Calibration systems

MODULE - III

STQC
Version 1.0 CERTIFIED CALIBRATION PROFFESSIONAL MIII/CH1/1

Calibration
A set of operations, performed in accordance
with a definite documented procedure, that
compares the measurements performed by an
instrument to those made by a more accurate
instrument or standard, for the purpose of
detecting and reporting or eliminating by
adjustment, errors in the instrument tested.
As per ISO/IEC Guide 2

STQC

Calibration
definition (a)
operation establishing the relation between quantity values
provided by measurement standards and the
corresponding indications of a measuring system, carried
out under specified conditions and including evaluation of
measurement uncertainty

definition (b)
operation that establishes the relation, obtained by
reference to one or more measurement standards, that
exists under specified conditions, between the indication of
a measuring system and the measurement result that
would be obtained using the measuring system
As per VIM
STQC

Why to Calibrate ?
• Initial calibration assures T&ME with in Spec

• Periodic calibration is essential to maintain control of measurement
process made by TME

• Assures common reference i.e Traceability to National / International
standards

• Ensures that equipment has been satisfactorily working since last
calibrated & assumed that the equipment continues to work satisfactorily
until next calibrated

• Calibration records study enables extending/reducing the calibration
interval

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OBJECTIVES OF CALIBRATION
Maintaining traceability of measurements

Uncertainty
limits

Traceability

Reference

measurements

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Why Calibration & Traceability are intertwined?

• To measure the “Same Measure”
• Interchangeability of products
• Legal requirement & consequence of
liability
• To demonstrate metrological confirmation
of product
• Consistent control of product/measurement

STQC

When is calibration not required?
• When equipment is not in use .
• When eqpt is used as null detector
• When eqpt is used as transfer device whose
measurement or output value is not explicitly
used.
• Fundamental / Absolute standards.
• When instrument is fail-safe
• When instrument makes measurements or
provides known outputs which are monitored by
a calibrated device, meter or gage during use.

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When to Calibrate ?
- Calibrate too often it is waste of time and
money.
- Calibrate too seldom it is waste of product or
wrong decisions.
- Balance between cost to calibrate and cost
not to calibrate
- Universally Applicable single best practice
for establishing & adjusting cal interval not
available.
- Refer DAP, RP1
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Where to Calibrate?
• Calibration is performed in the I/II/III party
laboratory under controlled environment.
(The environment need only to be controlled to the extent required.)

• Accredited Calibration Laboratory

• Manufacturer’s / Supplier’s Laboratory
ensuring valid traceability

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Where to Calibrate ?contd…
• Accredited Laboratory ensuring the quality of
calibration services.

• In the absence of the above, the services of
calibration laboratory for the parameter of
interest may be availed ensuring meeting
technical requirements of ISO/IEC 17025.

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Basic Requirements - Location/ Environment

• Noise Level
• Vibration
• EMI/EMC
• Cleanliness
• Lighting
• Power supply
• Accessibility

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Basic Requirements – Location/Environment
Quiet
* Away from heavy traffic, factories, workshop etc
* Effective separation from non compatible areas
* Noise : less than 60 dbA
* Vibration :
Taken care in building design & site selection
noticeable in galvanometers, mercury column, mass
balance, dimensional measuring equipment
0.25μm max displacement amplitude from 0.1Hz to 30Hz and
0.001 g max 30Hz to 200Hz
* EMI :
* taken care in site selection & use of shielding/ filtering
* field strength to be less than 100μV /m
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 Clean
Good house keeping
Higher degree of particulate control (Dimensional &
Mass Metrology)
 Good lighting
Recommended level of illumination is 450 – 700lux
Fluorescent lamps preferred to minimize heating effect
 Services
Separate feeder line
Uninterrupted / Regulated power supply (+- 5%)
Adequate measures against spikes & transients
Mains Earthing (< 1 ohm)
Adequate measures against ground currents
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 Accessibility

Standards / equipment
Firefighting devices
Quality System Document & Instrument
Manuals

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Calibration laboratory
- basic requirements
 Location – Permanent/On-site  Temperature
 Humidity
 Environment  Air flow
 Equipment  Filtration
 Electromagnetic Screening
 Staff  Noise Level
 Vibration
 Management  EMI/EMC
Documents  Cleanliness
Reference standards  Lighting
Records
Transfer Standards  Power supply
Calibration
Working standards  Accessibility
Training Connecting leads  Receiving & Calibration area
Authority adaptors/accessories
Responsibility Subsidiary equipment
Technical Computers & automation
Competence software

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Basic Requirements – Equipment

 Transfer Standards
 Reference standards (Optional)
 Working standards
 Connecting leads and adaptors
 Subsidiary equipment
 Computers & automation software

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Basic Requirements – Personnel

 Training
 Authority
 Responsibility
 Technical Competence

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Basic Requirements – Management

 Quality management & Technical
operations
 Traceability
 Calibration interval
 Audits/ Management reviews
 Implementation of corrective /preventive
actions

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Calibration System

Why Calibration system ?
- To meet the commitment of the industry to
provide quality product.
- TMI is required to be controlled to provide this
assurance.
- Through calibration
- Shall include all the elements necessary for
ready detection of equipment deficiencies
and provide objective evidence of
conformance in the form of records.

