Written by experts from the BHTA Beds and Support Surfaces and Pressure Care and Seating Sections.
A series of International Standards is being published encompassing the testing of mattresses and related products that are designed to be surfaces to interface with the body, to manage the health of the body’s skin tissues when lying down. These standards are being published in the ISO 20342 series.
The aim of this article is to highlight the importance and relevance of these standards to procurement, prescribers (clinicians/nurses), and healthcare providers. Each of these stakeholders will benefit from having a recognised ‘minimum standard’ of safety for these products.
In addition, these standards will also enable stakeholders, during a product selection process, to undertake a more meaningful comparison of important performance metrics, such as pressure redistribution, moisture vapour transfer rates, etc, across products. Some measures carry pass/fail criteria, while others provide a value along a scale where a higher value may be more beneficial for some individuals, whereas other people will be better off at the other end of a scale.
NOTE. The standards have been prepared by an ISO committee, but where they have been adopted in Europe, they have this added as EN in front of the ISO number, and where adopted in the UK, BS is added in front of the number e.g. BS EN ISO 20342-1. This lettering applies to the full standards, whereas the Technical Reports and Technical Specifications have CEN and PD prefixes instead of EN and BS respectively.
The standards have coined the acronym APTI, which stands for “Assistive Products for Tissue Integrity when lying down”. The scope of the ISO 20342 series includes devices that are intended to remain in situ during periods of lying and to prevent and/or treat pressure injuries. This encompasses a range of different lying support surfaces including mattresses, mattress overlays, and mattress coverings for pressure injury prevention mattresses.
In addition, these standards also cover assistive products primarily intended for tissue integrity both for changing a lying position, and for maintaining a lying position. This includes devices for changing position or direction of a person using sliding or turning techniques, where they are intended to be used on a person in a lying position and remain in situ as part of the lying support surface. Other product areas within the scope include positioning pillows, positioning cushions, and positioning systems, along with bedding such as draw sheets.
These devices are likely to include all pressure redistributing mattresses and overlays manufactured using a range of materials including foam, gel, air, and foam in combination with air (i.e. hybrid mattresses). These devices may be reactive (non-powered) or active (powered) mattresses and overlays.
This series does not apply to lying support surfaces used in combination with incubators or operating/surgical tables, nor to wheelchair seating products.
Medical devices are placed on the market with specific clinically related claims. The manufacturer has to justify these claims and also show that the product is safe and fit for purpose. Testing to, and passing, recognised standards is part of this process.
Historically, mattress manufacturers have typically used their own test methods to quantify and report on the key performance characteristics of their products, for example pressure reduction. Whist these metrics can help users understand the level of performance offered by one specific product, the significant variability between test methods, test equipment, and how the results are reported or presented by manufacturers typically precludes any meaningful comparison of the test results from different products.
This series of ISO 20342 standards, and the associated test methods described within them, are designed to enable stakeholders involved in mattress provision (i.e. clinicians, prescribers, compliance, procurement, medical engineering, etc.) a framework within which they can confirm device safety and compare relevant specific device performance characteristics across different support surfaces, without having to undertake their own internally-designed bench tests.
The standards set out a series of validated tests and ‘best practice’ for manufacturers to align with, where appropriate.
Where a manufacturer employs the standards, it demonstrates that they are seeking to attain the highest levels of device safety and that their claims around device performance can be supported by data from validated test methods.
When a healthcare provider goes out to tender for new mattresses, numerous devices are often considered simultaneously. It can be time-consuming and complex for the provider to assimilate the information supplied by the tendering manufacturers or suppliers and previously it has often been impossible to make meaningful comparisons between products from different manufacturers.
Because the standards describe detailed test processes utilising validated test methods, results from performance testing to ISO 20342 test methods can be tabulated, thereby permitting the same performance characteristics across products from different manufacturers to be compared directly with one another.
This enables the healthcare provider to perform an initial ‘desk-top’ comparison of various mattress device performance metrics which will help the provider determine which products to take forward to a local user evaluation with their staff and patients or residents.
The suite of ISO 20342 standards covers various aspects of device safety, performance, or technical information, including pressure redistribution, shear (horizontal stiffness) and microclimate. See Table 1 for a full listing of characteristics covered by the BS EN ISO 20342 standards.
