New standards for testing mattresses and related products: An introduction
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.
Why are these standards important?
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.
How can the ISO 20342 standards help healthcare providers and manufacturers?
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.
What areas do the standards cover?
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.
Table 1. The current standards in the BS EN ISO 20342 series summarising the different aspects which each one covers respectively.
SAFETY Standard = red TECHNICAL Standard = yellow PERFORMANCE Standard = green
Standard Title (and coverage)
BS EN ISO 20342-1:2022
Assistive products for tissue integrity when lying down. General requirements (Principally broader safety elements – see separate BHTA report)
PD CEN ISO/TR 20342-2
Microclimate (Heat and moisture vapour dissipation at the skin and device interface)
BS EN ISO 20342-3
Strength and impact (Tensile strength of materials, bursting strength/distension, seam/weld strength, carry handles, bottoming out, etc.)
BS EN ISO 20342-4
Durability (Resistance to repetitive loading, ageing (drop test/lifespan test/wear and tear/loading and unloading, etc.)
BS EN ISO 20342-5
Cleaning and disinfection (Test method to determine the resistance of waterproof coated textiles to liquid disinfectants and cleaning methods)
BS EN ISO 20342-6
Horizontal stiffness (Shear)
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)
BS EN ISO 20342-8
Pressure redistribution (Immersion, envelopment, and pressure relief)
BS EN ISO 20342-9
Flammability (Resistance to ignition by a specified heat source e.g. a smouldering cigarette equivalent)
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.
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.
Will all devices need to meet all the parts of ISO 20342?
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.
Do devices need to comply with these standards?
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.
What are the benefits of setting out the requirements for APTI safety?
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.
How can healthcare providers influence uptake of these standards?
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.
How can I access the current published standard documents and related materials?
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