale and

productivity and an increased risk of mishandling and contaminating the evidence. In

designing and planning for additional space or a new facility, future space requirements

should also be projected.

5.3.8 Design

The relative locations of functional areas should facilitate the use of equipment and

instruments. Adequate and proper lighting of minimum 100 lumen must be available for

personnel to carry out assigned tasks. Adequate and proper plumbing and wiring must

be available and accessible. The laboratory must have proper ventilation, adequate

heating, cooling and humidity control as per the requirements. Bench and floor surfaces

must be appropriate for the work being performed. The design should maximise

laboratory functions and activities, safeguard the physical evidence, protect the

confidential nature of the laboratory operations and provide a safe and healthy

environment. (Lack of fiscal resources are not acceptable reasons for unacceptable

laboratory practices).

Where a laboratory exists within a host agency facility, documented procedures may be

required to permit entry during off hours for emergencies.

The laboratory should have a fire detection system wherever applicable. In keeping with

any relevant statutory requirements appropriate fire extinguishing devices must be

available and policies and procedures of laboratory security must be clearly

documented. Laboratory personnel should be trained in fire fighting.


5.3.9 Health and Safety

Health and safety aspects are to be taken seriously. Details about the same are given in

Annexure A.

5.4 Validation 5.4.1 Laboratory, whenever using non-standard methods or a standard method beyond the

stated limits of operation is required to validate such test methods. The guidance

document on Validation of Test Methods, NABL 212 may be referred. Validation of a

method establishes, by systematic laboratory studies, that the performance

characteristics of the method meet the specifications related to the intended use of the

analytical results. The performance characteristics determined include:

- Selectivity & specificity

- Range

- Linearity

- Sensitivity

- Limit of Detection

- Limit of Quantitation

- Ruggedness

- Accuracy

- Precision These parameters should be clearly stated in the documented method so that the user

can assess the suitability of the method for their particular needs.

In theory the development should include consideration of all of the necessary aspects

of validation. However, the responsibility remains firmly with the user to ensure that the

validation documented in the method is sufficiently complete to fully meet his or her

needs. Even if the validation is complete, the user will still need to verify that the

documented performance can be met


5.4.2 Test and calibration methods and method validation/verification published by BIS,

ASTM, AOAC, etc. 5.4.2.1 A laboratory seeking accreditation for a more open set of terms of accreditation (where

groups of analytes, for example, “organochlorine pesticides” are specified rather than

individual analytes) must have fully documented procedures covering such elements as:

method selection, method development, method validation or verification, acquisition of

appropriate reference standards or reference materials and staff training. Records of the

application of these procedures will be reviewed as part of each assessment. 5.4.2.2 When standard methods are used, laboratories should verify their own satisfactory

performance against the documented performance characteristics of the method, before

any samples are analysed. Records of the verification must be retained. For published

test methods that do not include precision data, the laboratory must determine its own

precision data based on test data. All methods should include criteria for rejecting

suspect results.

Where a test can be performed by more than one method there must be documented

criteria for method selection. Where relevant the degree of correlation between the

methods should be established and documented.

5.4.2.3 Methods developed in-house must be validated and authorized before use. Where they

are available, certified reference materials should be used to determine any systematic

bias, or where this is not possible results compared with other technique(s), preferably

based on different principles of analysis.

5.4.2.4 All methods shall be fully documented including procedures for quality control, and the

use of reference materials. It is preferable that a common format be adopted for writing

up methods and suitable guidance is given in ISO 78-2:1982, Layout for Standards –

part 2: Standards for chemical Analysis.


5.4.2.5 Developments in methodology and techniques will require methods to be changed from

time to time. Obsolete methods should be withdrawn but must be retained for archive

purposes and clearly labelled as obsolete. The revised method must be fully

documented, and indicate under whose authority the new method was issued (signed

and dated).

Where a change in method involves only minor adjustments, such as sample size,

different reagents, the amended method should be validated and the changes brought to

the attention of NABL at their next visit. Where the proposed change in method involves

a change of scope, such as a significant change in technology or methodology, the

laboratory. Shall inform NABL for appropriate action.

5.4.2.6 Laboratories are required to estimate uncertainty of measurement for the tests being

carried out. This should be on the basis of EURACHEM and GUM where standard

methods include uncertainty factors, laboratories may use them for the estimates. 5.4.3 Use of Computer 5.4.3.1 In chemical testing laboratories, computers have a wide variety of uses including:

• control of critical environmental conditions;

• monitoring and control of inventories;

• calibration and maintenance schedules;

• stock control of reagents and standard materials;

• design and performance of statistical experiments;

• scheduling of samples and monitoring of work throughput;

• control chart generation;

• monitoring of test procedures;

• control of automated instrumentation;

• capture, storage, retrieval, processing of data, manually or automatically;

• matching of sample and library data;

• generation of test reports;

• word processing;

• communication


5.4.3.2 The chemical testing environment creates particular hazards for the operation of

computers and storage of computer media. Advice can usually be found in the operating

manuals, however particular care should be taken to avoid damage due to chemical,

microbiological or dust contamination, heat, damp and magnetic fields.

If a testing instrument cannot be isolated from the data processing system, the system

as a whole must be calibrated either statically or dynamically. Each such system will

have to be examined individually.

If the testing instrument can be isolated from the data processing system, the

opportunity is available to calibrate each component of the system separately. The

testing instrument can be calibrated (again, statically or dynamically) in the conventional

manner and a separate verification of the data processing system can be undertaken

incorporating the A/D converters and interfacing systems

5.4.3.3 Computer controlled automated system

Such systems will normally be validated by checking for satisfactory operation (including

performance under extreme circumstances) and establishing the reliability of the system

before it is allowed to run unattended. An assessment should be made of the likely

causes of system malfunction. Where possible the controlling software should be

tailored to identify and highlight any such malfunctions and tag associated data. The use

of quality control samples and standards run at intervals in the sample batches should

then be sufficient to monitor correct performance on a day-to-day basis. Calculation

routines can be checked by testing with known parameter values.

Electronic transfer of data should be checked to ensure that no corruption has occurred

during transmission. This can be achieved on the computer by the use of `verification

files’ but wherever practical the transmission should be backed up by a hard copy of the

data.


5.4.3.4 Laboratory information management systems (LIMS)

LIMS systems are increasingly popular as a way of managing laboratory activities using

a computer. A LIMS is a software package allowing the electronic collation, calculation

and dissemination of analytical data, often received directly from other instruments and it

incorporates word-processing, database, spreadsheet and data processing capabilities.

It can perform a variety of functions, typically sample registration and tracking;

processing captured data; quality control; financial control; report generation. Particular

validation requirements include control of access to the various functions and audit trials

to catalogue alterations and file management. 5.5 Equipment 5.5.1 As part of its quality system, a laboratory is required to operate a programme for the

maintenance and calibration of equipment used in the laboratory. Equipment normally

found in the chemical laboratory can be categorised as:

i) general service equipment not used for making measurements or with minimal

influence on measurements (eg hotplates, stirrers, non-volumetric glassware and

glassware used for rough volume measurements such as measuring cylinders)

and laboratory heating or ventilation systems;

ii) volumetric equipment (e.g. flasks, pipettes, pyknometers, burettes etc);

iii) measuring instruments (e.g. hydrometers, U-tube viscometers, thermometers,

timers, spectrometers, chromatographs, electrochemical meters, balances etc);

iv) physical standards (weights, reference thermometers);

5.5.2 General Service Equipment

5.5.2.1 General service equipment are maintained by appropriate cleaning and checks

for safety as necessary. Calibrations or performance checks will be necessary where the

setting can significantly affect the test or analytical result (eg the temperature of a muffle

furnace or constant temperature bath).


5.5.3 Volumetric equipment 5.5.3.1 The correct use of volumetric equipment is critical to analytical measurements and it

shall be suitably maintained and calibrated. The correct functioning of some specialist

volumetric (and related) glassware is dependent on particular factors, eg the

performance of pyknometers and U-tube viscometers is dependent on ‘wetting’ and

surface tension characteristics, which may be affected by cleaning methods etc. Such

apparatus may therefore require more regular calibration, depending on use. For the

highest accuracy, measurements can often be made by mass depending on properly

calibrated weighing mechanism with traceability to accredited calibration laboratories in

INDIA or abroad APLAC/EA Member Countries rather than by volume.

5.5.3.2 Attention should be paid to the possibility of contamination arising from the equipment or

cross-contamination from previous use. The type used (glass, PTFE, etc), cleaning,

storage, and segregation of volumetric equipment is critical, particularly for trace

analyses when leaching and adsorption can be significant.

5.5.4 Measuring instruments/equipments 5.5.4.1 Correct use combined with periodic servicing, cleaning and calibration will not

necessarily ensure an instrument is performing adequately. Where appropriate, periodic

performance checks should be carried out (eg to check the response, stability and

linearity of sources, sensors and detectors, the separating efficiency of chromatographic

systems, the resolution, alignment and wavelength accuracy of spectrometers etc). See

guidelines published by NATA relating to calibration of equipments / instruments

provided at Annexure B as guidance to the laboratories.

5.5.4.2 The frequency of such performance checks will be determined by experience and based

on need, type and previous performance of the equipment. Intervals between checks

should be shorter than the time the equipment has been found to take to drift outside

acceptable limits.

5.5.4.3 It is often possible to build performance checks – system suitability checks – into test

methods (eg based on the levels of expected detector or sensor response to calibrants,

the resolution of calibrants in separating systems, the spectral characteristics of

calibrants etc). These checks should be satisfactorily completed before the equipment is

used.


5.5.5 Physical standards 5.5.5.1 Wherever physical parameters are critical to the correct performance of a particular test,

the laboratory shall have or have access to the relevant reference standard, as a means

of calibration. 5.5.5.2 Reference standards and accompanying certificates should be stored and used in a

manner consistent with preserving the calibration status. Particular consideration should

be given to any storage advice given in the documentation supplied with the standard. 5.6 Calibration & Measurement Traceability 5.6.1 The overall programme for the calibration of measuring equipment in the chemical

laboratory shall be designed to ensure that, where the concept is applicable, all

measurements are traceable through certificates held by the laboratory, either to a

national or international standard or to a certified reference material. Where no such

reference standard or certified reference material is available, a material with suitable

properties and stability should be selected or prepared by the laboratory and used as a

laboratory reference. The required properties of this material should be characterised by

repeat testing, preferably by more than one laboratory and using a variety of methods,

see ISO Guide 35, Certification of reference materials – General and statistical

principles. 5.6.2 Analytical tests may be sub-divided into three general classes depending on the type of

calibration required:

(i) In general, standards exist for ensuring traceability to international or national

standards for equipment used for the direct measurement of fundamental properties

(e.g., mass, length, temperature and time) or the simpler derived properties (e.g.,

area, volume and pressure). Where these properties have a significant effect on the

results of an analysis, the requirements of ISO/IEC 17025: 2005 shall be met.


(ii) Where a test is used to measure an empirical property of a sample, such as

flashpoint, equipment is often defined in a national or international standard method

and traceable reference materials should be used for calibration purposes where

available. New or newly acquired equipment should be checked by the laboratory

before use to ensure conformity with specified design, performance and dimension

requirements.

(iii) Instruments such as chromatographs and spectrometers, which require calibration

as part of their normal operation, should be calibrated using chemicals of known and

purity or reference materials of known composition.

- See Annexure ‘C’ for calibration of the parameters associated with chemical

analysis. This is taken from ILAC proceedings 1993.

5.6.3 Individual calibration programmes shall be established depending on the specific

requirements of the analysis. Also, it may be necessary to check instrument calibration

after any shutdown, whether deliberate or otherwise, and following service or other

substantial maintenance. The level and frequency of calibration should be at least that

recommended by the manufacturer. 5.6.4 Reference materials and chemical standards

Reference materials and certified reference materials are defined in terms and

definitions.

5.6.4.1 Reference materials provide essential traceability in chemical measurements and are

used to demonstrate the accuracy of results, calibrate equipment and methods, monitor

laboratory performance and validate methods, and enable comparison of methods by

use as transfer standards. Their use is encouraged wherever possible. 5.6.4.2 Where matrix interferences exist, ideally a method should be validated using a matched

matrix reference material certified in a reliable manner. If such a material is not available

it may be acceptable to use a sample spiked with a chemical standard.


