IRR17 (32) - Duties of manufacturers etc of articles for use with work with ionising radiation (including critical examinations of x-ray equipment and other sources)
Published: Sep 29, 2021
Source: Ionactive Radiation Protection Resource
[Updated February 2025 with regards critical examination of portable / mobile x-ray equipment (particularly in the medical sector)]
Some definitions (supplier, article, substances)
This regulation extends the provisions of the Health and Safety at Work etc. Act 1974 (HSWA). In relation to work involving ionising radiation, this regulation requires that an appropriate critical examination of equipment is undertaken after installation. This regulation applies to suppliers of material goods, i.e. ‘articles’ or radioactive substances.
The aim of this regulation is to ensure that consideration is given to radiation protection throughout the supply chain, from design, through to manufacture, during supply and at the point of installation. The RPS and Radiation Protection Adviser are likely to be involved with the installer, during the critical examination.
For the purposes of this regulation, and its link with HSWA, a supplier can be defined as:
- someone who supplies articles or substances by sale, lease or hire (regardless of being a principle or agent in the supply chain), and will include designers, manufacturers, importers, installers and erectors etc.
In addition, an article can be defined as:
- any plant, machinery, equipment or appliance that is designed for use by persons at work, and this will also extend to any component of any article.
In the above definition is should be noted that an article will include equipment that produces adventitious radiation as well as intentional radiation. An example of this might be a radar installation which produces radar waves, but where the equipment may also produce adventitious x-rays.
Substances will mean:
- a sealed or unsealed radioactive substance, which could also include radioactive contamination.
The regulation requires that radiation protection considerations are incorporated into the design and construction stages of manufacture and are not left to the end user.
Critical examinations
There is no legal requirement for the Radiation Protection Adviser (RPA) to be directly involved in any critical examination. However, it is a requirement that the RPA:
- advises on the nature, scope and extent of the critical examination.
- gives advice on the results of any examination; ensuring that the safety features and devices designed to restrict exposure are functioning as intended.
- advises on how the results should be presented and retained.
Generally it is Ionactive experience that:
- For simple uses of ionising radiation (e.g. bench top x-ray QA unit) the installation / service engineer of the supplier will set up the equipment and carry out a critical examination.
- For higher hazard installations (e.g. linac / HASS / irradiators) the RPA for the installer is usually involved directly in the critical examination process (often working with the end user RPA / RPS).
When a new piece of equipment (an article) arrives on site which emits ionising radiations (whether entirely contained or otherwise), the person installing shall:
- where appropriate, undertake a critical examination of the way that it was erected or installed, for the purpose of ensuring in particular the safety features and warning devices operate correctly and there is sufficient protection for persons from exposure to ionising radiation.
- consult with the Radiation Protection Adviser appointed by himself, or the radiation employer (where the article is being installed), with regard to the complexity and extent of the critical examination and the results of that examination.
- provide the employer (who will use the article) with adequate information about proper use, testing and maintenance of the article (including a written record of the examination).
The RPS at the site when the equipment is being installed is very likely to be involved in the critical examination, if only to ‘supervise’ the work if it’s taking place in a designated area. Furthermore, many RPSs are also the users of the equipment and so have a personal interest in knowing that they have been installed and tested correctly.
Alternatively, for the higher hazard facility, at the point the critical examination is being carried out, the area may be under the control (so far as IRR17 is concerned) of the supplier, rather than customer (until the area is handed over).
The critical examination should test the article (radiation source) under the most extreme conditions likely to be encountered in normal usage and check that all safety features / interlocks / signs and signals are operative. The user must be informed of the results of the test, including results of proven performance and operational limitations.
This requirement for testing applies only to those aspects of the equipment that have a bearing upon radiation protection. Where articles are supplied for use in work with ionising radiation that have wider areas of application, then unless specific contractual arrangements have been made regarding suitability, the responsibility for testing will reside with the employer who is the customer, rather than the supplier. An example of this might be a fan motor which is used as part of a ventilation system which controls (mitigates) the release of radioactive material into the workplace.
Particular care must be taken with larger projects involving potentially high hazard radiation sources (for example a linear accelerator in a shielded bunker). Often there are several companies involved which maybe managed by a project management group. The shielding design, construction, electrical installation, services, soft fit and similar may be conducted by different companies. In these cases the 'installer' may not be as clear as you might expect and should be agreed before the project starts. The installer of the linac cannot be responsible for the radiation shielding, or the external active warning lights that interface with the linac, if these features were not within their remit and control.
Critical examinations - service and repair
The reader should note that whilst IRR17 (and it's ACoP) is fairly clear (for most matters) on what is required, the expectation of the UK regulator for ionising radiation (the HSE for work not on a nuclear licensed site), may well be revised from time to time.
Whilst service and repair, especially for larger systems, is demonstrability 'not installation' , the expectation is that safety checks on radiation protection related systems will take place following such work. Whereas it might be argued the checks are not a 'critical examination' (as far as discussed earlier), the intention is so close that 'critical examination' or 'critical examination - part thereof' are appropriate definitions. It is Ionactive advice that to argue this point (i.e. calling this a 'safety check' rather than a 'critical examination') has little practical merit.