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Calibration System

It is defined as a set of inter-related and
interacting elements which influence the
calibration process and ultimately
quality of calibration result.

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Elements of Calibration System

• Qualification
• Measurement traceability
• Adequacy of calibration procedure
• Calibration procedure
• Qualification labeling
• Sealing for integrity
• Calibration interval
• Records Maintenance

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Elements of Calibration System
contd…
• Environmental Controls
• Handling , Preservation & Storage
• Non- conforming Measurement Equipment
• Scheduling / Recall system
• Personnel requirement
• Audit requirement
• Calibration Quality
• Use of outside service
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ACCREDITATION REQUIREMENTS

The laboratory must demonstrate control and competence
 Environmental control
 Traceability of standards
 Calibration procedures
 Competence of staff / Authorization of personnel
 Participation in PT programmes
 In-service checks/ control charts
 Validation of methods
 Internal audit & Management review records

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CHAPTER - 1

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CALIBRATION PROCEDURES

Procedure

-Ensures consistency in operation

-Objective evidence

Calibration procedure provides

-Specified performance tolerance and functional criteria

-Essential information & instruction to determine the integrity of eqpt.

-Logical & timely sequence of necessary facts to understand and

verify DUC to its intended performance capability.

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- Guides personnel

- eqpt. Setup, interconnection, control operations

- specification interpretation

- tolerance limits

- any adjustment, correction

- Establish uniformity of methods/techniques

- Shall be written such that personnel shall take minimum interpretation,

effort and time.

- Shall be written by keeping performance of DUC in mind.
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Requirements

Source:

-Prepared internally

-Prepared by the manufacturer

-External agency

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Completeness:

- Sufficient instruction

Approval:

- shall be approved and controlled to meet regulatory and contractual

requirements.

Software:

- Validation and control

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BROADLY COVERS -

- Performance requirements of DUC

- Performance requirements of standard

- Preliminary operation

- Calibration process

- Calibration results

- Closing operation

- Storage and handling

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CALIBRATION PROCEDURES – TYPICAL CONTENT
• Appropriate identification / document control.

• Scope

• Purpose - description & performance requirements of unit being calibrated

• Parameters or quantities and ranges

• Calibration equipment/system/setup

• Reference standards and reference materials required

• Reference Documents – standard/specifications/manuals

• Adaptors/Accessories required

• Environmental conditions required including stabilization period needed.

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CALIBRATION PROCEDURES – TYPICAL CONTENT
• Description of the procedure, including –
 Apprising of identification mark, sampling, handling, transporting,

storing and preparation of items.
 Preliminary Checks to be made before the work is started.
 Checks that the equipment is working properly, and where required ,
 Calibration process & adjustments if any, of the equipment
 The method of recording the observations and results.
 Any safety measures/precautions to be observed.
• Criteria and / or requirements for approval / acceptance / rejection.
• Data to be recorded and method of analysis and presentation.
• The uncertainly or the procedure for estimating uncertainty.
• Calibration status/labeling
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CALIBRATION PROCEDURE CONTROL

 Deviations from instructions authorized & recorded
 Assign responsibility
 Establish document control with a standard format
 Draft, comment and edit procedures/instructions
 Review and authorize procedures
 Print, bind, present and make available to all operational
staff
 Regular review and amendment as needed
 Archive the superseded methods

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EXERCISE – 1

DEVELOPMENT & REVIEW OF PROCEDURES

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Section II

-table defining performance specification (minimum use specification)

required of the standard

-Listing of specific manufacturer model (representative eqpt.) which are

applicable and can operate with in the specified requirements. Equipment

which has no known substitute should be clearly identified and described.

-Environmental condition

-Any special jigs and fixtures required

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Section III

-Listing of all preliminary actions including functional checks to be performed

prior to calibration

Section IV

-Listing of instructions and all steps to be performed in measurement process

Section V

-A results data sheet blank form with nominal values and tolerance limits.

