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 its operations. This includes those presented by laboratory equipment. Assessing the risks associated with laboratory equipment also allows for development of mitigation of those risks to be implemented 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, use of one of the risk assessment tools provides for such assessment to be made in a consistent manner. As the assessment tools allow for considerable customisation to meet the requirements of the user, a procedure should be implemented to provide instructions on how to carryout 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 to consistently assign categories, or numerical values, in a consistent manner, 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 frequency that is sufficient to maintain confidence in the calibrated status of the equipment. The frequency of calibration should be consummate with the risk associated with the equipment. This will usually be dependent 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 that were, reported to customers.
2. Quality Non – Critical is all equipment that although not used to make measurements which are either reported, or incorporated in to results that are reported, to the customer, but 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 that are, 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 is 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, it need not be calibrated.
The frequency of use is the other key criterion used to determine frequency of calibration. Equipment with moving parts, used daily to make measurements that are either directly, or incorporated into results that are, reported to customers should usually be calibrated at intervals not exceeding twelve months. However, the actual frequency should be determined from an assessment of 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:
Following initial installation of equipment
Prior to, if possible, and after repair of the equipment
Prior to and after relocation of static equipment
If there is reason to doubt the validity of the calibration
The parameters that will be calibrated, together with 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 in accordance with 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 prior to the PM being carried out, and after preventative maintenance has been carried out.
7 Performance Qualification
Performance qualification (PQ) can be considered as documented evidence that provides a high level of confidence the equipment is consistently performing to prescribed criteria. Performance qualification consists of periodic, often daily, checks on equipment that creates 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 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 also needs to provide instructions on how to perform these checks and the results of these checks. The valuable results of performing periodic checks are 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.