5.6.4.3 It is important that the certified reference material has been produced and characterised

in a technically valid manner. Users of CRMs should be aware that not all materials are

validated to the same standard. Details of homogeneity trials, stability trials, the methods

used in certification, and the uncertainties and variations in the stated analyte values are

usually available from the producer and should be used to judge the pedigree. 5.6.4.4 For many types of analysis, calibration may be carried out using standards prepared

within the laboratory from chemicals of known purity and composition. Some chemicals

may be purchased with manufacturers certificates stating purity. Whatever the source, it

is the users’ responsibility to verify that quality of such standards is satisfactory.

Normally a new batch of a standard should be checked against the old. All chemical

standards should be subjected to inter/intra laboratory comparisons (amongst referred

laboratories).

Standards for compounds (for example: organic compounds) which are not available

with international traceability, should be procured from reputed manufacturers with

assured quality supported by certificate of analysis from the manufacturer

5.6.4.5 The purity requirements of chemical standards may be considered in relation to the

permitted tolerance of the method. For example, a tolerance of <0.1% of the target value

will require a chemical standard to have a certainty of concentration significantly better

than 99.9%.

5.6.4.6 Reference materials and chemical standards should be clearly labeled so that they are

unambiguously identified and referenced against accompanying certificates or other

documentation. Information should be available indicating shelf-life, storage conditions,

applicability, restrictions of use, etc. 5.6.4.7 Reference materials and standards should be handled in order to safeguard against

contamination or loss of determinant. Training procedures should reflect these

requirements.


5.7 Sampling and Sample Preparation 5.7.1 Selection of an appropriate sample or samples from a larger amount of material is a very

important stage in chemical analysis. It is rarely straight forward. Ideally, if the final

results produced are to be of any practical value, the sampling stages should be carried

out by, or under the direction of an experienced person, with an understanding of the

overall context of the analysis. Sampling is the operation of selecting part of the

elements of a set, so that it precisely represents the distribution of the properties that we

wish to measure in the total set.

The selection of the elements constituting the sample is determined by means of a

procedure known as the “Sample Plan”. The sample plan defines:

- The quantity of the sample

- The extraction system

5.7.2 The various terms used in sampling are dealt with in detail in recommendations

published by IUPAC. For the purposes of this guidance the definitions of sample, sample

handling, sub-sample, sample preparation and test portion are given in terms and

definitions. 5.7.3 If the test portion is not representative of the original material, it will not be possible to

relate the analytical result measured to that in the original material, no matter how good

the analytical method is nor how carefully the analysis is performed. The final result may

be dependent on the analytical method, it will always be dependent on the sampling

process. 5.7.4 As analytical methodology improves and methods allow or require the use of smaller test

portions the errors associated with sampling become increasingly important. Sampling

errors cannot be controlled by the use of standards or reference materials. Sampling is

always an error generating process and hence demands utmost care.


5.7.5 Sample packaging and instruments used for sample manipulation should be selected so

that all surfaces in contact with the sample are essentially inert. Particular attention

should be paid to possible contamination of samples by metals or plasticisers leaching

from the container or its stopper into the sample. The packaging should also ensure that

the sample can be handled without causing a chemical or microbiological hazard. The

enclosure of the packaging should be adequate to ensure there is no leakage of sample

from the container and that contamination cannot enter. 5.7.6 The extent to which laboratories become involved in sampling varies. Some laboratories

have no responsibility for sampling, others have partial involvement, while many have

total responsibility for both sampling and testing. It is essential that the laboratory have

available fully documented procedures for sampling. These may take the form of existing

National or International Standards. For in-house procedures, these will be assessed on

the basis of the suitability of the documented procedures for their intended purposes. All

sampling equipments and devices specified in a procedure will need to be available, be

well maintained and fully comply with dimensional and other tolerances specified in the

relevant standard.

Supervisory staff, responsible for the design and documentation of sampling procedures,

must be able to demonstrate the validity of the design of these procedures. The training

and supervision of samplers must be shown to be satisfactory. Sampling procedures will

usually be witnessed as part of on-site assessments of laboratories seeking such

registration.

5.7.7 Sample identification 5.7.7.1 All samples must be uniquely and clearly identified. Identification labels must be secure

and legible. Labelling on caps or lids is considered poor practice as it can lead to

possible mixing of sample identities during testing of like batches.

Containers should be leak-proof and impervious to possible contamination during

transport. Where specified, samples should be maintained within set temperature or

other environmental tolerances during transfer to the laboratory and prior to testing. In

some cases, it may be necessary for sample containers to be pre-tested prior to use to

ensure freedom from contamination.


5.7.8 Sample registration 5.7.8.1 On receipt, a sample must be registered into the laboratory records. The form of

registration may vary. In most laboratories, a sample register will be used, but in some

cases, the sample details may be written directly on worksheets or into workbooks.

Some sample information is essential and such criteria are covered in the subsequent

section “Records System”. 5.7.9 Sample retention and storage 5.7.9.1 Sample retention criteria cannot be standardised due to the varying stability and storage

considerations which apply for different materials. Each laboratory’s sample retention

and storage practices are, therefore, examined individually in the light of the types of

materials tested, the use-life of the products or materials which the samples represent

and the likely periods within which a recipient of the test results may request a retest. 5.7.9.2 Samples should be stored so that there is no hazard to laboratory staff and the integrity

of the samples is preserved. Storage areas should be kept clean and organised so that

there is no risk of contamination or cross-contamination, nor of packaging and any

related seals being damaged. Extremes of environmental conditions should be avoided,

which might change the composition of the sample, for example, causing loss of analyte

through degradation or adsorption. If necessary environmental monitoring should be

used. An appropriate level of security should be exercised to restrict unauthorised

access to the samples. 5.7.9.3 All staff concerned with administration of the sample handling system should be properly

trained. The laboratory should have a documented policy for the retention and disposal

of samples. The disposal procedure should take into account the guidelines set out

above


5.7.10 Reagents

The laboratory should purchase reagents only from reliable and reputed manufacturers.

The laboratory should also ensure that the quality of the reagents used is appropriate for

the tests concerned. The grade of reagent used (including water) should be as stated in

the method together with guidance on any specific precautions which should be

observed in its preparation or use. These precautions include toxicity; flammability;

stability to heat, air and light; reactivity to other chemicals; reactivity to particular

containers; and other hazards.

Labelling of reagents should identify substance, strength, solvent (where not water), any

special precautions or hazards, restrictions of use, and date of preparation and/or expiry.

The person responsible for the preparation of the reagent shall be identifiable either from

the label or from records.

Reagents used as primary standards for volumetric and gravimetric methods should

have a traceability to National and International standards. In cases where primary

standards are not available the reagents should be analytical grade (e.g. AR or GR) and

it should have certificate of analysis from the manufacturer along with it.

Acids and alkalies prepared for volumetric analysis should be periodically checked for

their strength and documented properly.

In the case of ultra-trace analysis using different instrumental techniques such as

GFAAS, ICPAES, ICPMS, etc. reagents such as water and acids and other organic

reagents should be purified further using ion exchange resins for water and sub-boiling

distillation for acids and organic reagents and also recrystallization and sublimation

procedures specifically for organic compounds


5.9. Assuring the quality of Test Results 5.9.1. Assurance and Quality Control

Analytical performance must be monitored by using quality control procedures

appropriate to the type and frequency of the testing undertaken. The range of quality

control activities available to laboratories include the use of :

� reference collections

� certified reference materials

� internally generated reference materials

� independent checks by other analysts/examiners

� statistical tables

� positive and negative controls

� control charts

� replicate testing

� alternative methods

� spiked samples, standard additions and internal standards

� correlation of results for different characteristics of an item

� retesting of retained items

Depending on the particular test/examination, one or more of these examples may be

appropriate. Quality control procedures must be documented. A record must be retained

to show that appropriate quality control measures have been taken, that quality control

results are acceptable or, if not, that remedial action has been taken. Where appropriate,

quality control data must be recorded in such a way that trends in analysis can be readily

evaluated. It is desirable to participate in proficiency testing for better quality assurance

of test results


5.9.2. Internal Quality Control

The level adopted should be demonstrably sufficient to ensure the validity of the results.

As a guide, for routine analysis the level of internal QC typically should be not less than

5% of the sample throughout, i.e. 1 in every 20 samples analysed should be a QC

sample. For more complex procedures, 20% is not unusual and on occasions even 50%

may be required. For analyses performed infrequently, a full system validation should be

performed on each occasion. This may typically involve the use of a reference material

containing a certified or known concentration of analyte, followed by replicate analyses

of the sample and spiked sample (a sample to which a known amount of the analyte has

been deliberately added). Those analyses undertaken more frequently should be subject

to systematic QC procedures incorporating the use of control charts and check samples.


6. GROUPWISE CODIFICATION FOR CHEMICAL TESTS This is a guideline for the applicant laboratories to describe the scope of testing w.r.t.

accreditation

6.1. Air, Gases & Atmosphere

• Ambient air monitoring

• Stack emission monitoring

• Fugitive emission monitoring

• Solid particulate matter

• Liquid mists, aerosols

• Gaseous pollutants excluding vehicular

• Industrial gases

• Gases for medical use & diving

• Reference gases & mixtures

• Liquified/compressed gases

• Vehicle emission

6.2. Alcohols & Alcohols based Chemical

• Industrial alcohols

• Alcohols based chemicals

6.3. Adhesives

• Starch based adhesives • Natural gums • Glues • Polymer based adhesives (Synthetic)

6.4. Building Materials

• Cement & other mortars

• Cement concrete

• Refractories

• Refractory cement

• Sand

• Clays & soils


• Pozzolonic materials

• Fly-ash

• Limestone, lime gypsum

• Waterproofing compounds

• Thermal insulation materials

• Masonry bricks/blocks, etc.

• Ceramics

• Glass

6.5. Coal, Coke & other Solid Fuel

• Coal/coke

• Coal carbonization products

• Coaltar/bitumen

• Charcoal

• Briquetted solid fuels

6.6. Cosmetics & Essential Oils

• Perfumes

• Essential oils

• Cosmetics and toiletries

• Intermediates and miscellaneous chemicals for cosmetics

• Herbal-based cosmetics

6.7. Dye & Dye Intermediates

• Synthetic dyes

• Dye intermediates

• Natural dyes & colouring materials

6.8. Disinfectants

• Disinfectants and their formulation


6.9. Drugs & Pharmaceuticals

• Synthetic drugs

• Natural drugs (medicinal plant preparations)

• Pharmaceutical formulation

• Drug intermediates and raw materials

• Veterinary preparations (herbal & synthetic)

