Document from the health department (NHS England)

HTM 2022 S 1
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The text below is an extract from the Health Department (NHS England).

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Dental compressed air and vacuum systems (HTM 2022 Supp 1 revised) (



This Supplement provides advice and guidance on the specific requirements for compressed air and vacuum systems for use in dental hospitals, dental teaching schools, clinics and surgeries and primary care trusts (PCTs). The Supplement should be followed for all new installations and refurbishment; existing installations should be assessed for compliance with this Supplement. Where necessary, a plan for upgrading the existing systems should be prepared, taking into account the priority for patient and staff safety and statutory requirements which may have become effective subsequent to any existing installations. Owners, occupiers, general managers and chief executives should ensure that the premises for which they have responsibility and any activities carried out therein comply with these statutory requirements. This compliance is obligatory. Managers will need to liaise with dental and estates colleagues and take account of other guidance published by the Department of Health to assess the system for technical shortcomings. The guidance given in HTM 2022 should generally be followed for these systems and plant accommodation, except where modified in this Supplement. This Supplement supersedes ‘HTM 2022 – Supplement 1: Dental compressed air and vacuum systems’ first published in November 1996. 



Dental hospitals, clinics and surgeries require compressed air to power dental instruments and a vacuum system to remove detritus from the operation site.  The performance requirements of dental compressed air and vacuum systems differ from those for medical air and vacuum, and they should be provided in addition to the medical gas pipework systems (MGPS). To avoid confusion they will be referred to as dental compressed air and vacuum systems (DAVS). Medical gas systems should not be used for dental purposes. However, it may be possible to extend a surgical air system into a dental department for dental surgical purposes, provided that the existing system is capable of meeting the resulting increase in demand without detriment to the performance of either system.  



Dental air is usually supplied via a compressor, which should be fitted with an air-intake filter and a postcompression filtration and dryer system. This ensures that the air is clean and dry, minimising the risk of contamination of the system by micro-organisms and improving the efficiency of dental instruments. 

  • The dryer system should be capable of producing air with an atmospheric dew-point not less than –20ºC.
  • The filter system should provide dust filtration down to 1 µm with a DOP (aerosol) efficiency of not less than 99.97% and bacteria filtration down to 0.01 µm with a DOP (aerosol) efficiency of not less than 99.9999%.



Wet and dirty air will eventually lead to damage and corrosion of instruments. Oil-free compressors offer a simple, cost-effective solution to the problem of oil contamination. However, for larger installations, there are implications of higher capital costs and noise levels. Whatever compressor system is used, the importance of properly conducted regular maintenance cannot be overstressed. Filters should be changed at least annually and more frequently if recommended by the manufacturer. 



The pipework distribution system for dental air should be of a material technically suited to the application. Copper and nylon are commonly used in pipework. Dental vacuum and exhaust line materials should also reflect current technology, with particular attention given to minimising the harmful effects of any effluent which pipework may carry. For example, copper pipe should not be used for wet vacuum systems, as it will be attacked by dental amalgam compounds. 



The exhaust from the vacuum system should be sited  outside, away from air intakes, opening windows etc (preferably above roof level) and be clearly labelled. A bacteria filter with particle removal to 0.01 µm with a DOP (aerosol) test efficiency of not less than 99.9999% should be inserted in the system, preferably between pipework and vacuum pumps. Small systems exhausting into the work area should have such a filter fitted to the pump exhaust.



The design and installation of the surgery’s water supply must take account of the Water Supply (Water Fittings) Regulations 1999, in particular the need to prevent contamination waste and undue consumption.  To prevent contamination of the sewerage drainage systems, amalgam separators should be fitted to all dental vacuum systems. 



Accommodation for dental compressor and vacuum pumps should be carefully controlled to prevent overheating of plant and contamination of dental air supplies, or freezing of and subsequent damage to drying systems and vacuum plant 



Installation, testing and maintenance of these systems should be carried out by competent authorities, that is companies certificated under BS EN ISO 9000 with a defined scope of expertise. The Quality Assurance Scheme 3720 1/206.1A for MGPS is currently under review and will be revised to include dental installations and maintenance of both MGPS and DAVS. 



In areas where anaesthetic agents are in use, particular attention should be paid to the requirements of the COSHH Regulations 1999. However, it must be remembered that these Regulations also apply to many other compounds used in dentistry.



An operational policy covering the day-to-day management and operation of the DAVS should be devised. Its preparation will usually be the responsibility of the senior partner/practice manager or the Authorised Person (MGPS), if the latter has responsibility for the DAVS.



Separate installations should be provided for pathology departments.



All new plant should be marked with the appropriate CE mark; plant which is not so marked should not be installed. It should be remembered, however, that presence of a CE mark is no guarantee of conformity with relevant standards."