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CALIBRATION METHODS

• Standard methods –
Direct/Indirect/Ratio/Substitution/Transfer/Differential

• Non-standard methods

• Laboratory developed methods NEEDS
VALIDATION

• Expansion of Scope

• Customer given method
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VALIDATION OF CALIBRATION METHODS

• Selectivity
• Uncertainty of the results
• Range
• Repeatability
• Reproducibility
• Linearity
• Limit of detection
• Limit of quantization
• Robustness
• Bias
• Precision

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GENERAL CALIBRATION TECHNIQUES

• SPANNING
• NULLING
• ZEROING
• LINEARIZATION

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GENERAL CALIBRATION METHODS
NULLING
• If the nominal value of UUC is same as that of reference
comparison may be made using Nulling process.

• Instruments like Galvanometers, Null Detectors &
Comparators work on this principle. The scale indicates
the sensitivity of detection in these meters.

• Nulling is used for more accurate measurements since
Null process can be quite sensitive to minute difference
between known & unknown values.

• Note that the Null detectors need not be calibrated at all
for the measured values & the sensitivity of detection is
by design, by scale of indication.

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ZEROING
• a compensation technique for
offset errors due to device to
device offset, variation (trim
errors), mechanical stresses
(mounting stresses), shifts
due to temperature and aging.

• For zero referencing for >0
measurements

• adjusting an instrument to
read zero manually / auto
zeroing

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SPANNING

- is adjusting the instrument to read the known
concentration of a gas / material / chemical

- Range of parameter which the unit/equipment can
measure

- Scale of measurement

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SPANNING & ZEROING

- are commonly performed during instrument
start-up or before calibration.

Ex.: The monitor’s combustible and toxic
sensors are zeroed (adjusted to zero) in a
known fresh air environment and the
oxygen sensor is spanned to fresh air
(21%). It is critical that this only be con-
ducted in a known fresh air environment.

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LINEARIZATION

To approximate a nonlinear system by a linear one
is called Linearization.

Ex.: Interfacing an NTC thermister to a computerized data acquisition
system linearization is used to convert the resistance output of the
thermister to voltage.

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CALIBRATION METHODS SELECTION

ensure laboratory selects and uses test and/or calibration
methods that:
• meet the needs of the customer
• are appropriate for the calibration task
• the customer has been informed of the method chosen (if not
specified)
• where appropriate, are based on latest international, regional or
national standards and where necessary the standard be
supplemented with additional details to ensure consistent
approach
• have been verified for use in the laboratory, if a standard
method

Ensure laboratory has competence to choose the appropriate methods

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CHAPTER - 3

STQC

Basic Requirements – Environment

 Temperature
 Humidity
 Air flow
 Filtration
 Electromagnetic Screening

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 Temperature
* Lab design to take into account heat generation through
personnel, equipment, light etc
* Recommended continuous & permanent recording
* Temperature monitoring to be installed at eqpt. or
operator level
* Avoid temp gradient through uniform air flow
* Precise metrology requires tight temp control &
measurement of actual temp. to apply meaningful
corrections
* Allow artifact / eqpt. to attain thermal equilibrium
(warm up)

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 Humidity
* Both low & high humidity to be avoided : static
electricity & leakage path
* 45 + 10% RH recommended for all general lab

 Air flow
* A well designed system to provide uniform air
circulation with out stratification to minimize temp
gradient in & around the lab
* Floor to ceiling vertical laminar flow of air is
recommended to minimize temp gradient to + 0.1 0C
* Air velocity of 0.71 + 0.28 cubic mts /minute
recommended (3 to 5 ft above the floor)
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 Filtration
* Provide filtration to limit particulates
* High degree of particulate control : optical, mass,
dimensional metrology etc.
 Electro-magnetic Screening
* Field strength to be less than 100μV/m
* For conducted electromagnetic energy on power lines,
open circuit voltage to be less than 100mV
* Provide adequate shielding/ filtering.

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Accommodation of Cal Lab.
Accommodation is the premises where the
laboratory functions are carried out.
Considerations :
• Design and construction materials
• Space including storage
• Services and facilities
• Access, housekeeping, security and
safety
• Separation of incompatible activities
• Area for administrative duties
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Control of Environmental Parameters

• Define critical environmental parameters that
affect quality of calibration result
• Define nominal values & tolerable limits
• Monitor environmental parameters
• Take remedial measures, if required
• Halt Calibration process, if environment is not
conducive.