• Vitamins

• Vaccines & sera

• Antibiotics

• Enzymes

• Hormones

• Chemicals used in compounding pharmaceuticals

6.10. Explosives & Pyrotechnics

• Ammunitions

• Industrial explosives & associated material

• Pyrotechnics

• Explosives chemicals and allied materials

6.11. Fertilizers

• Nitrogeneous fertilizers

• Phosphatic fertilizers

• Fertilizer mixtures

• Potash fertilizers

• Micronutrients

• Bio-fertilizers

6.12. Foods & Agricultural Products

• Alcoholic drinks & beverages

• Animal feeds

• Bakery and confectionery products

• Cereals, pulses, and by-products

• Coffee, coca and by-products


• Milk and dairy products

• Tea and tea products

• Starch can starchy products

• Fish and fishery products

• Food additives

• Colour, flavour & preservatives

• Honey and honey products

• Fruits and vegetable products

• Infant foods

• Meat and meat products

• Spices and condiments

• Sugar and by-products

• Tobacco and by-products

• Soft drinks

• Nuts & nut products

• Oil seeds & by-products

• Fruit juices & concentrates

• Egg & egg products

• Vitamins in foods

• Mycotoxins in food & feed

• Pesticides residues in food

• Polyhalogenated biphenyls

• Sensory evaluation-flavour

• Oil, fats and related products

• Shelf-life

6.13. Inks

• Printing inks

• Writing inks

• Duplicating inks


6.14. Industrial and Fine Chemicals

• Inorganic chemicals

• Organic chemicals

• Electroplating chemicals

• Solvents

• Laboratory chemicals

• Analytical reagents

• Speciality chemicals for: _ Leather industry

_ Rubber industry

_ Textiles industry

_ Electronics industry

_ Photographic industry

• Agricultural chemicals

• Firefighting chemicals

• Trace elements analysis

• Carbon black

• Wood and timber treatment chemicals

6.15. Lac & Lac Products

• Lac

• Lac products

6.16. Leather

• Leather

• Synthetic leather

6.17. Lubricants

• Trace elements

• Oils & greases

• Solid lubricants

• Aviation lubricants

• Lubricant additives

• Microcrystalline wax


6.18. Ores & Minerals

• Iron ores

• Copper ores

• Zinc ores

• Nickel ores

• Manganese ores

• Tin ores

• Lead ores

• Titanium ores

• Molybdenum and tungsten ores

• Chromium ores

• Precious metals ores

• Rare metals ores

• Radio active metals ores

• Bauxite

• Limestone & dolomite

• Rock phosphate

• Gypsum

• Silica sands

• Mineral sands

• Mineral for refractories

• Mineral for insulation materials

• Other minerals

• Minor elements

• Gem & semi-precious stones

• Geochemical samples for trace elements

6.19. Metals and Alloys

• Iron, steel and ferro-alloys

• Special steel

• Copper & its alloys

• Aluminium & its alloys

• Tin and tin alloys


• Zinc & inc alloys

• Lead & lead alloys

• Magnesium & magnesium alloys

• Nickel, chromium, cobalt & their alloys

• Titanium & titanium alloys

• Tungsten & its alloys

• Other metal alloys

• Precious metals

6.20. Paints and Surface Coating

• Paints and enamels

• Vehicles, solvents, thinners

• Pigments and extenders

• Polishes

• Painters materials (gums, driers, paint removers)

• Drying oils

• Powder coating

• Resin coatings

6.21. Paper and Pulp

• Pulp

• Paper, paper board and speciality papers

• Newsprint and board packing materials

• Composite packing materials

6.22. Petroleum

• Crude petroleum

• Fuels-gaseous, liquid & solid

• Aviation fuels

• Waxes and jellies

• Miscellaneous products, white oil, anti-freeze, solvents insulation oils, feed-stock

• Bituminous asphalt, tars and allied products

• Pour point depressants (flow improvers)


• Petrochemical feedstocks

• De-icing fluids

• Hydraulic fluids

• Fuel additives including corrosion preventives

• Trace analysis in petroleum products

6.23. Plastics and Resins

• Resin

• Plastics & polymers

• Raw materials

• Plastic films

6.24. Pesticides

• Synthetic pesticides & their formulations

• Natural pesticides & their formulations

• Pheromones, chitin inhibitors

• Weedicides

• Herbicides

• Fungicides

6.25. Pollution & Environment

• Liquid effluents

• Solid wastes

• Hazardous solid wastes

• Toxic waste

• Tests related to work place environment & hazards

6.26. Rubber & Synthetic Rubber

• Natural rubber

• Synthetic rubber

6.27. Soap Detergents and Toiletries

• Soaps

• Synthetic detergents

• Wetting and emulsifying agents


6.28. Textile & Textile Auxiliaries

• Fibre & filaments

• Yarns & chords

• Fabrics, garments and made-ups

• Auxiliaries

• Technical textiles (geo-textiles, medical textile, automotive textiles)

6.29. Water

• Potable and domestic

• Irrigation

• Industrial/cooling purposes

• Steam raising

• Medicinal purposes

• Distilled demineralized

• Waste water

• Trace metal elements

• Pesticides residues

• Bore water

• Saline water

6.30. Metallic Coatings and Treatment Solutions

• Metallic coatings

• Conversion coatings

• Plating solutions

• Anodizing solutions

• Metal finishing materials

6.31. Corrosion Tests

• Salt spray tests

• Dezincification tests

• Other tests


Annexure ‘A’

Health and Safety Health and safety are everyone’s responsibility and require the commitment of each employee

to be effective. Management’s commitment is essential for long term success of a health and

safety programme. Such a cooperative relationship will safeguard the employees of the

Laboratory as well as address management’s responsibility and liability.

All elements of the laboratory’s health and safety programme must be clearly documented in a

manual which is readily available to all staff.

Examples of procedures which must be included, where appropriate, are:

� procedure for handling chemical spills,

� cleaning and decontamination procedures for radioactive spills,

� evaluation procedures including a plan of the facility showing the location of safety

equipments and fire extinguishers,

� policy on the use of protective clothing eg. gowns, coats, gloves, goggles etc.

� policy on eating, drinking, applying cosmetics etc. in the laboratory,

� waste disposal procedures,

� routine cleaning and disinfection procedures for work benches, floors, centrifuges,

refrigerators, etc,

� accident reporting protocols,

� special procedures for handling hazardous substances.

Material safety data sheets must be available in conjunction with the safety manual. Work

related ‘Accident Insurance’ coverage for all employees shall be provided by the Management.

In large laboratories an officer may be designated as the Health and Safety Manager. Ideally,

the Health and Safety Manager should have received training in occupational health and safety

concepts and in the relevant legislative requirements. The health and safety programme must

be monitored regularly and audited at least annually to ensure that its requirements are being

met.


Proper equipment and material must be available to handle toxic and carcinogenic and or other

dangerous material spills. Where appropriate, the laboratory should have safety showers and

eye wash equipment of suitable locations and in good working condition. The operation of safety

showers must be checked regularly. If commercial eye wash preparations are used, it must be

ensured that the solutions are within their expiry dates or if distilled water is used the water must

be changed at least once a week.

Sufficient exhaust hoods must be available to maintain a safe work environment. Fume cabinets

must comply with relevant National/International Standards.

Sufficient first aid kits must be available and strategically located. An adequate number of

personnel must be trained in first aid procedures. Appropriate storage must be provided for

volatile, flammable, explosive and other hazardous materials. A flammable liquids storage

cabinet is required for all but small volumes. Acids and solvents should not be stored together. It

may be necessary to store some material in locked cabinets/cupboards and magazines.

Storage on high shelves is discouraged. Suitable carriers must be available to carry large

bottles. The emergency exits from the laboratory must provide safe passage in an emergency.

Evacuation routes must always be kept clear. General cleanliness and good house keeping

must be apparent. Food stuffs must not be kept in laboratory refrigerators/freezers/ ovens. .

There must be a documented ‘waste management programme’ which includes procedures for

the disposal of:

� chemical wastes

� sharp and broken glass

� uncontaminated waste, for example, paper waste

� radioactive waste

A register must be maintained of laboratory accidents, injuries and other incidents and the

follow-up action taken. Suitable protective clothing/equipment must be available at all the times.

The nature of these items will be dependent on the work being undertaken and might include:

� laboratory coats/gowns

� disposable gloves

� rubber gloves


� heat/cold resistant gloves

� protective eye wear

� face masks

� plastic/rubber aprons

� foot wear

When radioactive and X-ray work are performed, detectors must be used regularly to monitor

radiation levels and the wearing of film badges by staff may be necessary. Radiation badges are

to be worn by personnel working in X-ray and radiative hazardous areas. Laboratory shall

monitor control and record radiation levels as required by relevant specification methods and

procedures or where they influence the safety of personnel. Staff must be advised of

appropriate precautionary measures. It is recommended that relevant records be kept.

Appropriate hand-washing and hand-drying facilities must be available. Hand-basins should not

be fitted with domestic taps but with a suitable alternative, for example, elbow or foot-activated

devices. The use of communal towels is discouraged. Single use towels or automatic hand-

drying devices are preferred. A suitable cleaning agent must be available. Gas cylinders must

be secured. Samples/ specimens/exhibits referred to other laboratories must be transported in

accordance with the Indian Post or other relevant requirements.


ISO/IEC APPLIC APPLICATION TION DOCU DOCUMENT MENT Annexure - B

EQUIPMENT CALIBRATION INTERVALS (as per NATA Document)

Laboratory equipment calibration and check programs should cover: a) commissioning of new equipment (including initial calibration and checks after installation); b) operational checking (checking during use with reference standards or reference

materials); c) periodic checking (interim but more extensive checking, possibly including partial

calibration); d) scheduled maintenance by in-house or specialist contractors; e) complete recalibration. Some items of equipment, such as balances, require rechecking or recalibration if they are

moved or repaired. In general, NATA will accept recalibrations by laboratory staff of items marked * if the laboratory is suitably equipped, appropriate calibration procedures are documented (along with the applicable measurement of uncertainty) and the staff has demonstrated it is competent to perform such recalibrations. Where calibrations are performed by laboratory staff, full records of these measurements must

be maintained, including details of the numerical results, date of calibration and other relevant

observations. Note: These are not NABL requirements, but are being provided as a reference guideline for the benefit of the laboratories and their users.


CALIBRATION APPENDIX A: CALIBRATION OF COMMON TEST EQUIPMENT

The following requirements for frequency of recalibration and checks on test equipment with

reference to specific calibration and check procedures to be followed. The time intervals

indicated are maximum intervals and are dependent on the accuracy required and the type of

use the instrument is exposed to.

In general, the calibrations are carried out by an external calibrating authority and an endorsed

test report is obtained for this work. If a laboratory wishes to carry out these calibrations in-

house they must demonstrate the capability to do so according to the criteria set out in ISO/IEC

17025: 2005 sub-clause 5.6.2.1.

Checks are normally carried out in-house by the laboratory staff. If however, the checks are

carried out by an external authority then an endorsed test report must be obtained.

ITEM OF EQUIPMENT Calibration Interval (years)

Checking Interval

(months)

Procedures

and

References

AIR FLOW NOZZLES Initial 12 Check throat diameter

ANEMOMETERS 1 AUTOCLAVES Initial

1

Each Cycle

Temperature profiling of typical loads. NATA Technical Note 5 Check temperature distribution with no loading. Record the temperature, pressure, time and type of load.

BALANCES See also weighing instruments

3

12

6

1

Each weighing

External by NATA accredited calibration authority or in-house using calibrated masses refer to Calibration of Balances Prowse. Service Repeatability check. One point check Zero point check

BAROMETERS

Fortin Initial

Aneroid 1

60

One point check with transfer instrument.

CALLIPERS (VERNIER) 2 AS 1984

DIAL GAUGES 2 AS 2103


ELECTRICAL INSTRUMENTS

Digital multimeters 1 6 Compare with meters of similar resolution.

Analog meters 2 6 Compare with meters of similar resolution.

Data loggers 1 1 Check at zero and the maximum point.

ENVIRONMENTAL

CONDITIONING CHAMBERS

3

On use

IEC 600688-2-1,-2,-3,-33,-38,-39

Check at the working temperature

FORCE TESTING MACHINES

Dead weight 5 AS 2193

Elastic dynamometer 2 AS 2193

Hydraulic, pneumatic 2 AS 2193 FURNACES Initial

12

On use

AS 2853 Check variation within the working zone at the working temperature Monitor temperature

HYDROMETERS

Reference 5

Working - glass 12 Check against reference hydrometer or in newly prepared solutions of known density.

AS 2026, ASTM-E126

Working - metal 6 ISO 649.1, .2, ISO 650

HYGROMETERS

Assmann and sling psychrometers

10 6 Compare thermometers at room temperature with wick dry. AS 2001.1 Appendix C.

Thermohygrographs Weekly Check against a calibrated psychrometer

Electronic types 1

MANOMETERS

Reference, liquid 10

Working, liquid 3 36 Check the cleanliness of the fluid

Electronic 1 36 Check the cleanliness of the fluid

MASSES

Reference – of integral stainless steel or nickel chromium alloy

3 then 6 subsequent

Working – stainless steel,

nickel chromium alloy

3

Working – other alloy 1

MICROMETERS 5

1

AS 2102

Check zero and one point against gauge block. Inspect anvils.

ORIFICE PLATES Initial

6

BS 1042.1

Visual check for wear and damage.


PRESSURE EQUIPMENT

Test gauges used for calibration of industrial gauges

1 AS 1349

Industrial gauges not subject to shock loading

1 AS 1349

Industrial gauges subject to shock loading

6 months AS 1349

Pressure transducers 1

Calibrators 1

SIEVES Initial 12

On use

Compliance certificate to AS 1152, BS 410. Depending on the accuracy required, more or less frequent checks may be required against a reference set or a suitable reference material.

Visual check for wear and binding.

