hoklas supplementary criteria no. 2

7/27/2019 HOKLAS Supplementary Criteria No. 2

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HOKLAS Supplementary Criteria No. 2

All Test Categories Equipment Calibration and Verification

1 Introduction

1.1 The HOKLAS criteria on calibration and traceability for non-medical laboratories

stated in Sections 5.5 and 5.6 of HOKLAS 003 and on calibration for medical

laboratories stated in Section 5.3 of HOKLAS 015 apply to all laboratory

equipment. All equipment used for tests and/or calibrations, including equipment

for subsidiary measurement having a significant effect on the accuracy or validity

of the result of the test, calibration or sampling shall be calibrated. This document

sets out the requirements and recommendations for calibration requirements and

calibration intervals for selected types of equipment in Appendices C to I as

follows :-

Appendix C provides general calibration requirements for common equipment

applicable to all Test Categories. Where specific requirements are

given in Appendices D, E, F, G, H and I for specific test areas of

testing or measurement, those requirements should take precedence.

Appendix D covers calibration of standards of measurement and instrumentation

applicable to electrical and electronic testing.

Appendix E covers equipment relevant to engineering metrology.

Appendix F covers calibration using comparative techniques, of analytical

instruments used predominantly in chemical testing laboratories.

Appendix G covers equipment and calibration requirements applicable to

construction materials testing.

Appendix H covers calibration requirements of toy testing equipment.

Appendix I covers calibration requirements for electrical and electronic product

testing

Appendix J covers calibration, performance check and preventive maintenance

requirements for common medical testing equipment

For equipment not included in the above appendices and equipment peculiar to

particular test methods, this document explains how the calibration requirements

and calibration intervals should be determined.

1.2 General recommendations for determining calibration programmes and operation ofthe calibration systems are given in Section 5.


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1.3 This document also explains the available sources of calibration.

2 Calibration Requirements

2.1 Parameters of equipment to be calibrated

Where the values of parameters are specified in the relevant standard specifications,

they shall be calibrated. Where tolerances are given, the measured values should

be checked against them. Where tolerances are not specified, the requirements

given in section 3 of this document should be followed.

2.2 Calibration procedures and intervals

Where the standard specifications state the calibration procedures and the

calibration intervals, these shall be followed.

Where they are not specified, the laboratory should determine appropriate

calibration procedures and intervals after considering all relevant factors. For

dimensions and weights, a period of six months is generally acceptable. Section 5

gives more detailed recommendations for determining calibration programmes.

2.3 Unspecified parameters

For parameters which may affect equipment operation but are not specified, theeffects of change (for example, due to wear) should be assessed during regular

equipment inspection and functional checks. Where necessary, specific

procedures should be derived to assess the effects. It is a good practice to record

initial values as a reference for later comparison.

2.4 All equipment calibrations should be recorded.

3 Parameters With No Stated Tolerance

3.1 Where the tolerances of specified parameters are not given, the laboratory shoulddetermine whether the parameters are critical and how critical they are.

3.2 For critical parameters, justification for adopting particular tolerances should be

documented and HOKLAS will examine them during assessments.

For dimensional and angular measurements, a laboratory may select from

ISO 2768-1: 1989 a suitable tolerance class. As a rough guide, the medium

tolerance class in Table 1 and Table 3, for dimensional and angular measurements

respectively, is acceptable for most equipment.

3.3 In the case of non-critical dimensions, HOKLAS will normally accept that theimplied tolerance is that the next significant figure should not result in rounding to


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a value other than the stated dimension. For example :-

stated parameter implied tolerance6 mm

3.2 mm

1.0 kg

1.000 kg

6 mm 0.5 mm

3.2 mm 0.05 mm

1.0 kg 0.05 kg

1.000 kg 0.0005 kg

4 Source of Calibration

4.1 If calibration of equipment is required, there are two choices :-(a) internal calibration; or

(b) external calibration.

4.2 HOKLAS encourages laboratories to develop their internal calibration capability

and to calibrate their own equipment. A calibration can be performed internally if

the laboratory has the necessary reference standards and materials and the

laboratory staff are competent to perform the calibration. Internal calibration

procedures should be documented.

4.3 Calibrations which require equipment not available to the laboratory or demand

specialist techniques outside the capabilities and experience of the laboratory staff

(see HOKLAS 003, Clause 5.6.H (d)) should be performed externally.

4.4 External calibration shall be performed by a competent calibration body defined in

HOKLAS 003. A laboratory should take the following approaches to find a

competent calibration body :-

(a) Check the HOKLAS Directory of Accredited Laboratories (the up-to-date

scope of accreditation can be found from the HOKLAS internet website at

http://www.itc.gov.hk/en/quality/hkas/hoklas/directory/directory.htm) to see if

a laboratory is accredited for the calibration.

(b) Contact HKSAR Standards and Calibration Laboratory to see if they can

perform the calibration.

(c) Contact HOKLAS calibration Mutual Recognition Agreement (MRA) partners

to see if there is a laboratory which can perform the calibration accredited by

them.

(d) Contact nominated primary standard institutions listed in HOKLAS internet

website at

http://www.itc.gov.hk/en/doc/quality/hkas/supplementary%20criteria/SC2-Ap

pendixB.pdfto see if they can perform the calibration.

HKAS Executive should be consulted if no suitable calibration laboratory could be

found using the above approaches.


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5 Calibration Programme and Operation of Calibration System

5.1 Determination of calibration programmes

The calibration programme applicable to an individual laboratory should be

determined by the laboratory management with due regard to the following factors:

(a) Which items of equipment can be calibrated internally and the interval

between recalibrations.

(b) Which items of equipment need to be calibrated by a competent calibration

body (refer to HOKLAS 003, Section 5.6.H) and the interval betweenrecalibrations.

(c) For each item of equipment, what ranges and cardinal points should be

calibrated, the calibration uncertainty requirements and the conditions under

which calibrations should be performed. These should be determined based

on the requirements of the tests or measurements for which that item of

equipment is being used. Laboratories should document such requirements

and provide them to external calibration laboratories when soliciting

calibration services.

(d) When determining the recalibration intervals, the following should be takeninto consideration:

- HOKLAS recommendations;

- manufacturer recommendations;

- frequency of use;

- equipment condition;

- equipment stability and previous calibration and maintenance history;

- the accuracy and precision requirements of the tests for which that item of

equipment is being used (Where the standard specification states the

calibration intervals, these should be followed);

- the likely influence of the working environment, e.g. corrosion, dust,

vibration, frequent transportation and rough handling;- the availability and reliability of in-service verifications and functional

checks, e.g. the availability of equipment, reference standards or materials

and expertise for conducting in-service verifications and functional

checks (Where in-service checks are not carried out between calibrations,

the calibration interval must be shortened).

For new test instruments, it is advisable to specify a shorter recalibration interval.

When successive calibration results demonstrate that the characteristic of an

instrument is stable, its recalibration interval may be extended. To facilitate the

determination of calibration intervals, laboratories are recommended to plot curves

of instrument drifts against time.


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For more information for determination of equipment recalibration intervals, please

refer to OIML International Document No. 10.

The calibration programme should be documented and reviewed regularly.

5.2 Designated officers of the laboratory shall be assigned the responsibility for the

calibration of equipment and the management of reference materials. Laboratories

should operate a system to alert staff of calibration or verification due dates for all

items of equipment and reference materials. There should also be a mechanism to

ensure that equipment or reference materials due for recalibrations can be released

promptly from routine operation.

5.3 Equipment overdue for calibration should generally be taken out of serviceimmediately. Under exceptional circumstances, the laboratory management may

consider temporarily extending the equipment calibration validity for a short period

of time. Extension of calibration validity should only be allowed when the

equipment calibration history shows that the drift of the instrument is acceptable

and in-service verifications and functional checks demonstrate that the instrument

is functioning normally in every aspect. Nevertheless, the measurement

uncertainty of the instrument may have to be increased according to the drift trend.

