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Management of Equipment in an ISO/IEC 17025:2017 Accredited Laboratory

Part 2: Equipment Lifecycle Models


5 Risk Assessment

Clause 8.5 of the ISO/IEC 17025:2017 International Standard requires laboratories to consider the risks associated with their operations, including those presented by laboratory equipment. Assessing the risks associated with laboratory equipment also allows for the development of mitigation of those risks and their implementation during installation, calibration, and daily use (performance qualification) of the equipment. The procedures for assessing the risks associated with laboratory equipment should be the same as those associated with all aspects of the laboratory’s activities.


Although not required by the ISO/IEC 17025:2017 International Standard, using one of the risk assessment tools provides for such assessment to be made consistently. As the assessment tools allow for considerable customisation to meet the user’s requirements, a procedure should be implemented to provide instructions on carrying out an assessment. Some assessment tools require the level of risk to be assigned to a category (such as high, medium, and low) or assigned a numerical value depending upon the severity of the consequences associated with the respective risk. To help users consistently assign categories or numerical values, laboratories should establish criteria for assigning categories or numerical values. The procedure should also explain the records  to be retained  

 

6 Calibration and Preventative Maintenance

Clause 6.4.7 of the ISO/IEC 17025:2017 International Standard requires laboratories to establish a calibration program. Laboratory equipment needs to be calibrated at a sufficient frequency to maintain confidence in the calibrated status of the equipment. The calibration frequency should be consummate with the risk associated with the equipment; this will usually depend on the use of the equipment and its frequency of use. The previous paper2 in this series discussed the concept of quality criticality, advocating applying the following levels to laboratory equipment

1. Quality Critical is all equipment used to make measurements that were either directly or incorporated into results reported to customers.

2. Quality Non–Critical is all equipment that, although not used to make measurements that are either reported or incorporated into results reported, to the customer, is used to assure the quality of such measurements or results.

3. Non–Critical is all equipment not used to make measurements or produce results that are reported to the customer, nor used to assure the quality of the results that are reported to the customer.


This classification is useful when making decisions regarding the interval between calibrations. As equipment assigned to the quality critical category is used to make measurements that are either directly or incorporated into results reported to customers, it will usually present a greater risk than equipment assigned to the quality non – critical category. Equipment assigned to the quality critical category should be calibrated more frequently than equipment assigned to the quality non – critical category. As equipment assigned to the non – critical category is not used to make measurements or produce results reported to the customer, nor used to assure the quality of the results reported to the customer, it need not be calibrated.


The frequency of use is the other key criterion used to determine the frequency of calibration. Equipment with moving parts, used daily to make measurements that are either directly or incorporated into results reported to customers, should usually be calibrated at intervals not exceeding twelve months. However, the actual frequency should be determined by assessing how long it could reasonably be expected to remain within the established specification. In addition, to periodic calibration, equipment needs to be calibrated as follows:

1. Following initial installation of equipment

2. Before, if possible, and after repair of the equipment

3. Before and after the relocation of static equipment

4. If there is reason to doubt the validity of the calibration


The parameters that will be calibrated and their respective specifications should be established as operational requirements during the selection phase. The parameters to be calibrated should be discussed in the equipment procedure required by Clause 6.4.3.


Preventative maintenance (PM) should, at least, be carried out according to the manufacturer’s recommendations. If preventative maintenance may affect the calibration status of equipment, the calibration needs to be performed both before to provide evidence that the instrument was operating within specifications before the PM being carried out and after preventative maintenance has been carried out to provide evidence the PM did not affect the equipment’s performance.


7 Performance Qualification

Performance qualification (PQ) can be considered documented evidence that provides a high level of confidence the equipment is consistently performing to prescribed criteria. Performance qualification consists of periodic, often daily, equipment checks that create evidence the instrument conforms to predetermined criteria. Examples of these checks include checking:

1. The balance readout when a specific weight is loaded

2. The output intensity and stability of a UV spectrophotometer lamp

3. Conductivity and total organic carbon content of purified water


The periodic checks need to be discussed in the procedure required by Clause 6.4.3. This procedure also needs to provide instructions on how to perform these checks and record the results of these checks. The value of performing periodic checks is that they provide prewarning of a possible instrument failure and provide evidence of acceptable previous performance should the instrument be damaged or fail a calibration. Thus, reducing the need to perform retests or recalibrations in the event of instrument damage or calibration failure.


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