Key:
SAFETY Standard = red
TECHNICAL Standard = yellow
PERFORMANCE Standard = green
| Standard Part | Standard Title (and coverage) | Published |
|---|---|---|
| BS EN ISO 20342-1:2022 | Assistive products for tissue integrity when lying down. General requirements (Principally broader safety elements – see separate BHTA report) | 2022 |
| PD CEN ISO/TR 20342-2 | Microclimate (Heat and moisture vapour dissipation at the skin and device interface) | TBC |
| BS EN ISO 20342-3 | Strength and impact (Tensile strength of materials, bursting strength/distension, seam/weld strength, carry handles, bottoming out, etc.) | TBC |
| BS EN ISO 20342-4 | Durability (Resistance to repetitive loading, ageing (drop test/lifespan test/wear and tear/loading and unloading, etc.) | TBC |
| BS EN ISO 20342-5 | Cleaning and disinfection (Test method to determine the resistance of waterproof coated textiles to liquid disinfectants and cleaning methods) | TBC |
| BS EN ISO 20342-6 | Horizontal stiffness (Shear) | TBC |
| PD CEN ISO/TR 20342-7:2022 | Assistive products for tissue integrity when lying down — Part 7: Foam properties, characteristics and performance. (Resilience; density; hardness; compression set; tensile strength; tear strength; air flow/permeability; resistance to fatigue; and microbial resistance) | 2022 |
| BS EN ISO 20342-8 | Pressure redistribution (Immersion, envelopment, and pressure relief) | TBC |
| BS EN ISO 20342-9 | Flammability (Resistance to ignition by a specified heat source e.g. a smouldering cigarette equivalent) | TBC |
| PD CEN ISO/TS 20342-10:2022 | Assistive products for tissue integrity when lying down. Guide to cleaning, disinfecting and care of polyurethane APTI covers. | 2022 |
The ISO 20342 series currently consists of ten published or in-preparation parts, however this is an ongoing programme of work within ISO and whilst the parts listed above cover the essential elements of safety and performance testing, it is likely that additional parts will be added in future.
No. Certain elements of the standards such as Part 1 General Requirements or Part 9 Flammability are likely to be relevant to almost all devices. However, it is envisaged that manufacturers will only perform testing in areas where they make a performance claim i.e. they will test against Part 8 if they are making claims of pressure relief or redistribution and Part 4 if they are making claims relating to durability.
Testing can be performed in house (where manufacturers have the capability of running the specified tests) or at an independent external test house. Some tenders may require the testing to have been carried out by test labs audited to ISO 17025.
Compliance with ISO standards is not generally mandatory, unless this is stipulated within a tender document, stipulated by local regulations, or where an ISO standard has been harmonised in the EU.
Most manufacturers are aware of the standards, and many of these manufacturers will be actively working towards ensuring that their products are compliant with the elements of the standard that apply to their devices. Where products have medical claims these products will be UKCA marked for GB and CE marked for Europe – the results of testing to the standards will be part of the Declaration of Conformity technical files.
Although the European Medical Device Regulation (MDR) and its predecessor the Medical Device Directive (MDD) (which is still in force in Great Britain), offer a broad framework for what is expected from a safe, compliant medical device, there has never been a clearly defined safety standard that is APTI specific and applies to every APTI irrespective of device classification.
ISO 20342-1:2022 is the first APTI specific safety standard. As well as providing some general guidance on certain aspects of device performance, it sets the minimum threshold a device (i.e., replacement mattress or mattress overlay) should reach in order to maximise the safety of users.
Due to the way in which the medical device classification rules are written, APTIs may either be designated as Class I medical devices or Class IIa medical devices.
Whilst APTIs classified as Class IIa devices are regulated by Independent Notified Bodies for CE marking (or GB Approved Bodies for UKCA marking), APTIs that are classified as Class I medical devices are self-certified by the legal manufacturer and are thus unregulated by an independent, external body.
The resulting differences in regulation and approach to APTI classification is less than ideal and can cause confusion in the marketplace, both from a manufacturer’s perspective and that of the healthcare provider and product prescriber.
Healthcare providers can help encourage uptake of these standards by listing compliance with them as a prerequisite on mattresses and related devices tender documentation. If manufacturers have to comply with specific elements of the standard (e.g. Part 1, General Requirements) to be considered for the tender, this would greatly encourage industry compliance with these requirements from the ISO 20342 series.
