SOP for Inhouse Calibration

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Company Name Standard Operating Procedure for in-house calibration of various items in the Laboratory

1. Introduction

In compliance of SOP No. Date. Revision No. Pages

ISO 17025 : 2005 ATL / IHC / 01/08/2013 00 1/7

:

In house calibration is an accepted practice for most of the industries. Aimil Testing Lab follows the same practice for the in-house calibration of inspection/measuring and testing equipment as per the working standards and as per written and authorized procedure. While doing so, Aimil Testing Laboratory takes into account the following: a)

An appropriate environment for carrying out the calibration

b)

Appropriately trained personnel to both carry out and check the calibrations.

c)

Reference Standards, Certified Reference materials or reference measuring instruments that are traceable with appropriate measurement uncertainties.

d)

A documented procedure, for each type of calibration.

e)

An appropriate means of recording and reporting the data and results of Calculations; and finally,

f)

A measurement uncertainty budget and calculations associated with it and a suitable report to authenticate and document the calibrated status of the items. The responsibility of in-house calibration of inspection/measuring and testing equipment in Aimil testing laboratory lies with Technical Manager (TM). Following is the record of procedure for the in-house calibration of inspection/measuring and testing instruments which elaborates periodicity status of the calibration.

2. Scope

: This standard Operating Procedure specifies the requirementsfor Commonlaboratoryequipments, the calibration procedures and the reagents for the testing of the properties of various laboratory tests covered under the NABL accreditation scope of Aimil Testing Laboratory.

3. Definitions

:

For the purpose of this SOP, the following Definitions apply

1.

Calibration Set of operations that establish, under specified conditions, the relationship between values of quantities indicated by a measuring instrument or measuring system, or values represented by a material measure or a reference material, and the corresponding values realized by standards.

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Standard Operating Procedure for in-house calibration of various items in the Laboratory


ISO 17025 : 2005 ATL / IHC / 01/08/2013 00 2/7

2. Reference Standards for in-house Calibration These are the standards, whose certificate of calibration and the associated uncertainty declared therein are un-brokenly traceable to National / International Standards. 3. Devices / Equipments These are the objects / accessories that form part of measurement systems / equipments / accessories used for testing of some or all of the parameters that are covered under the scope of accreditation. 4.

RESPONSIBILITY

:

The overall responsibility for implementation of this procedure lies withthe technical manager and individual responsibility is assigned by the technical manager based on competency of the individual staff concerned.

5. ABBREVIATIONS AND DEFINITIONS: SOP DUC TM QM

: : : :

Standard Operating Procedure Device Under Calibration Technical Manager Quality Manager

6. ACT and METHODS Sl.No. 5.1

5.2

5.3

5.4

5.5

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Activity Responsibility Calibration schedule is monitored periodically such that whenever a device is due for calibration, it is TM taken up for recalibration before the due date. Identify the staff individual and assign the in-house calibration task based on the individual staff TM member’s competency. Periodically verify the calibration procedure and update / modify procedure to align to the current TM requirements if any. Verify the physical conditions and the status of the calibration Master equipments used for in-house TM/Staff calibration are valid and has an unbroken chain of assigned traceability Calibrate the device as per the method appropriate Staff assigned

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Reference F / IHCR / 5.5 Staff training record Calibration

Calibraion Master Records

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5.6

5.7

5.8

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Once the in-house calibration is completed, check the calibration data and the details of calculation of TM the uncertainty therein and prepare a in-house calibration certificate as per format Decide the calibration intervals based on the consistent performance of the device being calibrated and its stability of performance and the TM actual practical usage in day to day work. Also take into consideration any specific criteria of NABL / BIS or any statutory requirements. Fix a Status sticker on the device immediately after TM / Staff the calibration. assigned

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ISO 17025 : 2005 ATL / IHC / 01/08/2013 00 3/7 In-house calibration certificate format

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ISO 17025 : 2005 ATL / IHC / 01/08/2013 00 4/7

Details of the in-house Calibration Methods: 1. Slake Durability Apparatus: The only parameter that require verification is the speed of rotation of Drum, which is to be held constant at 20 + / - 1 rpm for a period of 10 minutes. Step 1: Check the cleanliness of the Instrument and load the drum with appropriate quantity (weight )of material usually, 400 to 600 gms . Step 2: Make a mark on the periphery of the drum using a permanent marker Step 3: Switch ON the machine. The drum will start rotating. Make a reference point, external to the drum. Two successive crossing of the mark made on the drum will constitute one rotation of the drum. Step 4: Using a calibrated stop watch, which is set to ten minutes count down, count the no. of rotations of the Drum every minute. Step 5: Record the time interval in minutes Vs No. of rotations of the Drum as shown in the table and evaluate the variations in RPM at every minute interval for at least 10 minutes. Exactly at the end of the set time, switch off the machine. If the observed RPM of the Drum when loaded is 20 +/- 1 RPM, the apparatus is said to meet the requirement of IS : 10050. There is no requirement of making an uncertainty budget for this function. Prepare the calibration certificate as per standard in-house calibration certificate format.