TAPE MEASURES, RULES

Tape measures Initial AS 1290.4, BS 4035

Steel rules Initial

2 to 5 Check at maximum length, depending on use and accuracy required.

BS 4372

TEMPERATURE

CONTROLLED ENCLOSURES

Ageing 5

Daily

AS 2853

Monitor temperature

BOD On use Check the temperature at the start of the test. The maximum and minimum temperature of the laden chamber must be monitored for the test period.

Drying Initial

24

Temperature variation and evaporation rate must be checked.

AS 2853, AS 1289 Part 0, BS 2648

Check temperature variation within the working zone.

On use Monitor temperature

Vacuum 24 Check temperature variation and pressure in the working space.

AS 2853m VS 3898, BS 3718

TEMPERATURE (DIGITAL) INDICATING SYSTEM

1 Calibrate against a reference temperature measuring system.

Hand-held, bench type and temperature loggers

Initial

6

Check efficacy of automatic cold junction compensation with the temperature sensor at the ice point.

Check at ice point.


THERMOMETERS

Reference, platinum resistance 10 CSIRO/NML Temperature Measurement Course Book 2

Before use Check at ice point

Reference, liquid-in-glass 10

Before use

Check at ice point

AC temperature bridge 5 Check linearity and resistance ratio. Working - liquid-in-glass Initial

6 Check at ice point or at one point in the working range against a reference thermometer.

Working - resistance 5

6

Check R at ice point

Working - digital display 1

6

Check at ice point or at one point in the working range against a reference thermometer.

THERMOCOUPLES

“K” type, sheathed Initial For use up to 400°C. For use above 400°C to 1100 °C the same immersion must always be used.

“K” type, wire Initial (reel of wire)

For use up to 400°C.

Replace if used above 400ºC.

“T” type, wire Initial (reel of wire)

For use up to 350°C.

“K” and “T” types 6 Check at ice point.

TIMING DEVICES

Stop watches, clock

6

Test aurally against the Telstra speaking clock. Two measurements separated by one hour (ie. a one hour period) must be carried out.

WEIGHING INSTRUMENTS

See also balances

2 Non-automatic weighing instruments.

Uniform Test Procedures, Inspectors Handbook No 2 for class III and IV Instruments.


CALIBRATION APPENDIX B: CALIBRATION INTERVALS FOR CHEMICAL TESTING EQUIPMENT

The following table sets out the nominal maximum periods between successive calibrations of

general equipment, not listed in the previous table, for laboratories holding accreditation in the

field of Chemical Testing. Subsequent appendices in this section list specific calibration

requirements for special purpose testing. This table also contains information that expands on

the previous table to aid the chemical laboratories.

ITEM OF EQUIPMENT Maximum period between

successive Calibrations or

Checks

Procedures

and

Comments

Note 1: Balances with in-built calibration check facilities must also have monthly and 6-monthly checks carried out.

BALANCES

Note 2: Electronic balances with more than one range must have monthly and 6-monthly checks carried out on all ranges.

BAROMETERS For Fortin barometers see NAR Calibration Appendix 1.

Aneroid barometers (mechanical and electronic) should be checked at least six-monthly. One point is sufficient. Refer to NATA Technical Note 8 for subsequent recalibration and checking requirements.

CENTRIFUGES *1 year (where operating speed

is specified)

Tachometer (mechanical stroboscope or light cell type).

COMPARATORS

Lovibond

*2 year

Check condition of discs (this check could be done with a spectrophotometer referenced to standards)

DENSITY BOTTLES,

PYKNOMETERS

*1 year

AS 2378; BS 733 App A; IP 190

*Initial; whenever test temperature is changed or cell

cleaned

ASTM D4052

* Daily With pure substance of known density.

DENSITY METERS

*1 week Air and double-distilled water.

FLOWMETERS

Rotameters (Reference)

High flow, ie >1 L/min *2 years ASTM D3195

Low flow, ie <1 L/min *2 years Soap bubble flow meter.

Rotameters (Working) *Each time on use

Soap bubble flow meter.


Orifice plates Initial BS 1042 Part 1 (calibration by an approved testing authority)

*6 months Visual inspection for damage, wear or contamination.

Wet test meters *2 years ASTM D1071

Anemometers 2 years Calibration by an approved testing authority.

Pitot tubes *Initial Check dimensional compliance with BS 1042 Sec 2.1 Annex A.

*On use Inspect tip for damage, blockage, etc as required by BS 1042 Sec 2.1

FURNACES (FOR USE AT SPECIFIED TEMPERATURES) (In addition to other requirements)

*On use Monitor temperature with an appropriate sensor

GAS METERS *2 years

GAUGE BLOCKS 4years (reference)

Calibration by an approved testing authority

*2 years(working) Check against reference blocks.

† GLASSWARE

(1) Specialised calibrated glassware water traps, sulphonation flasks, centrifuge tubes etc

*Initial AS 2162.1

(2) Piston operated *Initial AS 2162.2 volumetric apparatus (see below)

*Initial AS 2162.1

Pipetters *Initial Check volume delivered. For adjustable devices check volume delivered at several settings (refer to AS 2162.2).

*3 months Check volume delivered at settings in use.

Dispensers *Initial Check volume delivered. For adjustable devices check volume delivered at several settings (refer to AS 2162.2).

*3 months Check volume delivered at settings in use.

Diluters *Initial Check sample and diluent volumes or dilution ratio and total volume (refer to AS 2162.2).

*6 months Check sample and diluent volumes or dilution ratio and total volume (refer to AS 2162.2).

Displacement burettes *Initial Check volume delivered at maximum and two other settings.

*When barrel/plunger is

changed

Check volume delivered at maximum and two other settings.

HYDROMETERS

In addition to other requirements *On use Check that scale has not slipped.

OVENS

In addition to other requirements

*On use

Monitor temperature throughout use, with appropriate sensor, and record temperature daily.

Ageing *Daily Monitor with appropriate sensor and record.

Drying *On use Monitor with appropriate sensor and record.


PENETRATION CONES AND NEEDLES

5 years Calibration by an approved testing authority. ASTM D217; IP 50; ASTM D5; ASTM D1321.

*On use Visually inspect needle tips.

POTENTIOMETERS

Reference 5 years Calibration by an approved testing authority. Working *One year Check against reference potentiometer.

PRESSURE GAUGE TESTERS

Deadweight 5 years Calibration by an approved testing authority Manometers 10 years

PYROMETERS

Reference 3 years BS 1041 (Part 5). Calibration by an approved testing authority

Working *6 months Check against reference pyrometer

REFRACTOMETERS *On use Check against distilled water

*6 months Check against bromonaphthalene or other reference compound of known refractive index.

REFRIGERATORS Where critical, the temperature of the working space must be monitored by an appropriate temperature sensor throughout use and recorded.

TACHOMETERS

Reference 5 years BS 3403. Calibration by an approved testing authority

Working *1 year Check against reference tachometer

VISCOMETERS

U-tube Reference *Initial Against reference oils. ASTM D2162

*10 years

Working *Initial Using quality oils against reference tubes or using reference oils.

*2 years ASTM D2162/D445; IP 71

Others

Brookfield *Initial Against reference oils. ASTM D2556

*2 years Against quality (ie. manufacturers’) oils

*1 month

Ferranti *Initial Against reference oils.

*3 months

Zahn *Initial Against reference oils

*1 year

* commonly done by laboratory staff † Volumetric plasticware is not acceptable because it is prone to irreversible volume changes and deformation. IS


CALIBRATION APPENDIX C: PERIODICAL CALIBRATION OF EQUIPMENT FOR MONITORING STANDARD OPERATING CONDITIONS FOR ASTM METHODS D2699, D2700 (RON AND MON)

Checks as specified in Calibration Appendices A and B must be carried out on all thermometers, burettes, viscometers, dial gauges and other items of equipment. Maintenance and standardisation checks must be done at the intervals specified in ASTM methods D2699 and D2700. Full records of these checks must be kept. CALIBRATION APPENDIX D: CALIBRATION OF EQUIPMENT FOR TESTS ON COAL AND COKE



Checks

Procedures

and

Comments

BOMB CALORIMETERS *On use Checks on calorimeter dimensions and for thread slackness

*3 months Determination of the water equivalent (bomb factor) Refer AS1038 Part 5

Pressure, mechanical and dimensional tests on bombs

3 years or 1000 firings depending

on use

Checks as prescribed in AS 1038 (see also BS 4791). More frequent checks required if calorimeter is damaged or used repeatedly.

Calibration by an appropriate testing authority.

CRUCIBLE SWELLING NUMBER BURNERS

*1 month Heating profiles of all burners Refer AS 1038 Part 12.1

DENSITY BOTTLES *3 months Refer AS 1038 Part 21

DILATOMETER *6 months Temperature (absolute and gradient), piston assembly mass and tube wear. Refer AS 1038 Part 12.3

FROTH FLOTATION CELLS *12 months Check cell block and impeller dimensions. Refer AS 4156.2.1

FURNACES

Ash *12 months Measure and record test zone temperature by the

use of a certified reference thermocouple, or a working thermocouple † or a calibrated electronic thermometer. Refer AS 1038 Parts 3,6, 12.2, 15

Gray-King *12 months Tube *12 months Volatile Matter *6 months Ash Fusion *3 months

GIESELER PLASTOMETER

Bath temperatures * 6 months Remove thermocouple and check against reference. Refer AS 1038.12.4.1

Torque Test *1 month Check against torque meter. Rabble Arms *Initial Check dimensions.

*50 determinations Check for wear.


HARDGROVE GRINDABILITY

Apparatus *12 months Calibrate against four national reference coal samples with certified grindability indices. Refer AS 1038 Part 20.

Mill revolutions *12 months Check number of revolutions per minute.

HYDROMETERS

Working, for float and sink testing

*12 months Preferably check side by side against certified reference hydrometers. If not available check against freshly prepared solutions of known density. Refer AS 2026. Laboratory may isolate own reference set of hydrometers after in-house calibrations.

INSTRUMENTAL ANALYSERS

For carbon, hydrogen, nitrogen or sulphur

*On use

Check precision (refer AS 1038 Part 16) against Standard Method ( AS 1038 Part 6) or against certified reference materials which cover the full working range.

MICROSCOPE PHOTOMETER

For reflectance measurements

Prior to each sample, at fifteen

minute intervals and at end of sample

measurement

Calibrate using glass or mineral reflectance standards. Refer AS 2486

OVENS

Direct gravimetric *12 months Check temperature gradient over sample area Drying *12 months Check temperature of working space Minimum free-space *12 months Check temperature

SHALE BREAKDOWN

APPARATUS

Andreasen sizing apparatus * Initial Check flask volume, height of stem and pipette volume.

Refer AS 4156.1

Drum tumbler * 12 months Check revolution counter on tumbler. Refer AS 4156.1 * commonly done by laboratory staff † Check every six months against certified reference thermocouple. (A Gray-King furnace is quite convenient as a

heat source).

NOTES (I) The period given between successive calibrations is a maximum period. More frequent calibrations may be

required if the equipment is repaired, moved, is in constant use or a change in operating circumstances occurs.

(II) Accredited coal laboratories must maintain adequate quality control in supervision of equipment performance

by the use of appropriate reference materials on a regular basis. (III) Whenever possible, unless otherwise stated in the relevant standard, equipment should contain all items of

apparatus specified in the test method when being calibrated. (IV) The calibration requirements for other general items of equipment used in coal and coke testing (eg. balances,

thermometers, thermocouples, volumetric glassware, etc) are found in this booklet in Calibration Appendices A and B.


CALIBRATION APPENDIX E: PERIODICAL RECALIBRATION OF EQUIPMENT FOR PHYSICAL TESTS ON PAINTS TO AS 1580



Checks

Procedures and Comments

METHODS 101.1, 101.4, 101.5

Thermohygrograph *1 month (retain charts)

Against calibrated psychrometer

Psychrometer 10 years Complete.

*6 months Against reference thermometer

Anemometer 2 to 5 years depending on

use.

Illumination meter

METHOD 101.3

Forced draught oven *6 months Check oven thermometer against reference thermometer. Stoving 5 years or *2

years to 5 years depending on

use.

Temperature variation in working space. (Refer AS 2853) By approved testing authority. Calibration by laboratory staff.