Refer RP 6 on Laboratory Design

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Recommended Env. Conditions
- as per RPCL by CLAS in PALCAN Handbook published by Council of Canada

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ACCOMMODATION & ENVIRONMENT - TYPICAL

1. Clean & vibration free location for Monitoring &
Measuring devices.
2. Temperature : Ambient / 23 ± 1 °C OR 23 ± 2 °c
3. Humidity : 50 ± 10 %
4. Illumination level : 250 – 450 (700 lux)
5. Noise level – Below 60 dBA where meas. are affected
6. Rigid table for installation of equipment
7. Noisy vacuum source and Pneumatic cylinder to be
outside the calibration/inspection room/area

REFER NABL SPECIFIC CRITERIA 121 - 126

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Laboratory Storage Space
Storage must also be such as to not interfere
with test or calibration results.
Proper storage is needed for :
 Calibration jobs (current and retained)
 Working materials/consumables/adaptors/accessories/cables
etc.
 Laboratory documents
 Hazardous substances
 Staff belongings
 Clerical materials and equipment
 Laboratory records
REFER NABL SPECIFIC CRITERIA

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CHAPTER - 4

STQC

a) Handling, storage, preservation, transportation, safety &
security of Calibration unit/equipment/job
b) Customer requirements
c) Laboratory capabilities – availability of personnel, cal
facilities, technical competence, cal method,
accommodation & environment, traceability, sampling
etc.
d) Calibration – measurement data, computations,
uncertainty budget, compliance of results
e) Reporting results – preparation, approval, issue
f) Labeling
g) Post cal service activities

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Calibration Equipment

• is available and functioning properly
• is capable of achieving required accuracy
• complies with relevant specifications
• has calibration programs established for key quantities or
values
• is calibrated or checked before being placed into service
• is checked and/or calibrated before use (see 5.6 also)
• is operated by authorised personnel
• has current instructions on use and maintenance
• is uniquely identified, where practicable

Record of specification checking and maintained evidence.
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Equipment Records
• identity of the equipment and its software
• manufacturer’s name, model, and serial number or other
unique identification
• evidence that the equipment complies with the accuracy
requirements and specifications relevant to the tests or
calibrations
• current location, where appropriate
• the manufacturer’s instructions, if available, or reference
to their location
• calibration history and due date of next calibration
• the maintenance plan, where appropriate, and maintenance
carried out to date
• any damage/malfunction/modification/repair to the equip.

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Equipment handling
ensure procedures for measuring equipment are
documented and include:
• safe handling
• transport
• storage
• use
• planned maintenance –
Preventive/Breakdown/In-service Checks,
Intermediate Checks
• where applicable, that copies of correction
factors are correctly updated
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Equipment out-of-service
ensure equipment subjected to overloading or mishandling,
giving suspect results, or shown to be defective or outside
specified limits is taken out of service, and is:

• isolated or clearly labelled or marked as being out of
service
• examined for the effect of the defect or departure from
specified limits on previous tests and/or calibrations
• addressed under the “Control of nonconforming work”
procedure

Have a procedure for handling such situations
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Calibration Status
• Ensure equipment calibration status is identified
• Calibration labelling based on Cal agency
Label that indicates date of calibration due date for next
calibration, person responsible for calibration.
For items where marking cannot be done it e.g. Weights,
gauges, the status can be put in the Register/colour
coding etc.
• where practicable and where intermediate checks
are needed to maintain confidence in the
calibration status that a procedure is documented
to carry out these checks
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CALIBRATION AS A PROCESS

Process A – Preparation of list all test & measuring equipment that
need to be under calibration control.

Process B – Calibration of various test and measuring equipment
(in-house calibration), if facility exist.

Process C - Calibration of test & measuring equipment (from
external Calibration lab)

Process D -Verification of calibration results for compliance to
measurement requirements

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Measuring Equipment – Process Model

MEASURING PROCESS

I/P Sensor Instrumentation Display
O/P

Measurand Result

Sensor may not be required in every case

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Measuring Equipment

• Measuring instrument/system
• Software
• Reference standard/material
• Auxiliary apparatus/Adaptors/Accessories/Cables etc.
• Any combination of the above

Measuring equipment requires metrological confirmation

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Leading Instrumental Characteristics
• Range
• Error
• Resolution
• Drift
• Input Impedance (Loading effect)
• Compatibility between sensor & Instrumentation
• Input – Output relationship (characteristic)
• Hysterisis
• Ruggedness
• Mounting

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Checks on Measuring Equipment

• Mechanical Zero / Zeroing /Auto zero
• Check-up of readings during ascent & descent
• Check-up of resolution
• Check-up of linearity error, if any
• Repeatability of measurements
• Reproducibility of measurements

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Metrological Confirmation of Eqpt.

• Set of operations required to ensure that
measuring equipment conforms to the
requirement for its intended use.

