What are ‘Standards’?

Standards are used to define agreed ways of doing things.

This could be the protocol for a medical trial, a means of defining what is a medical device or types of medical devices, the method of testing a medical device (i.e. a wheelchair) or even simply agreeing the definition of terms to describe equipment, measurement or performance.

Standards form a structure which is supported from the top down (e.g International Standards Organisations – ISO; European – EN; British Standards – BSI) … and from the bottom up, in which related standards are cross referenced to ensure consistency (i.e. a standard relating to the testing of wheelchair performance may reference other standards regarding agreed terminology; electrical safety; flammability testing; measurement; and an agreed reporting format).

Standards are developed using a process of consultation and review, drawing on groups of experienced parties within relevant fields of expertise to distil knowledge into each standard.

The benefit to Posture and Mobility Group members is that the availability of these standards can guide and govern the levels of quality, safety, reliability, efficiency and compatibility – at the very least - in wheeled mobility and postural support.

The British Standards Institute explains further what a ‘standard’ is here.


The Medical Device Directive

The Medical Device Directive (MDD), and its subsequent revisions (available here), provides a definition of medical devices, their classification, and governs their use within the European Union. Wheelchairs and postural devices are classed as Class I medical devices by the MDD. If the manufacture of a device can demonstrate that their equipment meets the essential requirements of the MDD and any other relevant standards, then CE Marking may be applied to the equipment – the CE stands for Conformité Européene (i.e. European Conformity). The equipment can then be used within the EU.


British Standards Institute

The British Standards Institute (BSI) is the oldest standards organisation in the world, promoting best practice on behalf of British industry and the public. The BSI facilitates the development of standards through technical committees (TCs) and subcommittees (SCs) of representatives of interested parties. Standards relating to wheelchairs and wheelchair seating are the responsibility of sub-committee CH173/1.

What does the BSI CH173/1 wheelchair sub-committee do?

CH173/1 works on national standards relating to wheelchairs and wheelchair seating, as well as providing UK input into European and international wheelchair and wheelchair seating standards such as CEN (European) and ISO (international). For international standards development CH173/1 nominates a delegate to the international committee, as well as experts to international standards working groups.

The voluntary membership of sub-committee CH173/1 is constituted of nominated representatives from professional bodies and trade organisations, including representatives from:

  • Department of Transport (DfT)
  • Posture and Mobility Group (PMG)
  • British Healthcare Trades Association (BHTA)
  • Chartered Society or Physiotherapy (CSP)
  • Rehabilitation Engineering Services Management Group (RESMaG)
  • Institute of Physics and Engineering in Medicine (IPEM)

The sub-committee also co-opts experts with appropriate skills and knowledge.



British standards are developed and adopted by the BSI, and carry the prefix BS.

As a member of the International Standards Organisation (ISO), BSI has the option of adopting an ISO (international) standard as a British standard. This type of standard is then published in the UK with the prefix BS ISO. However, it should be noted that BSI does not have to adopt an ISO standard, for example if the standard is considered irrelevant to UK interest. However, as a member of the European Committee for Standardization (CEN), and also the European Committee for Electrotechnical Standardization (CENELEC), the BSI is obliged to adopt all European standards, and withdraw any BS standards which would conflict with them. The same requirement applies to all EU states, and this ensures the conformity of standards throughout the EU. 

CEN standards are published in the UK with the prefix BS EN.

Where an ISO standard is adopted by CEN and BSI, it is published in the UK with the prefix BS EN ISO.

How to obtain a standards document?

Standards are copyrighted documents which are usually purchased from their publishing body (i.e. BSI, CEN or ISO). Some documents, e.g. the MDD, are published for public download.

If a standard is adopted by the UK, it will be listed for sale on the BSI website. If you have an Athens account through the university or hospital where you work, it is possible that you may have access to these standards documents for free. If you have an Athens account, then you should be able to visit the British Standards Online webpage -

On arriving on the page you should click on Institutional Login, as shown via first link below.

You will then be taken to the Institution Login page (see via second link) where you can either utilise your university of organisation login, or alternatively use your Open Athens login which should be readily available to NHS staff through their education & training teams.

If you're unable to access the standards by either of the methods above, your employer may have an organisation membership of the BSI which then allows for discounted purchase of many standards.  Lastly, some libraries have access to the BSI catalogue for viewing on site.