METHOD 107.3 Reference wheel gauge 5 to 10 years

depending on use Calibration by an approved testing authority

Working gauges 2 years Calibration by an approved testing authority, or *1 year Against reference wheel gauge.

METHOD 108.1

Shims Initial only plus frequent visual

examination

Shims bearing ASTM or NIST stamps do not require initial

external calibration.

Magnetic instruments *On use Against calibrated shims

METHOD 108.2

Paint inspection gauge * Initial only Graticule and cutting angle of cutting tip

METHODS 202.1; 202.2 Pycnometer *Initial Check capacity.

(at least 50ml capacity) *6 months

METHOD 204.1 Fineness of grind gauge block and scraper

Reference 5 to 10 years depending on

use.

Calibration by approved testing authority.

Working *1 year plus frequent visual

examination

Against reference using at least four paints covering the working range


METHOD 211.1, 211.2 Settling spatula *Initial only Dimensions and mass

*6 months Re-examine for wear and change

METHOD 214.1 † Krebs-Stormer Viscometer *Initial only +Masses and paddle dimensions

*Initial, then 1 year

++Against standard oils stored in sealed container

Reference oils 2 years Replace. Store as directed, well sealed, clean

METHOD 214.2

Flow cup *Initial only Dimensions

*Initial, then ++ Against standard oils stored in sealed container *3 months (for

cups in constant use), or

++Against standard oils stored in sealed container

*1 year (other) ++Against standard oils stored in sealed container

Reference oils 2 years As for 214.1

METHOD 214.3

Cone and plate viscometer Initial Verification of plate temperature *On use ++Against standard oils stored in sealed container Reference oils 2 years As for 214.1

METHOD 214.4

Roto thinner viscometer * Initial, then 1 year

++Against standard oils stored in sealed container.


METHOD 214.5 Brookfield viscometer * Initial, then 1

year ++Against standard oils stored in sealed container

*1 month Against manufacturer’s oils


METHOD 301.1, 301.2

Oven *6 months Oven thermometer against reference thermometer

*2 years Temperature variation in working space.

METHOD 401.1

Spoon * Initial Dimensions and mass of beads delivered

METHOD 401.6 Mechanical thumb * Initial only Dimensions and masses (those that cannot be

disassembled must be checked against one known to conform).

2 years Hardness of rubber plunger

METHOD 401.8 Ramp/roller * Initial Dimensions and mass

Roller rubber bands 2 years Hardness.


METHOD 402.1

Bend test apparatus and mandrels

* Initial only Dimensions.

METHOD 403.1

Scratch test apparatus Initial only Needle dimensions.

*1 year Inspect under microscope for wear and damage

METHODS 408.1, 408.3

Adhesion test apparatus Initial only Dimensions of cutting tips and points

*1 year Re-examine under microscope

METHOD 459.1

Sponge and holder machine * Initial Mass, length and rate of travel

METHODS 459.1, 461.1,

481.1,481.2, 482.1

Grey scales

Reference 10 years Replace.

Working *3 months Check against reference set.

METHOD 601.1

Light booth 100 hours Check lamps, voltage and illumination levels.

Colour blindness test * Initial Refer “Tests for Colour Blindness” by S Ishihara

METHODS 601.2, 601.3

“Colour master” *On use Calibration of photometer scale using reference tiles supplied by manufacturer

“Colour eye”

METHOD 602.1

Specular gloss

standards Initial External certificates (NIST)

METHOD 602.2

Gloss tiles

Primary 5 years Supplied by manufacturer

Secondary *6 months Against primary tiles

Instrument *On use Against secondary gloss tiles * Commonly done by laboratory staff † Krebs-Stormer viscometer is considered acceptable as long as it gives a value within ± 15% of the expected

load for 200 rpm for a given oil and within ± 5% of the consistency in Krebs units. + If dimensions do not conform, the instrument must be calibrated with two standard viscosity oils to ASTM D562 ++ Standard oils need only be replaced every 2 years if correctly stored (in the dark, at the room temperature, in

closed glass or tinned metal containers, free from contaminants).


NOTES DETERMINATION OF COLOUR AND VISCOSITY OF RESINS Accreditation for colour and viscosity of resins using Gardner colour standards and Gardner-

Holdt viscosity standards (to Federal Test Method. Standard No 141a and ASTM Methods) is

granted on the basis that the applicant can obtain results comparable with laboratories already

accredited for these tests, as an alternative to fundamental calibration of these standards. QUALITY CONTROL TESTS NATA Technical Note 1 details requirements for accreditation of quality control testing of paint.


CALIBRATION APPENDIX F: CALIBRATION OF GAS ANALYSERS (Except for Motor Vehicle Emission Testing to Australian Design Rules - See Appendix G)

These calibrations should be performed by approved testing authorities using gases of known

concentrations or NATA approved blending techniques appropriate to the gas being measured.

ITEM OF EQUIPMENT Maximum period between successive Calibrations or

Checks

Procedures

and Comments

GAS DETECTION INSTRUMENTS for use in mines, and also for industrial and commercial applications

Before use Span and zero check (weekly on field instruments used for

continuous monitoring)

1 point span check made on 75%-90% of full scale of range being used. (At approximately 50% for combustible gas detectors with an output scale of zero to 100% lower explosive limit).

*6 months complete recalibration

Six point (and zero) for NDIRS (with recommended values of 15, 30, 45, 60, 75 and 90% full scale deflection).

Three point (and zero) (see note vi) for other types including UV, chemiluminescence, refactive index, catalytic, FID, electrochemical, thermal conductivity, paramagnetic and zirconium oxide detectors.

Two point (and zero) (see note vi) for fixed or stationary instruments (catalytic) and combustible detectors with an output scale of zero to 50% lower explosive limit. 1 point for single point alarm instruments (see note vii).

2 years Full calibration, including maintenance and overhaul to be conducted above ground.

REFERENCE GASES

Non-reactive reference gases at a concentration greater than 100 ppm

4 years or once the cylinder pressure drops below

700kPa (100 psi), whichever comes first.

Non-reactive reference gases at a concentration of 100ppm or less whichever comes first.

2 years or once the cylinder drops below 700kPa

(100psi)

Reactive reference gases 2 years or once the cylinder pressure drops below

700kPa(100psi), whichever comes first

* commonly done by laboratory staff


NOTES (i) Frequency given is MAXIMUM period between calibrations. (ii) Instruments must be completely recalibrated after significant maintenance.

(iii) The calibration history for each instrument must be recorded. (iv) The initial calibration must check interferences. The laboratory should be aware of the

contaminants which may create cross-sensitivity.

(v) Calibrations must be performed more frequently (see Note (ii)) if poisons are likely to be

present for any catalytic sensor.

(vi) Calibrations using 2 or 3 points (and zero) must adequately cover the range. One point

must be between 75% and 90% of full scale, except for fixed or stationary instruments

used in explosive atmospheres with scales 0 - 100% lower explosive limit, the highest

calibration point approximately 50% lower explosive limit.

(vii) For single point instrument alarms, a one-point calibration is performed at the level at

which the instrument alarms.

(viii) Fixed instruments with remote head should be calibrated in-situ, where possible, but if

calibrated in a laboratory suitable leads (same resistance) must be used. Also a polarity

check should be made when the instrument is reassembled.

(ix) The gas flow rates necessary for optimum response of flame ionisation detectors should

be checked regularly. Zero checks must be made with high purity gases (depending on

precision and accuracy required). Oxygen-quenching effects must be determined on

commissioning only.

(x) For low level alarms (and semiconductor type detectors) all operating parameters must

be included on the calibration certificate and the instrument must be calibrated with the

gas type which the instrument is to measure.

(xi) A non-linear instrument, such as non-dispersive infrared analyser, which has a

linearising circuit is not considered to be a linear instrument. A nominally linear

instrument is linear if its response is within 2% of linearity over its range. (xii) Wosthoff pumps and gas dividers should be checked annually by an accredited testing

authority.


METHOD OF REPORTING Test documents relating to the calibration of gas analysers must meet NATA’s general

requirements set out in this booklet. The conditions of tests (temperature, gas mixtures,

laboratory, in-situ, etc.) must be clearly stated and the meaning of the test result must be

unambiguous.

Endorsed test documents must only relate to the calibration of the instrument. Any servicing,

maintenance or opinions on the performance of the instrument must appear on a separate, non-

endorsed attachment.

In addition, there must be traceability to the reference gases used for calibration or the method

of generating references (eg. Wosthoff Pump). This must be stated, either on the report or on

the relevant work sheets.


CALIBRATION APPENDIX G: PERIODIC RECALIBRATION OF EQUIPMENT FOR VEHICLE EMISSION TESTING LABORATORIES The following table lists the requirements for periodical calibration of instruments and test

equipment used for motor vehicle emission testing by testing laboratories holding accreditation

in the field of Chemical Testing: 7.90 Motor Vehicles

.01 Vehicle emissions

.02 Fuel consumption tests

It also shows the reference standards for calibration and, where available, the standards

describing detailed procedures for calibration. These are taken from National Standards and

from Australian Design Rules, and also from current emission laboratory testing practice in

Australia. In general, NATA will accept recalibrations carried out by laboratory staff of items

marked *, provided that the laboratory is equipped with the required calibration standards and

the staff is competent to perform such recalibrations.

ITEM OF EQUIPMENT Maximum period between successive

Calibrations or Checks

Procedures

and

Comments

CONSTANT VOLUME

SAMPLER

Positive Displacement Pump

*500 hours of use after stabilising period or major maintenance

ADR 37/00 - Appendices 5 (Method), 12

Critical Flow Venturi *As indicated by CVS system verification

Reference Standard; Air Flow Meter (Laminar Flow Element, Subsonic Venturi or orifice plate). Calibration traceable to NIST. Accuracy 1 % of air flow.

System verification *1 week or after Using CP Propane (C3H8) or Carbon Monoxide or Carbon Dioxide.

Propane maintenance or servicing of system

Carbon Monoxide System accuracy in the order of 2% critical flow orifice or “bomb” method

Carbon Dioxide NOTE: Precautions for use of pure carbon monoxide

Correlation car *As required to supplement other

methods

Approved in-house laboratory methods.


DYNAMOMETERS

Chassis

Load scale AS 2193. NML Class B Certified Masses

Knife edge 5 years

Pneumatic/ Hydraulic link 2 years

Electronic 2 years

Bourdon tube 6 months

Roller speed *3 months Digital counter with stop watch

Power absorption *1 month

Performance check *1 week

Distance measurement *6 months

Engine

Load scale AS 2193. NML Class B Certified Masses.

Knife edge 5 years

Pneumatic/ Hydraulic link 2 years

Electronic 2 years

Bourdon tube 6 months

Speed *3 months Digital counter with stop watch

DYNAMIC GAS BLENDING DEVICE

Standard gas dividers *1 year Using gas analyser and primary gas standards for each gas type.

*Each use Single point

FANS

Engine cooling *On commissioning or major overhaul

Anemometer


FLOWMETERS

Air Flow Meter

Laminar Flow Element (LFE) *100 hours of use or more frequently if drift

occurs

Visual inspection for damage, wear and contamination

Orifice Plate 10 years Calibration traceable to NIST Master within ± 1%, ADR 37/00, Appendix 5

Venturi Flow Meter 10 years

Anemometers 2 years

Rotameters (see Note below)

Reference High flow >1 L/Min

*2 years ASTM D3195

Low flow

<1 L/Min

*2 years Soap bubble flow meter

Working *On use Soap bubble flow meter

Fuel Flowmeters *6 months

Gas analyser

For motor vehicle exhaust emissions

*Span and zero check before and after each

analysis on each analyzer

ADR 37/00 Appendices 10, 12, 13

*Complete recalibration of all analysers at one

month intervals

6 points at 15, 30, 45, 60, 75, 90 % of range, plus zero for calibration on all instruments.

Using reference gases traceable to national or international standards.


Dynamic gas blending devices such as standard

gas divider accurate within ±1 % may be used to generate the points for a calibration.

NOx Convertor efficiency *1 week ADR 37/00 – Appendix 10

HC Optimisation of performance

*On first commissioning; 1 year and after major

maintenance

ADR 37/00 – Appendix 10

HC oxygen quenching effect *On first commissioning; 1 year and after major

overhaul

SAE J1094a Constant Volume Sampler Systems for Exhaust.

