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NABL 121

NABL

NATIONAL ACCREDITATION BOARD FOR TESTING AND CALIBRATION LABORATORIES

SPECIFIC CRITERIA for

CALIBRATION LABORATORIES IN ELECTRO – TECHNICAL DISCIPLINE

ISSUE NO : 04 ISSUE DATE: 07.03.2007

AMENDMENT NO : 00 AMENDMENT DATE: -


AMENDMENT SHEET Sl

Page

Clause

Date of

No.

No.

Amendment

Amendment made

Reasons

Signature

Signature

QM

Director

1 2

3

4

5

6

7

8

9

10

National Accreditation Board for Testing and Calibration Laboratories Doc. No: NABL 121 Issue No: 04

Specific Criteria for Calibration Laboratories in Electro-Technical Discipline Issue Date: 07. 03.2007 Last Amend No: 00 Amend Date: --

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CONTENTS Sl

Title

Page No.

Amendment Sheet

i

Contents

ii

Introduction

iv

PART – I : Specific Criteria for Accreditation of Calibration Laboratories

in

the

Field

of

Electro-Technical

Measurements 1.

Scope

1

2.

Criteria for Accreditation

2

3.

Scope of Accreditation

2

4.

Organisation

3

5.

Management System

4

6.

Personnel

5

7.

Accommodation and Environment Conditions

6

8.

Calibration Methods & Uncertainty of Measurement

9

9.

Equipment

10

10.

Measurement Traceability

12

11.

Handling of Calibration Items

12

12.

Proficiency Testing

13

13.

Calibration Certificate/ Report

13

14.

Guidance for Assessments and Scope Recommendation

14

PART – II : Guidelines Regarding Generally Achieved Measurement Capabilities

in

Calibration

for

Electro-Technical

Measurement General Remarks and Environmental Conditions

17

1.

Table 1 : DC Voltage

18

2.

Table 2 : AC Voltage

19

3.

Table 3 : L.F. & H.F. Voltage

20

4.

Table 4 : DC Current

23

5.

Table 5 : AC Current

24

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6.

Table 6 : L.F. & H.F. Current

25

7.

Table 7 : AC Power & Energy

26

8.

Table 8 : L.F. & H.F. & Microwave Power

27

9.

Table 9 : AC Ratio

29

10.

Table 10 : Phase Angle

30

11.

Table 11 : L.F. & H.F. & Microwave Attenuation

31

12.

Table 12 : Capacitance & Dielectric Loss Angle (Tanδ) 50 Hz

33

13.

Table 13 : Capacitance (120 Hz & 1 kHz)

34

14.

Table 14 : L.F. & H.F. Capacitance

36

15.

Table 15 : Inductance (1 kHz)

38

16.

Table 16 : L.F. & H.F. Inductance

39

17.

Table 17 : DC Resistance

40

18.

Table 18 : AC Resistance 1 kHz

42

19.

Table 19 : L.F. & H.F. Impendence

43

20.

Table 20 : Microwave Impedence & Q Values

44

21.

Table 21 : Time and Frequency / Time Interval

45

22.

Table 22 : Magnetic Measurements

47

Technical Committee for Electro-Technical Measurement

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INTRODUCTION This document specifies additional requirements for the calibration laboratories in the ElectroTechnical field and seeking NABL accreditation in accordance with ISO/ IEC 17025: 2005. The specific requirements given in this document does not cover all the requirements of ISO/IEC 17025: 2005 but only those clauses which need amplification and are stated as additional requirements. These requirements should be read in conjunction with the relevant requirements of ISO/IEC 17025:2005. This criteria can be used by laboratories and those who are associated with the programme of accreditation of calibration laboratories e.g. experts, assessors, officials engaged with day-today activities of accreditation. This document provides the laboratories with necessary information in preparing for accreditation and the requirements for assessment / surveillance / reassessment. The information in this document has been compiled in two parts.

PART – I Specific Criteria for Accreditation of Calibration Laboratories in the Field of ElectroTechnical Measurements This part provides information on additional requirements for the laboratories engaged in calibration in the field of Electro-Technical measurements, seeking accreditation in accordance with ISO/ IEC 17025: 2005.

PART – II Guidelines Regarding Generally Achieved Measurement Capabilities in Calibration for Electro-Technical Measurement This part contains guidelines on uncertainties typically achieved in calibration laboratories for Electro-technical parameters, if the laboratories use available standards and equipment of different accuracy specifications.

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PART – I

SPECIFIC CRITERIA FOR ACCREDITATION OF CALIBRATION LABORATORIES IN THE FIELD OF ELECTRO-TECHNICAL MEASUREMENTS


1.0

SCOPE

1.1

Calibration laboratories are accredited by NABL after it is demonstrated that a laboratory complies with the requirements of international standard ISO/IEC 17025: 2005. In view of generic nature of the standard the requirements stated there in, need to be further redefined in specific fields of calibration. This specific criteria lays down those specific requirements in the field of Electro-technical calibration. This part of the document thus amplifies the generic requirements for Electro-technical calibration and supplement the requirements of ISO/IEC 17025:2005. Laboratories seeking NABL accreditation in the field of Electro-technical calibration must also comply with the requirements stated in this part.

1.2

Best Measurement Capability (BMC) is one the parameters that is used by NABL to define the scope of an accredited calibration laboratory, the others being parameter/quantity measured, standard/master used, calibration method used and measurement range. The BMC is expressed as”the smallest uncertainty that a laboratory can achieve when calibrating a device that is effectively ideal”. It is an expanded uncertainty estimated at a confidence level of approximately 95% corresponding to a coverage factor k=2. The laboratory’s ability to achieve their claimed BMC shall be evaluated based on its performance during the on-site assessment and by review of proficiency testing results, wherein the laboratory has participated.

1.3

The definition of BMC implies that within its accreditation a laboratory is not permitted to report a smaller uncertainty of measurement than the BMC endorsed on its scope of accreditation. This means that the laboratory shall be required to state a uncertainty not better than that corresponding to the BMC whenever it is established that the actual calibration process adds significantly to the uncertainty of measurement. The BMC is applicable only to the results for which the laboratory claims its status as accredited laboratory. It is therefore a realistic means for customers to select and compare accredited laboratories’ capabilities. The scope of accreditation of calibration laboratory shall be identified as source and measure. Source shall define the sourcing capability of a laboratory where as measure shall define the measuring capability of a laboratory.

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1.4

All the parameters for which accreditation is sought must be expressed in S.I. Units, wherever applicable.

2.0

CRITERIA FOR ACCREDITATION Accreditation of an Electro-technical calibration laboratory will require assessment of the laboratory for compliance to ISO/ IEC 17025: 2005 (General Requirements for the Competence of Testing and Calibration Laboratories) and NABL 121 (Specific Criteria for Calibration Laboratories in Electro-Technical Discipline).

3.0

SCOPE OF ACCREDITATION

3.1

The scope of accreditation of an accredited laboratory in the field of Electro-Technical calibration shall be defined in terms of its capability to calibrate sources and/or of measuring equipments for various parameters. Therefore, a scope should be identified as “Source” and “Measure” because it provides more information to users of calibration laboratories. “Source” as appearing in the accredited scope of the laboratory reflects the sourcing capability of the laboratory (e.g. calibrators, discrete resistances, inductance, capacitance, frequency generator etc). “Measure” as appearing in the accredited scope of the laboratory reflects the measuring capability of the laboratory (e.g. high end multimeters, frequency counters etc). Laboratories can apply for accreditation for only source or only measure or both.

3.2

A calibration laboratory seeking accreditation to offer calibration services in the field of Electro-Technical measurements will generally carry out calibration in: a)

DIRECT CURRENT Voltage, Resistance, Current, their Ratios and Power.

b)

ALTERNATING CURRENT (Up to 1kHz) Voltage, Current, Power, Energy, Voltage and Current Ratio, Phase Angle and Power Factor, Resistance, Capacitance & Dielectric Loss Angle, Inductance & Dissipation Factor.

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c)

LOW FREQUENCY (1kHz to 30kHz) Voltage, Current, Power, Energy, Voltage and Current Ratio, Phase Angle and Power factor, Attenuation, resistance, Capacitance, Inductance, Dissipation Factor, Modulation Index, Distortion and Noise, Impedance.

d)

HIGH FREQUENCY (30kHz to 1GHz) Voltage, Current, Power, Attenuation, Lumped and Distributed Impedance, Capacitance, Noise, Modulation Index, Distortion, Pulsed RF Voltage and Power.

e)

MICROWAVE (1GHz and above) Power, Impedance, Phase Shift, Attenuation, VSWR and Noise.

f)

SPECIAL HF INSTRUMENTS EMI/ EMC related parameters including field strength and power density etc.

g)

TIME AND FREQUENCY Time Instant, Time Interval, L.F. & H.F. Frequency, Microwave Frequency.

h)

MAGNETIC MEASUREMENTS Flux Density, Field Strength, Magnetic losses and allied parameters, Area turns (search coils).

i)

ELECTRICAL SIMULATION TECHNIQUES (THERMAL) Temperature controller, indicator, simulator using simulation techniques.

4.0

ORGANISATION (clause 4.1 of ISO/IEC 17025:2005)

4.1

The calibration laboratory shall be organized in such a way that all staff members are aware of both the extent and the limitations of their area of responsibility.