5.4 Calibrations should be conducted according to the calibration requirements as

explained in 5.1(c). Where an external calibration laboratory or a different section

of the same laboratory is contracted to perform the calibration, they should beclearly and unambiguously informed of the calibration requirements. These

requirements would generally include the calibration range, the cardinal points, the

required calibration uncertainties and the conditions under which calibrations are to

be performed. It is recommended that a copy of the documented calibration

requirements be provided to the calibration laboratory accompanying the

instrument to be calibrated.

5.5 After an instrument is calibrated, the laboratory should assign a staff member to

check whether the characteristics of the instrument as shown by the calibration

results are still within the acceptable tolerance range. Out of tolerance instruments

should be repaired and recalibrated before use. Alternatively, such instrumentsmay be downgraded for less demanding purposes provided that they are

appropriately labelled.

5.6 The suitability of the calibration programme and the adequacy of the calibration

system will be examined and discussed during assessments.


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6. Address

6.1 Addresses of the various HOKLAS calibration MRA partners and their nominatedprimary standards institutions can be found from the HKAS website at

(http://www.itc.gov.hk/en/quality/hkas/hoklas/agreement.htm).

HKAS Executive

Issue Date: 30 November 2005

Implementation Date: 1 June 2006


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APPENDIX A

ACCREDITATION BODIES WHICH HAVE MUTUAL RECOGNITION

AGREEMENTS WITH HOKLAS ON CALIBRATION

Please refer to the website http://www.itc.gov.hk/en/quality/hkas/hoklas/agreement.htm for

up-to-date information.


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APPENDIX B

ADDRESSES OF NOMINATED PRIMARY STANDARDS INSTITUTIONS

Please refer to the website

http://www.itc.gov.hk/en/doc/quality/hkas/supplementary%20criteria/SC2-AppendixB.pdf

for up-to-date information.


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Items marked * in the table are those which can be carried out by the staff of a laboratory if it is suitably

equipped and the staff is competent to perform such calibrations.

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APPENDIX C

CALIBRATION AND PERFORMANCE CHECK REQUIREMENTS - GENERAL

This Appendix lists the current recommended calibration requirements for specific items of

equipment. These are general recommendations applicable to all Test Categories for which

a laboratory is accredited.

Where specific requirements are given in Appendices D, E, F, G, H, I and J for specific areas

of testing or measurement, those requirements should take precedence.

Type of equipment

Recommended maximum period

between successive calibrations

Calibration procedure or

guidance documents andequipment requirements

ACCELEROMETERS

(i) Reference(ii) Working

Five years (check annually)Two years

ACOUSTIC CALIBRATORS One year

Intercompare every six months

ANEMOMETERS Two years

AUTOCLAVES Initial (on-commissioning) and after

significant repair*Monthly check*

Each use*

Each month*

Every 6 months*

Temperature measurement at

strategic sitesEffectiveness of sterilisation (withbiological indicators)Pressure

Timer accuracy

Heating profiles of typical loads

Effectiveness of sterilization bysuitable means such as chemical

indicators, temperature and timerecord

Effectiveness of sterilisation (withbiological indicators)

Temperature controller calibrationTimer accuracy


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Type of equipmentRecommended maximum period




BALANCES and SCALES Three years

orThree years*

Both alternative accompanied by

(i) Each weighing*,(ii) Daily*, and

(iii) Six months*

By a competent calibration bodyas defined in clause 5.6.H (d) ofHOKLAS 003

Calibrate using calibrated masses.Refer The Calibration of Weightsand Balances published by

CSIRO

(i) zero check(ii) one-point check using a

known mass.(iii) repeatability check.

BAND PASS FILTER SETS Two years

BAROMETERS (Fortin) Five years (cleanness of mercury,vacuum space and one-point)

BEAT FREQUENCY

OSCILLATORS

One year

CALIBRATION BATHS

AND FURNACES

Initial complete temperature survey.Check temperature distribution at

one temperature every five yearsCALIBRATION UNIT FOR

AUDIO-FREQUENCYVOLTMETERS

Check annually. Calibrate the

ac/dc transfer error of thermalelement and multiplier every fiveyears

CENTRIFUGES One year (where operating speedspecified)*

Tachometer (mechanicalstroboscope or light cell type)

Temperature calibration (where

applicable)

DENSITY BOTTLES,

PYCNOMETERS

One year* AS 2378; BS 733 App A; IP 190

DENSITY METERS Initial and whenever testtemperature is changed, thereafter*One week checks with air anddouble distilled water*

ASTM D4052

DIAL GAUGES Two years or less, depending onuse*

AS 2103; BS 907


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DIES AND CUTTERSFor preparation of test specimenssuch as dumb-bell rubber specimens

Frequent examination for damage.Full dimensional check whenever

resharpened

EXTENSOMETERS

(a) Level and mirror types

(b) Micrometer screw types

(c) Dial indicator types

(d) Recording types with electricaloutput

Five years

Five years

Two years

Two years

AS 1545 Grade D (for proof stresstests load-extension curves for

pre-stressing wires)

AS 1545 Grade B (for modulus ofelasticity determinations)(BS EN 10002-4)

FLOWMETERS

(a) Rotameters (Reference)High flow,i.e. greater than 1 L/minLow flow,i.e. less than 1 L/min

Two years*

Two years*

ASTMD3195

Soap bubble flowmeter

(b) Rotameters (Working) Each time on use* Soap bubble flowmeter

(c) Orifice plates,Venturi nozzles

(d) Wet test meters

(e) Anemometers

(f) Pitot tubes

Initial

Six months*

One year*

Two years

Initial*On use*

BS 1042: Section 1.2: 1989ISO 5167-1: 1991ISO 9300: 1990

Visual inspect tip and other parts for

damage, wear or contamination

ASTM D1071

Check dimensional compliance withBS 1402 Sec. 2.1 Annex A

Inspect tip for damage, blockage,etc., as requested by BS 1042 Sec.2.1


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FORCE TESTING MACHINES(tension, compression, universal)

TYPE 1 - Mechanical ForceMeasuring Systems

(a) Dead weight(b) Knife edge, lever and

steelyard(c) Pendulum dynamometer

(d) Elastic dynamometer(e.g. spring, ring with dialgauge)

Note: Chain testing and similarmachines in frequent use

TYPE 2 - Hydraulic or PneumaticForce MeasuringSystems

(a) Mechanical systemincorporating a pneumatic or ahydraulic link, e.g.,

proportional cylinder(b) Bourdon tube or diaphragm

pressure gauge as forceindicator

Five yearsFive years

Two years

Two years

One year

Two years

Six months

AS 2193BS 1610: Part 1BS 1610: Part 3

BS 5214 (rubbers and plastics only)EN 10002-2

(c) Type (b) fitted also with amaster gauge which can be

disconnected during normaltesting

(d) Bourdon tube or diaphragmgauge used only as a nulldetector for a mechanicalsystem

(e) Bourdon tube with electrical

transducer

TYPE 3 - Electrical ForceMeasuring Systems

One year (plus frequent checks byuser of working gauge against

master gauge)

Two years

Two years

Two years

FREQUENCY ANALYSERS(Acoustic Measurements) Five years

FREQUENCY RESPONSETRACERS(Acoustic Measurements) Check annually

FREQUENCY STANDARDS(a) For acoustic measurements

(b) For time and frequencymeasurements

Two years

One year


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FURNACESFor use at specified temperatures One Year* BS 4309, AS 2853

GAS STERILISERS Effectiveness of sterilisation.(Regular checks with biologicalindicators at representativelocations in typical loads)*

GAUGE BLOCKS

(a) Used as reference standards

(b) Used as working equipment

Four years

Two years*

BS 4311: Parts 1, 2 & 3

HARDNESS TESTERS FOR

METALS

(a) Brinell, Vickers and Rockwellmachines including portable

testers(b) Portable Brinell microscopes

(c) Diamond indenters

(See Note 1 at end of this

Appendix)

One year (partial)Three years (complete)

One year (with calibrated graticule)

One year (inspection) *

Routine check by user each day fortester in use.

