HTM 01-05 Dental Decontamination Room Layout

HTM 01-05, Decontamination in primary care dental practices, is NHS England's guidance on how dental instruments are cleaned, sterilized and stored, and the room they are processed in is a large part of it.^[1] The guidance follows the Code of Practice on the prevention and control of healthcare associated infections under the Health and Social Care Act 2008, and it is written to help dental providers meet the duty that code places on them to provide a clean and appropriate environment.

For the building, three things in it matter more than anything else. The flow: used instruments must never be at risk of meeting processed ones. The separation: how far the decontamination work sits from the patient, and whether it has a room of its own. And the fabric: surfaces, floors, sinks and ventilation that can be kept clean and do not recontaminate what has been sterilized.

A practice registered with the Care Quality Commission is also inspected against the regulations on safe care and treatment, which includes preventing and controlling the spread of infection, and on premises and equipment.^[2][3] HTM 01-05 is how a dental practice shows what that means in its decontamination room.

HTM 01-05 sets the two levels out in paragraphs 1.7 and 1.8, and expects every practice meeting the first to have a plan for moving towards the second.^[1] For a new practice or new premises it goes further and advises that the full best practice provisions are used wherever reasonably practicable.

Of all of those, the building decides two: where decontamination happens, and how far clean and dirty are kept apart. They are also the two a practice cannot change by changing its procedures. A washer-disinfector can be bought next month. A separate room has to be built.

HTM 01-05 is explicit that removing decontamination from the treatment room should be a priority as practices progress, and that where a practice is setting up new premises or planning significant modification, separation of the decontamination area from the clinical area is recommended.^[1] It also accepts that some practices cannot get there: where building alterations are restricted, or purpose-built premises are hard to find, best practice may not be achievable, and the guidance says so plainly in paragraph 5.8.

In practice the question is usually answered by the building. A practice with a spare room off the corridor, or space to borrow from a store, can almost always form a local decontamination unit. A practice with neither can still improve separation inside the surgery, with the reprocessing bench as far from the chair as the room allows and the workflow arranged so nothing used ever passes back over anything processed.

Where a dedicated room is built, the guidance asks for enhanced dirty to clean separation in both its design and its operation. That is a layout decision, and it is made at the drawing stage.

HTM 01-05's example layouts, in figures 1 to 3, draw exactly that: a delivery point at the dirty end, washing and rinsing sinks, an optional ultrasonic cleaner, a washer-disinfector where one is fitted, an inspection point, the sterilizer, and storage at the clean end, with ventilation supplied at the clean end and extracted at the dirty end.^[1]

The details that most often go wrong are the ones the drawing hides: a hand basin placed where staff have to reach across the dirty sink to use it, a sterilizer on the same stretch of worktop as the set-down point, or a store that can only be reached by walking back through the dirty end. Each of those breaks the line, and none of them can be fixed with a procedure once the cabinetry is in.

Paragraphs 6.40 to 6.45 of HTM 01-05 deal with ventilation, and they are deliberately practical.^[1] In buildings that were never designed for it, controlling airflow is hard, and the guidance asks responsible persons to find a good standard without unreasonably complex or expensive systems. Mechanical ventilation can be worthwhile, particularly where a practice is pursuing best practice, but it costs more to install and to run.

Whatever the system, three rules carry through. Mechanical extract units, where used, should be ceiling or wall mounted. Air should move from clean to dirty, so anything released at the washing end is drawn away from the sterilized instruments rather than across them. And where a full mechanical system is used, the extract should be sized and placed to draw about one third of the air across the decontamination benches in that clean-to-dirty direction, with coarse filtration on the supply.

The sterilizer and the washer-disinfector put heat into a small room, so the ventilation is sized for that load as well as for air quality.

Paragraphs 6.38 and 6.46 to 6.48 set out the finishes.^[1] Surfaces, including walls, should be continuous wherever possible and free from damage and abrasion. Work surfaces should be impervious and easily cleanable, jointless as far as is reasonable, and where they are jointed, welded or sealed. Flooring in clinical and decontamination areas should be impervious and easily cleanable, its joins welded or sealed, and coved to the wall so dirt cannot collect where floor meets wall. Carpets, even washable ones, should not be used. Surfaces should be easy to reach and should dry quickly.

The guidance also asks practices to check with manufacturers that the detergents and disinfectants in use are compatible with the surface materials. That is a question for the specification, not the cleaning rota: a worktop that cannot take the disinfectant in the protocol will fail long before its expected life.

These are the decisions that make a decontamination room pass its first inspection and keep passing them: a sealed, coved floor, a jointless worktop, sinks and a basin that can each be kept to their own job, and a layout in which nothing processed ever meets anything used.