This

organization shall specify and document the responsibility and authority of the Head of the calibration laboratory, Technical Manager and Quality Manager who will have direct access to the top management. All personnel will perform or verify work affecting the quality of calibrations as per general guidelines and specific criteria laid down for the accredited parameters. The calibration laboratory shall be organized in such a way so as to ensure the integrity of its staff. The training of its employees and operations of the laboratory shall be conducted for ensuring unbiased calibration.

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4.2

The laboratory shall clearly nominate Authorized Signatory for authorizing calibration certificates/ reports issued by the laboratory. Authorized signatories shall be approved by NABL.

5.0

MANAGEMENT SYSTEM (clause 4.2 of ISO/IEC 17025:2005)

5.1

The calibration laboratory shall have a Quality Manual which shall be maintained up-todate and shall be in compliance with ISO/ IEC 17025: 2005 and NABL requirements, with emphasis on following information: a)

A quality policy statement, including objectives as evidence of commitment by the top management.

b)

A statement on the organization of the calibration laboratory.

c)

Names, qualifications and experience of the persons responsible for managerial, and scientific/ technical activities.

d)

A clearly defined charter of responsibility showing the relationship between technical management, quality management and support services.

e)

Scope and operation of the laboratory along with information on measurement capability and traceability of calibration results of measuring instruments including reference and working standards to national measurement standards, which are realization of SI system of units.

f)

The reference of document number on detailed calibration procedures adopted in the laboratory, which should be compiled in the form of a manual for the use of calibration staff.

g)

The reference list of all specification/standards being referred to or used in the performance

of

calibration

work

(copies

of

such

specifications/standard

specifications should be available in the laboratory for the use of calibration staff.) h)

All amendments made in any of the documents must be updated and listed in the relevant document.

5.2

The calibration facilities established in accordance with the general guidelines and specific criteria shall be audited periodically and reviewed by or on behalf of the management to ensure the continued effectiveness of the system.

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5.3

The calibration laboratory shall clearly specify, document and make known to the customers, the administrative and other procedures to be followed for getting calibration done from the laboratory. The procedure for redressal of complaints should also be clearly specified and documented.

5.4

The laboratory shall have authorized signatories for approving and issuing calibration certificates for each calibration parameter as mentioned in the scope of accreditation. Any officer competent to evaluate calibration results critically and occupying a position involving responsibility for the adequacy of calibration results is eligible for approval by NABL as an authorized signatory of endorsed calibration documents. Approved authorized signatories must demonstrate understanding of NABL requirements, and must be competent in the relevant area of calibration.

6.0

PERSONNEL (clause 5.2 of ISO/IEC 17025:2005)

6.1

The calibration laboratory shall have adequate number of qualified competent and trained personnel as follows: Laboratory personnel performing calibration: Diploma in Engineering (relevant branch) or Science graduate (with Physics, Chemistry and Mathematics) with 1 year of relevant experience or ITI with at least 5 years of relevant experience. Authorized Signatory: Bachelor of Engineering/Post Graduate in Science (relevant branch) with 1 year of relevant experience or Diploma in Engineering (relevant branch) with minimum 3 years of relevant experience. The relevant experience should be in the field of Electro-Technical measurements and calibration practices. For any relaxation in terms of qualification and experience for above personnel, the assessment team should give explicit reasons and written recommendations on their competence.

6.2

Arrangements for improvement of qualifications and periodic refresher courses and practical training should also exist for the laboratory personnel so as to keep them in touch with latest developments in the relevant fields.

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7.0

ACCOMMODATION AND ENVIRONMENTAL CONDITIONS

(clause 5.3 of

ISO/IEC 17025:2005)

7.1

GENERAL

7.1.1

The environmental conditions maintained in the laboratory shall be such that it does not adversely affect the required accuracy of measurement. Facilities should be provided for recording environmental parameters such as temperature, humidity etc. prevailing during calibration. The environmental conditions maintained in the laboratory during calibration should be reported in the calibration report/ certificate. Wherever applicable, laboratory is required to maintain appropriate environmental conditions related to Line regulation, Harmonic content in supply voltage, EMI/EMC, Stray magnetic fields , Vibration, Dust level, Acoustic noise level, Illumination level etc and keep a record of the same.

7.1.2

The laboratory shall specify limits on the environmental conditions to be achieved in the laboratory. The condition shall be appropriate to the level of its capability required for the calibration undertaken by the laboratory.

7.1.3

The environmental conditions shall be monitored at appropriate intervals and calibrations stopped when the environmental conditions are observed to be outside the specified limits.

7.1.4

As far as possible, only the staff engaged in the calibration activity shall be permitted entry inside the calibration area. Access of other persons shall be controlled and defined.

7.2

SPECIAL ENVIRONMENTAL REQUIREMENTS OF LABORATORY

7.2.1

The calibration laboratory shall make arrangements for regulated and uninterrupted power supply. The recommended regulation level is Âą 1% or better on the calibration bench.

7.2.2

Relevant IS specifications (IS: 1248, IS: 4722) regarding total harmonic content and variation in supply frequency should be followed. Voltage stabilizers of low harmonic content and variation in supply frequency should be used to comply with these requirements.

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7.2.3

For Inductance (low frequency) and DC Resistance, the temperature variation must be controlled such that the calibration uncertainty does not exceed 10% due to temperature variation.

7.2.4

For High Voltage Capacitors/ Transformers, the temperature variation should be < 1째 during calibration period. The inductive voltage divider should be protected against the effects of AC magnetic fields.

7.2.5

For High voltage calibration, temperature and humidity shall be recorded by the laboratory and correction shall be applied wherever required.

7.2.6

The laboratory shall use, if necessary, isolation transformers and filters etc. to ensure minimization of ground current and effects of mains hum interference.

7.2.7

The power supply to the calibration laboratory shall be directly obtained from the substation as far as possible and shall not be on the same feeder line which is supplying power to workshops and other production areas which require operation of heavy duty machines.

7.2.8

The calibration area shall be adequately free from vibrations generated by central airconditioning plants, vehicular traffic and other sources to ensure consistent and uniform operational conditions. The laboratory shall take all special/ protective precautions like mounting of sensitive apparatus on vibration free tables and pillars etc., isolated from the floor, if necessary.

7.2.9

Acoustic noise level in the laboratory shall be maintained to facilitate proper performance of calibration work. A threshold noise level of 60 dBA is recommended unless otherwise stated.

7.2.10 The calibration area shall have adequate level of illumination.

Where permissible,

fluorescent lighting is preferred to avoid localized heating and temperature drift. The recommended level of illumination is 450-700 lux on the working table with glare index of 19 for the laboratory.

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7.2.11 Effective earthing shall be provided for mains in accordance with relevant specification IS: 3043. Laboratories are required to maintain earth resistance to less than 1 ohm and earth to neutral voltage to less than 1 volt. This shall be periodically checked and stray couplings minimized. 7.2.12 Special care shall be taken about the location of magnetic field sources like, transformers, looped wires, ferrous materials etc., in order to minimize magnetic interference in the measurements. 7.2.13 Adequate screening of the laboratory against electromagnetic interference may be done if necessary. By pass filters should also be provided to minimize conducted interference effect on the electronic equipment. Special shielding chambers should be provided in the laboratory for measurements, particularly when signal to noise ratio is a disturbing factor for accurate measurements. 7.2.14 The reference standards shall be maintained at temperatures specified for their maintenance in order to ensure their conformance to the required level of operation. The laboratory should have specific facilities required for carrying out the calibration of parameters chosen. 7.2.15 The laboratory shall be sealed against dust and external air pressure. Positive air pressure, if necessary shall be maintained inside the laboratory. 7.2.16 Adequate protective measures, like use of transient suppressors etc, shall be taken by the laboratory to ward off high current spikes and transients emanating from switching on and off, of heavy machines, surges in power lines and other such reasons, from reaching the electronics equipment in general and computer based systems involving data storage facilities in particular. 7.3

SAFETY PRECAUTIONS

7.3.1

Relevant fire extinguishing equipment for possible fire hazards should be available in the corridors or convenient places in the laboratory. Adequate safety measures against electrical, chemical fire hazards must be available at the work place. Laboratory rooms/ areas where highly inflammable materials are used/ stored should be identified. Access to relevant fire equipment should be assured near these rooms/ areas.

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7.3.2

Specification SP.31-1986, a special publication in the form of a wall chart, giving the method of treatment in case of electric shock, should be followed. The chart should be placed near the power supply switchgear and at other prominent places as prescribed under Indian Electricity Rules 1956.