AS 1816 (Brinell)AS 1817 (Vickers)

AS 1815 (Rockwell)

HARDNESS TESTERS FOR

PLASTICS AND EBONITE

(a) Dead weight testers forplastics

(b) Meters (durometer) forrubber

Three years

Frequent checks by user usingreference hardness blocks

ISO 48 : 1994Method N, H, L & M

ISO 7619 : 1997

HYDROMETERS

(a) Reference(b) Working - glass

- metal

InitialOne year against reference or withfreshly prepared solutions of known

density*Six months*

AS 2026; IP 160; ASTM E126

ISO R649

HYGROMETERS

(a) with electric impedance sensor(b) with chilled mirror sensor

Two yearsSix years

IMPACT TESTING MACHINES

(Pendulum type)

(a) Charpy, Izod and Universaltesters for metals

(b) Charpy and Izod testers forplastics

(c) Notching tools

AS 1544.4; BS 131

AS 1146.3

Check regularly and whenever

reground


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IMPEDANCE MATCHINGNETWORKS

(Acoustics measurements)

5 years.Check annually

INCUBATORS and CONSTANT

TEMPERATURE CHAMBER

for BIOCHEMICAL OXYGEN

DEMAND

Every six months against referencethermometer*Constant daily monitoring oftemperature variation duringtesting*

Maximum/minimum thermometersshould also be used to ensuretemperature stays within rangeduring testing.

LENGTH MEASURING

DEVICES

(a) Reference steel rules(b) Working rules and vernier

callipers

InitialMonthly or less depending on use*(zero and general condition)

For making measurements whichwill not affect test results, rules andvernier callipers from reputablemanufacturers may be used without

calibration

LINEAR VARIABLE

DIFFERENTIAL

TRANSDUCERS (LVDTS)

Daily or whenever used*

Two years* (complete calibration)

Check against length standard such

as a micrometer

MANOMETERS(a) Reference

(b) Working

Ten years

Three years*

Check fluid every three years

Check against reference

MICROMETERS One month (zero, one point andcondition of anvils)*

Against gauge blocks. See alsoAS 2102; BS 870 and BS 959

MICROPHONES

(LS1P or LS2P)

Check every three months.

Calibrate annually or when 1 dBchange is detected, whichever is thesooner.

MICROPHONE AMPLIFIERS Check response annually

NEUTRAL DENSITY FILTERS Ten years


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OVENS (Temperature of load spaceshould be monitored by appropriatetemperature sensor throughout use)

(a) Ageing

(b) Drying

(c) Vacuum

Five years (temperature variation,recovery time, rate of ventilation)

Three years (temperature variationand evaporation rate in working

space)*

Five years (temperature variation,evaporation rate, pressure inworking space)*

BS 2648, AS 2853

AS 2853 and AS 1289.0

PENETRATION CONES ANDNEEDLES

Five years ASTM D217; IP 50; ASTM D5;ASTM D1321. Visually inspectneedle tips prior to use.

PHOTOCELLS Check linearity of response everysix months. Check spectralresponse annually with colourfilters; calibrate every five years orwhen apparent filter transmittances

change significantly.

PHOTOMETRIC TEST PLATEFor luminance measurements

Five years

PRESSURE AND VACUUM

GAUGES

(a) Test gauges for calibration of

working gauges(b) Working gauges subject to

shock loading(c) Working gauges not subject

to shock loading

One year

Six months or less depending onuse*One year*

AS 1349; BS 1780: Part 2

PRESSURE GAUGE TESTERS

(a) Dead weight(b) Manometers

Ten yearsTen years


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PROVING DEVICES FORCALIBRATION OF FORCE

TESTING MACHINES

TYPE 1 - Elastic devices(a) Dial gauge for deflection(b) Micrometer screw for

deflection measurement(mechanical or optical

indication)(c) Electrical deflection

measurement

TYPE 2 - Proving levers

TYPE 3 - Weights

Two yearsFive years

Two years

Five years

Ten years

PSYCHROMETERS, ASSMANN

HYGROMETERS and SLING

TYPE PSYCHROMETERS

Ten years (complete)Six months (compare thermometersat room temperature with wickdry)*

AS 2001.1 Appendix C

PYRHELIOMETERS Five years

PYROMETERS

(a) Reference(b) Working

Three yearsSix months*

BS 1041: Part 5

QUARTZ CONTROL PLATES Ten years

RADIOMETERS Calibrate after one hundred tests

REFERENCE BALLASTS Five years

REFERENCE GLASS FILTERS

(a) Spectrophotometry

(b) Colorimetry(d) Luminous transmittance

Five years

Five yearsFive years

REFRACTIVE INDEX

STANDARDS

(a) Liquid(b) Solid

Five years10 measurements or 10 years,whichever is the sooner.


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SIEVES Six months Sieves should comply with theGrade B requirements of AS 1152unless the test method specifies

otherwise.Sieves supplied with a record cardas prescribed in BS 410 areaccepted as complying with

AS 1152 requirements. (SeeAppendix B, AS 1152).

Laboratories requiring more thanone set of sieves should have areference set meeting the aboverequirements and one or moreworking sets.Working sieves should be given a

performance check against thereference set using material typicalof the samples normally subjectedto sieve analysis in the laboratory.

SOUND LEVEL METERS One year

Check every three months*

SOUND POWER SOURCES Five years

STANDARD LAMPSLuminous flux, luminous intensity,illuminance, spectral radiance,spectral irradiance

Five years or after each 20-hourperiod of burning

STOPWATCHES(timers)

Three months* Comparisons against time andfrequency broadcasts fromshort-wave stations such as JJY

(Japan) at 2.5, 5, 8, 10, and 15 MHzfor at least ten minutes.Comparisons against timing signalsbroadcasted by Radio TelevisionHong Kong is also acceptable.

TACHOMETERS

(a) Reference(b) Working

Five yearsOne year*

BS 3403

TAPE RECORDERS(for Acoustic Measurements)

Five yearsCheck annually*


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THERMOHYGROGRAPHS One week against calibratedhygrometer or psychrometer whenused to determine actual RH and

temperature*One month against calibratedhygrometer or psychrometer whenused only as indicator of RH and

temperature variations*

AS 2001.1 Appendices C & D

THERMOCOUPLES

(a) Reference(Preferably noble metal type)

Three years (complete)Six months (one-point)*

BS 1041: Part 4; BS EN 60584-1;ASTM E220; ASTM E230

(b) Working In general, same as for referencethermocouples. Working

thermocouples subject to frequentstress and strain should be checkedmore frequently depending on theirphysical condition and theinhomogeneity effect.

Thermocouples used in hightemperatures have definite life

spans that must be taken intoconsideration.

THERMOMETERS

(a) Liquid-in-glass

(1) Reference

(2) Working

(b) Electronic

(c) Platinum resistance

(d) A.C. resistance bridge

Ten years (complete)Six months (zero-point)*Initial check at sufficient points tocover the expected working rangefollowed by single-point checks at

six-monthly intervals*

Three years (complete)Six months (one-point)*Ten years (complete)Check ice-point before use or at

least every 6 monthsFive years (resistance ratios)

NML Technical Papers No. 1 and 5;ASTM E77Check against a calibrated referencethermometer; NML TechnicalPapers No. 1 and 5;

IANZ Technical Guide No. 3NML Technical Paper No. 5

THICKNESS GAUGES(for compressible materials) Two years Dial gauge, dimensions and

pressure of plunger base

VELOCITY TRANSDUCERS Calibrate sensitivity and frequencyresponse every two years.

Check every six months*


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VISCOMETERS

(a) U-tube

(1) Reference(2) Working

Ten years (against standard oils) *Two years (using quality oil againstreference tubes or standard oils)*

ASTM D2162; BS 4708ASTM D2162/D445; IP 71

(b) Others

(1) Brookfield

(2) Ferranti(3) Zahn

Two years (using standard oils) plusone-months checks using

manufacturers oils, covering thenormal range of operation of theinstrument*Three months (using standard oils)*One year (using standard oils)*

ASTM D2556

VOLUMETRIC APPARATUS

(a) Volumetric glassware(pipettes, burettes, volumetricflasks, distillation receivers)when used for tests where the

error contribution fromglassware to the overallaccuracy required is significantor where methods specifyglassware meeting nominatedstandards.

