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David Trew

Consulting Ltd

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

Part 1: Classifications of Laboratory Equipment

2.2 Measuring Instrumentation Categories

The risks associated with laboratory instrumentation usually increase significantly as the complexity of the instrumentation increases. Thus, the effort required to provide the required level of confidence that the instrument can provide valid results is often dependent on the complexity of the respective equipment. Therefore, classifying instrumentation according to its complexity will ensure that instrumentation of similar complexity is calibrated and maintained to a level that is constantly consummate with risks associated with the instrument.

The scheme presented here is particularly useful in laboratories carrying out physical testing or calibrations.

1. Category 1 includes standard equipment with no measurement capability but are used to establish a reference standard. Examples of equipment in this category are standard weights used to calibrate balances and fixed-point temperature cells, such as the water triple point cell, used to calibrate thermometers.

2. Category 2 includes standard equipment and instruments that are capable of measurement but have no capacity for adjustment. Examples of equipment in this capacity include platinum resistance thermometers and float densitometers.

3. Category 3 includes commercial off the shelf equipment that is either:

i. Firmware controlled

ii. Controlled by software with limited functionality and internal to the equipment

iii. Capable of independent adjustment in order to conform to specifications

iv. Does not have a computer with a full operating system controlling the system

Examples of equipment in this category include: a precision thermometry bridge, pH meter, laboratory balance.

4. Category 4 includes commercial off-the-shelf equipment with a computer with a full operating system driving the equipment. But which have no capacity for configuration, apart from that required to enable users to operate the equipment and to assign user privileges. This category includes UV and FTIR spectrophotometers and gas and high-performance liquid chromatographs (HPLC).

5. Category 5 includes commercial off-the-shelf computer-driven equipment connected to a computer network, with single or multiple terminals capable of controlling, and/or monitoring, and/or processing data from multiple sensors or instruments. Examples include a networked environment monitoring system or a networked instrument control, data capture and processing system.

When a new instrument is added to an existing network, such as adding a new HPLC to an existing data collection network, a question that can arise is should this be treated as a category 5 instrument or some other category that is determined by the characteristics of the instrument, as if it was not connected to the network, for example, an unnetworked HPLC is a category 4 instrument, but should it be treated as a category 5 instrument if it is added to an existing network of instruments? This needs to be clarified in the respective standard operating procedure. There are several potential solutions to this type of scenario. Probably the easiest is to apply change control procedures and/or establish a process addressing the addition of new instruments and sensors to the respective network when it is first installed.

6. Category 6 includes all bespoke equipment.

2.3 Analytical Instrumentation Categories

This system applies to laboratories that carry out chemical testing.

1. Category 1 includes standard equipment with no measurement capability or usual requirement for calibration. Examples of equipment in this group are nitrogen evaporators, magnetic stirrers, vortex mixers, and centrifuges.

2. Category 2 includes standard equipment and instruments providing measured values and equipment controlling physical parameters (such as temperature, pressure, or flow) that need calibration. Examples are balances, melting point apparatus, light microscopes, pH meters, variable pipets, refractometers, thermometers, titrators, viscometers, muffle furnaces, ovens, refrigerator-freezers, water baths, pumps, and dilutors.

3. Category 3 includes instruments and computerised analytical systems, where user requirements for functionality, operational, and performance limits are specific for the analytical application.

4. Category 4 includes all networked or customised instruments and customised analytical systems. The comment discussed category 5 equipment in Section 2.2 also apply here.

5. Category 5 includes all bespoke equipment

2.4 Software Categories

All equipment with associated software shall be allocated a software category according to the following criteria:

1. Category 1 Infrastructure Software. This includes:

Operating systems


programming languages


office software

statistical programming tools and spreadsheet packages.

network monitoring software



help desk

IT configuration management tools and other network software

2. Category 2 Firmware; This is software embedded into a piece of laboratory equipment, such as laboratory balances, pH meters or digital thermometers, to make it work.

3. Category 3 Non – Configured Software: This software can be installed and can operate without modification. Included in this is the software that controls much of the analytical equipment used in the laboratory, such as spectrophotometers and chromatographs.

4. Category 4 Configured Software: This software can be configured by the user to optimise its performance to meet the user’s requirements. Included in this is software that controls networked equipment and data collection and monitoring systems. Also included in this category are configured Excel spreadsheets not containing macros.

5. Category 5 Custom Software: This is software that has been developed and written for a specific organisation and purpose, including applications containing a configuration or scripting language that allows the user to modify a program’s functions and includes macros for Microsoft Office applications.

3 References

1. ISO/IEC 17025:2017 General Requirements for the Competence of Testing and Calibration Laboratories. International Organisation for Standardisation, Geneva, 2017

2. UKAS Guidance LAB 11 Traceability of Temperature Measurement: Platinum Resistance Thermometers, Liquid-in-glass Thermometers and Radiation Thermometers, Ed 4, United Kingdom Accreditation Service, Staines-upon-Thames, 2012

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Please Click Here to Find Out How David Trew Consulting Ltd Can Help Your Laboratory Manage its Equipment in an ISO 17025 Environment