8.0

CALIBRATION METHODS AND UNCERTAINTY OF MEASUREMENT (clause 5.4 of ISO/IEC 17025:2005 )

8.1

COMPARISON METHOD OF CALIBRATION

The laboratory while using the comparison method of calibration (using a nominal source of good short term stability and a measurement standard/master) shall devise methods to evaluate the short term stability of the sources/supply. Records of the short term stability shall be available with the laboratory for verification by NABL. For comparison method of calibration, it is not mandatory to calibrate the source/supply. However, the laboratory is required to demonstrate the short term stability of the source/supply during the assessment. The suitability of the comparison method (especially in case of low voltage, low/high current, low/high resistance, high frequency voltage measurements) shall be established by the laboratory by studying the effects of factors like capacitive / inductive / resistive loading, allowable current, compliance voltage etc. on measurement. Assessor shall verify the same during assessments. The stability data generated by the laboratory for the source/supply needs to be used as a Type-B contribution towards uncertainty of calibration. Other possible contributions towards Type-B, depending on the type of comparison method used, shall have to be identified by the laboratory and included in the uncertainty budget. This shall be verified by the assessor during assessment. 8.2

VALIDATION OF SOFTWARE

Any software used by laboratories for performing automated calibration shall be validated so that all parameters and ranges intended to be calibrated using the software are taken care of. Records for the same shall be available with the laboratory during assessment. Such software needs to be verified by the user laboratory periodically. Periodicity of these verifications may be decided by the user laboratory. Re-validation of software is required whenever there is a change in the version of the software used. National Accreditation Board for Testing and Calibration Laboratories Doc. No: NABL 121 Issue No: 04

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8.3

MINIMUM TYPE ‘B’ COMPONENTS FOR UNCERTAINTY CALCULATIONS

The following Type B components shall be necessarily considered as a minimum for estimation of measurement uncertainty: • U1: Uncertainty reported in the calibration certificate of the standard(s)/master(s) • U2:

Uncertainty

arising

from

stability

data

of

the

measurement

standard(s)/master(s) used for calibration (Detailed explanation for this component is provided below) • U3: Uncertainty from the resolution of the Device/Unit under Calibration • U4, U5 etc: Uncertainty due to other influential factors such as temperature, humidity variation etc affecting the measurements. Clarifications pertaining to U2 component: Stability data shall be generated by laboratories by preparation of control /trend charts based on successive calibration of their standard(s)/master(s) (preferably without adjustments)*. This shall be established by laboratories within two years from the date on which laboratories apply for NABL accreditation. For the accredited laboratories, this shall be established within a period of two years w.e.f. the date of this issue. The laboratories may need to get their standard(s)/master(s) calibrated more frequently to generate the stability data within the above stipulated time. Till

such

time,

the

stability

data

provided

by

the

manufacturer

of

the

standard(s)/master(s) can be utilized for estimation of uncertainty. In case the stability data from the manufacturer is also not available, the accuracy specification as provided by the manufacturer can be used. However, manufacturer’s data will not be acceptable after the two year period as mentioned above since the laboratories are expected to establish their own stability data by that period. * In cases where the standard(s)/master(s) are adjusted during its calibration, preadjustment data needs to be used for preparation of control/trend charts.

9.0

EQUIPMENT (clause 5.5 of ISO/IEC 17025:2005)

9.1

The calibration laboratory shall have measurement standards and equipment of required accuracy in respect of each parameter covered by it in order to be able to realize and to substantiate the corresponding measurement capability claimed. Stability of the standards, accuracy of the values realized through them and repeatability, should be regularly monitored.

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9.2

Any bias resulting from ageing of standards should be precisely determined. Instructions for operating each standard and equipment/ instrument should be readily available for use by the laboratory staff members.

9.3

The standards/ measuring equipment of the laboratory should be calibrated at regular intervals, with higher accuracy standards.

The calibration certificates, performance

history sheets in respect of the reference secondary/ working standards and measuring equipment should be held safely by the laboratory. 9.4

Proper record shall be maintained for each standard and equipment with the following information:

9.5

a)

Name of the equipment

b)

Manufacturers name and address

c)

Type, range, identification and serial number

d)

Date of procurement and commissioning

e)

Details of Calibration

f)

Details of maintenance and repairs

g)

Performance history with dates

h)

Availability of service manual

Details of periodic calibration schedule of new and old standards and measuring equipment should be worked out in consultation with higher capability laboratory and this schedule should be observed.

9.6

Details of re-calibration of used, serviced and repaired equipment should also be available and proper precautions shall be observed to identify equipment, which are not in service.

9.7

Any alterations in the observations/ data shall be signed by the calibration staff and duly authenticated. Instructions to this effect should be printed on data sheet used for writing observations/ data in the laboratory.

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9.8

REPAIR AND MAINTENANCE

9.8.1

A separate repair and maintenance facility, adequately equipped with repair facilities and qualified and experienced manpower, shall be available in-house or by any other means effectively accessible to the calibration laboratory. This facility shall also assist in identifying the preventive maintenance measures, which should be brought to the attention of the personnel engaged in calibration work for taking necessary actions. The repair facility should cover digital and programmable instruments also.

9.8.2

Every repaired equipment shall invariably be re-calibrated through in-house facility or by higher capabilities laboratory before being used for further calibration work.

10.0

MEASUREMENT TRACEABILITY (clause 5.6 of ISO/IEC 17025:2005)

10.1

All calibration laboratories shall follow NABL 142 (Policy on Calibration and Traceability of Measurements) to achieve traceability. For this (irrespective of manual and software calibrations), standard(s)/master(s) used by laboratories need to be calibrated for all parameters and ranges under its scope of accreditation. For each range, standard(s)/master(s) are required to be calibrated at least at two points (preferably minimum and maximum points) of the range assuming ranges to be linear.

10.2

When same standard(s)/master(s) are used both for a parameter and its derived parameter (e.g. reciprocal counter for measurement of Time and Frequency), traceability achieved for the main parameter automatically ensures traceability for the derived parameter. However, the derived parameter(s) needs to be separately demonstrated identifying the appropriate uncertainty contributions and subsequently included in the scope of accreditation.

11.0

HANDLING OF CALIBRATION ITEMS (clause 5.8 of ISO/IEC 17025:2005)

11.1

The standards/ measuring instruments/ equipment received by the laboratory for calibration shall be safely stored in proper environmental conditions according to the instructions given by the customer/manufacturer.

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11.2

The laboratory shall have adequate arrangements for packaging of calibrated instruments and may assist the user, if necessary, about the procedure and precautions to be taken by the organization for packaging and transportation of the equipment to the calibration laboratory.

12.0

PROFICIENCY TESTING (clause 5.9 of ISO/IEC 17025:2005)

12.1

Laboratories shall follow NABL 163 (Policy & Procedures for Inter-Laboratory Comparisons and / or Proficiency Testing) and NABL 164 (Guidelines for interlaboratory comparison for calibration laboratories where formal PT programmes are not available) for participation in PT/ILC programmes.

12.2

In order to assure validity of calibrations undertaken and demonstrate its technical competence, a laboratory will be required to participate, from time to time, in Proficiency Testing Programmes. The laboratory shall remain prepared to participate in the Proficiency Testing Programme through inter-laboratory, inter-comparison schemes wherever it is technically feasible. In case any abnormalities, in terms of En number are detected through these inter-comparisons, appropriate corrective action will be taken, the standards/ equipment shall be replaced/ repaired and re-calibrated with a higher accuracy standard. Reports on such inter-comparisons should be documented with reference. The Proficiency Testing practice should be included in the Quality Manual.

13.0

CALIBRATION CERTIFICATE/ REPORT (clause 5.10 of ISO/IEC 17025:2005)

13.1

The result of calibration carried out by the calibration laboratory, shall be presented in a comprehensive manner, using a standard format which shall unambiguously and objectively present the measurement results and all relevant information in order to facilitate easy comprehension and usage.

13.2

The calibration report/ certificate shall include the following additional information: a)

Date of receipt of the item and date of completion of the calibration work.

b)

Environmental conditions maintained during the measurements.

c)

Signature and title of authorized person (authorized signatory) accepting responsibility for the report and date of issue.

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d)

A statement of the accreditation measurement capability relevant to the job under calibration.

e)

NABL Symbol identifying the scope of accreditation of the laboratory.

f)

The Uncertainty of measurement.

g)

An evidence that the measurements are traceable to National/ International Standards through unbroken chain of Accredited Laboratories.

13.3

The calibration report/ certificate shall not contain any recommendation on the calibration interval except where this has been agreed with the client. This requirement may be superseded by legal regulations.

13.4

Laboratories accredited for main parameters are not allowed to use NABL symbol for parameters derived from these parameters since the associated uncertainty of the derived parameter is not known and the same is not verified by NABL.

13.5

All laboratories are required to retain a replica (either hard copy or soft copy ) of the certificates issued to their customers. Laboratory may decide on the appropriate retention period.

14.0

GUIDANCE FOR ASSESSMENTS AND SCOPE RECOMMENDATION

14.1

For initial assessment, the calibration for each parameter, as applied by the laboratory, shall be witnessed. For all ranges under a parameter, atleast the minimum and maximum point of a range, shall be witnessed. The witnessing may be reduced if proper records are available with the laboratory. This needs to be examined by the assessor. The assessor may select additional appropriate critical points for evaluating the laboratoryâ&#x20AC;&#x2122;s competence. For surveillances and re-assessments, sampling plan for witnessing of parameters / ranges, provided by NABL shall be followed as far as possible.

14.2

Recommendation of scope shall be in the order- source and / or measure wise, parameter-wise and range wise, as shown as an example in Form 73 (Recommended Scope of Accreditation) in the next page.

In special cases, e.g. calibration of

oscilloscopes, electrostatic discharge etc, the scope shall be recommended instrumentwise, keeping in mind the uniqueness of calibration or the customer requirement. National Accreditation Board for Testing and Calibration Laboratories Doc. No: NABL 121 Issue No: 04

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Page No: 14


14.3

AC parameters to be recommended as under (frequency ranges followed by voltage/current ranges). Resistance parameter should be clearly recommended as AC or DC. For oscilloscope calibration, minimum parameters that need to be calibrated are amplitude, time base and bandwidth.