(b) Specialised glassware (watertraps, sulphonation flasks,centrifuge tubes, etc.)

(c) Piston operated volumetricapparatus (micropipettes)

Initial (on commissioning)*

Initial*

Initial*3 months*

AS 2162.1; BS 1797; BS 6696;ISO 4787

AS 2162.1; BS 1797

Check volume delivered. Foradjustable devices check volume

delivered at several settings (refer toAS 2162.2, ISO 8655 Parts 1-6)


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WEIGHTS(a) Reference weights of integral

construction, stainless steel or

nickel chromium alloy

Five years initial;Ten years subsequent

ASTM E617

(b) Working weights, Class B,stainless steel or nickel

chromium alloy

Three years* ASTM E617

(c) Working weights, Class B, notstainless steel or nickelchromium alloy

One year*

Note: weights used for routine calibration of balance are considered working weights.

NOTE 1 - ADDITIONAL REQUIREMENTS FOR HARDNESS TESTING ON METALS

(1) Laboratories shall carry out a performance check test at the start of each day on which

hardness tests are to be performed.

(2) Hardness blocks with assigned values from established block manufacturers (such as Vickers,

Avery, Wilson and Yamamoto) may be used.

(3) The check should be carried out using forces close to those involved in the tests to be

conducted on that day. So far as is practicable, the hardness values should also match those

involved on that day. Laboratories shall have an adequate range of blocks to cover the range

of hardness and the forces normally encountered.

(4) Laboratories are encouraged to have an accredited metrology laboratory do a limited

calibration on their blocks at the forces applied in the laboratory but which are not included in

their original calibration, but it is recognised that in practice there will be occasions when a

laboratory has to use a force for which the block has not been calibrated.

(5) For Vickers and Rockwell hardness tests, laboratories may use uncalibrated indenters,

provided those indenters have been checked by performance tests on hardness blocks withassigned values and by inspection at a magnification of a least 50x.


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APPENDIX D

CALIBRATION REQUIREMENTS FOR ELECTRICAL AND ELECTRONIC

MEASURING EQUIPMENT

The following table sets out recommended maximum periods between successive calibrations

for a number of reference standards and measuring instruments. It must be stressed that

these periods are generally considered to be the maximum appropriate in each case providing

that the other criteria as specified below are met :-

that the equipment is of good quality and of proven adequate stability, and

that the laboratory has both the equipment capability and staff expertise to performadequate internal checks, and

that if any suspicion or indication of overloading or mishandling arises, the

equipment will be checked immediately and thereafter at fairly frequent intervals

until it can be shown that stability has not been impaired.

Where the above criteria cannot be met, appropriately shorter intervals may be specified.

The nominal maximum period may be extended in special cases where the laboratory has

demonstrated exceptional self-checking capability or successful participation in proficiency

testing programmes involving portable standards.



ATTENUATORS Three years (frequency response)

BRIDGES Five years (full calibration)Check against laboratory standard annually

CAPACITORS Five yearsIntercompare annually

DIGITAL METERS One year

INDUCTORS Five yearsIntercompare annually

INSTRUMENTS, INDICATING

AND RECORDING

Five years

Intercompare every six months, or more frequently as required

INSTRUMENT and RATIO

TRANSFORMERS

Ten years

INSTRUMENT TRANSFORMER TEST

SETS

Five years (full calibration)


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POTENTIOMETERS Five years

RESISTORS Five yearsIntercompare annually

RF POWER MEASURING EQUIPMENT Three years

SIGNAL GENERATORS One year (frequency accuracy, output level and attenuatorratio)

STANDARD CELLS Two yearsIntercompare at least six-monthly

TIME, TIME INTERVAL and

FREQUENCY STANDARDS

Calibration intervals dependent on equipment frequency, typeand accuracy required. This may be as frequently as daily ifthe highest possible performance is required.

TRANSFER STANDARDS, AC-DC Eight yearsIntercompare immediately after calibration and then every four

years

VOLTAGE CALIBRATING

TRANSFORMERS

Ten years

VOLT RATIO BOXES Five yearsIntercompare annually

WATTHOUR METERS

(ELECTRO-MECHANICAL)

Two yearsIntercompare every three months

WATTMETERS AND WATTHOUR

METERS (ELECTRONIC)

One year with regular intercomparisons - interval to be basedon history of performance


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APPENDIX E

CALIBRATION REQUIREMENTS FOR ENGINEERING METROLOGY

INSTRUMENTS

The following table sets out the maximum recommended period between initial calibration

and the first recalibration, and the maximum period between subsequent recalibrations

provided that the first two calibrations indicate that the item is stable. The recalibration

interval for each specific item will be examined during the assessments of the laboratory.

Account will be taken of factors such as general condition and frequency of use.

Item

Maximum period between

initial calibration and thefirst recalibration (years)


subsequent recalibrations(years)

ANGLE GAUGES(a) reference(b) working

42

84

DIVIDING HEADS 5 8

GAUGE BLOCKS(a) reference

(b) working

4

2

8

4

HEIGHT SETTING MICROMETERS AND

RISER BLOCKS

3 3

LENGTH BARS(a) reference(b) working

42

84

LEVELS (precision) 4 4

LINEAR (precision) 5 10

OPTICAL FLATS 3 6

OPTICAL PARALLELS 3 6

PRECISION POLYGONS 5 10

ROLLERS AND BALLS 4 8

ROUNDNESS STANDARDS 5 10

ROUGHNESS STANDARDS 4 4

SCREW CHECK PLUGS FOR RING

GAUGES

3 6


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Item


initial calibration and thefirst recalibration (years)


subsequent recalibrations(years)

SCREW PITCH REFERENCE STANDARDS

3 6

SETTING CYLINDERS 3 6

SETTING RINGS 3 6

SQUARES

trysquares block squares

24

58

SURFACE PLATES cast iron granite

34

58

THREAD MEASUREMENT CYLINDERS 4 6

THREAD MEASUREMENT VEE PIECES 2 5


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APPENDIX F

CALIBRATION AND PERFORMANCE CHECKS REQUIREMENTS FOR

ANALYTICAL INSTRUMENTS FOR CHEMICAL TESTING

1. Introduction

1.1 Analytical instruments used in chemical testing are frequently calibrated by comparative

techniques, that is, the response signals of the instrument are related to the

concentrations or amounts of the analyte through the use of reference materials. Many

types of analytical instruments require calibration before use and calibration thus forms

an integral part of the analytical procedures.

1.2 Correct use combined with proper calibration may not necessarily ensure an instrument

is performing adequately. Where appropriate, periodic checks on the performance

characteristics should be carried out. These instrument performance characteristics

include, for example, response, stability and linearity of sources, sensors and detectors,

the separation efficiency of chromatographic systems, the alignment and wavelength

accuracy of spectrometers, etc. The purpose of these checks is to verify the performance

of the instruments against the specified requirements of the tests for which the

instruments are being used.

1.3 This Appendix sets out specific calibration and performance checks requirements for

analytical instruments used for chemical testing. Laboratories should refer to Sections

5.5 and 5.6 of HOKLAS 003 and other sections of this supplementary criteria for

general requirements on calibration of equipment. Equipment in common with other

testing fields are listed in Appendix C.

1.4 The laboratory should document and implement a calibration and/or performance checks

programme appropriate to the circumstances involved. The performance characteristics

to be checked as well as the acceptance criteria for and frequency of checks should be

based on the requirements of the tests concerned taking into consideration the

recommendations given in Table 1 and factors given in clause 3.1 of this appendix. It is

the responsibility of the laboratory to demonstrate that the programme is suitable for thecircumstances involved.

1.5 Since standard practice for operation of analytical instruments are generally unavailable

or highly specific to a particular application, the laboratory shall document its practice

for use of analytical instruments. This should include, as appropriate, a description of the

operation of the instrument, procedures and acceptance criteria for calibration and

performance checks, frequency of use and nature of quality control samples, and

maintenance procedures.