BS EN ISO 20342-1:2022 – TC | 31 Aug 2022 | BSI Knowledge
Guidance relating to this standard has been compiled by the BHTA in the document: Guidance to the mattress and related devices General Requirements standard BS EN ISO 20342-1:2022
PD CEN ISO/TR 20342-7:2022 | 31 May 2022
Further guidance on foams used in mattresses can be found in the BHTA publication: What Lies Beneath
PD CEN ISO/TS 20342-10:2022 | 31 Jul 2022 | BSI Knowledge
Further guidance on cleaning and disinfection of mattresses can be found in the BHTA publication: Protect, Rinse and Dry
Further information on Standards is available from the BHTA article: An introduction to understanding standards
We all come across items in our daily lives that are regulated by standards, even if we do not know it. Meeting standards leads to increased safety, better compatibility between items, and better practice.
In this article, we cover the hierarchy of standards across the world as they benefit us in the UK and reflect on their importance, with particular reference to medical devices and ultimately the safety of our customers, clients, and patients.
Most of us will have come across the BSI Kitemark™. The BSI Kitemark originated as the British Standards Mark in 1903 for use on tramway rails when standardisation reduced the number of rail sizes from 75 to five. Today the BSI Kitemark can be seen on hundreds of products from manhole covers to condoms, from security locks to fire extinguishers and riding helmets.
Having a BSI Kitemark associated with a product or service confirms that it conforms to a particular standard: each BSI Kitemark scheme involves a determination of conformity to the relevant standard or specification of the product and an assessment of the management system operated by the supplier. This symbol is one that is trusted across the UK, and indeed across the world.
So what are these standards that are being referred to?
A standard is an agreed way of doing something. It could be about making a product, managing a process, delivering a service, or supplying materials. Standards can cover a huge range of activities undertaken by organisations and used by their customers.
Standards are the distilled wisdom of people with expertise in their subject matter and who know the needs of the organisations they represent, such as manufacturers, sellers, buyers, customers, trade associations, users, or regulators.
BSI, in its role as the UK National Standards Body, has a portfolio that extends to more than 30,000 current standards. They are designed for voluntary use so it’s up to you – you’re not forced to follow a set of rules that make life harder for you, you’re offered ways to do your work better.
Standards are knowledge. They are powerful tools that can help drive innovation and increase productivity. They can make organisations more successful and people’s everyday lives easier, safer, and healthier.
As a result, standards share good ideas and solutions, technological know-how, and best management practices. They identify safety issues of products and services and make products compatible so that they fit and work well with each other. An example of the latter are the HDMI or USB ports on your computer.
There is a generally accepted hierarchy of standards, starting with the International Organization for Standardization (ISO*) being adopted worldwide, the European Committee for Standardization (CEN)’s EN standards being adopted across Europe, and national standards being created and adopted by individual countries (e.g. BS standards in Britain, under the auspices of the BSI (British Standards Institute)).
Some International standards will have been adopted (and ‘harmonised’) across the EU and also adopted in, say, the UK, and as a result will have the letters BS, as well as EN and ISO, in front of them.
The added bit of fun is that at each level, the adopting body can add its own foreword to make minor alterations to the standard, for their local jurisdiction.
*Notice that ISO’s acronym doesn’t match ISO’s name? It’s not meant to. “ISO” is derived from the Greek word isos (equal), so that it’s the same in all languages.
Standards are prepared by Technical Committees (TCs – e.g. ISO TC173 Assistive Products or CEN TC 293 Assistive Products and Accessibility). Each TC has its own field of operation (scope) within which a work programme of identified standards is developed and executed. TCs work on the basis of national participation by the ISO or CEN Members, where delegates represent their respective national points of view. This principle allows the TCs to take balanced decisions that reflect a wide consensus.
A Subcommittee (SC) can be established within a TC, in the case of large programmes of work. The real standards development is undertaken by Working Groups (WGs) where experts, nominated and appointed by the ISO or CEN country members, but speaking in a personal capacity, come together and develop a draft that will become the future standard. This reflects an embedded principle of ‘direct participation’ in the standardisation activities.
The aim of the WGs is to have a balance across potential stakeholders, from commercial providers, public sector, etc, through to end user.
Individual countries opt to be participating members of any committee, or observers (where in this case they do not have a vote), or decide not to participate at all. Each country that participates tends to have its own national ‘mirror’ group, which feeds back each country’s comments and votes to the TCs and thereby the WGs.