14.4

The recommended ranges shall be split on the basis of capability of the standard(s)/master(s) used and different methods/procedures adopted by the laboratory. It is advisable to split ranges to keep less variation in Best Measurement Capability (BMC) and shall be split in such a manner that linearity is ensured for each range. Wherever linearity is not possible in a range, single value shall be recommended. When single value standard(s) /master(s) are used, recommendation shall also be a single value.

14.5

Laboratories are expected to report measurement uncertainty in SI units in the calibration certificates issued by them. It is desirable that NABL assessor recommends BMC in SI units (wherever possible). The assessor shall recommend the BMC of each range giving due consideration to factors like laboratoryâ&#x20AC;&#x2122;s claim and demonstrated uncertainty and shall be rounded off to two significant digits.

14.6

In form 73, â&#x20AC;&#x153;Remarks/Methodsâ&#x20AC;? column will mention the specific calibration method used by the laboratory e.g. comparison method, null method etc. Wherever required, foot notes may be added to the scope of accreditation for the purpose of clarity and/or completeness.

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Form 73

RECOMMENDED SCOPE OF ACCREDITATION (For Calibration Laboratories)

Laboratory:

Date(s) of visit:

Facility: Sl

1

2

Discipline(s):

Parameter / Quantity measured (equipment wise) Measure

Standards / Masters Used

AC Voltage

Fluke 8508A DMM

DC Voltage

Fluke 8508A DMM

Source

Best measurement capability**

Range(s)*

Claimed by Laboratory

Observed by Assessor

Recommended by Assessor

10Hz to 10kHz 1mV to 100mV 100mV to 100V 100V to 1000V

0.002mV to 0.006mV 0.006mV to 0.017V 0.017V to 0.022V

0.004mV to 0.016mV 0.016mV to 0.013V 0.013V to 0.018V

0.004mV to 0.016mV 0.016mV to 0.017V 0.017V to 0.022V

10kHz to 100kHz 1mV to 100mV 100mV to 100V 100V to 1000V

0.0069mV to 0.03mV 0.03mV to 0.14V 0.14V to 0.91V

0.0069mV to 0.43mV 0.43mV to 0.1V 0.1V to 0.81V

0.0069mV to 0.43mV 0.43mV to 0.14V 0.14V to 0.91V

100µV to 10mV 10mV to 100mV

0.012 µV to 0.0042mV 0.0042mV to 0.0005mV

0.012 µV to 0.0042mV 0.0042mV to 0.0004mV

0.012 µV to 0.0042mV 0.0042mV to 0.0005mV

SAMPLE

1

DC Resistance

Wavetek 4808 Calibrator

1mΩ to 10Ω 0.0004mΩ to 0.012Ω 10Ω to 100kΩ 0.012Ω to 0.0011kΩ 100kΩ to 100MΩ 0.011kΩ to 0.019MΩ

0.0004mΩ to 0.042Ω 0.042Ω to 0.0021kΩ 0.021kΩ to 0.026MΩ

0.0004mΩ to 0.042Ω 0.042Ω to 0.0021kΩ 0.021kΩ to 0.026MΩ

2

DC Current

Wavetek 4808 Calibrator

100µA to 100mA 0.004µA to 0.005mA 100mA to 1A 0.005mA to 0.00011A 1A to 10 A 0.00011A to 0.001A

0.014µA to 0.006mA 0.006mA to 0.00014A 0.00014A to 0.0029A

0.014µA to 0.006mA 0.006mA to 0.00014A 0.00014A to 0.0029A

∗ For Electro-technical Discipline, wherever applicable, the ranges may be mentioned frequency wise ** Best measurement capability is expressed as measurement uncertainty at a confidence level of 95%/

Signature & Name of Lab Representative

Signature & Name of Assessor(s)

Signature & Name of Lead Assessor

National Accreditation Board for Testing and Calibration Laboratories Doc. No: NABL 121 Issue No: 04

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Remark / Method used


PART – II

GUIDELINES REGARDING GENERALLY ACHIEVED MEASUREMENT CAPABILITES IN CALIBRATION FOR ELECTRO-TECHNICAL MEASUREMENT (TABLES ARE ARRANGED PARAMETER WISE COVERING ALL FREQUENCY RANGES)


GENERAL REMARKS The following pages may be referred as guidelines and not mandatory requirements for the laboratories. The accredited calibration laboratories are no longer required to be categorized into Echelon/ level I, II, III.

Part II of this document aims at providing guidance to the

laboratories with respect to environmental conditions to be maintained as appropriate to respective BMC of the laboratories. The laboratories, on their own, should decide to have environmental conditions in their calibration area to achieve the BMC claimed in their scope of accreditation applied for. The tables given in subsequent pages show that generally achieved measurement capabilities expressed as expanded uncertainty in Electro-technical calibration laboratories if the laboratories control environmental condition as given in the table for various levels viz. I, II and III. Further, It may also be noted that: 1)

The measurement capability is expressed as expanded uncertainty at a confidence level of 95% approximately.

2)

The term uncertainty in these tables pertains to the corresponding measurement capability of the laboratory in respect of each parameter

3)

The values of uncertainty of measurement shown in the following tables are at 95% confidence level unless stated otherwise.

ENVIRONMENTAL CONDITIONS Standard environmental conditions for calibration laboratory in an Electro-Technical Measurement Laboratory shall be as follows: Level

I

II

III

Temperature

250C ± 0.50C

250C ± 2.50C

250C ± 4.00C

Relative humidity

350C to 65%

35 to 65%

not to exceed 70%

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TABLE 1 DC VOLTAGE Parameter

DC Voltage

DC Voltage

Standard Values/ Ranges

Uncertainty Level-I

Level-II

Level-III

1mV

1x10-4

1x10-3

5x10-3

10mV

1x10-5

1x10-4

5x10-4

100mV

1x10-6

1x10-5

5x10-5

1V

1x10-6

2x10-6

1x10-5

10V

1x10-6

5x10-6

5x10-5

100V

2x10-6

1x10-5

1x10-4

1000V

5x10-6

5x10-5

5x10-4

a) Standard Values

b) Measurement Capability 10 µV to 100 µV

5x10-2 to 5x10-3

5x10-2 to 1x10-2

100 µV to 1mV

5x10-3 to 5x10-4

1x10-2 to 5x10-3

2x10-2 to 1x10-2

1mV to 10mV

5x10-4 to 5x10-5

5x10-3 to 5x10-4

1x10-2 to 1x10-3

10mV to 100mV

5x10-5 to 5x10-6

5x10-4 to 5x10-5

1x10-3 to 1x10-4

100mV to 1V

5x10-6 to 1x10-6

5x10-5 to 5x10-6

1x10-4 to 2x10-5

1 to 10V

1x10-6 to 2x10-6

5x10-6 to 1x10-5

2x10-5 to 2x10-4

10 to 100V

2x10-6 to 5x10-6

1x10-5 to 5x10-5

2x10-4 to 2x10-3

100 to 1000V

5x10-6 to 2x10-5

5x10-5 to 1x10-4

2x10-3 to 2x10-2

1000 to 1500V

2x10-5 to 5x10-5

1x10-4 to 2x10-4

2x10-2 to 5x10-2

1500 to 100kV

5x10-5 to 2x10-4

2x10-4 to 1x10-2

To be worked out

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Page No: 18


TABLE 2 AC VOLTAGE Parameter

AC Voltage

AC Voltage

Standard Values/ Ranges

Uncertainty Frequency

Level-I

Level-II

Level-III

a) Standard Values 10 µV

50 Hz

5x10-4

1x10-3

1x10-2

10mV

,,

1x10-4

1x10-3

5x10-3

100mV

,,

5x10-5

1x10-3

2x10-3

250mV

,,

2x10-5

5x10-4

2x10-3

1V

,,

5x10-6

2x10-4

2x10-3

3V

,,

5x10-6

2x10-4

2x10-3

10V

,,

1x10-5

2x10-4

2x10-3

30V

,,

1x10-5

5x10-4

2x10-3

100V

,,

5x10-5

5x10-4

2x10-3

300V

,,

5x10-5

5x10-4

5x10-3

1000V

,,

5x10-5

5x10-4

5x10-3

b) Measurement Capability 10µV-10mV

,,

5x10-4 to 1x10-4

5x10-2

5x10-2

10mV-250mV

,,

1x10-4

5x10-2 to 1x10-3

1x10-1 to 5x10-3

250mV-3V

,,

1x10-5

1x10-3 to 5x10-4

5x10-3 to 2x10-3

3V-300V

,,

2x10-5 to 1x10-4

5x10-4 to 1x10-3

2x10-3 to 5x10-3

300V-1kV

,,

1x10-4

1x10-3 to 2x10-3

5x10-3

1kV-40kV

,,

1x10-4 to 5x10-4

1x10-2

2x10-2

>40kV

,,

__

2x10-2

5x10-2

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Page No: 19


TABLE 3 L.F. & H.F. VOLTAGE Parameter

L.F. Voltage

Standard Values/ Range

Frequency

Uncertainty Level-I

Level-II

Level-III

1kHz to 30 kHz 5x10-5 to 1x10-4

1x10-3

__

a) Standard Values 1mV 10mV

,,

5x10-5 to 1x10-4

1x10-3

5x10-3

100mV

,,

5x10-5 to 1x10-3

1x10-3

2x10-3

1V

,,

5x10-6 to 1x10-5

2x10-4

2x10-3

3V

,,

5x10-6 to 1x10-5

2x10-4

2x10-3

10V

,,

2x10-6

2x10-4

2x10-3

100V

,,

5x10-6

5x10-4

2x10-3

__

__

__

5x10-4 to 1x10-4

5x10-2 to 1x10-3

To be worked out later

Primary Standard

b) Measurement Capability 1µV to 10µV

1kHz to 10kHz

10µV to 1mV

,,

5x10-4 to 1x10-3 1mV to 10mV

,,

1x10-4

1x10-3

1x10-2

10mV to 250mV

,,

1x10-4

1x10-3

1x10-2

5x10-2

5x10-2

5x10-3 to 2x10-3

2x10-2 to 5x10-2

1x10-3 to 5x10-

1x10-2 to 5x10-3

5x10-4 to 1x10-

5x10-3 to 1x10-2

1x10-3 to 2x10-

1x10-2

10µV to 10mV

10kHz to 30kHz 1x10-2 to 1x10-4

10mV to 250mV

,,

5x10-5 to 1x10-4

250mV to 3V

,,

2x10-5 to 2x10-5

3V to 300V

1kHz to 30kHz

2x10-5 to 1x10-4

300V to 1kV

,,

1x10-4

4

3

3

Contd.