1.6 Calibration and performance checks can normally be conducted by the staff of a

laboratory. The laboratory should, however, ensure that sufficient reference materialsand required equipment are available, and the persons involved should possess the


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required skills, experience and training.

1.7 The laboratory shall ensure that all calibration and/or verification of analyticalinstruments are traceable to national or international standards of measurement or to

reference materials produced by competent producers (see HOKLAS Supplementary

Criteria No. 1).

2. Calibration

2.1 Normally, either the manufacturers of the instruments and/or the test standards

themselves specify the calibration procedures and requirements. These instructions

should be followed, if available. In some cases, check samples are used during analyses

to confirm the validity of the calibration. Re-calibration of instruments should be carriedout when such checking procedure indicates that previous calibrations are no longer

valid.

2.2 Acceptance criteria for calibration and criteria for re-calibration should be based on the

test standards, if available, or determined by the requirements of the tests concerned.

These criteria shall be documented and strictly adhered to.

2.3 Acceptance criteria for calibration should include a criterion for the acceptability of the

calibration function and, when applicable, a criterion for the performance of instruments.

An example of the former criterion is correlation coefficient of a linear calibration graph

whilst the latter may include, for example, the slope of the calibration graph or themagnitude of the detector response at a specific level of analyte. The latter instrument

performance check (IPC) during calibration should not be confused with that described

in Clause 3 below. This IPC should be regarded as a routine start-up check on the

usability of instruments as distinguished from the verification of equipment against

requirements of tests.

3. Performance check

3.1 It is inappropriate to specify a rigid frequency for performance checks since the

frequency depends on a number of factors including :-- type of equipment;

- manufacturers recommendation;

- trend data obtained from previous performance checks records;

- recorded history of maintenance and servicing;

- extent and severity of use;

- tendency to wear and drift;

- frequency of cross-checking against other reference standards;

- environmental conditions (temperature, humidity, vibration, etc.);

- accuracy and permissible limits of errors.

3.2 Acceptance criteria for performance checks should be based on the requirements of test


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standards, if available, taking into consideration recommendations given by the

manufacturers of the instruments. Test standards may sometimes explicitly state the

acceptance criteria for various performance characteristics but, frequently, suchacceptance criteria have to be derived from the requirements of test standards. For

instance, the detection limits of an instrument may have to be derived from the

specification limits of the standards.

3.3 Instruments shall be taken out of service when results of performance checks fall outside

the acceptance criteria. Suitable corrective measures and servicing should be taken when

results of performance checks indicate that there is a system degeneration. An

instrument should not be put back into service unless subsequent checks indicate that its

performance fulfils the acceptance criteria.

3.4 The performance characteristics to be checked depends on the type of the instrument.Table 1 lists those performance characteristics of common analytical instruments that

require to be checked.

4. Calibration and Performance Check Frequency

4.1 Table 1 sets out the normal frequencies for calibrations and performance checks of

common analytical instruments. The frequencies, when given, are recommended

maximum periods. They serve as a starting point for initial selection of

re-calibration/performance checks intervals.

4.2 Intervals of calibration/performance checks should be reviewed regularly and

adjustments of these intervals may be made based on experience. However, any revision

of frequency shall be justified (e.g. changes of usage, environment, required accuracy,

etc.). The guidelines given in OIML International Document No 10 for the

determination of recalibration period should be followed.

4.3 Test standards may sometimes specify a shorter calibration/performance check intervals

than that listed in Table 1. In such cases, the frequency recommended by the test

standards shall be followed. In addition, if major mechanical or electronic maintenance

is carried out, the appropriate checks should be conducted when the instrument is

re-commissioned.


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Table 1 Calibration and Performance Checks Requirements

for Analytical Instruments

Type of equipmentRecommended period between

successive calibrations

Calibration procedure or guidance

documents and equipment

requirements

BOMB CALORIMETERS 6 months or after any significantpart of the system has been changed

Determine the effective heat capacityusing certified benzoic acid. Referto ISO1928.

CONDUCTIVITY METERS 6 months Determine cell constant usingpotassium chloride standard

solutions appropriate to each desiredmeasuring range. Refer to ISO7888/OIML R56 & 68.

DISSOLVED OXYGEN

METERS

Calibrate before useCheck linearity before using theinstrument for routine purposes andmonthly thereafter

Calibrate at zero and a value nearsaturation. Check linearity. Refer toISO 5814.

pH METERS Calibrate on useCheck performance for new

electrodes, and once every 2 weeksthereafter

Calibrate the instrument with twostandard buffers on use, appropriate

to the anticipated pH of the samplebeing measured. Check performancecharacteristics such as liquid junction

error, shift on stirring and noise.Refer to ISO 10523.

TURBIDIMETERS Calibrate on use Calibrate the apparatus using

formazine standard solutions. Atleast five points with each measuringrange should be used for plotting thecalibration graph. Refer to ISO 7027.

CHROMATOGRAPHS Calibrate on use. Checkperformance yearly

(a) Gas chromatographs check thefollowing, as appropriate:

i. Overall system checks,

precision of repeat sampleinjections, carry-over;

ii. Column performance(capacity, resolution,retention);

iii. Detector performance(detection limit and

linearity);iv. System heating/

thermostatting (accuracy,precision, stability, rampingcharacteristics);

v. Autosampler (accuracy and

precision of time routines).Refer to OIML R82/83/113


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successive calibrations

Calibration procedure or guidance

documents and equipment

requirements

CHROMATOGRAPHS(contd)

Calibrate on use. Checkperformance yearly

(b) Liquid chromatographs checkthe following, as appropriate :

i. Overall system performance;ii. Detector sensitivity;iii Mobile phase delivery system

(precision, accuracy,pulse-free)

Refer to OIML R112.

SPECTROMETERS AND

SPECTROPHOTOMETER

Calibrate on use. Check

performance yearly

(a) UV/Visible - Check wavelength

accuracy, stray radiation,absorbance accuracy and zero

absorbance line flatness. Referto AS3753.

(b) Infra-red - Check wavenumber

accuracy, wavenumberreproducibility and beambalance. Refer to ASTM E932.

(c) Atomic Absorption - Checkprecision, sensitivity and

detection limit of metals ofinterest. Refer to OIML R100.

(d) Atomic Emission usingarc/spark discharge - Checkprecision and background

equivalent concentration. Referto AS 2883.

(e) Inductively Coupled PlasmaAtomic Emission - Checkrepeatability, backgroundequivalent concentration and

detection limit. Refer toAS3641.2/OIML R116.

(f) X- Ray Fluorescence - Checkprecision, counter resolution,dead time. Refer to

AS2563/OIML 123


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Annex I

(Informative)

Bibliography

Part 1 General Principles of Equipment Calibration

Laboratory staff responsible for equipment calibration and verification are strongly advised to

consult the following references.

1. CITAC/EURACHEM Guide 1 International Guide to Quality in Analytical Chemistry.

An Aid to Accreditation.

2. ISO10012 Measurement management systems - requirements for measurement process

and measuring equipment.

3. ISOGuide 32 Calibration in analytical chemistry and use of certified reference

materials.

4. ISOGuide 33 Uses of certified reference materials.

5. ISO/TR 13530 Water quality - Guide to analytical quality control for water analysis.


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Part 2 Recommended Practices for Specific Equipment

The following references contain description of the operation, calibration and/or performancecheck procedures. Operation staff of laboratories are strongly advised to familiarize

themselves with these references.

A. UV/Visible Spectrophotometers

1. AS3753 Recommended practice for chemical analysis by ultraviolet/visible

spectrophotometry.

2. ASTME131 Standard terminology relating to molecular spectroscopy

3. ASTME169 Standard practices for general techniques of ultraviolet quantitative

analysis

4. ASTME275 Standard practice for describing and measuring performance of ultraviolet,

visible and near-infrared spectrophotometers

5. ASTME925 Standard practice for monitoring the calibration of ultraviolet-visible

spectrophotometer whose spectral slit width does not exceed 2 nm

6. ASTME958 Standard practice for measuring practical spectral bandwidth of

ultraviolet-visible spectrophotometers.