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ISO 17025 : 2005 ATL / IHC / 01/08/2013 00 5/7

2. Laboratory oven. Step 1: Ensure that the oven to be checked is kept in good working condition. Ensure there are no loose connections resulting in intermittent working. If there are issues call the maintenance people and fix the problem before attempting to calibrate the Oven. Step 2. Using a Calibrated thermometer, measure the ambient temperature. Compare the reading with the reading shown in the digital temperature read-out of the oven. If there are initial adjustments required to set the ambient temperature, make suitable adjustments and ensure that the read-out on the oven and the calibrated thermometer read similar values. Take three readings at suitable intervals say 30 minutes each in order to record the stability / repeatability of the temperature control. Step 3. Now, set the Oven temperature controller to the maximum working temperature required. Allow the oven to reach the set maximum temperature and allow the temperature to stabilize for a period of one hour minimum. Using the Calibrated thermometer, verify the oven maximum temperature. Take three readings at suitable intervals say 30 minutes each in order to record the stability / repeatability of the temperature control. Step 4. Choose few temperature settings in between the ambient and maximum operational range, say about five discrete zones, which will cover the calibration range into seven zones. Take three readings at suitable intervals say 30 minutes each in each of the defined zones covering the operational range in order to record the stability / repeatability of the temperature control. Step 5. From the recorded readings, estimate the zero shift error if initial value is not adjustable and also the temperature repeatability values at each of the zones for which the readings are taken.

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ISO 17025 : 2005 ATL / IHC / 01/08/2013 00 7/7

Step 6. Compute the uncertainty calculations as per the budget given below.

Standard Uncertainty +/- ⁰C Thermometer certificate 1.01 Normal B 2 0.55 Dial Setting Included as part of temperature repeatability Zone Differential 1 Rectangular B √3 0.577 Temperature Repeatability 1 N A 1 0.5 Combined Standard Uncertainty (RSS) = +/- 1.505 Coverage factor k=2.45 Expanded Uncertainty = 2.45 X 0.641 ⁰C = +/- 1.57 ⁰C Source of Uncertainty

Value ⁰C

Distribution

Type

Devisor

v= v (uc/uA)4= 2( 1.505/2)4

≈ 0.641 ( the coverage factor for 6 degrees of freedom is 2.45.) A

Step 7. Prepare a Calibration certificate as per in-house calibration certificate format.

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ISO 17025 : 2005 ATL / IHC / 01/08/2013 00 7/7

3. Method for Dimensional Calibration to ensure functionality of the moulds used in Testing. ( Cubemoulds, cylindrical moulds etc…) Step 1: Ensure that each mould carry a unique identity number and that all the individual parts of the moulds are not mixed with another mould. This is possible when one mould is taken for calibration at a time. Step 2: Before making any dimensional measurements, ensure that the moulds are clean and it is kept in the calibration environment for at least few hours before making any measurement of the dimensions. Step 3: Using a calibrated vernier calipers, make the dimensional measurements and record the values. Make repeated measurements and record the values to ensure Type A component is included. The temperature and cosine errors are categorized under type B uncertainty.

Source of Uncertainty

Value mm

Distribution

Type

Devisor

Vernier Calipers certificate Resolution Cosine Errors Temperature Measurement Repeatability Combined Standard Uncertainty Coverage Factor k= 2

0.015 0.02 3 Deg 0.05 0.02

N (k=2) Triangular R R R

B B B B A

2 √6 √3 √3 √3

Standard Uncertainty +/- ⁰C 0.0075 0.049 0.046 0.029 0.011

0.0126 Expanded Uncertainty= 0.025 mm

Step 4: Make out a Calibration certificate as per in-house calibration certificate format. 7.Records Generated : In-house Calibration Certificates as per format

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SOP for Inhouse Calibration

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