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Page No: 20


Table 3—Contd. H.F. Voltage

(a) Standard Values 10µV

100kHz

2x10-2

__

__

1mV

,,

1x10-3

2x10-3

__

1V

,,

2x10-5

5x10-4

1x10-3

10V

,,

2x10-4

5x10-4

1x10-3

100V

,,

5x10-5

5x10-4

__

10µV

30MHz

2x10-2

__

__

1mV

,,

5x10-3

1x10-2

__

1V

,,

1.5x10-3

5x10-3

__

10V

,,

1.5x10-5

5x10-3

__

100V

,,

2x10-3

5x10-3(50V)

__

10µV

100MHz

3x10-2

__

__

1mV

,,

1x10-2

__

__

1V

,,

3x10-3

1x10-2

__

10V

,,

5x10-3

1x10-2

__

100V

,,

5x10-3

__

__

10µV

300MHz

3x10-2

__

__

1mV

,,

1.5x10-2

1V

,,

3x10-3

2x10-2

__

10V

,,

5x10-3

3x10-2

__

10µV

1000MHz

3x10-2

__

__

1mV

,,

1.5x10-2

__

__

1V

,,

5x10-3

3x10-2

__

10V

,,

1x10-2(7V)

Contd.

National Accreditation Board for Testing and Calibration Laboratories Doc. No: NABL 121 Issue No: 04

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Page No: 21


Table 3—Contd. (b) Measurement Capacity

10µV-250mV

250mV-10V

10V-100V

100V-300V

30kHz-1MHz

2x10-4 to2x10-2

1x10-2 to3x10-2

3x10-2 to 1x10-1

1MHz100MHz

2x10-3 to 3x10-2

3x10-2

In all ranges

100 MHz1GHz

1x10-2 to 4x10-2

3x10-2 to 5x10-2

,,

30kHz-1MHz

1x10-4 to 2x10-4

1x10-3

,,

1MHz-100MHz 2x10-4 to 5x10-3

1x10-2

,,

100 MHz-1GHz 5x10-3 to 1.5x10-2

3x10-2

,,

1x10-4 to 5x10-4

5x10-3 to 1x10-2

,,

1MHz-100MHz 2x10-4 to 1x10-2

1x10-2 to 3x10-2

30kHz-100kHz 1x10-4

3x10-2 to 5x10-2

30kHz-1MHz

,,

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Page No: 22


TABLE 4 DC CURRENT Parameter

Uncertainty

Standard Value/Range

Level-I

Level-II

Level-III

1µA

1x10-3

5x10-2

1x10-1

10µA

5x10-4

1x10-3

5x10-3

100µA

1x10-4

5x10-4

1x10-3

1mA

5x10-5

1x10-4

5x10-4

10mA

1x10-5

2x10-5

5x10-5

100mA

5x10-6

1x10-5

2x10-5

1A

2x10-6

5x10-6

1x10-5

10A

5x10-6

2x10-5

1x10-4

100A

1x10-5

5x10-5

2x10-4

1µA to 1mA

*5x10-2 to 5x10-5

1x10-1 to 1x10-4

2x10-1 to 2x10-4

1mA to 1A

5x10-5 to 2x10-6

1x10-4 to 5x10-6

2x10-4 to 2x10-5

1A to 10A

2x10-6 to 5x10-6

5x10-6 to 2x10-6

2x10-5 to 2x10-4

10A to 100A

5x10-6 to 1x10-5

2x10-5 to 1x10-4

2x10-4 to 5x10-4

100A to 1000A

1x10-5 to 1x10-4

1x10-4 to 1x10-3

5x10-4 to 5x10-3

1000A to 5000A

1x10-4 to 5x10-3

1x10-3 to 1x10-2

5x10-3 to 5x10-2

a) Standard Values DC Current

b) Measurement Capability DC Current

Requirements of current measurements associated with active semiconductors have been taken into account.

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Page No: 23


TABLE 5 AC CURRENT Parameter

AC Current

Standard Values/ Range

Frequency

Uncertainty Level-I

Level-II

Level-III

5x10-4 to 1x10-3 at selected values

To be worked out later

(a) Standard Values 1mA

50 Hz-1kHz

5mA

,,

5x10-5

10mA

,,

,,

100mA

,,

5x10-5

,,

,,

1A

,,

,,

,,

,,

10A

,,

,,

,,

,,

(b) Measurement Capability

â&#x20AC;˘

1mA to 1A

,,

1x10-4

5x10-4

5x10-3

1A to 20A

,,

1x10-4

5x10-4

5x10-3

20A to 100A*

,,

5x10-4

1x10-4

1x10-2

100A to 1000A*

,,

5x10-4

1x10-3

1x10-2

1kA to 30 kA/100kA*

,,

__

1x10-2

5x10-2

Only at 50/60 Hz

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Page No: 24


TABLE 6 L.F. & H.F. CURRENT Parameter Standard Values/ Range (i) L.F. Current

Frequency

Uncertainty Level-I

Level-II

Level-III

(a) Standard Values 1mA

1kHz-30kHz

5x10-5

To be worked out later

To worked out later

5mA

,,

5x10-5

,,

,,

10mA

,,

5x10-5

,,

,,

100mA

,,

5x10-5

,,

,,

(b) Measurement Capability

(ii) H.F. Current

1mA to 1A

,,

1x10-4

5x10-4

5x10-3

1A to 20A

,,

5x10-4

1x10-3

5x10-3

30kHz100kHz

5x10-5

To be worked out later

To be worked out later

10mA

,,

5x10-5

,,

,,

100mA

,,

1x10-4

,,

,,

(a)Standard Values 1mA

(b) Measurement Capability 1mA to 100mA

,,

5x10-5 to 1x10-4

5x10-4 to 7x10-4

1x10-3 to 5x10-3

100mA to 5A

,,

1x10-4 to 2x10-4

5x10-4 to 7x10-4

1x10-3 to 5x10-3

5A to 20A

,,

2x10-4 to 5x10-4

5x10-4 to 1x10-3

__

National Accreditation Board for Testing and Calibration Laboratories Doc. No: NABL 121 Issue No: 04

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Page No: 25


TABLE 7 AC POWER & ENERGY Parameter

(i) AC Power

Standards Values/ Range

Frequency

Uncertainty Level-I

Level-II

Level-III

50Hz

1x10-4

5x10-4

1x10-3

,,

1x10-4

5x10-4

1x10-3

,,

-4

2x10

2x10

-3

5x10-3

0.5PF

,,

5x10-4

1x10-3

2x10-3 to 5x10-3

UPF

,,

2x10-4

1x10-3

2x10-3 to 5x10-3

Below 0.5PF

,,

8x10-4

1x10-3

2x10-3 to 5x10-3

,,

1x10-4

1x10-3

2x10-3 to 5x10-3

1 to 0.5PF

,,

1x10-3

1x10-3

5x10-3

Below 0.5PF

,,

b) Measurement Capability Single phase

100mW-2 kW UPF 0.5PF 0.2PF 2kW-50kW

Three phase

1W-5kW 1 to 0.5PF 5kW-50kW

AC Energy

__

__

__

b) Measurement Capability Single Phase 1Wh to 2kWh

a) 0.5 to UPF

,,

1x10-4

5x10-4 to 1x10-3

2x10-3 to 5x10-3

b) 0.2PF

,,

2x10-4

2x10-3

5x10-3

,,

5x10-4

1x10-3 to 2x10-3

5x10-3

0.5 to UPF

,,

1x10-4

2x10-3

5x10-3

5kWh to 1MWh

,,

1x10-4

2x10-3

5x10-3

0.5 to UPF

,,

0.1x10-3

2x10-3 to 5x10-3

5x10-3 to 1x10-2

2kWh to 100kWh 0.2 to UPF Three Phase 1Wh to 5kWh

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Page No: 26


TABLE 8 L.F., H.F. & MICROWAVE POWER Parameter

i) L.F. Power

Standard Values/ Ranges

Frequency

Uncertainty Level-I

Level-II

Level-III

a) Standard Values 1mW

1kHz

1x10-4

1x10-3

To be worked out later

1W

,,

1x10-4

1x10-3

,,

1kW

,,

1x10-4

1x10-3

,,

b) Measurement Capability

ii) H.F. Power

1mV to 100W

1kHz to 30kHz

5x10-4 to 1x10-3

5x10-3

2x10-2

100W to 5kW

,,

1x10-3 to 5x10-3

5x10-3

2x10-2

a) Standard Values 1mW

30kHz to 2GHz

2x10-3 to 1x10-2

1.5x10-2

3x10-2 to 5x10-2

10mW

,,

2x10-3 to 5x10-3

1.510-2

3x10-2 to 5x10-2

100mV

,,

5x10-3

b) Measurement Capability 10ÂľW-1mW

30kHz to 1 GHz

5x10-3 to 1x10-2

1.5x10-2

5x10-2

1mW-10mW

,,

3x10-3 to 1x10-2

1.5x10-2

3x10-2

10mW100mW

,,

3x10-3 to 8x10-3

1.5x10-2

3x10-2

100mW-30W

,,

8x10-3 to 1.5x10-2

3x10-2

5x10-2

8.2GHz to 12.4 GHz (X Band)

5x10-3 to 7x10-3

1.0x10-2 (1.4GHz)

To be worked out later

9,10,11

(1.02 SWR)

1.5x10-2

iii) Microwave a) Standard Values Power 10mW

Contd.