Emissions or instrument manufacturer’s recommendations.

CO Analyser interference of CO2, H20

*On first commissioning; 1 year and after major

overhaul

Exhaust emissions of engines at idle NDIR CO, CO2, HC

*Electrical check before each reading

*1 week span and zero Gas check.

*1 month Multi-point calibration using standard gases. SHED

(Sealed housing for evaporative determinations)

ADR 37 Appendices XI, XII

Background emissions *1 year

HC retention check *1 month

HC analyser (FID) *1 month Six point calibration not including zero (see gas analysers)

Homogeneity test *On commissioning and after major service

Homogeneity response time *On commissioning and after major service

Time to achieve homogeneity

Recovery or validation test *On commissioning and after major service

Volume of SHED *On commissioning and after major service

REFERENCE GASES

Non reactive Reference gases: at a concentration greater than 100ppm

4 years or once the cylinder pressure falls below 700kPa (100psi) whichever occurs first

Non-reactive gases: at a concentration of 100ppm or less

2 years or once the cylinder pressure falls below 700kPa (100psi) whichever occurs first

Reactive Reference gases 2 years or once the cylinder pressure falls below 700kPa (100psi) whichever occurs first

* commonly done by laboratory staff


NOTE: In vehicle emission testing (gas analyser and CVS) rotameters are used as

indicators of flow rather than as flow measuring devices.

Non-linear instruments such as NDIR are not considered to be “linear” when

fitted with linearising circuits.


CALIBRATION APPENDIX H: CALIBRATION DATA MEASUREMENT FOR A CONSTANT VOLUME SAMPLER (CVS) FOR POSITIVE DISPLACEMENT PUMP (PDP) TYPE OR CRITICAL FLOW VENTURI (CFV) TYPE. PA

PARAMETER SYMBOL TOLERANCE INSTRUMENT

Atmospheric pressure PB ± 0.03 kPa Barometer

Ambient temperature TA ± 0.3°C Thermometer

Air temperature into LFE ETi ± 0.15°C Thermometer

Pressure depression upstream of LFE

EPl ± 0.01 kPa Manometer

Pressure differential across LFE

EDP ± 0.001 kPa Manometer

Air temperature at:

PDP inlet; PTi ± 0.3°C Thermometer

or CFV inlet Tv ± 0.3°C Thermometer

Pressure depression at:

PDP inlet; or CFV inlet PPi ± 0.01 kPa Manometer

Pressure at PDP outlet PPO ± 0.01 kPa Manometer

Air temperature at PDP outlet (optional)

PTO ± 0.3°C Thermometer

PDP revolutions during test phase

N ± one Revolution counter

Elapsed time for test phase t ± 0.1 s Stopwatch or equivalent

Air flow (litres/minute) Qs ± 0.5% Laminar flow element or sub-sonic venturi flowmeter

RAMETER ARAMETER SYMB SYMBOL OL TOLERANCE INSTRUMENT


CALIBRATION APPENDIX I: CALIBRATION OF EQUIPMENT FOR ASBESTOS (FIBRE COUNTING AND IDENTIFICATION) AND OTHER WORKPLACE ENVIRONMENT MONITORING

ITEM OF EQUIPMENT Maximum period between successive

Calibrations or Checks

Procedures and

Comments

MICROSCOPE * Yearly service Details at end of table

* Regular cleaning The microscope, lenses and objectives must be kept clean

HSE/NPL TEST SLIDE *On use Used when setting up the microscope prior to counting each batch of slides. Use to be recorded

WALTON –BECKETT

GRATICULE

*Measured on installation then every

12 months and whenever the

interpupiliary distance, objective,

intermediate magnification, or, on some microscopes, the eyepieces are

changed.

Note: For microscopes embodying a

magnification change, the graticule must be

measured prior to counting each batch

of slides.

NOHSC Guidance Note, 1988

PUMPS

(Where accreditation is held/sought for volume measurement.)

Direct automatic flow control consecutive tests

*12 months. After 3 consecutive tests (ie.

2 years) showing results within ±5% of the expected result, the interval can be

lengthened to 3 years.

Constant flow compensation. Refer to calibration Appendix J

Indirect automatic flow- control

*6 months. After 3 consecutive tests (ie. 12 months) showing results within ±5% of the expected result, the interval can be lengthened to 12

months

As above


ALL PUMPS *On use Where accreditation for volume measurement is held,

the flow rate must be checked in the field before and after use

*Regular maintenance and battery checks

Records must be kept

ROTAMETERS

Small bore, long flow meter, spherical float

*Monthly for 3 months then, if measurements are within ± 3% of the expected result, the

interval can be lengthened to 1 year

Against primary flow meter over the range of use (including high flow rates where used)

Large bore, short/medium flow meter, cylindrical float

*As above except, if the measurements

are within ±3% of the expected result, the

interval can be lengthened to 2 years

Against primary flow meter over the range of use(including high flow rates where used)

ELECTRONIC SOAP FILM FLOW METER (eg. gilibrator, mini-buck)

*Monthly for 3 months then, if measurements are within. ±3% of the expected result, the

interval can be lengthened to 6

months.

Against primary flow meter over the range of use (including high flow rates where used)

MANUAL SOAP FILM FLOW METER

*On commissioning Check volume using an appropriate measuring device

EFFECTIVE FILTER AREA *On commissioning and whenever the

filter, filter holder or any aspect of the filter

clearing is changed

NOHSC Guidance Note, 1988

REFRACTIVE INDEX OILS *1 year High grade proprietary oils

*3 months Chemical blends mixed by laboratory

FURNACE * Initial Check using thermocouple or optical pyrometer * commonly done by laboratory staff SERVICING OF MICROSCOPES The following servicing must be done on microscopes annually and all defects rectified as

necessary. The service may be carried out either in-house by suitably trained laboratory staff or

externally.


1. Phase Contrast Microscopes

- Checking, lubricating (as necessary) and adjusting all mechanical moving parts, such as

condenser rack, stage controls and field diaphragm.

- Checking all optical alignments such as oculars, objectives, binocular tube, condenser

and illumination system for surface and mount defects.

- Cleaning all optical components as necessary.

- Checking for vertical, horizontal and rotational displacement of images in binocular tube 2. Polarising Light Microscopes


condenser rack, stage controls and field diaphragm.

- Checking all optical alignments such as oculars, objectives, binocular tube, condenser

and illumination system for surface and mount defects.


- Checking for vertical, horizontal and rotational displacement of images in binocular tube.

- Checking directions of polariser, analyser and accessory plate.

- Checking correct operation of iris diaphragm in relation to dispersion staining. 3. Stereo Microscopes


focusing rack and zoom controls.

- Checking all optical alignments such as oculars, binocular tube, objective and

illumination system for surface and mount defects.


- Checking and adjusting for parfocal operation throughout zoom range.

ISO/IEC


CALIBRATION APPENDIX J: ASBESTOS - PUMP CALIBRATION CHECKS 1. Indirect Automatic Flow - Control Pumps

Before being placed into service, after three months, and then after a further three months,

the following tests must be done on every indirect automatic flow-control pump used by

the laboratory.

a) Test each pump at each flow rate that is used. For example, if the pump is used at

1.0, 2.0 and 4.0 litres/ minute, then it must be tested at 1.0, 2.0 and 4.0 litres/

minute.

b) Set the pump flow rate to the chosen flow rate using a flow meter. No other flow

resistance should be in the circuit.

c) By inserting an adjustable or specially chosen flow resistance, select the resistance

so that the pressure drop equals or exceeds approximately 2 kPa for each one

litre/minute flow rate. (For example, for 4 litres/minute, the pressure drop must be 8

kPa or greater). This pressure drop can be determined by using devices such as a

simple “U” tube water manometer or a Magnehelic differential pressure gauge.

d) Without adjusting the pump, re-measure the flow rate. e) If the flow rate changes by more than 5%, the pump’s constant flow compensation

must be reset.

f) Repeat steps a) to e) with the pump set to each relevant flow rate.

g) If the above tests produce results inside the +/-5% range for tests on three

consecutive occasions, ie. 12 months, then future tests need only be done at twelve-

monthly intervals.

h) If any internal components of the pumps have been serviced or changed, the test

must be repeated before the pump is placed back into service. Pumps that have the

circuit board flow compensation potentiometers accessible must not be used until

the access is blocked so as to prevent accidental adjustment.


i) Some manufacturers of indirect automatic flow control pumps specify that flow rates

of 1.0 and 2.5 litres/minute are to be used when electronically adjusting for correct

“constant flow compensation”. This should not be confused with the mandatory

requirements stated in paragraph (a) above, where pump testing is to be done at

every flow rate used.

2. Direct Automatic Flow Control Pumps

a) Before any “direct” automatic flow control pump is placed into service, and after a

twelve month period, the tests as described in section 1 above (with the exception of

paragraphs g) and i)), must be conducted on every direct automatic flow control

pump used in the laboratory.

b) If any internal components of the pumps have been serviced or changed, the test

must be repeated before the pump is placed back into service. Pumps that have the

circuit board flow compensation potentiometers accessible must not be used until

the access is blocked so as to prevent accidental adjustment.

c) If these tests produce results inside the +/-5% range after two consecutive tests (ie.

one year), then future tests need only be done at three yearly intervals.

Note: The tests are based on the flow rate/pressure drop characteristics of 25mm

diameter, 0.8mm pore size and mixed esters of cellulose membrane filters.

Different test conditions may be necessary if other types of filters are used.

3. Automatic Pump Timers

The above mentioned calibration procedures must be adhered to for automatic pump

timers. In addition to these requirements, the following aspects must also be demonstrated

to check that automatic pump timers:

a) reliably deliver the correct flow rate immediately after automatic switch-on

i. set pump at initial “nominal” flow rate

ii. program pump to start at least 1 hour later

iii. measure and record pump flow rate within 5 minutes to auto switch-on

iv. repeat steps i to iii for each flow rate used

v. repeat steps i to iv for each pump used

vi. repeat steps i to v on three separate occasions

vii. accept a pump if any flow rate is within +/-5% of initial “nominal” reading

viii. reject a pump if any flow rate is more than +/-5% of initial “nominal” reading


b) reliably deliver the correct flow rate immediately before automatic switch-off over the

time cycle chosen


ii. program pumps to finish at least 1 hour later

iii. measure and record “final” pump flow rate within 5 minutes before auto switch-off



vi. repeat steps i to v on three separate occasions

vii. accept a pump if any “final” flow rate is within +/-5% of initial “nominal” reading

viii. reject a pump if any flow rate is more than +/-5% of initial “nominal” reading

c) reliably display the sample duration to +/-1% or better

i. time in-built pump timer over a typical sampling period and record timer’s

“elapsed time”

ii. repeat step i for each sampling period likely to be used

iii. repeat steps i to ii for each pump used

iv. repeat steps i to iii on three separate occasions

v. accept a pump if pump timer elapsed time is within +/-1% of actual elapsed time ISO/IEC 1 7025 APPLIC APPLICATION TION DOCU DOCUMENT

d) reliably switch off automatically in the event of a flow fault such that the final flow rate

is within +/-10% of the initial flow rate


ii. progressively restrict pump suction so as to cause “flow fault” condition

iii. during step ii measure and record pump flow rate just before auto switch-off



vi. repeat steps i to v on three consecutive occasions

vii. accept a pump if final flow rate is within +/-10% of initial “nominal” reading

viii. reject a pump if any final flow rate is more than +/- 10% of initial “nominal”

reading


e) reliably switch off automatically in the event of a low battery such that the final flow

rate is within +/- 10% of the initial flow rate.


ii. progressively reduce voltage supply to pump so as to cause “low battery” fault

iii. during step ii, measure and record pump flow rate just before auto switch-off



vi. repeat steps i to v on three consecutive occasions

vii. accept a pump if final flow rate is within +/-10% of initial “nominal” reading

viii. reject a pump if any final flow rate is more than +/- 10% of initial “nominal”

reading

Each pump must be tested and records kept of all of the aspects described above.

If the tests described under d) and e) above have not been done, any sample subject to

automatic switch-off due to a flow fault or low battery must be rejected.

A laboratory can submit to NATA for review and approval an alternative series of tests to

those described above, provided that they achieve the same aim. One alternative may be

the measurement of air volumes, actually sucked by a pump during automatic operation.