In addition to ‘normative’ (i.e. prescriptive) standards, some will be called Technical Reports (TR) or Technical Specifications (TS), and these are informative.
A number of these informative standards become updated to become normative standards, as the material in them has been shown to stand the test of time. In the UK, BSI also produces Publicly Available Specifications (PAS), which, with time, can move onto being BS (British Standard) versions.
Standards go through an iterative process on the road to final acceptance and publication. ISO tends to have more steps than CEN or BSI. The ISO steps are generally as follows, though often the Working Groups get permission to skip a step or two. The earliest stage is when a perceived need for a new standard, or revision of a standard, has been identified, and this goes out to international vote, at which stage it is called a NWIP (New Work Item Proposal). When approved by a minimum of 5 countries (who also have to put forward experts to work on the project), it becomes an AWI (Approved Work Item).
The document itself it may start as a WD (Working Draft) or as a CD (Committee Draft), which is put out for international comments and vote. The Working Group then works through the comments, and if the feeling is that these have been addressed, the next stage is a DIS (Draft International Standard – the European equivalent is prEN) (or else it goes back for another round of CD comments and voting).
At the DIS stage any technical concerns should have been addressed, so when this draft goes out for voting, any comments coming back should really be editorial, unless some technical issues had been overlooked. If everyone agrees technically with the DIS, then it can be agreed to go straight to publication (with any editorial corrections addressed), or else it goes for one more round of voting as an FDIS (Final Draft International Standard – the European equivalent is FprEN), after which with majority approval it can be published. The drafts from DIS onwards can be referenced and worked with in the public domain.
Most standards have to be purchased, and are available through the BSI shop. For the ISO standards, it is possible to download the Introduction, Scope, and Terms and Definitions, for each standard for free from the platform: https://www.iso.org/obp/ui
Medical devices are placed on the market with specific clinically-related claims. The manufacturer has to justify these claims and also show that the product is safe and fit for purpose. Testing to, and passing, recognised standards is part of this process. If the manufacturer claims that their product is a medical device, they have to have it CE/UKCA marked in the EU and Great Britain respectively.
The placement of a CE or UKCA mark, and the MD symbol, on the product and its packaging, indicate that the product has been assessed against these criteria and registered in the relevant marketplaces.
Testing to ISO standards is voluntary, but if a manufacturer chooses to take another route, they need to have strong justifications not to use a recognised published standard. Where a product is sold in the EU or Northern Ireland, and there is a harmonised EN standard, then it is appropriate that the standard be followed.
Outside the regulatory framework above, as a prescriber you are following better practice for client safety and product assurance if you select an item that has been tested to, and passed, one or more of these recognised standards, than if the product is selected on, say, purely price grounds. The price may be slightly higher, but you will have the peace of mind that the manufacturer has picked up the costs of product testing, and thereby that your client is protected.
While some standards cover product testing, others provide guidance to best clinical practice, as well. Over and above the latter standards, there are also other sources of guidelines, such as the BHTA range of guidance publications, the Posture and Mobility Group Best Practice Guidelines, and RESNA’s position papers, all of which are free to download from these respective organisations.
BSI, and the Working Groups, welcome all applications to become a standards maker: you only need to have relevant knowledge and experience, or to represent a relevant group of stakeholders such as BHTA.
Please get in contact with BSI via standardsmakers@bsigroup.com
Technical Committee: TC173 Assistive Products*
Sub-committees:
TC173 SC1 Wheelchairs, which has four active Working Groups
TC173 SC2 Classification and terminology
TC173 SC3 Aids for Ostomy and Incontinence
TC173 SC7 Assistive products for persons with impaired sensory functions
TC173 also has the following individual Working Groups:
Technical committee: TC293 Assistive Products and
Accessibility, which has a number of working groups:
Working Groups are disbanded when the standard they have been working on has been published, and they have nothing else currently on their work programme. TC293 Working Groups WG2, WG3, WG4, and WG8 are currently inactive for this reason.
CH 173 – ISO TC173 and TC293 Mirror Group
CH 173/1 – ISO TC173 SC1 and TC293 WG9 Mirror Group
*ISO TC173 has a website from which it is possible to link with some of the TC173 activities, and access documents which are in the public domain: https://committee.iso.org/home/tc173