National Accreditation Board for Testing and Calibration Laboratories Doc. No: NABL 121 Issue No: 04

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Page No: 27


Table 8—Contd. b) Measurement Capability Coxial: 1µW-100mW

2GHz to 18 GHz

7x10-3 to 1.5x10-2

3x10-2 to 5x10-2

5 to 8%

Wave Guide: 1µV-100mW

(i) 8.2 GHz to 12.4 GHz

8x10-3 to 1x10-2

3x10-2 to 5x10-2

To be worked out later

(ii) 5.8GHz to 8.2 GHz

1x10-2 to 1.5x10-2

3x10-2 to 5x10-2

(iii) 12.4 GHz 1x10-2 to 1.5x10-2 to 18.0 GHz

3x10-2 to 5x10-2

To be worked out later

Notes •

Accuracy & Measurement Uncertainty quoted at Level I and Level II are exclusive of mismatch errors.

The exact generated standard values may be different, but the uncertainty limits will remain unchanged.

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TABLE 9 AC RATIO Parameter Standard Values/ Ranges

Frequency

Uncertainty Level-I

AC Ratio

Level-II

Level-III

a) Standard Values Voltage Ratio

50Hz

IVD based 0.00000001 to

1x10-7 to 3x10-8 of the input voltage

1x10-6 of the input voltage

5x10-5

5x10-4

5x10-3

5x10-5

5x10-4

5x10-3

1x10-6-5x10-8

5x10-6 to 1x10-5

0.99999999 Standard PT based 3, 5, 6, 10, 15, 20, 30, 40 kV/100V

,,

2.5x10-3

230, 460, 1150, 2300, 3450, 6900V/115V Standard CT based 100, 200, 400, 800, 1600, 3200, 6400A/5A

,,

b) Measurement Capability Voltage Ratios (Calibration of IVDs)

,,

0.00000001 to 0.99999999 (Calibration of PTs) 230V/115V6900V/115V

,,

2.5x10-3

3kV-40kV/100V 40kV/100V100kV/100V (Calibration of CTs)

,,

2x10-4 to be created

5x10-3

1x10-3

5A/5A-2000A/5A 2000A/5A6000A/5A

,,

2x10-4 to be created

2x10-3

5x10-3

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Page No: 29


TABLE 10 PHASE ANGLE

Parameter

Standard Values/ Ranges

Frequency

Uncertainty Level-I

Phase Angle

Level-II

Level-III

a) Standard Value 0°

50 Hz

10 milli Rad

20 milli Rad

To be worked out later

30°

,,

10 milli Rad

20 milli Rad

,,

60°

,,

10 milli Rad

20 milli Rad

,,

90°

,,

5 milli Rad

10 milli Rad

,,

120°

,,

5 milli Rad

10 milli Rad

,,

150°

,,

5 milli Rad

10 milli Rad

,,

180°

,,

5 milli Rad

10 milli Rad

,,

,,

10-5 milli Rad

20’

,,

20 milli Rad

40

b) Measurement Capability Single Phase

0°-360° Three Phase

0°-360°

Note:- Exact frequency at which calibration has been done shall be mentioned in the calibration data.

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Page No: 30


TABLE 11 L.F., H.F. & MICROWAVE ATTENUATION Parameter

(i) L.F. Ratio & Attenuation

Standard Values/ Ranges

Frequency

Uncertainty Level-I

Level-II

Level-III

(a) Standard Values (A) 0.00000001 to 0.99999999 Voltage Ratio

1kHz to 10kHz

1x10-7 of input

1x10-6 of input

To be worked out later

(B) 0-100dB (Attenuation)

1kHz to 30 kHz

0.007dB/10dB

0.02dB/10dB

0.02dB/10dB

(b) Measurement Capability

(ii) H.F. Attenuation

(A) 0-100dB (600 Ohm)

,,

0.005dB/10dB

0.01dB/10dB

0.05dB/10dB

(B) 0-100dB (50 Ohm)

,,

0.005dB/10dB

0.01dB/10dB

0.1dB/10dB

0.005dB/10dB

0.01dB/10dB

0.05dB/10dB to 0.1dB/10dB

(a) Standard Values 0 to 60 dB

30 MHz

(b) Measurement Capability (A) Fixed Attenuator 0to 10dB

30kHz-1GHz

0.005dB/10dB to0.01dB/10dB

0.01dB/10dB 0.01dB/10dB

0.01dB/10dB to 0.2dB/10dB

10 to 60dB

,,

0.005dB/10dB to0.02dB/10dB

0.05dB/10dB

0.1dB/10dB to 0.2dB/10dB

0 to 10dB

,,

0.005dB/10dB to 0.01dB/10dB

0.05dB/10dB to 0.1dB/10dB

0.2dB/10dB

10 to 60dB

,,

0.005dB/10dB to 0.02dB/10dB

0.05dB/10dB

01dB/10dB

60 to 100dB

,,

0.005dB/10dB to 0.05dB/10dB

0.01dB/10dB to 0.3dB/10dB

0.1dB/10dB to 0.3dB/10dB

(B) Variable Attenuator

Contd.

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Page No: 31


Table 11--Contd (iii) Microwave (a) Standard Attenuation Value 0 to 60dB

30 MHz

0.005dB/10dB

0.01dB/10dB

0.05dB/10dB

(b) Measurement Capability (A) Coaxial System 0 to 10dB

1GHz-18GHz

10 to 60dB

,,

0.015dB/10dB to 0.02dB/10dB (VSWR 1.05)

__

__

0.02dB/10dB (VSWR 1.05)

0.03dB/10dB to 0.1dB/10dB

0.1dB/10dB to 0.3dB/10dB

2.6 to 3.95 GHz (S Band)

0.02dB/10dB

0.05dB/10dB

To be worked out later

5.3 to 8.2 GHz (XN Band)

0.02dB/10dB

0.05dB/10dB

,,

8.2 to 12.4 GHz (X Band)

0.02dB/10dB

0.05dB/10dB

,,

12.4 to 18 GHz (ku Band)

0.02dB/10dB

0.5dB/10dB

,,

(B) Wave Guide System 0-60dB (Rotary Vane Attenuator)

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Page No: 32


TABLE 12 CAPACITANCE & DIELECTRIC LOSS ANGLE (tanδ) 50 Hz

Parameter

Standard Values/ Ranges

Frequency

Uncertainty

0.01µF, 0.1µF, 1µF, 10µF, 100µF, (0-600 Volts peak, 400 volts rms)

50Hz

2x10-4

5x10-4

5x10-3

10,100,1000, 10,00pF, (100V to 35kV)

,,

1x10-4

2x10-4

To be worked out later

Level-I

Level-II

Level-III

i) Capacitance

Measurement Capability 0.01µF-250µF (0-600 Volts peak)

,,

5x10-4 to 5x10-3

1x10-3 to 1x10-2

1x10-3 to 3x10-2

100pF-1000pF (100V-35kV)

,,

2x10-4

5x10-4

To be worked out later

50-1x10-2

50-10

50-10

ii) Dielectric Loss angle (tan) Measurement Capability 0.00001 to 0.1 (1kV)

,,

Note: Exact frequency at which calibration has been done shall be mentioned in the calibration data.

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Page No: 33


TABLE 13 CAPACITANCE (120 Hz & 1 kHz) Parameter

(i) Capacitance (120 Hz)

Standard Values/ Ranges

Frequency

a) Standard/ Values

100/120Hz

Uncertainty Level-I

Level-II

Level-III

1mF

,,

1x10-3

1x10-2

10mF

,,

1x10-3

1x10-2

,,

100mF

,,

5x10-3

2x10-2

,,

1000mF

,,

2x10-2

1x10-1

,,

1x10-3 to 2x10-2

1x10-2 to 1x10-1 5x10-2 to 2x10-1

,,

2x10-4

5x10-4

1x10-3

1pF (Air dielectric)

,,

2x10-5

2x10-4

1x10-3

10pF, 100pF (silica)

,,

5x10-7

2x10-6

10,100,1000pF (Air)

,,

2x10-6

1x10-5

2x10-4

0.001, 0.01F (Mica)

,,

2x10-5

1x10-4

5x10-4

10µF

,,

2x10-4

1x10-3

__

100µF

,,

5x10-4

5x10-3

__

1000µF

,,

1x10-3

1x10-2

__

To be worked out later

b) Measurement Capability 1mF-1F (ii) Capacitance 0.001,0.01,0.1pF, (1kHz) (Air dielectric)

100/120Hz to 1kHz

__

Contd.

