Excel calibration certificate template
Excel calibration certificate template
This article provides details of Excel calibration certificate template that you can download now.
A calibration certificate is a digital file that contains all the information relating to a certified calibration.
ADVANTAGES OF THE ELECTRONIC CALIBRATION CERTIFICATE
Like any file, an electronic calibration certificate can be:
- Recorded on digital media (hard disk of PC, network, CDROM / DVD and on the internet
- Sent by email within your organization or to your customers
- Kept in your databases
- Included or linked by hyperlinks in your documents
- Printed on demand as often as you like.
Microsoft Excel software under a Windows environment is required to use this template
These Excel calibration certificate template, work on all versions of Excel since 2007.
Examples of a ready-to-use spreadsheet: Download this table in Excel (.xls) format, and complete it with your specific information.
To be able to use these models correctly, you must first activate the macros at startup.
The file to download presents four Excel calibration certificate template
Objective Of Calibration
- The prime objective of calibration is to ensure that measurements taken are accurate at all times taking into consideration wear and tear, degradation and abuse. It is with this in mind that we need to adopt and appropriate methodology to do a proper calibration.
Scope of Calibration
In developing a calibration program, the following should be taken into consideration :
- Involve all testers or those who use measuring and test equipment
- Calibration must be conducted on all equipment used to verify product compliance.
- Engineering measuring equipment must all be calibrated.
Hierarchy of Standards
- The hierarchy of standards used in a calibration is shown asfollows :
- Primary or National standards are the ultimate reference standards for determining a measurement. As an example, a standard measurement of a meter is set by a steel rod of this length which is the primary standard. All other standards used to conduct a calibration must be checked with reference to this standard from the working to the reference standard
- Working standard used to calibrate internal measuring equipment must be traceable to either a National or Primary Standard. In addition, their accuracy must be 4 to 10 times more accurate compared to the equipment to be calibrated. For instance, portable water analyzer such as pH meter, NTU meter with the standard measurement scale, can be calibrated internally by using the standard solution that provided.
- Occasionally, an equipment may be state of the art and hence, there is no reference standard available. In this case, this equipment can be calibrated with another equipment of the same type, make and model.
Traceability of Calibration
- In a country, a calibration must be traceable to a National Standard held by a national body (eg. SIRIM or other government agencies of Malaysia). If this national standard is not available. The calibration must be traceable to another country. Traceability of a calibration is important as an incorrect reference standard used will not ensure that the equipment calibrated has the required accuracy.
- As most companies send out their equipment for calibration, mandatory that they check the capability of the calibration agent. Those that are certified to the ISO 9000 Guide 25 will be able to provide an appropriate traceability. For others, you will need to check the reference standards used and their respective traceability.
Factors to Consider in a Calibration
- Calibration Environment
- Interval of Calibration
- Accuracy of Standard Master
- Out of Tolerance Equipment
- Subcontractor Controls
- Uncertainty of Measurement
- Handling the Storage
- Identification and Status of Calibration
- Documentation and Records
Environment conditions which could affect a calibration are as follows. This will largely dependent on the sensitivity of an equipment to the various conditions. Consult the equipment manufacturer to determine the appropriate environmental conditions required to do a calibration.
- Air Movement
- Magnetic Field
Some examples where controlling certain environment factors is critical for the different types of measurement are as follows :
- § Chemical Analyses – pH value and NTU are critical
Interval of Calibration
- Interval between one calibration to another is an important aspect to ensure the continuing accuracy of an equipment. This must be established for all measuring and test equipment, each may be set at different intervals dependent on the degree of usage and other factors such as:
- Frequency of Use
- Purpose of Use
- If you are unsure which is the best interval to choose, always follow the equipment manufacturer’s recommendations. This interval should be reviewed from time and as a rule of thumb, it should be adjusted based on the calibration history. For example, if an equipment is calibrated on a six monthly basis and it is found to be out of calibration frequently, then the calibration interval should be changed either 2 or 3 monthly.
- What actions and the calibration interval on the equipment would you recommend to the user for the following :
- An instrument is found to have failed 2 times in the last 2 calibrations performed at 6 monthly
- A newly purchased pH on-line analyzer which will be used in production daily. Calibration interval recommended by manufacturer is 3
- A Magnetic Flow Meter used to measure the flow of water with specification of 0.5 to 1 %
Accuracy of Magnetic Flow Meter is 0.5 to 1% with Calibration interval of yearly using the Flow Meter Verificator.
ACCURACY OF REFERENCE STANDARD
- As discussed in the previous section, the reference standard used to do a calibration must be at least 4 to 10 times more accurate than the equipment. In general, a 95% confidence level is preferred and this gives a + 2 sigma (standard deviation) or 4 sigma capability in a measurement.
OUT OF TOLERENCE EQUIPMENT
- When an equipment is found to be out of tolerance or not having the required accuracy, certain steps must be taken. Actions to be taken include decisions on whether the equipment can be used or not and what needs to be done on the affected products as follows :
- Review all measurements prior to and after adjustment is made to the affected equipment.
- Decide on whether the equipment can be used or has to be thrown away or used for lesser accuracy measurements.
- Review previous batches of products ( 1 week or more) where measurements have been taken using this out of tolerance equipment prior to and after an adjustment has been made to correct the out of calibration situation. Decide whether they meet specification or not.
- If the equipment can be used but needs correction to their readings, then the compensation or offset factors must be stated on the equipment.
- In choosing an appropriate subcontractor to perform your calibration, it is critical that an accredited calibrating lab or agent is used (those certified to ISO 9000 Guide 25). Ask for a copy of their certification before selecting them. You will also need to ensure that the reference standards used by the calibrating lab or agent is traceable to national standard. The calibration method used should also be checked to ensure they used an appropriate or recognized procedure. Both of these requirement can be verified on their Certificate of Calibration, which is issued to you upon completion of a calibration for each set of equipment.
Uncertainty Of Measurement
The uncertainty of measurement of a calibration needs to be calculated to determine all the possible sources of errors. It is given by the formula :
Uncertainty of Measurement = + t (from a Students t-table) x s (standard deviation of variation).
As a rule of thumb, the uncertainty of measurement must not exceed 30% of the tolerance of a measurement. If it does, it’s mean that the equipment is not suitable for use as its required accuracy is not sufficient. A measurement taken using this equipment will give a false or inaccurate value.
Handling and Storage
- The proper handling and storage of measuring equipment and their reference standards are an essential part of establishing an effective Calibration Program. Some of the guidelines to follow are as follows:
- Handling – ensure the equipment is appropriately handled during use, storage and transportation.
- Proper Storage – ensure equipment is stored in their respective casing or special storage container under appropriate environmental conditions as required.
- Proper Packing for Transportation – ensure the equipment is appropriately packed to protected them from movement and damage during transportation (eg. Use “bubble bags” or impact absorbent materials).
- Check that the calibration status is valid before issuing an equipment for use (especially newly purchased equipment).
- Ensure that the equipment is appropriately sealed with a tamper-proof sticker or marking, etc to prevent unauthorized adjustment or repair.
Identification and Status of Calibration
- Upon completion of a calibration, each equipment must be appropriately labeled to indicate their status. Depending on the size of the equipment, it may not be possible to attach a calibration label on all instruments. For an equipment such as thermometer it may not be practical to stick such a label. Therefore, other means such as color coding can be used instead of a label to indicate their calibration status. Alternatively, the label may be attached to the casing or container.