B. Infra-red Spectrophotometers

1. ASTME168 Standard practice for general techniques of infrared quantitative analysis

2. ASTME275 Standard practice for describing and measuring performance of ultraviolet,

visible and near-infrared spectrophotometers

3. ASTME932 Standard practice for describing and measuring performance of dispersiveinfrared spectrophotometers

C. Atomic Absorption Spectrophotometers

1. AS2134 Recommended practice for chemical analysis by atomic absorption

spectrometry: AS2134.1 Flame atomic absorption spectrometry, AS2134.2 Graphite

furnace spectrometry and AS2134.3 Vapour generation AAS

2. AS3550.6 Determination of filtrable calcium - Flame atomic absorption spectrometric

method


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3. ASTME1184 Standard practice for electrothermal (graphite furnace) atomic absorption

analysis

4. APHA3111 Metals by flame atomic absorption spectrometry

5. APHA3112 Metals by cold-vapour atomic absorption spectrometry

6. APHA3113 Metals by electrothermal atomic absorption spectrometry

7. APHA3114 Arsenic and selenium by hydride generation/atomic absorption

spectrometry

D. Atomic Emission and X-Ray Fluorescence

1. AS1502 Glossary of terms used in X-ray spectroscopy

2. AS2563 Wavelength dispersive X-ray fluorescence spectrometers - determination of

precision

3. AS2883 Analysis of metals - Procedures for the setting up, calibration and

standardization of atomic emission spectrometers using arc/spark discharge

4. AS3641.1 Recommended practice for atomic emission spectrometric analysis Part 1Principles and techniques

5. ASTME135 Standard terminology relating to analytical chemistry for metals, ores and

related materials

6. ASTME158 Standard practice for fundamental calculations to convert intensities into

concentrations in optical emission spectroscopy analysis

7. ASTMD305 Standard establishing and controlling spectrochemical analytical curves

8. ASTME826 Standard practice for testing homogeneity of materials for the developmentof reference materials

E Inductively Coupled Plasma

1. AS3641.2 Recommended practice for atomic emission spectrometric analysis Part 2

Inductively coupled plasma excitation

2. APHA3120 Metals by plasma emission spectroscopy using inductively coupled plasma

source


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F. Gas and liquid chromatographs

1. AS3741 Recommended practice for chemical analysis by ion-chromatography

2. ASTMD1945 Standard test method for analysis of natural gas by gas chromatography

3. ASTMD4626 Standard practice for calculation of GC response factors

4. ASTME260 Standard practice for packed column chromatography

5. ASTME355 Standard practice for gas chromatography terms and relationships

6. ASTME516 Standard practice for testing thermal conductivity detectors used in gas

chromatography

7. ASTME594 Standard practice for testing flame ionization detectors used in gas or super

critical fluid chromatography

8. ASTME682 Standard practice for liquid chromatography terms and relationships

9. ASTME685 Standard practice for use of fixed wavelength photometric detectors used

in LC

10. ASTME697 Standard practice guide for use of EC detectors in gas chromatography

11. ASTME840 Standard practice guide for use of FP detectors in gas chromatography

12. ASTME958 Standard practice for measuring spectral bandwidth of UV/Vis

spectrophotometers

13. ASTME1151 Standard practice for ion chromatography terms and relationships


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APPENDIX G

CALIBRATION REQUIREMENTS FOR CONSTRUCTION MATERIALS TESTING

EQUIPMENT

This appendix lists the items of equipment and their calibration requirements within the

Construction Materials Test Category in the test areas covering aggregates, bituminous

materials, concrete and steel. Specific calibration requirements for other test areas are

included in other Supplementary Criteria listed as follows:

Supplementary Criteria No. 15 for non-destructive tests of welding

Supplementary Criteria No. 16 for foundation testing

Supplementary Criteria No. 17 for building components and related testing

Supplementary Criteria No. 18 for ground investigation testing and sampling

Supplementary Criteria No. 19 for soil and rock testing

For construction materials testing equipment, the criteria in this appendix should be read first

over any other appendices in this supplementary criteria. Where conflicting criteria exist,

the requirements of this appendix shall take precedence. The calibration periods listed here

are the maximum acceptable, and shorter time periods may be required due to frequency of

use and storage conditions.

Environment

General policy on environment is covered under section 5.3 of HOKLAS 003.

In addition to the comments therein it is possible for an accreditation to be granted for tests

conducted under more than one set of environmental conditions provided that these are :

In accordance with the standard concerned and

The test report indicates clearly which criteria have been adopted.

Equipment

Criteria are contained elsewhere in this Supplementary Criteria in respect of other items

under different Test Categories. Several of the construction materials standards do however

contain details of items of equipment peculiar to the test method concerned. Calibration and

maintenance of these items should generally satisfy one of the following :-


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Where the standard concerned gives a calibration procedure, this procedure shall be

followed and the maximum period between successive calibrations shall be that

specified in the standard.

Where no calibration procedure is given in the standard but tolerances on

dimensions or mass are provided, a check against the specified values shall be

made and recorded at least once every 12 months unless a calibration interval is

given in the standard.

Equipment for which no detailed criteria or tolerances are given should be regularly

inspected.

Solutions

There are many instances where solutions are required in connection with both the physical

and chemical testing of materials.

It is not practical to give detailed guidance on the storage and shelf life of these but

laboratories involved should either;

Make up fresh solutions as and when required, where the standard concerned gives

a calibration procedure but without a calibration interval, the calibration interval

shall be 6 months, or

Initiate a programme for ascertaining the shelf life of the solutions concerned.

In the case of distillation and/or de-ionizing of water, the equipment concerned should be

checked for satisfactory performance at least once every 6 months.

Reference Materials

Reference materials called up in standards shall be obtained from the sources stated in the

standard and stored in the prescribed manner. Specific HOKLAS policy on referencematerials is covered under clause 5.6.H (f) of HOKLAS 003.

Specific HOKLAS Calibration Criteria

The following table sets out the maximum periods between successive calibrations for

equipment to be used in connection with testing of aggregates, bituminous materials, concrete,

steel, and soils within the Construction Materials Test Category. Specific HOKLAS policy

for calibration is covered under section 5.6 and 5.6.H of HOKLAS 003.


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guidance documents and equipment

requirements

2 years By a competent calibration body asdefined in clause 5.6.H (d) of HOKLAS003.

6 months Repeatability check using referencemasses of higher grades.

BALANCE(Reference)

1 month One-point check using reference massesto balance capacity

(a) 3 years or immediately

following servicing

Calibrate using reference masses in

accordance with the national standardmethod or other equivalent standards.

(b) 6 months Repeatability check using referencemasses in accordance with a standard

method. Adjust the balance and carryout a full calibration if the requiredtesting accuracy is exceeded.

(c) Daily before use One-point check using a known mass ator close to a frequently encounteredvalue or the balance capacity for a

specified range.

BALANCE

(Working)

(d) Each weighing Zero check after tare.

CALLIPERS

(Vernier or digital readout)

(Accuracy equal to and betterthan 0.01mm)

2 years By a competent calibration body asdefined in clause 5.6.H (d) of HOKLAS

003

(Accuracy between 1 mm and

0.01mm)

1 year Calibrate using reference gauge blocks

or callipers checker. A sufficient

number of readings shall be takencovering the expected working range.

(Accuracy not better than 1mm) Initial only Callipers from reputable manufacturersmay be used.

Callipers of any accuracies Before use Zero check.


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guidance documents and equipmentrequirements

DIAL GAUGE

(Accuracy equal to and better

than 0.01mm)

1 year By a competent calibration body as

defined in clause 5.6.H (d) of HOKLAS003

(Accuracy not better than0.01mm)

1 year Calibrate using reference gauge blocksor a micrometer type calibrator forcompliance with BS907 or AS2103.