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Page No: 34


Table 13—Contd. b) Measurement Capability 0.001 pF-1pF

1kHz

5x10-4 to 5x10-5

1x10-3 to 5x10-4 5x10-3 to 1x10-3

1pF-1000pF

,,

5x10-5 to 1x10-5

5x10-4 to 5x10-5 1x10-3 to 5x10-4

0.001µF-1µF

,,

5x10-5 to 1x10-4

2x10-4 to 5x10-4 1x10-3

1µF-1F

,,

1x10-4 to 1x10-2

5x10-4 to 1x10-2 1x10-3 to 5x10-2

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Page No: 35


TABLE 14 L.F. & H.F. CAPACITANCE

Parameter

Standard Values/ Ranges

Frequency

Uncertainty Level-I

Level-II

Level-III

i) L.F. Capacitance a) Standard Values 1pF, 10pF, 100pF (Air Dielectric)

10 kHz

1x10-4

2x10-4

2x10-4

1000pF (Air Dielectric)

10kHz

5x10-5

1x10-4

2x10-4

b) Measurement Capability 0.001pF-1pF

100kHz

1x10-3 to 2x10-4

5x10-3 to 5x10-4

To be worked out later

1pF-1000pF

,,

2x10-4

5x10-4

1x10-3

0.001µF-1µF

upto 100kHz

2x10-4 to 2x10-3

5x10-4 to 5x10-3

1x10-3 to 5x10-3

1µF-10µf

upto 20kHz

1x10-3 to 5x10-3

1x10-3 to 5x10-3

1x10-3 to 5x10-3

1pF

upto 1000MHz

2x10-4 to 1x10-3

2x10-3 to 5x10-3

To be worked out later

2pF

upto 1000MHz

-3 2x10-4 to 1x10-3 2x10 to 5x10-3

,,

3.3333pF

upto 800MHz

-3 2x10-4 to 1x10-3 2x10 to 5x10-3

,,

4pF

upto 700MHz

-3 2x10-4 to 1x10-3 2x10 to 5x10-3

5pF

upto 600MHz

-3 2x10-4 to 1x10-3 2x10 to 5x10-3

6.6667pF

upto 500MHz

-3 2x10-4 to 1x10-3 2x10 to 5x10-3

ii) H.F. Capacitance a) Standard Values

Contd.

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Page No: 36


Table 14â&#x20AC;&#x201D;Contd. 10pF

upto 300MHz

2x10-4 to 1x10-3 2x10-3 to 5x10-3

20pF

upto 200MHz

2x10-4 to 1x10-3 2x10-3 to 5x10-3

1pF, 10pF, 100pF, 1000pF, (4TP)

upto 10MHz

1x10-3 to 5x10-3

b) Measurement Capability 0-50pF

100kHz-250MHz

5x10-4 to 5x10-3 1x10-3 to 1x10-2

1x10-3 to 5x10-2

0-20pF

250MHz-1000MHz

5x10-3 to 2x10-2 1x10-2 to 3x10-2

1x10-2 to 5x10-2

50-100pF

100kHz-100MHz

5x10-4 to 5x10-3 1x10-3 to 1x10-2

2x10-3 to 5x10-2

100-1000pF

100kHz-30MHz

1x10-3 to 5x10-3 2x10-3 (Only upto 1MHz)

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Page No: 37


TABLE 15 INDUCTANCE (1kHz)

Parameter

Inductance

Standard Values/ Ranges

Frequency

Uncertainty Level-I

Level-II

Level-III

a) Standard Value 2µH,3µH

1kHz

5x10-3

1x10-2

5µH

,,

5x10-3

1x10-2

10µH

,,

1x10-3

5x10-3

1x10-2

100µH

,,

1x10-4

5x10-4

1x10-3

1mH

,,

5x10-5

2x10-4

1x10-3

10mH

,,

1x10-5

1x10-4

5x10-4

100mH

,,

1x10-5

1x10-4

5x10-4

1H

,,

5x10-5

5x10-4

1x10-3

10mH

,,

5x10-4

5x10-3

1x10-2

b) Measurement Capability 1µH-10µH

,,

1x10-2 to 2x10-3

2x10-2 to 5x10-3

5x10-2 to 1x10-2

10µH-100µH

,,

2x10-3 to 5x10-4

5x10-3 to 1x10-3

1x10-2 to 2x10-3

1mH-100H

,,

2x10-4 to 5x10-3

1x10-3 to 1x10-2

1x10-3 to 5x10-2

Note: The same standards can be assigned values at 50 Hz also through Capacitance - Inductance transfer techniques.

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Page No: 38


TABLE 16 L.F. & H.F. INDUCTANCE

Parameter

Standard Values/ Ranges

Frequency

Uncertainty Level-I

(i) L.F.

(a) Standard Values

Inductance

10µH, 100µH, 1mH, 10mH

10kHz

Level-II

Level-III

5x10-4

1x10-3

2x10-3

(b) Measurement Capability

(ii) H.F. Inductance

1µH-10µH

upto 20kHz

5x10-4

1x10-3

1x10-3

10µH-100µH

upto 20kHz

5x10-4

1x10-3

1x10-3

100µH-1mH

upto 10kHz

5x10-4 to 1x10-3 1x10-3

1x10-3

5x10-4 to 2x10-3 To be worked out later

To be worked out later

(a) Standard Values 5nH

upto 1000MHz

8nH

upto 800MHz

10nH

upto 700MHz

25nH

upto 300MHz

50nH

upto 200MHz

0.05µH to 25mH (2T)

50kHz to 250kHz

1x10-3 to 1x10-2

100µH (4TP)

upto 10MHz

2x10-3

100µH (4TP)

upto 1MHz

1x10-3

(b) Measurement Capability 10nH

250MHz-1000MHz

5x10-3 to 2x10-2

1µH-500µH

100kHz-250MHz

-3 1x10-3 to 5x10-3 5x10 (upto 10MHz only)

To be worked out later

100µH-1mH

30kHz-10MHz

-3 2x10-3 to 5x10-3 5x10 to 1x10-2

2x10-3 to 5x10-3

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Page No: 39


TABLE 17 DC RESISTANCE Parameter

Standard Values/Ranges

Uncertainty Level-I

Level-II

Level-III

DC Resistance 100µOhm

2x10-3

2x10-3

1x10-2

1m Ohm

1x10-4

2x10-4

1x10-3

10m Ohm

1x10-5

2x10-5

1x10-4

100m Ohm

1x10-6

5x10-6

5x10-5

1 Ohm

5x10-7

5x10-6

5x10-5

10 Ohm

1x10-6

5x10-6

2x10-5

100 Ohm

2x10-6

1x10-5

5x10-5

1000 Ohm

5x10-6

2x10-5

5x10-5

10000 Ohm

5x10-6

2x10-5

5x10-5

100,000 Ohm

5x10-6

2x10-5

5x10-5

1 mega Ohm

1x10-5

5x10-5

1x10-4

10 mega Ohm

2x10-5

1x10-4

5x10-4

1µ Ohm to 1m Ohm

1x10-1 to 1x10-4

2x10-1 to 5x10-4

5x10-1 to 1x10-3

1m Ohm to 1 Ohm

1x10-4 to 1x10-6

5x10-4 to 2x10-6

1x10-3 to 5x10-5

1 to 103 Ohm

1x10-6 to 2x10-6

2x10-6 to 5x10-6

5x10-5 to 1x10-4

103 to 106 Ohm

2x10-6 to 1x10-5

5x10-6 to 2x10-5

1x10-4 to 2x10-4

106 to 107 Ohm

1x10-5 to 2x10-4

2x10-5 to 5x10-4

2x10-4 to 2x10-4

107 to 1015 Ohm

2x10-4 to 1x10-2

5x10-4 to 5x10-2

__ Contd.

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Page No: 40


Table 17â&#x20AC;&#x201D;Contd. Operating voltages are given below Resistance value

Operating voltage

106 Ohms

1-5V

107 Ohms

1-50V

108 Ohms

1-500V

109 Ohms

1-1000V

1013 Ohms

1-1000V

1014 Ohms

10-1000V

1015 Ohms

100-1000V

Facilities have to be created for measurement of Resistance value between 106-108 Ohm at operating voltage of 500 to 1000 volts.