- Brings in the concept of “Calibration”

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Calibration

• Comparison of an unknown measurement device
against an equal or better device (TUR/TAR)
• Unknown device is called
– Equipment under Calibration (EUC)
– Unit under Calibration (UUC)
– Device under Calibration (DUC)
– Device being Calibrated (DBC)
• Equal or better device is called “Standard”

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Calibration Process
• Identification of need/Customer’s requirements
• Availability of specifications for DUC
• Serviceability status of DUC
• Laboratory Capability
• Availability of validated method/competence
• Availability of Instruments /Standards
• Technical comparison of DUC with Instrument / Standards
• Repair / adjustment / recalibrate, if required
• Verification of Confirmation
• Uncertainty computation
• Preparation of Calibration Report/Certificate
• Status Identification

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CALIBRATION JOB FLOW

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Calibration - Job Flow Chart
Ext Int
Check points
Customer Service Y

N Y
Job Job card to SCL
Any
N
accepted
Non-confor- CERT. Cleared
mance
Calibrate
TP&C
Int. DUC
Compile result error/uncert.
Out of Spec
CERT. Issued
Fix label with Item
R&M

DUC with cal report
DUC after R&R EXT INT

TP & C
CAL
QA
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Calibration v/s Business Processes

Control of outside supplies
and services

Evaluati In-house Report and record Delivery /
Receiving Calibrations processing Shipping
on

In-house repair

Customers

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Role, Responsibilities & Authority
 Job descriptions
• HOL,Technical & Quality Managers
• Scientists and Technicians
• Attendants
• Those who verify, test and check
• Sampling officers
• Those who act in Emergency
 Performance Criteria
 Performance appraisal

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Laboratory Manager/Chief Executive

• Provide direction and coordinate the departmental activi-ties in
technical, commercial and service establishment
• Reviews and analyzes reports, records, and other information for
planning laboratory’s growth, such as new commitments, status of
work in progress and problem encountered.
• Assigns or delegates respon-sibility for, specified work or functional
activities and disseminates policy to down the line.
• Gives work directions, resolves problem and set deadlines to ensure
timely completion of work.
• Coordinates activities of various departments with related activities
of other departments to ensure efficiency and economy.
• Monitors and analyzes costs and prepares budget.
• Prepares reports and records on department activities for
management.
• Evaluate current procedures and practices for accomplishing
department objectives to develop and implement improved
procedures and practices.

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The Role of Quality Manager
• Assurance of Quality of Calibration Results
• Ensuring implementation of Management system
• Document Control activity
• Planning, conducting, compiling & analyzing Internal audit
programme
• Organizing, conducting Management Review &
maintaining records
• Monitoring corrective & preventive actions on non-
conforming cal services ensuring effectiveness
• Handling, investigating, analyzing & resolution of
Customer complaints
• Liaison with internal/external customers, accreditation
body w.r.t quality matters affecting calibration.
• Reports to Management
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The Role of Technical Manager
• selection, approval and commissioning of test methods
• Management and training of staff
• Evaluation and sign-off of staff competency
• Management of laboratory equipment and facilities
• Design and implementation of the QC programme
• Stopping work when QC criteria are exceeded
• Attention of matters relating to impartiality and
confidentiality
• Responsibility for the technical validity of results
• Liaison with the QM in relation to Quality matters
affecting testing or calibration.
• Reports to TM
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The Role of METROLOGIST
• Develops and evaluates calibration system that measure
characteristics of objects, substances, or phenomena, such as
length, mass, time, temperature, electric current, luminous intensity,
and derived units of physical or chemical measure
• Identifies magnitude of error sources contributing to uncertainty of
results to determine reliability of measurement process in
quantitative term
• Redesigns or adjusts measurement capability to minimize errors
• Develops cal-ibration methods and techniques based on principles
of measurement science, technical analysis of measurement
problem, and accuracy and precision requirements
• Directs engineering, quality and laboratory personnel in design,
manufacture, evaluation, and calibration of measurement standards,
instru-ments, and test system to ensure selection of approved
instrumentation
• Advises others on methods of resolving measurement problem and
exchanges information with other metrology personnel through
participation in govern-ment and industrial standardization
committees and professional societies
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The Role of Laboratory In-Charge
• Review/Acceptance/follow-up of jobs received from
customer service to meet committed PDC for the same.
• Preparation of calibration schedule if required and
Allocation of work
• Maintenance of lab. environment conditions ensuring
good house keeping
• Periodic monitoring of observations/ measurements/
compiled data during execution of the job & responsible
for the technical validity of results
• Preparations of test/cal procedures & implementation
after due approvals
• Qualifying label for the T&M equipment calibrated
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The Role of Laboratory In-Charge
• Maintenance of equipment in the qualifying condition
along with respective manuals/ technical data & history
log books ensuring traceability
• Maintaining registers used in the laboratory of the
laboratory area
• Co-ordination with lab. staff, customer service & other
support services
• Technical guidance to the laboratory personnel in
calibration & Implementation of the QC programme
• Attention of matters relating to impartiality and
confidentiality
• Liaison with the Quality Manager in relation to Quality
matters affecting calibration.
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Roles of Cal Lab. personnel
• Responsible for the calibration activity
• Carrying out Calibration as per standard/validated cal methods
• Preparation of Cal reports, affixing cal label on equipment calibrated.
• Building technical competence in the area of service being provided
• Any cal facility giving intermediate operation/ambiguous results/mal-
functioning should be immediately reported to LIC/TM
• Maintain the laboratory facility with appropriate use
• Maintaining calibration service related records
• Maintaining records reg. environmental controls
• Maintaining Calibration/Maintenance manuals of cal facilities & traceability
records
• Reporting to LIC/TM
• Any other as assigned from time to time
STQC