LINEAR DISPLACEMENT

MEASURING DEVICE

(LVDT, digimatic gauge, Demecgauge or any other transducertypes)

(Accuracy equal to and betterthan 0.01mm)

1 year

Before use

By a competent calibration body asdefined in clause 5.6.H (d) of HOKLAS003

One-point check using gauge block.

1 year Calibrate the measuring device togetherwith the same readout unit as is used for

test using reference gauge blocks or a

micrometer type calibrator. Thereadout unit can be an electrical displayunit, digital display unit or data logging

system.


Before use One-point check using gauge block.

MASS(Working-hanger weights)

1 year Calibrate using reference balance.

MICROMETER

(Accuracy equal to and better

than 0.01mm)

2 years By a competent calibration body as



1 year Calibrate using reference gauge blocks.A sufficient number of readings shall betaken covering the expected workingrange.

Micrometer of any accuracies Before Use Zero Check.


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OVEN (a) 3 years or immediatelyfollowing servicing or eachchange in temperature setting

Check temperature variation in workingspace using different referencethermocouples at the same time and also

check evaporation rate for compliancewith the requirements of AS 2853 andAS 1289 or other relevant standardmethods.

(b) 6 months Check temperature at centre of usable

oven space inside an empty oven using areference thermocouple. Ten readingsshall be taken at 3-minute intervals with

the oven set at the working temperaturerange.

PRESSURE GAUGECALIBRATOR

(Reference standard)

Dead weight tester 5 years By a competent calibration body asdefined in clause 5.6.H (d) of HOKLAS003

Manometer 5 years By a competent calibration body as

defined in clause 5.6.H (d) of HOKLAS

003

PRESSURE GAUGE(Reference)(Electrical transducer type)

2 years By a competent calibration body asdefined in clause 5.6.H (d) of HOKLAS003

PRESSURE GAUGE

(Working gauge)

Bourdon tube or hydraulictype

1 year By a competent calibration body asdefined in clause 5.6.H (d) of HOKLAS003

Transducers types 1 year By a competent calibration body asdefined in clause 5.6.H (d) of HOKLAS003

RULE 2 years Check against reference length standardwith a higher accuracy. Check at aminimum of 5 points over the entire

length.


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SIEVE

(Reference woven wire cloth

sieves, for performance checkingof test sieves)

Initial only Sieves with recognized manufacturers

certificates which certify conformancewith BS410: 1986 shall be used.Reference sieves shall be downgraded totest sieves after 30 passes.

(Perforated plate test sieves

apertures larger than or equal to4mm)

300 passes but not exceeding 6

months

Check aperture and bridge width using

calibrated callipers, optical projection, orother appropriate devices in accordancewith BS410 : 1986.

(Woven wire cloth test sieves apertures less than 4mm)

300 passes but not exceeding 6months

Check aperture using optical projectionor other appropriate equipment in

accordance with BS410 : 1986.Alternatively, check performance ofapertures using certified referencesamples or performance check sampleswith reference sieves in accordance withBS 812:Part 100: 1990 or BS 1377:Part1:1990. Sieves with manufacturers

certificates which certify conformancewith BS410:1986 may be used directlywithout initial checking.

THERMOCOUPLE(for checking ovens)


003

6 months One-point check, at ice point or someother appropriate temperature.

THERMOMETER -(Mercury-in-glass)

(Accuracy equal to and betterthan 0.5C)


003


(Accuracy not better than 0.5C) 5 years Calibrate over the expected workingrange using a reference thermometer and

suitable calibration bath.



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THERMOMETER (Electronic, digital and platinumresistance)


003


TIME MEASURING DEVICE

(a) Accuracy equal to or betterthan 0.5 second

(b) Accuracy not better than 0.5

second

1 year

3 months

Calibrate against reference time standardin accordance with relevant calibration

standard.

Check against time given by radio time

(RTHK) signal for at least half an hour.

VACUUM GAUGE

(a) Mechanical or hydraulic

(b) Transducer

2 years

1 year

By a competent calibration body asdefined in clause 5.6.H (d) of HOKLAS003

By a competent calibration body as


VOLUMETRIC

GLASSWARE(burettes, pipettes, volumetricflasks including measuring

cylinders)

Initial only Check by weighing the amount ofdistilled water that the vessel contains ordelivers at a measured temperature,applying any temperature corrections

necessary using the Tables inBS1797:1987. The mass of water shallbe determined to within 0.01%. Thechecking shall be repeated a sufficientnumber of times to obtain the averagevolume. Where a vessel is to be used at

a particular graduation mark only,checking may be limited to that mark butthe vessel must be labelled to indicateclearly the limited checking.

AGGREGATES

ABRASION MACHINE 1 year Check dimensions of moulds, trays and

plates; speed of rotation of machine andmass of weights in accordance with BS812:Part 113: 1990


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ACCELERATED

POLISHING MACHINE

1 year Check rate of flow of flowmeter,rotational speed of rad wheel, planes ofrotation of tyred and road wheels, free

force of rubber wheels, and rubber tyredand road wheel dimensions inaccordance with BS 812:Part 114:1990.

ELONGATION GAUGE 1 year Check with calibrated callipers ormicrometer

FRICTION TESTER 1 year Check dimensions and mass of rubberslider in accordance with BS 812:Part

114:1990.

Before use Check specimen contact angle of rubberslider and verticality of column inaccordance with BS 812:Part 114:1990.

IMPACT TESTING DEVICE 1 year Check dimensions of cylindrical steelcup and metal hammer, mass of circular

metal base and metal hammer, and fallof hammer in accordance with BS812:Part 112: 1990.

THICKNESS GAUGE

(for determination of flakinessindex)

1 year Check with calibrated callipers or

micrometer.

BITUMINOUS MATERIALS

CENTRIFUGE(for extraction of binder)

TACHOMETER

1 year

5 years

Check the operating speeds using acalibrated tachometer

By a competent calibration body asdefined in clause 5.6.H (d) of HOKLAS

003

MARSHALL TESTING

MACHINE

(a) Stability load

measurement

6 months By a competent calibration body as

defined in clause 5.6.H (d) of HOKLAS003 in accordance with BS 1610 or BSEN 10002 or other equivalent standards.

(b) Flow displacementmeasurement

1 year Refer to previous section on dial gaugeor linear displacement measuring device.


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CONCRETE AND ITS CONSTITUENT MATERIALS

CEMENT FINENESS

TESTING APARATUS

(a) Lea & Nurse 1 year By use of certified reference materialas defined in clause 5.6.H.(f) of

HOKLAS 003.

(b) Rigden or Blaine 3 months By use of certified reference materialas defined in clause 5.6.H.(f) of

HOKLAS 003.

CHLORIDE ION

PENETRATION TESTER

(a) Voltage measuring device 1 year By a competent calibration body as

defined in clause 5.6.H (d) of HOKLAS003 in accordance with a relevant

standard.

(b) Current measuring device

(c) Reagent NaCl and NaOH

1 year

Freshly made

By a competent calibration body asdefined in clause 5.6.H (d) of HOKLAS003 in accordance with a relevant

standard.

Reagents to be at least analytical grade

COMPACTING FACTOR

APPARATUS

1 year Check compliance with requirement inaccordance with CS1 : 1990.

COMPRESSION TESTING

MACHINE

(a) Load rate 1 month By use of calibrated timing device

against criteria for tests in accordance

with CS1: 1990.

(b) Load verification 6 months or after relocation of the

machine (Note: An additional checkat 3 months shall be performed if

the two previous checks haveindicated a change of machinegrading)

By a competent calibration body as

defined in clause 5.6.H (d) of HOKLAS003 in accordance with BS 1610 or BS

EN 10002 or other equivalent standards.


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COMPRESSION TESTING

MACHINE(Contd)

(c) Machine plattens auxiliaryplattens and spacer blocks

(i) Surface condition 1 month Visual inspection check for signs ofwear and damage.

(ii) Flatness, parallelism 1 year Using reference checking devices inaccordance with CS1 : 1990.