The test procedures for any alternative would need to be described in detail.


CALIBRATION APPENDIX K: CALIBRATION OF INSTRUMENTATION (COMPARATIVE TECHNIQUES)

The reference and working equipment listed in previous appendices are calibrated (in most

cases) by reference to fundamental physical standards of measurement and their derivatives.

Other techniques have been included in the previous appendices to be consistent with the

grouping of equipment for specific testing procedures.

This Appendix lists major analytical instrumentation used in the laboratory, that are calibrated

primarily in-house by use of reference materials of known composition.

In the field of Chemical Testing the following general principles apply to the use of analytical

instrumentation.

a) Sufficient and appropriate reference materials must be used to calibrate instruments over

the full analytical range required to establish the measurement characteristics of the

instrument (linearity, sensitivity, etc).

b) Stability of measurement must be assessed with reference materials to establish the

required frequency of calibration.

c) Effects of interfering substances and differing matrices must be assessed.

d) Limits of detection must be established if the instrument is to be used at concentrations

approaching the limit of detection.

e) Operating parameters as set in manufacturer’s instructions and maintenance schedules

must be available and details of critical checks must be recorded. Where Australian Standards have been published for particular instrumental techniques it is

expected that these will be used in the laboratory. Where this is not the case, relevant ASTM or

other verified procedures must be used. In many cases published procedures for the operation

of analytical instrumentation are unavailable or are specific to a particular application. NATA will

then require a laboratory to document its practice for use of analytical instrumentation. For

example, this may include a description of the operation of the instrument, calibration

procedures, specification of error-boundaries on the nominal values of calibration standards,

frequency of use and nature of quality control samples, the analytical precision at various

concentration levels, and maintenance procedures.


Specific items of instrumentation are listed below together with some guidelines for their in-

house calibration, operation and maintenance.

Calorimeters Determine water equivalents using certified benzoic acid at six monthly intervals

Conductivity Meters Conduct a one-point check on use and check the complete scale each year. Refer ASTM

D1125.

Dissolved Oxygen Meters Conduct a one-point check on use and compare with a Winkler titration once a month. Refer

APHA 4500-O C.

pH Meters Check on use with at least 2 standard buffer solutions appropriate to the anticipated pH of the

sample being tested. A record of the checks must be kept. Refer to APHA 4500-H and BS 1647.

The reference electrode junction must also be checked at least weekly, or more frequently if

samples are solid or semi-solid. Refer AS 2300.1.6 and NATA Technical Note 21.

Turbidimeters Conduct a one-point check appropriate to the anticipated turbidity of the sample being

measured, and a complete calibration each year. Refer APHA 2130B. (Reference standards

may be purchased or made up in the laboratory. Check Hach standards annually against

formazin standards.)

Autoanalysers Appropriate reference materials must be analysed at regular intervals during each run of the

instrument and records kept of within batch and between batch uncertainties. (The scheduled

use of duplicates and recovery checks by spiking samples is also recommended.) Daily, weekly,

monthly and yearly maintenance and calibration checks must be carried out in accordance with

manufacturer’s specifications or with practical scientific alternatives derived from experience.

Maintenance and calibration procedures must be established and a log kept of maintenance

carried out and the results of calibration checks.


A full calibration check must include the photometer or other form of detector, sample and

reagent metering devices and the temperature- controlling device used on the analyser. Spectrophotometers A great number of the quantitative analyses performed in a chemical testing laboratory involve

some form of spectrophotometric or colorimetric measurement. It is essential that a laboratory

carry out regular, recorded calibration checks on all spectrophotometers or automated devices

employing spectrophotometers or colorimeters. A new calibration curve must be drawn at least

every month.

Such calibrations must include checks on wavelength accuracy, absorbance, linearity, straylight

and matching of cells. These calibrations must be carried out in accordance with the

manufacturer’s instructions and/or the codes of practice listed below at intervals appropriate to

the test procedures and the physical environment within which the instrumentation is used (but

at least every three months).

All instruments must be checked on use against appropriate reference materials. A blank and at

least two points on the calibration curve must also be checked. These calibrations should be

compared over time to detect any system deterioration.


Relevant standards for the checking and use of spectrophotometers include: a ) Ultraviolet / visible:

AS 3753 Recommended practice for chemical analysis by ultraviolet visible

spectrophotometry.

ASTM E131 Terminology relating to molecular spectroscopy.

ASTM E169 Practices for general techniques of ultraviolet quantitative analysis.

ASTM E275 Practices for describing and measuring performance of ultraviolet, visible

and near infrared spectrophotometers.

ASTM E925 Practice for periodic calibration of narrow bandpass spectrophotometers.

ASTM E958 Practice for measuring practical spectral bandwidth of ultraviolet-visible

spectrophotometers. b) Infrared:

ASTM E168 Practices for general techniques of infrared quantitative analysis.

ASTM E275 Practices for describing and measuring performance of ultraviolet, visible

and near infrared spectrophotometers.

ASTM E932 Practices for describing and measuring performance of dispersive

infrared spectrophotometers. Spectrometers Instrument performance must be routinely monitored during use with reference materials.

Calibration graphs must be prepared using a blank and three to five solutions of standards

covering the expected concentration range of analyte in the sample. Linearity checks must be

done in the absorbance mode. Spectrometer components and supporting equipment must also

be adequately maintained and checked periodically in accordance with documented procedures

to ensure optimal instrument performance. (This may need to be done by external technicians.)

Relevant standards for the checking and use of spectrometers include:


a ) Atomic Absorption:

AS 2134 Recommended practice for chemical analysis by atomic absorption

spectrometry.

Part 1 Flame atomic absorption spectrometry

Part 2 Graphite furnace spectrometry

Part 3 Vapour generation atomic absorption spectrometry

AS 2135 Glossary of terms used in flame atomic absorption spectroscopy.

ASTM E663 Practice for flame atomic absorption analysis.

ASTM El184 Practice for electrothermal (graphite furnace) atomic absorption analysis.

APHA 3111 Metals by flame atomic absorption spectrometry.

APHA 3112 Metals by cold-vapour atomic absorption spectrometry.

APHA 3113 Metals by electrothermal atomic absorption spectrometry.

APHA 3114 Arsenic and selenium by hydride generation/ atomic absorption

spectrometry. (b) Atomic Emission and X-R ay Fluorescence:

The Association will consider submissions from any laboratory that proposes the use of a

factory calibrated atomic emission (arcspark) spectrometer. Each case will be considered

on its merits.

AS 1502 Glossary of terms used in X-ray spectroscopy.

AS 2563 Wavelength dispersive X-ray fluorescence spectrometers - Determination

of precision.

AS 2883 Analysis of metals - Procedures for the setting up, calibration and

standardization of atomic emission spectrometers using arc/spark

discharge.

AS 3641 .1 Recommended practice for atomic emission spectrometric analysis - Part

1 Principles and techniques.

ASTM E135 Terminology relating to analytical chemistry for metals, ores and related

material.

ASTM E158 Practice for fundamental calculations to convert intensities into

concentrations in optical emission spectrochemical analysis.


ASTM E172 Practice for describing and specifying the excitation source in emission

spectrochemical

analysis.

ASTM E305 Practice for establishing and controlling spectrochemical analytical

curves.

ASTM E876 Practice for use of statistics in the evaluation of spectrometric data. (c) Inductively Coupled Plasma

AS 3641.2 Recommended practice for atomic emission spectrometric analysis

Part 2 Inductively coupled plasma excitation

APHA 3120 Metals by plasma emission spectroscopy.

Direct Current Plasma spectrometric techniques may also be used in laboratories. (d) Nuclear Magnetic Resonance

ASTM E386 Practice for data presentation relating to high resolution NMR

spectroscopy. Chromatographs (a) Gas chromatographs:

Instrument performance must be routinely monitored during use with reference materials.

System components (eg. integrators, ovens, electronic amplifiers and detectors) must also

be checked periodically, and records kept. (b) Liquid chr chromatography omatography omatography, , including high

performance (or high pressure) liquid chromatographs (HPLC) and ion chromatography:

The total system must be monitored during use with reference standards. Loss of

efficiency may be detected by chronological comparison of reference material

measurements. System components (eg. pumping system and detectors) must be subject

to periodic checks and details must be recorded.


Relevant standards for the checking and use of chromatographic instrumentation include:

AS 3741 Recommended practice for chemical analysis by ion-chromatography.

ASTM D1945 Test methods for analysis of natural gas by gas chromatography.

ASTM D4626 Practice for calculation of GC response factors.

ASTM E260 Practice for packed column gas chromatography.

ASTM E355 Practice for gas chromatography terms and relationships.

ASTM E516 Practice for testing thermal conductivity detectors used in gas

chromatography.

ASTM E594 Practice for testing flame ionization detectors used in gas

chromatography.

ASTM E682 Practice for liquid chromatography terms and relationships.

ASTM E685 Practice for testing fixed wavelength photometric detectors used in liquid

chromatography.

ASTM E697 Practice for use of electron capture detectors in gas chromatography.

ASTM E840 Practice for using flame photometric detectors in gas chromatography.

ASTM E958 Practice for measuring practical spectral band width of UV/Vis

spectrophotometery.

ASTM E1151 Practice for ion chromatography terms and relationships.

ISO 6326 Gas analysis: Determination of sulphur compounds- in natural gas

Part 2 – GC method using an electrochemical detector for the

determination of odoriferous sulphur compounds.

ISO 6326 Natural gas: Determination of sulfur compounds – GC method using FID

for the determination of hydrogen sulfide, carbonyl sulfide and sulfur

containing oderants.

ISO 6568 Natural gas - simple analysis by gas chromatography.

ISO10301 Water quality – Determination of highly volatile halogenated hydrocarbons

by gas chromatography.

BS 684 Methods of analysis of fats Sec 2.35 and fatty acids – Other methods-

Analysis by gas-liquid chromatography of methyl esters of fatty acids.

BS 5443 Recommendations for a standard layout for methods of chemical analysis

by gas chromatography.


Particle size analysis

Instrument performance should be routinely monitored during use with reference

materials.

ASTM F660 Practice for comparing particle size in the use of alternative types of

particle counters.

ASTM F661 Practice for particle count and size distribution measurement in batch

samples for filter evaluation using an optical particle counter.

ASTM F662 Method for measurement of particle count and size distribution in batch

samples for filter evaluation using an electrical resistance particle counter. Computerised systems

ASTM E622 Guide for computerised systems.

ASTM E627 Guide for documenting computerised systems.

ASTM E792 Guide for selection of a clinical laboratory information management

system.

ASTM E1013 Terminology relating to computerised systems.


Annexure C (Taken from ILAC Proceedings, 1993)

INTRODUCTION Purpose of the Guide Quality assurance in a testing laboratory, particularly in the case of its assessment, highlights

the need to consider closely the question of the accuracy of its measurements and analytical

results, and to ensure that the principles necessary to establish demonstrated accuracy have

not been omitted.

The calibration of the parameters associated with chemical analyses and material tests

deserves particular attention. Because major errors can be made by neglecting or ignoring the

basic principles of metrology which also apply to these areas. This text identifies a number of

general recommendations for those who are faced with this problem, either as laboratories or as

assessors. Basic considerations Any measurements, particularly any quantitative chemical analysis, must employ reference

elements to ensure demonstrated traceability to the relevant basic quantities. This is an

essential condition for the accuracy of the results.

The metrological quality of the calibration performed depends on: • The intrinsic uncertainty of the reference used {set of calibration masses, titrated solutions,

gas mixtures, composition CRMs* etc. (see remarks)}

• The appropriateness (or fitness for purpose) of this reference under the practical

conditions of use, also taking account of the analytical method used and the samples

tested.


The total uncertainty of calibration results from these two components, and it must be optimized

without ignoring either of them. Figure 1 as given below illustrates the problem. The combination

of uncertainties being presented as a quadratic function as recommended by BIPM.

Figure 1

The analyst should compare the uncertainty of calibration with the required total analytical

uncertainty (which should normally be agreed between the customer and the operator). This

comparison provides a useful guide for choosing between different available calibration

procedures and in the longer term, for improvements to the methods and procedures.