“Approved Signatory”
Personnel Technical Competence including:
 Relevant qualifications and/or experience.
 Close involvement in the day-to-day operations.
 Familiarity with test procedures including scientific basis
and technical limitations.
 Ability to make critical evaluation of test results.
 Knowledge of Quality Management system.
 Knowledge of and commitment to AB and their criteria
and ISO/IEC 17025.
 Sufficient time in the laboratory to become fully familiar
with the operating systems of the laboratory.
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SCHEDULING

- CALIBRATION INTERVAL

- CONFIRMATION INTERVAL

- RECALL NOTIFICATIONS

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Calibration Interval / Reports

Initial Calibration: Calibration adj. Final calibration:
Procedure adopted
Comparison To ensure the To confirm the
w.r.t tracking of the successfulness
common reference Measurand to that Of the operation
Either to know of reference
The deviation/value (cal adj.procedure
(measurand & Implementation)
Measurement (Report2)
Uncertainty
(Report 1) Report1-Report2

?

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Within Calibration Interval….

Effect of drift on uncertainty of
measurement

Uncertainty of measurement

Time

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Calibration Interval Management

Effect of right time cal. Adj.
on uncertainty of measurement

adjustment carried out

Uncertainty of measurement
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Scheduling Calibration Interval

• Client agreed
reported as ‘Client Agreed Calibration Interval - '.

• Client specified
reported as 'Client Specified Calibration Interval - '.

• Manufacturer's recommended
reported as 'Manufacturer's Recommended Calibration Interval - '.

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INITIAL CHOICE OF CI
• MANUFACTURER’S RECOMMENDATION
• EXTENT & SEVERITY OF USE
• MAX. ALLOWED DEVIATION
• UNCERTAINTY OF MEASUREMENT REQUIRED
• INFLUENCE OF ENVIRONMENT
• ADJUSTMENT/CHANGE REQUIRED
• PUBLISHED DATA ON SIMILAR DEVICES
• BY EXPERIENCE
• HISTORY OF EQUIPMENT
• QUALITY OF CALIBRATION & COST FACTOR

T&ME or M&ME ARE TO BE CALIBRATED WHENEVER THEY ARE REPARIED.
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OPTIMUM INTERVAL
A BALANCE BETWEEN THE COST TO CALIBRATE &
THE COST NOT TO CALIBRATE SHOULD BE
EVALUATED.

AT PRESENT THERE IS NO UNIVERSALLY
APPLICABLE SINGLE BEST PRACTICE FOR

ESTABLISHING AND ADJUSTING CAL INTERVAL.
STQC

RECALL NOTIFICATION

• INTERNAL EQUIPMENT

• EXTERNAL EQUIPMENT

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CHAPTER - 5

STQC

Manual Calibration
The traditional method of obtaining parameters, requiring extensive
training, time, and labor
• Availability of Calibration facilities / System
• Qualified & trained personnel
• Availability of suitable environment
• Traceability of standards
• Device under calibration
• Calibration Method (Validated)
• Measurement records
• Uncertainty computations
• Calibration Reporting
STQC

Automated Calibration

1. Computer Systems or Automated Equipment

2. Calibration software / Automated SW Program are
useful to process
• Large quantity of TME
• Lower skilled personnel
• Large volume of data used for capture, processing ,
recording, reporting, storage or retrieval of calibration data.

3. Interface / Compatible DUC

STQC

Examples: Automated Calibration
- to the extent supported by HW
1. DMM Calibration batch-wise

2. Batch temp. probe calibration

3. Batch Energy Meter Calibration

4. Calibration of ref. pressure transducers

5. Calibration of RF Power sensors

6. AC/DC Transfer standards Calibration

7. Etc..
STQC

Software Programme

• Design Application Software

• Develop/Construct Application Software

• Test Application Software

• Procure Application Software

• Operate Application Software

• Maintain Application Software

STQC

Major Elements of Software Programme

• Software development

• Software procurement

• Software Configuration Management

• Software operations

• Documents

• Record keeping

STQC

Software Development

• Quality planning based on requirements

• Multi-phased Software Life Cycle Process
– Requirements, design, construction, testing,
installation, operation, maintenance &
retirement

• Software Review, Verification & Validation

STQC

Software Validation

• Comparison of manual and
automated methods

• Inspection of procedure.