(d) Performance 6 months or after relocation of themachine

By a competent calibration body asdefined in the clause 5.6.H (d) of

HOKLAS 003 in accordance with BS1881 or CS1:1990.

(e) Strain cylinders(for checking theperformance of the machine)

2 years By a competent calibration body asdefined in the clause 5.6.H (d) ofHOKLAS 003 in accordance with NIS0409 or BC415

(f) Proving devices(for calibration of force

testing machines)

2 years By a competent calibration body asdefined in the clause 5.6.H (d) of

HOKLAS 003 in accordance with BS1610 or BS EN 10002 or otherequivalent standards.

CREEPTESTINGAPPARATUS(Load verification with aservo-controlled system)

Each test By a competent calibration body asdefined in the clause 5.6.H (d) ofHOKLAS 003

CURING TANK

(CUBE OR OTHER SAMPLE) 6 months

Daily

Check the efficiency of circulation andtemperature distribution at 60%

capacity, with different referencethermometers at minimum 9 points at thesame time.

Check the max/min temperature.

CUBE MOULD

Dimensions, flatness, squarenessand parallelism

6 months Check compliance with requirement inaccordance with CS1 : 1990..


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CYLINDER (Reference-check

the cylindricity of concrete

core)

5 years By a competent calibration body asdefined in the clause 5.6.H (d) ofHOKLAS 003 or by means of

appropriate reference devices

FLOW CONE 1 year Check apparatus in accordance withASTM C939 Clause 8 using a referencetime measuring device

FLOW TABLE 1 year Check apparatus in accordance withBS1881:Part 105:clause 3.1

MIST CURING ROOM 6 months

Daily

Check temperature using differentreference thermometers at a minimum of

9 points at the same time or checkmaximum temperature fluctuation using

a reference thermometer at minimum of9 points, and check humidity distributionto ensure no dry surfaces. Compare theeffectiveness with equivalent tank cured

specimens

Check the max/min temperatureCheck wetness of surfaces

PFA FINENESS TESTING

APARATUS(check aperture size of standardsieve)

6 months By use of certified reference materialsas defined in clause 5.6.H.(f) ofHOKLAS 003.

SLUMP

(a) Cone 1 year Check dimensions in accordance withCS1:1990.

1 week Check ovality of base and top to

CS1:1990.

(b) Rod 1 year Check dimensions in accordance withCS1:1990.

STEEL

ANCHOR BOLT PULL OUT

AND PROOF LOAD TESTERLoad verification or forcetransducer

1 year By a competent calibration body asdefined in clause 5.6.H (d) of HOKLAS003 in accordance with a relevantstandard


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BENDING TESTING

MACHINE

(a) Load rate 1 month By use of calibrated timing deviceagainst criteria for tests in accordancewith CS1:1990

(b) Formers 1 month Visual inspection for wear

EPOXY COATED BAR

(a) Coating thickness gauge 1 year By use of reference device in accordance

with relevant standards

(b) Holiday detector 1 year By use of reference device in accordancewith relevant standards

EXTENSOMETER

(for rebars and structural steel) 1 year By a competent calibration body asdefined in clause 5.6.H (d) of HOKLAS003 in accordance with BS 3846:1970.

EXTENSOMETER(for coupler and strand)

(a) Mechanical type 1 year By a competent calibration body asdefined in clause 5.6.H (d) of HOKLAS003 in accordance with a relevantstandard.

(b) Optical and transducer types 1 year By a competent calibration body asdefined in clause 5.6.H (d) of HOKLAS003 in accordance with a relevant

standard.

HARDNESS TESTER

(a) Brinell, Vickers and

Rockwell Machines


defined in clause 5.6.H (d) of HOKLAS003 in accordance with a relevantstandard.

(b) Indenter 3 years By a competent calibration body asdefined in clause 5.6.H (d) of HOKLAS003 in accordance with a relevantstandard.


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IMPACT TESTER

Charpy V or U notch

machine


defined in clause 5.6.H (d) of HOKLAS003 in accordance with a relevantstandard.

TORQUE WRENCH(For checking of power-operated

and hand-operated friction bolts)


defined in clause 5.6.H (d) of HOKLAS003 in accordance with a relevantstandard

TENSILE TESTING

MACHINE

(a) Load rate 1 month By use of calibrated timing device

against criteria for tests in accordancewith BS 18.

(b) Load verification 6 months or after relocation of themachine (Note: An additional checkat 3 months shall be performed iftwo previous checks have indicated

a change of machine grading.1 month)

By a competent calibration body asdefined in clause 5.6.H (d) of HOKLAS003 in accordance with relevantstandards.

(c) Specimen gaugingequipment

Spot check on prepared samples.


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APPENDIX H

CALIBRATION REQUIREMENTS FOR SELECTED PHYSICAL AND

MECHANICAL TOY TESTING EQUIPMENT

The general principles in Appendix C apply to common equipment such as thermometers,

balances, mass, thermohygrographs, stopwatches, pressure gauges, ovens, vernier callipers,

micrometers, glassware, rules, furnaces, etc. For chemical testing, the general principles for

the use of analytical instrumentation as explained in Appendix F are relevant.

The calibration requirements for selected equipment used in toy testing are detailed below.


successive calibrationsCalibration procedure

and requirements

FORCE AND TORQUE

MEASURING EQUIPMENT

USED FOR TOY TESTING

SUCH AS PUSH PULL GAUGE,

TORQUE GAUGE AND

TENSION GAUGE

(a) Portable spring type with dialgauge

(b) Non-portable spring type withdial gauge

One year (complete)*Six months*

(repeatability of zero)

Two years* (complete)Six months*

(repeatability of zero)

Dial gauge mechanism should bechecked for repeatability of zero with

fast and slow movement in tensionand compression, or clockwise andanticlockwise directions whereappropriate

FIXTURESincluding accessibility probes, smallparts cylinder, bite test clamp, rattletest fixture, flexure tester,compression test disc, tyre removal

metal hooks, metal cylinders, straightrods, pins, steps construction for

tumble tests, etc.

Initial calibration for dimensionalcompliance *

Yearly inspection for damage and

wear *

IMPACT MEDIUM FOR DROP

TEST

Initial calibration for hardness ofmedium *

Yearly inspection for damage and

wear *

PROJECTILE VELOCITY

TESTER

Two years * The distance between the starting andstopping sensor and the accuracy ofthe timer should be calibrated. Thesoftware for calculating the velocityfrom the distance and time readings

should be verified.


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successive calibrationsCalibration procedure

and requirements

SHARP EDGE TESTER Initial calibration*

(complete)

One month*(force calibration)Six months *(inspection of mandrel condition)

Calibration should be in accordance

with the requirements of relevant toytesting standards, such as those formandrel diameter, rotation speed,surface hardness, surface roughnessand force. Mandrel force calibrationmay be performed using a calibrated

dead weight.

SHARP POINT TESTER Initial calibration *Six months *(inspect the end cap for wear)

Calibration should be in accordancewith the requirements of relevant toytesting standards, such as those for

dimensions of gauging slot, thicknessof end cap, micrometer graduation

and force of spring.

After a piece of equipment is calibrated, a staff member of the laboratory should check

whether the characteristics of the equipment as shown by the calibration results are within the

tolerance range specified by the test standard. Use of out of tolerance equipment is not

recommended. In exceptional cases where it is impractical to repair or replace the

equipment, the out of tolerance equipment may be used only if the following conditions are

met :

(a) The laboratory has at least one set of working equipment with characteristics withinthe specified tolerance range which can be used to determine compliance for critical

cases.

(b) The laboratory has evaluated the effects of the out of tolerance equipment and

documented the conditions under which the out of tolerance equipment will not affect

test results.

(c) The out of tolerance equipment is properly labelled to alert test operators that such

equipment is out of tolerance and should only be used under the conditions

documented in (b). Under all other conditions, the equipment mentioned in (a)

should be employed.

(d) Test operators are properly trained and fully aware of the meaning of the label

mentioned in (c), the limitations of the use of the out of tolerance equipment and the

actions to take when the defect of the equipment may affect test results.


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