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Dental X-ray testing and compliance: IRR17, IRMER17 and critical examination
X-ray equipment sits under the strictest regulatory regime in the practice, and it is the one area where two separate sets of regulations apply at once. This guide sets out the testing obligations in plain English — with one caveat stated up front and repeated deliberately: your Radiation Protection Adviser is the authority on how this applies to your practice. Nothing here replaces their advice.
Two regulations, two purposes
| IRR17 | IRMER17 | |
|---|---|---|
| Full name | Ionising Radiations Regulations 2017 | Ionising Radiation (Medical Exposure) Regulations 2017 |
| Protects | Staff and the public | Patients |
| Enforced by | HSE | CQC (in England) |
| In one line | Keep the equipment safe and tested | Keep patient exposures justified, optimised and verified |
Both apply to every practice taking radiographs. Compliance with one is not compliance with the other — and they each generate their own testing obligations.
What the regulations actually require of the equipment
IRR17 regulation 11(1) requires that X-ray equipment “be properly maintained so that it remains fit for the purpose for which it was intended” and “be adequately tested and examined at appropriate intervals”.
IRMER17 requires the employer to undertake adequate:
- testing of equipment before it is first used for a medical radiological purpose;
- performance testing at regular intervals; and
- performance testing following any maintenance procedure capable of affecting the equipment's performance.
That third clause is the one practices miss. An annual test sits in the calendar and gets booked. A re-test triggered by a repair does not — nothing reminds you, and the obligation arises exactly when everyone's attention is on getting the surgery running again. If an engineer has worked on an X-ray unit, ask the question before it goes back into clinical use: does this need re-testing?
Critical examination and acceptance testing
When X-ray equipment is newly installed or modified, a critical examination is required under IRR17. It confirms the installation is safe: no risk to patients, staff or the public from accidental exposure, and no over-exposure due to miscalibration. A report of the results should be provided before clinical use begins.
Installers often carry out acceptance testing on behalf of the practice at the same time — but they are distinct checks with distinct purposes. When you have a new unit installed, confirm explicitly with the installer that both the critical examination and the acceptance test will be carried out and reported. Do not assume one implies the other.
The people the regulations require
A key requirement of both IRR17 and IRMER17 is the need to seek expert advice. For dental practices this means:
- Radiation Protection Adviser (RPA) — an external consultant advising on compliance with IRR17: equipment, room layout, risk assessments, local rules.
- Radiation Protection Supervisor (RPS) — a trained person within the practice supervising day-to-day compliance with the local rules.
If you cannot immediately name your RPA and RPS, that is the first gap to close — ahead of any equipment question. Your RPA is also the right person to confirm your practice's registration position with HSE for work with ionising radiation.
What this means as a working checklist
| Obligation | When | Driven by |
|---|---|---|
| Critical examination + report | New or modified equipment, before clinical use | IRR17 |
| Acceptance testing | At installation, alongside the above | Good practice / IRMER17 first-use testing |
| Performance testing | At regular intervals — your RPA advises the interval for your equipment | IRMER17 |
| Re-testing after maintenance | After any work capable of affecting performance | IRMER17 |
| Maintenance | Ongoing, so equipment remains fit for purpose | IRR17 reg 11(1) |
| RPA appointed, RPS named | Standing arrangement | IRR17 / IRMER17 |
| Reports retained | Life of the equipment | Evidence for CQC and HSE |
Where this intersects with your engineer
Engineering work and radiation compliance meet at two points, and both are worth managing deliberately.
Installation and relocation. Moving or installing an X-ray unit is a modification — it triggers the critical examination requirement. If you are refurbishing a surgery or relocating equipment as part of a surgery design project, the radiation compliance steps belong in the project plan, not as an afterthought once the unit is on the wall.
Repair and maintenance. Any repair capable of affecting performance brings the IRMER17 re-testing obligation with it. A good engineering visit on X-ray equipment ends with a clear statement of whether re-testing is needed — if you are not told, ask.
Planning an installation, relocation or refurbishment involving X-ray equipment? Tell us what is moving and we will make sure the compliance steps are sequenced into the work rather than discovered after it. Ask us.
Frequently asked
What testing does X-ray equipment legally need?
Maintenance and adequate testing at appropriate intervals under IRR17; testing before first use, at regular intervals, and after performance-affecting maintenance under IRMER17.
What is a critical examination?
A safety check on newly installed or modified equipment, reported before clinical use. Distinct from acceptance testing — confirm both are being done.
Does a repair trigger re-testing?
If it is capable of affecting performance, yes. Ask before the unit returns to clinical use.
Who advises on all this?
Your Radiation Protection Adviser. If you do not have one appointed, that is the first thing to fix.
X-ray equipment moving, failing or due for replacement?
We install and service dental equipment across the UK, and where X-ray units are involved we sequence the compliance steps — critical examination, testing, reporting — into the job from the start.
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