• Inter-laboratory comparison

STQC

Software Procurement

• Requirements & Activities

• Applicable Guidelines

• Dedicated/designed/custom made

STQC

Software Configuration Management

• Identification

• Change Control

• Status Accounting

STQC

Software Operations

• Access Control

• Backup & Recovery

• Problem Reporting & Corrective Action

STQC

Documentation/Records

• Software Design & Development Procedure
• Plan for Software QA
• Software Requirements Documentation
• Software Design & Implementation Documentation
• Software verification & validation Documentation
• User Documentation
• Standards / Specifications applicable

STQC

Automated Calibration
SAMPLE OF AUTOMATED AND MANUAL SYSTEM EQUIPMENT COSTS
(Fluke analysis)
Equipment Automated Manual
SPRT $ 3,000 $ 3,000
Recording thermometer $ 7,000
Nano volt meter / Mohm $ 3,500
Ice point reference for T/Cs $ 600
Dual Dry-Block –35 ºC to 670 ºC $ 8,900 $ 8,900
Computer $ 1,500 $ 1,500
Automated software $ 1,300
Report generation software $ 500
Total $ 21,700 $ 18,000

Automated batch calibration systems for industrial sensors may have
batch/volume efficiency advantages, in time savings and increased
productivity for calibration laboratories that find themselves with
increasing temperature probe workloads.
STQC

Internet Enabled Calibration
Recommendations as per NPL, UK Report CMSC 28/03

TECHNIQUES SECURITY ISSUES

• userid/password protection • Authentication
• Access Control
• Algorithms for encryption of
sensitive measurement data
• Confidentiality
• Integrity
• Message authentication • Non-repudiation
code for certificate, • Availability
Measurement data • Audit
• MySQL vulnerabilities • Privacy
• Certification
• Backups and fire safes • General Protection

STQC

STQC

CHAPTER - 6

STQC

Calibration Results

- Based on following technical records

• Original Observations

• Calculations/Computations and data transfers

• Calibration Report Format

STQC

Reporting Calibration Results

Report and Certificate format
• Appropriate to each type of
test/calibration
• For easy understanding / to
avoid misuse

STQC

Calibration Reports / Certificates
• Calibration Report
A calibration report usually provides a set of results that show the performance
of the instrument being calibrated in comparison to a reference instrument or
standard. Measurements are recorded for each function, range and points
tested, and the uncertainty of each measurement is reported.

• Calibration Certificate
A calibration certificate usually states the compliance of an instrument with the
manufacturer's specification. Measurements made by the instrument being
calibrated are compared to the manufacturer's specification. If the instrument
is within specification, a statement that the instrument meets the
manufacturer's specification at the points tested is made in the conformance
certificate. Any points that are outside specification, or not able to be
determined, are reported as exceptions. Assessment of meeting the
manufacturer's specification takes into account the measurement uncertainty.
A statement of conformance to the manufacturer's specification may also be
given in calibration reports.

STQC

Calibration Reports / Certificates

• Accurate, clear, unambiguous & objective
• No recommendation for Calibration interval,
unless asked for
• Confidentiality in electronic transmission
• Specified & approved format
• Specific statement for amendment
• Must include information requested by customer

Sample report/certificate formats refer NCSL, RP-11

STQC

Contents of A Calibration Report
a) A title -Test report/Calibration certificate

b) Name and Address of laboratory

c) Unique identification of the report/certificate

d) Name and address of customer

e) Identification of method used

f) Unambiguous identification of item

g) Date of receipt / performance of Test / Calibration

h) Reference to sampling plan / procedure
STQC

Contents of Calibration Report contd..
I) Test/Calibration results and units of measurement

j) Name, function, Signature of person authorizing the report/certificate

k) Statement-result related to the item Tested/Calibrated

l) Calibration Results with Units

m) Name(s), function(s) and signature(s) or equivalent identification of
person(s) authorizing the report or certificate;

n) Statement to the effect that the results relate only to the items tested
or calibrated, where relevant;

o) Subcontracted results clearly identified.

