In this In Focus segment we review the new guidance on POU Filters included in the recently published BS 8580-2. We discuss the implications for users of POU filters in healthcare settings and how T-safe complies with these new requirements through our market leading water filtration solution.
What is BS 8580-2?
BS 8580-2 to give its full title is “Water Quality Part 2: Risk Assessments for Pseudomonas aeruginosa and other Water Borne Pathogens – Code of Practice”. The standard sets out guidance for those responsible for undertaking Risk Assessments for the control of P. Aeruginosa and some additional 12 groups of waterborne pathogens of concern outlined in Annex A of the document. Whilst BS 8580-2 has a strong focus on healthcare, it is applicable to all settings and has a section dedicated to recreational water systems in beauty, health spa and leisure premises.
BS 8580-2 and POU Filters
POU filters are an established supplementary control measure for the prevention of infection by waterborne bacterial pathogens and are recommended for use as such in both HSG274 Part 2 and HTM 04:01. However, guidance on the correct selection, management, and control of POU filters is somewhat limited. Considering how critical these elements are to their effectiveness as an infection control measure, the lack of further guidance has been conspicuous by its absence for some time. Recognising the important role that POU Filters play in infection prevention, BS 8580-2 builds on the existing guidance, highlighting additional considerations for POU Filters for those undertaking Risk Assessments for the control of Pseudomonas aeruginosa and other water borne pathogens.
The choice of filter should be suitable for its intended purpose (0.2 µm sterilising grade filters intended for use in healthcare settings to prevent the dissemination of waterborne bacterial pathogens) (section 14.5 a).
For filters used in the control of waterborne pathogens, a pore size rating of 0.2 µm is required to achieve the FDA definition of a sterilising grade filter¹ proven through ASTM F838 (Standard Test Method for Determining Bacterial Retention of Membrane Filters Utilised for Liquid Filtration)². To be classified as such, a filter must demonstrate retention to 1*10⁷ (10 million) CFU of Brevundimonas diminuta per cm² effective filtration area under specific operating conditions (equivalent to >7 Log reduction) using the ASTM F838 test.
T-safe provides sterilising grade membrane filtration, which exceeds the requirements of the ASTM F838 standard by delivering the total retention of waterborne pathogens, as opposed to a log reduction. The microbial retention efficacy of T-safe filters has been independently tested in accordance with ASTM F838, in laboratory-based life cycle studies with intermittent use and bacteria spiking, and in life cycle studies conducted in major acute hospitals in the UK.
There should be documented procedures agreed by the WSG for fitting, changing, and cleaning filters, and where fitted as a short-term measure there are pre-determined criteria for when filters can be removed (sections 14.5 b, d).
As the only POU filter manufacturer to hold membership of the Legionella Control Association (under the Plant & Equipment Services standard), we have robust processes and procedures for the safe installation, maintenance, cleaning, exchange, disposal, and management of filters. We work closely with Water Safety Group stakeholders to support the deployment of T-safe as a water filter solution, through the provision of standard operating procedures, training, and ongoing product technical support.
There should be suitable training and competence checks in place to verify filters are connected to the tap correctly without any leakage, and that training of cleaners and ward staff is provided so that they understand the risks of removal, cross contamination, and cleaning (sections 14.5 c, h).
Training of ward, cleaning and estate operational staff is critically important in ensuring the ongoing efficacy of filters as an infection control measure. As filters act as the first line of defence against a known waterborne bacterial pathogen risk in the system, it is vital that filters are traceable, correctly installed, maintained, and regularly cleaned. To that end, our Technical Account Management team provide a range of bespoke support packages to our customers, ensuring that stakeholders are appropriately informed, trained and equipped to handle T-safe filters. This includes the provision of how to guides, SOPs and 1-2-1 training.
There should be sufficient ‘activity space’ to wash hands or fill drinking water receptacles without contact with the drain or any surfaces (section 14.5 f).
By virtue of their very nature, the installation of any POU filter will inevitably have an impact on activity space. In some cases, this can render the outlet unusable, breach the air gap and or increase the risk of retrograde contamination. Due to the transmissibility of P. aeruginosa filters are susceptible to retrograde contamination through contact during use or from back splashing. The consequence is that the presence of bacteria on the outer surface of the filter housing may be picked up in the filtrate water, compromising the filter as a control measure. Therefore, sufficient activity space should be maintained to enable the outlet to be used without contaminating the filter³.
The unique design of the T-safe Medical Tap Filter overcomes the issues of tap compatibility and impact on activity associated with conventional filters. Featuring a side mount and adjustable swivel mechanism, T-safe optimises the usable activity space for handwashing, whilst helping to maintain an air gap that prevents back splashing, reducing retrograde contamination risk.
Filters should be fitted with an appropriate air gap (section 14.5 e).
Compliance with the Water Supply (Water Fittings) Regulations requires that a suitable air gap is maintained when a filter is installed. Filters that are WRAS approved will have installation requirements, specifically under IRN R040 that specify a minimum a vertical distance between the outlet and the spill over level (depending on the fitting size) and in some cases, where additional back flow protection may be required.
It is therefore important to consider the compatibility of a given filter and its design, with the tap assembly that is to be installed onto, as this can impact on both activity space and result in a breach of the air gap. T-safe filters are WRAS approved products and can be located within the WRAS Approvals Directory.
There should be sufficient stock of filters and adapters, to verify that they are changed at the frequency required, with spares (section 14.5 g).
Managing the process of installing and exchanging filters can be a cumbersome task for maintenance teams, that operate across complex and disparate estates. In addition, any lapse in control could have a potentially cataclysmic impact on patient safety, if a filter was not installed at a location where it was required, was not exchanged, became clogged or contaminated.
At T-safe we recognise the criticality of robust filter management and therefore offer Zeta Safe as a free to use application that enables NHS estates teams to keep track of filter usage. T-safe Medical Filters incorporate a unique product identification system using a laser engraved GS1 compliant datamatrix, that enables full traceability from installation to exchange and disposal. ZetaSafe’s powerful exception reporting and scheduling capabilities help streamline the filter management process, providing full visibility and an audit trail that offers assurance to the Water Safety Group.
- 1. Guideline on Sterile Drug Products Produced by Aseptic Processing. Technical guideline, FDA, Bethesda, MD, USA, 1987.
- 2. ASTM F838-15a – Standard Test Method for Determining Bacterial Retention of Membrane Filters Utilized for Liquid Water treatment. Test standard, Oct 2015.
- 3. Health Technical Memorandum 04-01: Safe water in healthcare premises- Part B: operational management.