In tests based on measurements of physical quantities, the principle of traceability of the

standards and/or measuring instruments of the accredited laboratory to a national primary

standard through a national calibration system is generally applied. Relevant principles for

ensuring the traceability of chemical analyses are presented later in this document; the use of

CRMs for that purpose has been gaining importance in the last decades and may be expected

to develop even more if and when they are available.

R1 > R2

Appropriateness Error : 1 % R1

Standard Solution (0.1 % relative)

Calibration without CRM

Appropriateness Error : 0.5 %

R2

Composition CRM (0.5% relative)

Calibration with CRM


• Remarks:

a) The definitions of RMs and CRMs can be found in ISO Guide 30. RMs can also be

sued to validate methods (see ISO Guide 33). They may also be used to check the

drift with time and possibly to correct an instrumental drift. They also serve as a

basis for a conventional scale (e.g. octane index). These aspects of the use of RMs

are not dealt with here, apart from a few remarks and the reader can refer to ISO

Guide 33. One can refer also to more general documentation, such as the VM

(International Vocabulary of Metrology).

b) The analytical chemist is often a user of analytical materials or reagents. These

products must not be confused with CRMs. A CRM in fact corresponds to in

identified batch of material of which the certified characteristics have been

determined with an optimized and defined accuracy. An analytical reagent is only

characterized by a nominal value determined without high accuracy. It is the users

duty to observe all necessary precautions to ensure, when used, that an analytical

reagent meets his needs.

1. SELECTION OF CALIBRATION PROCEDURES IN CHEMICAL ANALYIS The first step is to classify the analytical procedure used by reference to the following

categories:

- Calculable method

- Relative method

- Comparative method

Each of these categories is associated with:

• a basic principle

• a number of basic pre-requisites. When the user classifies a method, it should be done by means of a detailed and close

examination of all the parameters of the analytical procedure. He must never be satisfied

with simplifications which would only be applicable to the detection principle applied under

idealized conditions. This approach generally has the effect of under estimating the

necessary conditions for a reliable calibration and of generating systematic errors.


Calibration does not make an inaccurate method true (e.g. presence of major interferences).

The variability of the factors of influence should only cause negligible variation in the

analytical signal. The above classification is merely designed to identify the relevant calibration mode (s). It

must not be used as a scale of value of the methods. Calculable method This is a method that produces the anticipated result by performing a calculation defined on

the basis of the laws governing the physical and chemical parameters involved, using

measurements taken during the analysis, such as:

o weight of the test sample, volume of titration reagent,

o weight of precipitate, volume of titration product generated.

Relative method

This method compares the sample to be analysed with a set of calibration samples of known

content, using a detection system for which the response (ideally linear) is recognised in the

relevant working area (without necessarily being calculable by theory). The value of the

sample is determined by interpolation of the sample signal with respect to the response

curve of the calibration samples.

This implies that any other difference of composition, form, etc. between the calibration set

and the different samples analysed will have no effect, or a negligible effect compared with

the uncertainty on the signal. For this condition to be satisfied the analytical procedure

could include:

o Means to reduce sensitivity to differences (e.g. spectral buffer, treatment of samples

before analysis)

o A procedure to give similar form to the calibration set and the samples:

- Reduce the complex sample to a simpler sample, by acid digestion, the removal of

major interferents or selective extraction of analyte.

- Synthesize a more complex calibration set, by multi-element matrix simulation or

the use of a special medium (e.g. oils).

o Limitation of the field of application.


Comparative method For this type of method, the sample to be analysed is compared to a set of calibration

samples, using a detection system which has to be recognised to be sensitive not only to

the content of elements or molecules to be analysed, but also to differences of matrix (of

any type whatsoever). If this influence is ignored it will generate a systematic error (bias). For this type of method to be really appropriate for use, it is essential:

• To identify the type(s) of samples routinely analysed (type of matrix, type of structure

etc.) and to draw up procedures to identify the introduction of “abnormal” samples in

comparison with the identified types.

• To make up a set of CRMs suitable for each type of sample previously identified.

• To evaluate whether or not “intra-type” differences are liable to generate an

unacceptable bias in the analysis.

Some examples of these three types of methods are given below:

EXAMPLES * 1) Nickel in alloy steel Calculable method: Gravimetry of Ni after selective precipitation as Ni

dimethylglyoxImate

Relative method: Atomic Absorption after acid digestion of sample

Comparative method: X-ray Fluorescence on solid sample 2) Water in powders

Calculable method: Karl Fisher Titration

Relative method: Extraction of H2O by isopropanol, GC detection

Comparative method: Infra-red Reflexion on solid sample


3) Others…. Other methods Any analytical method that fails to ensure traceability to the base units by one of these

approaches is liable not to yield results of demonstrated accuracy. Even if it offers

appreciable advantages of repeatability and reproducibility, the results obtained are liable to

be distorted by a systematic error.

If it is used by a single laboratory to analyse drift, or to transfer information within a restricted

circle of users who are aware of the limitations of the result, vigilance will be necessary to

ensure that these results are not presented or used as accurate outside the circle.

Assessors giving accreditation to such methods should take great care to check that the

method is undertaken in such a way that appropriate accuracy is ensured through relevant

procedures and means and preferably that they are widely recognized as state of the art

methods. 2. CALIBRATION PROCEDURES

• Calculable method

The basic procedure is to identify every quantity whose measurement is necessary to

establish the analytical result by calculation.

It is recommended that a “provisional list of uncertainties” be drawn up which will

estimate the uncertainty of each measured quantity, against the total analytical

uncertainty. This will help to identify the main sources of uncertainty and to exercise

special care in selecting the calibration procedures.

With this type of method, CRMs are used for verification (see ISO Guide 33). Note that

the CRM must be analysed as presumed unknown, the result obtained being compared

with the certified value. If an abnormal deviation is observed, the laboratory must

identify the cause and correct it. It is not recommended (except for very specific cases)

to deduce a correction factor for the difference between the value found and the certified

value.


• Relative method

For this type of method, the working standards generally consist of a determined

quantity of analyte “diluted” in a larger quantity of “diluent”. They are obtained by

measuring the masses or volumes of the different pure, dilute and diluent materials.

Depending on each case, metrological traceability implies the following:

• Calibration of the mass measurements by calibration or verification of the balances

and/or calibration of the volume measurement system.

• Calibration of the system for measuring the correction parameters applied to the

foregoing measurements (e.g. temperature, pressure, relative humidity). Since the

uncertainties of these quantities are generally of the second order with respect to

the total analytical uncertainty, a simplified calibration procedure is often adequate.

• Knowledge of the purity of the basic materials used, together with their

uncertainties.

For the substance which is diluted, it is necessary to ensure that:

- It is the compound of interest.

- The nature of the impurities is identified (e.g. inorganics in an organic substance).

- The stoichiometry is correct.

For “diluents” particular attention must be paid to the residual level of impurities such as:

- The substance to be diluted.

- Any substance exhibiting a similar analytical response

- Any substance likely to react with the substance being diluted.

For practical or economic reasons, laboratories may decide to use commercial standard

solutions. If so, it is important to make sure that the uncertainty on their content is

known, as required, and that the basic rules set forth above are complied with by the

manufacturer, as attested by appropriate documentation.

For this type of method, CRMs are chiefly used as a means of verification.


CRMs are sometimes used to prepare a calibration solution by a simple dissolution of a

known test sample of CRM, possibly followed by spiking. This practice is comparable to

that of using commercial standard solutions and must be treated as such.

• Comparative method

Since these methods are sensitive to matrix effects, the calibration procedures employed

must take account of these effects. The use of an appropriate CRM is the preferable

calibration method. The choice of the CRM to be used must therefore satisfy two types

of necessary conditions:

- That the certified property is known with sufficient reliability.

- That the matrix of the standard is sufficiently similar to the samples being analysed

and that the existing differences are not liable to generate a bias in the results that is

incompatible with the total uncertainty desired.

The selection of a suitable CRM should aim to achieve an optimum between these two

types of necessity.

The CRM must initially be defined in the form of a tentative specification; the points to be

considered include:

- What are the elements whose concentrations must be known with sufficient accuracy

to permit the establishment of the calibration? Over what concentration range? With

what uncertainty? For what sample size?

- What should be the type of matrix; type of material and main components (which

could have a “chemical” or “physical” influence on the response of the analyzer)?

- What other properties or characteristics of the samples and the standards should be

similar to avoid generating a bias in the responses of the analyzer? For example:

form, viscosity, particle size distribution, metallurgical structure, etc.


• SELECTION OF CRMs

The first approach in this search is to compare the tentative specification of the CRM

required with the lists of CRMs available on the international market. The laboratory

should consult:

- The catalogues of the different manufacturers

- The COMAR data bank

- Branch publications or recommendations examining the best choices of CRM in a

specific field if they are available.

The laboratory must ensure that the CRMs that were short-listed after a first

examination:

- Are effectively certified for the element concerned, and that the value is not merely

indicative (see certificate)

- That the certification procedure exhibits an appropriate level of metrological reliability

(see ISO Guide REMCO 35) and that is sufficiently well documented (ISO Guide 31).

Any traceability defined in principle only, but without an evaluation of the uncertainty,

does not constitute a properly demonstrated traceability.

As to similarity of matrix, the laboratory must weigh the fact that it is not economically

and technically possible to obtain a perfect match between CRMs and samples in all

cases. Reasonable similarity must be deemed acceptable. If not, the entire analytical

procedure has to be reconsidered.

The use of a CRM available on the market is usually capable of ensuring:

• The best guarantee of accuracy.

• The best performance / cost ratio.

The laboratory that decides not to use appropriate available CRMs should accordingly

justify the reasons for this decision in its procedures.


• USE OF INTERNAL RMs

Should the market fail to offer a CRM to meet a laboratory’s identified needs, it may

attempt to develop its own internal RM. Since this usually means a lengthy and costly

operation, involving the use of special resources and experience, it would be wise to

firstly explore the following possibilities:

- Contact those manufacturer(s) of CRMs capable of developing such a new CRM. A

request for a new CRM for which the potential market would not amount to more

than several dozen per year over several years cannot normally be considered.

- Contact groups of users with the same need and try to set up a joint project, possibly

with the assistance of the national laboratory responsible for CRMs.

The preparation and use of an internal RM must offer guarantees of metrological

traceability as well as the use of a CRM. It can allow for a lower level of accuracy than a

CRM, which is offset by better fitness for purpose or imposed by the absence of CRM.

An internal RM must therefore accordingly have been prepared by a procedure that

guarantees the following:

- Sufficient availability over several years

- Demonstrated homogeneity and stability

- An internal certification analysis assuring demonstrated traceability and ensuring the

absence of bias which might have an effect on total analytical uncertainty.

- A quantified estimation of uncertainty, which is also compatible with the total

analytical uncertainty; for the characterization of an internal RM, this requirement

usually entails the application of calculable or relative methods, preferably validated

by the use of CRMs.

In some cases, an internal RM is developed to help conserving an expensive CRM. It

can be calibrated (against a set of similar CRM) using a comparative method. As this

new link will deteriorate the uncertainty of the Working RM, the interest of such RMs

must be seriously assessed.


Internal RMs must never be samples of which the reference value used is not known

through a procedure of demonstrated traceability with a definite and sufficient

uncertainty. If the development of an internal RM necessary to properly calibrate a given

method is not technically or economically feasible, the user will have to reconsider the

choice of method and/or procedure, and use on that does not demand the missing CRM. General Remarks Calibration is an integral part of analysis and its cost is an integral part of the cost of analysis. It

must be planned and provided for, especially if it involves purchasing CRMs or developing

internal RMs. An under estimation of these costs does not justify an inadequate calibration

procedure.

The calibration of chemical analyses must meet a number of essential requirements, such as

those set forth in this Guide. Compliance to such requirements may involve different forms in

different fields. These general recommendations are not sufficient conditions for quality in

calibration. Every user must indicate:

- His additional specific conditions.

- Any exception to the general rules.

At all events, he must identify and analyse his need in its different aspects and draw up and

implement a response for each.

Accurate analyses depend not only on the metrological quality of the calibration but also on

other factors including random and systematic errors which occurs during the analysis.

Note: This annexure may be treated as a guideline and not as NABL requirement.

National Accreditation Board for Testing and Calibration Laboratories 3rd Floor, NISCAIR

14, Satsang Vihar Marg New Mehrauli Road New Delhi – 110 067

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