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Page No: 41


TABLE 18 AC RESISTANCE 1kHz Parameter

Standard Values/Range

Frequency

Uncertainty Level-I

Level-II

Level-III

AC a) Standard Values Resistance 1kHz

1x10-4

5x10-4

1 Ohm, 10 Ohm, 100 Ohm

,,

5x10-6

5x10-5

,,

1000 Ohm

,,

1x10-6

1x10-5

,,

10,000 Ohm

,,

5x10-6

1x10-5

,,

100,000 Ohm

,,

1x10-6

1x10-5

,,

1000,000 Ohm

,,

5x10-5

5x10-4

,,

1m Ohm, 10m Ohm, 100m Ohm

To be worked out later

b) Measurement Capability

Note:

200m Ohm 1 Ohm

,,

5x10-4 to 1x10-5

5x10-3 to 5x10-4 5x10-2 to 1x10-3

1 Ohm-10k Ohm

,,

1x10-5 to 5x10-5

1x10-4 to 5x10-4 1x10-3 to 5x10-3

10k Ohm-1M Ohm

,,

5x10-5 to 5x10-4

5x10-4 to 2x10-3 5x10-3 to 1x10-2

1. The same standards can be assigned values at 50Hz. 2. Time constants of standards can also be determined at 1 kHz.

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Page No: 42


TABLE 19 L.F. & H.F. IMPENDENCE Parameter Standard Values/Ranges

Frequency

Uncertainty Level-I

Level-II

1x10-4 to 5x10-4

2x10-4 to 1x10-3 To be worked out later

Level-III

i) L.F. Impedence (a) Standard Values 1 Ohm, 10 Ohm,

10 kHz

100 Ohm, 1k Ohm, 10k Ohm, 100k Ohm b) Measurement Capability 1 Ohm-100 Ohm

Upto 20 kHz

5x10-4 to 1x10-3

1x10-3

1x10-3

100 Ohm-100k Ohm

,,

5x10-4 to 1x10-3

1x10-3

1x10-3

100 k Ohm-1 M Ohm

,,

1x10-3 to 1x10-2

3x10-2

3x10-2

1M Ohm-10M Ohm

,,

1x10-2 to 3x10-2

5x10-2

5x10-2

0.5m Ohm, 1m Ohm, 1MHz- 300 2m Ohm, 5m Ohm MHz

5x10-4to 2x10-3

To be worked out later

To be worked out later

33.33 Ohm, 41.67 Ohm, 45.45 Ohm, 100 Ohm, (Coaxial discs)

1MHz to 300MHz

1x10-3 to 5x10-3

2x10-3 to 5x10-3 To be worked out later

0.1 Ohm, 1 Ohm, 10 Ohm, 100 Ohm, 1k Ohm, 10k Ohm, 100 Ohm (4TP)

10kHz to 10MHz

1x10-3 to 5x10-3

ii) H.F. Impedence a) Standard Values

(b) Measurement Capability 1 Ohm to 100 Ohm

30kHz1MHz

1x10-3 to 2x10-3

20 Ohm to 10k Ohm 12MHz250MHz

3x10-4 to 5x10-3

2x10-2

20 Ohm to 1k Ohm

2x10-3 to 2x10-2

1x10-3 to 2x10-2

250MHz1000MHz

To be worked out later

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Page No: 43


TABLE 20 MICROWAVE IMPEDENCE & Q VALUES Parameter

Standard

Frequency

Values/ Ranges (i) Microwave Impedence

Uncertainty Level-I

Level-II

Level-III

(a) Standard Values Wave Guide Standard Short (Reflection Coeff. 1.0000)

X and XN Band (5.3 to 12.4 GHz)

0.9993

0.990

To be worked out later

Precision Waveguide Refl. Coeff. 0.0002

0.002

0.01

,,

SWR 1.0004

1.004

1.02

,,

(b) Measurement Capability Refl. Coeff.

SWR

Refl. Coeff.

Ref. Coeff.

0.0476

1.1

0.0020

0.02 to 0.05

,,

0.0909

1.2

0.0025

0.02 to 0.05

,,

0.1304

1.3

0.0027

0.02 to 0.05

,,

0.200

1.5

0.0030

0.02 to 0.05

,,

1 to 18 GHz

0.002 to 0.003 in the SWR range 1.05 to 1.5

0.01 to 0.02 in the SWR range 1.05 to 2.0

0.03 to 0.05 in the SWR range 1.1 to 2.0

2x10-2

5x10-2

10x10-2

COAXIAL Refl. Coeff. 0.002 to 0.2 in the SWR range 1.004 to 1.5 (ii) Q Values

Measurement Capability Q Value upto 600

Upto 300MHz

National Accreditation Board for Testing and Calibration Laboratories Doc. No: NABL 121 Issue No: 04

Specific Criteria for Calibration Laboratories in Electro-Technical Discipline Issue Date: 07. 03.2007 Amend No: 00 Amend Date: --

Page No: 44


TABLE 21 TIME AND FREQUENCY/ TIME INTERVAL Parameter

(i) L.F. Frequency

Standard Values/ Ranges

Uncertainty Level-I

Level-II

Level-III

100kHz, 1MHz, 5 MHz & 10MHz (Cesium Std)

1x10-12

__

__

1MHz

2x10-11

5x10-11

1x10-8

100 MHz

2x10-11

5x10-11

1x10-8

1Hz

2x10-11

5x10-11

1x10-8

10 Hz

2x10-11

5x10-11

1x10-8

100 Hz

2x10-11

5x10-11

1x10-8

1 kHz

2x10-11

5x10-11

1x10-8

10 kHz

2x10-11

5x10-11

1x10-8

100 kHz

2x10-11

5x10-11

1x10-8

(a) Standard Values

(b) Measurement Capability

(ii) H.F. Frequency

1MHz to 30kHz (by counter technique) 100kHz, 1MHz, 5MHz 10MHz

2x10-11

1x10-10

1x10-8

±1 Count

±1 Count

±1 Count

(by phase Meas. Tech)

5x10-12

__

__

(a)Standard Values 30kHz-1GHz

2x10-11

5x10-11

To be worked out later

30kHz-1GHz

2x10-11

5x10-11

5x10-10

MW Stds

±1 Count

±1 Count

±1 Count

5x10-11

5x10-10

To be worked out later

(b) Measurement Capability

(iii) Microwave Frequency

(a) Standard Value 1GHz-18GHz (1KHz steps from 1 to 12 GHz)

Contd.

National Accreditation Board for Testing and Calibration Laboratories Doc. No: NABL 121 Issue No: 04

Specific Criteria for Calibration Laboratories in Electro-Technical Discipline Issue Date: 07. 03.2007 Amend No: 00 Amend Date: --

Page No: 45


Table 21â&#x20AC;&#x201D;Contd. (b) Measurement Capability 1GHz-18GHz (iv) Time Instant (Epoch)

5x10-11

5x10-10

To be worked out later

100 nanosecond

10 microsecond

1 milli-second

100 nanosecond

20 microsecond

1 milli-second

(a) Standard Values 1pps (pulse per second) (b) Measurement Capability

National Accreditation Board for Testing and Calibration Laboratories Doc. No: NABL 121 Issue No: 04

Specific Criteria for Calibration Laboratories in Electro-Technical Discipline Issue Date: 07. 03.2007 Amend No: 00 Amend Date: --

Page No: 46


TABLE 22 MAGNETIC MEASUREMENTS Parameter

Field Strength (Standard Magnets)

Standard Values/ Ranges

Frequency

Uncertainty Level-I

Level-II

Level-III

0.01T, 0.05T, 0.02T

2.5x10-3

__

__

0.1T, 0.5T, 1T

1x10-2

__

__

1x10-2

__

__

5x10-3-1x10-2

__

__

5x10-3-1x10-3

__

__

(a) Standard Values Transverse:

Coaxial : 0.03T, 0.05T (b) Measurement Capability Field strength Standard Magnets Gaussmeter Calibration

10-3T-1T

Area-turns (Search coils)

1cm2-40cm2

30Hz

Flux Fluxmeter (Calibration)

10-5wb-10-2wb

5x10-3-1x10-2

National Accreditation Board for Testing and Calibration Laboratories Doc. No: NABL 121 Issue No: 04

Specific Criteria for Calibration Laboratories in Electro-Technical Discipline Issue Date: 07. 03.2007 Amend No: 00 Amend Date: --

Page No: 47


Technical Committee for Electro-Technical Measurement 1.

Dr. P.C. Kothari (Chairman) Head, Electrical & Electronics Standards NPL, New Delhi

2.

Mrs. Kowsalya Varadan Retired – Coordinator STQC Calibration Services, Bangalore

3.

Mr. S.K. Kimothi Retired – Director ERTL(N), New Delhi

4.

Mr. R.K. Vapta Retired – Senior Manager BHEL, Bhopal

5.

Dr. V.N. Ojha Scientist ‘F’, Electrical & Electronics Standards NPL, New Delhi

6.

Mr. B.S. Kumar Director ETDC, Bangalore

7.

Mr. B.M. Vyas Manager, Yadav Measurements Pvt. Ltd. Udaipur

8.

Dr. Sulbha M. Gupta Director, NABL

9.

Mr. Anil Relia Quality Manager, NABL

10.

Dr. Rubeena Saleem Accreditation Officer, NABL

11.

Mr. Bibin Philip Trainee Accreditation Officer, NABL

12.

Mr. Jaydip Kanango (Convener) Accreditation Officer, NABL

National Accreditation Board for Testing and Calibration Laboratories Doc. No: NABL 121 Issue No: 04

Specific Criteria for Calibration Laboratories in Electro-Technical Discipline Issue Date: 07. 03.2007 Amend No: 00 Amend Date: --

Page No: 48


National Accreditation Board for Testing and Calibration Laboratories 3rd Floor, NISCAIR 14, Satsang Vihar Marg New Mehrauli Road New Delhi – 110 067 Tel.: 91-11 26529718 – 20, 26526864 Fax: 91-11 26529716 Website: www.nabl-india.org


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