STQC

Calibration Reporting
Calibration Result Interpretation where necessary
ensure calibration certificates include the following:

• Calibration conditions
• Uncertainty of measurement
• Measurement traceability statement
• Statement of compliance with an identified
metrological specification or clause
• Compliance data records
• Repairs/adjustments if any
• Calibration Interval
• Estimated Uncertainty

STQC

STQC

Amendment/Supplement to Report

• Identification or reference to the original
report identity.
• when a complete new test report or
calibration certificate is required, it must
be uniquely identified and include a
reference to the original it replaces

STQC

Acceptance of Calibration Report

• Do you accept them or not?
• How do you know if they are okay to
accept?
• What are the related issues? What are the
steps to determine what is okay and what
is not?

STQC

Acceptance of Calibration Report
• evaluate the "scope of accreditation." The laboratory scope, which is
published with the accreditation or recognition certificate, defines the
parameters and associated uncertainties that have been assessed by
the accreditation bodies.
• An accreditation body logo
• evaluate standards to ensure suitability & Forward traceability report
5.6.2 Show unbroken chain of traceability from an instrument to
national standards.
• Rights to revoke acceptance of certificates for cause (bad
measurement results) & seek clarifications
• Calibration certificate contents as per 5.10 of ISO/IEC 17025.
• Due for calibration 5.6.1 – determine instrument exceeded cal interval.
• Reverse Traceability report 4.9.1- Identify all the instruments that
are affected if corrective action is neccessiated

STQC

HANDLING DEVIATIONS
- FROM CALIBRATION QUALITY LEVEL

1. Interval adjustment
2. Procedure Changes
3. Specification Revision
4. Derating or limited Calibration
5. Removal of equipment from services
6. Instrument Repair & Recalibration
7. Upgradation of equipment
8. Replacement

STQC

CALIBRATION LABELLING

Valid Calibration: when all instrument parameters have been calibrated &
meets the manufacturer’s specifications. If not affix following type of labels.

LABELING LIMITAION OF USE (Refer NCSL RP- 6)

Labeling location, content, color & size depends on Calibration agency
STQC

External Calibration

When Cal Service is subcontracted, ensure:
Approval from customer, preferably in writing,
when the lab intends to subcontract.
Ensure and demonstrate subcontractors
competence through evaluation & review
Laboratory’s responsibility for subcontractors
work.
Maintain a register of all subcontracting work

STQC

External Calibration
When Cal Services is availed, ensure:

 Credibility of Cal agency through accreditation & scope of accreditation
covering your requirements

 Gain confidence in their services through visits/audits on:
– type of calibration service
– applicable documents, technical reference, or standard
– equipment specification
– service performance requirements
– physical, environmental, and data-format requirements
– safety and biohazard requirements
– confidentiality and security requirements
– certificate of calibration requirements

STQC

CHAPTER - 7

STQC

REQUIREMENTS FOR DOCUMENTING RECORDS

1. ISO/IEC 17025:2005, clause 4.12, paragraph 4.12.2.1, states: "The laboratory
shall retain records of original observations, derived data. . . to estab-lish an
audit trail . . . for a defined period. The records for each calibration shall contain
sufficient information to . . . enable the test or calibration to be repeated."
Paragraph 4.12.2.2 states: "Observations, data and calculations shall be
recorded at the time they are made. . . ."
2. ISO 9001:2000, clause 7.6.on Control of Monitoring & Measuring equipment.
3. ISO 14001:2004, Clause 4.5.2 on equipment used for environmental
maesurements.
4. ISO 10012:2003, clause 6.2.3 states: "Records containing information
required for the operation of the measurement management system shall
be maintained. Documented procedures shall ensure the identification, storage,
protec-tion, retrieval, retention time and disposition of records."
5. NCSLI RP-6, clause 5.6, Records, states: "Records should be maintained for all
test and measuring equipment that is included in the calibration system

STQC

Why Calibration Records are necessary?

• Understanding the relationship of historical data
and stability of a standard
• As Found, and when needed, As Left readings
giving reliability of equipment
• Log book of Instruments logging Calibration
history on maintainability
• Trend of measurements from periodic Calibration
Reports
• Authentication of Calibration Data/Results

STQC

Calibration Records
• Service Request Forms
• Work Orders/Job Orders
• Planning / Job allocation Records
• Observations/data computations/Measurement sheets, Uncertainty
Budget records
• Preliminary performance/verification records
• Calibration records of equipment used for cal. Control Charts on
trends of calibration standards
• Calibration Report / Certificates
• Replicate/ Retesting records
• Training records
• Proficiency/ Inter-laboratory Comparison records
• Nonconforming calibration, Customer complaints, CA/PA records
• Calibration System Audit records
• Repair/Adjustment/Maintenance Records STQC

Management of Calibration Records

• Legibility & Indelibility of records
• Identification of records
• Storage of records
• Maintenance/Preservation of records
• Retention & Disposition of records
• Amendment of records with authentication

STQC

STQC

Calibration systems

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