However, generally (but perhaps not always in the medical sector where you have experienced clinical scientists and engineers), the service engineer will know best regarding the radiation safety impact of a particular job. Consider the following examples:
Full change of x-ray tube (requiring removal and replacement of collimator assembly) - This work will likely involve significant disassembly, removal of parts, replacement of parts, alignment and so on. Cables may have been unplugged and reattached during the process, so a critical examination would be required to test all relevant system systems. [Ionactive comment: Note that whilst patient exposure and quality assurance may feature as part of the checks, other than for x-ray tube leakage these matters are for IRMER17 and not IRR17].
- Replacing a unit illuminated status indicator (which may or may not be radiation safety related) - This work may or may not require a cover to be removed, it might be a swift and simple replacement. It is likely that no other safety systems will be touched (this will of course be assessed on a case by case basis), but it is unlikely to require an extensive critical examination, at most a 'critical examination, part thereof'.
A third party asks / is asked / offers to undertake the critical examination
The supplier / installer (as set out above) is responsible for the critical examination. An exception could be where a service engineer, not employed by the original supplier / installer, is undertaking work - in this case the current employer of the third party engineer would be responsible, following a service / repair, for at least a 'critical examination - part thereof'.
In some cases the supplier / installer may contract a third party to undertake a critical examination. In other cases the customer receiving the x-ray unit installation (or following service or repair), may ask (or even insist!) that they do a critical examination (this might be more common in a UK hospital environment). So options other than the actual supplier / installer might be (if suitably qualified):
- An RPA
- An RPS
- The customer
- A contracted service engineer
Regardless of who performs the critical examination, the supplier / installer (or a third part service engineer if they have specifically worked on the x-ray equipment during service or repair), are responsible for ensuring that the critical examination is completed, written up and provided to the end user of the equipment.
Scenario A - A supplier / installer asks their customer to perform the critical examination (e.g. medical physics staff at a hospital). The supplier / installer is still responsible for ensuring that a suitable critical examination is performed, recorded and that they have a record of this. [Ionactive comment - a clear direction of flow required, so it must be clear who is responsible, and who is issuing and receiving the critical examination report, regardless of who carried it out].
Scenario B - A service engineer changes an indicator light on a fixed medical x-ray unit. The customer offers to undertake the critical examination. The customer insists they perform a full critical examination of the entire system, including e-stops, external active room signage, door interlocks (if fitted), x-ray tube leakage and so on (and they note they will charge for their time). The onus is on the engineer completing the indicator light replacement (i.e. their employer) to determine the suitability of the critical examination. In this case the critical examination scope (and therefore any charges for it) may be excessive compared to what is actually required.
[Ionactive comment - where a customer completes a critical examination on behalf of the supplier / installer, the customer should at the very least consult with the supplier / installer's RPA, since they are responsible for ensuring the critical examination is completed satisfactorily, not the customer].
Critical examination of portable x-ray equipment (updated February 2025)
Portable x-ray equipment could mean any of the following:
- Cabinet x-ray system (benchtop) that is easily moveable
- Handheld portable x-ray system (such as an XRF unit)
- Portable / mobile x-ray unit used in medical applications (i.e can be wheeled around the workplace)
The following advice and comment could apply to any of the above uses. However, it most significantly applies to the mobile medical x-ray units which are by their very nature 'open beam' (i.e. between x-ray collimator and patient). Whilst this definition may also apply to the portable XRF handheld unit, the exposure potential is significantly less (low kV, low mA, finely collimated beam etc, true whole body exposure not reasonably foreseeable). Also note that typical x-ray units used at airports (carry on baggage screening) and in the food industry (quality assurance), would not be classed as portable even though they can be physically moved (with some effort).
Over the years there has been some debate over the interpretation of 'install' (or erect) when considering portable / mobile x-ray (or other) sources, as they are often unpacked from a box completely built and ready for use. However, interpretation aside, in many cases portable x-ray systems (and especially medical systems) create similar ionising radiation hazards as compared to fixed systems. In fact, there are scenarios where the risk of unplanned exposures are higher with these mobile systems where reliance is often placed on 'doing the right thing' (e.g. supervising the controlled area around the unit by sight), as apposed to relying on engineered features such as shielding walls and screens, installed active signage and similar.
The HSE in February 2025 updated their expectations based on their own legal advisors. This is included in full below.
IRR17 Regulation 32(2) Critical Examination
This regulation requires a person who "erects or installs an article" to "to undertake a critical examination". HSE's legal advisers have recently clarified that this applies to any item of "work with ionising radiation" that is brought into use. This includes articles that might be considered "mobile" devices (i.e. those not requiring any physical/mechanical fixings). Whilst it may have been customary to say that mobile equipment did not require a Critical Examination, it has always been HSE's expectation that safety features and warning devices, etc, should be checked before first use and the medical sector has typically been able to demonstrate that that this takes place. RPAs would usually be involved in determining the nature and extent of these tests, as well as being consulted if any anomalies were found.
In keeping with the above legal advice, these tests should now be referred to as a Critical Examination. The levels of testing HSE has observed appear to be fit for purpose and no additional tests should be required. Further to this, there is no need to conduct a new Critical Examination on any equipment already in use, providing that appropriate tests have been carried out and this can be demonstrated.
Our interpretation of the last line ('... no need to conduct a new critical examination on equipment already in use...'), simply means that users are not required to retrofit a critical examination to already in use portable x-ray systems, which may have previously undergone a safety assessment or simlar.
However, in noting our comments on critical examinations for service and repair earlier, this also applies to portable ionising radiation sources, and in particular mobile x-ray systems in the medical sector. A critical examination, or a 'critical examination - part thereof', is required following service / repair to mobile x-rays systems where this work may have impacted radiation safety related systems.