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Raising the standard with stainless steel

Raising the standard with stainless steel

Water quality plays a crucial role in the decontamination and reprocessing of reusable medical devices, and stainless steel has helped facilitate the standard required for their sterilisation. 

The release of AS/NZS 4187:2014 Reprocessing of reusable medical devices in health service organisations requires hospitals across Australia to comply with a range of stringent new requirements consistent with European and global standards for sterilisation processes. Its aim is to ensure reusable medical devices are adequately cleaned, disinfected and sterilised to protect patients and prevent infection.

Water quality is critical for sterile processing, and one requirement of the revised standard includes the replacement of non-compliant cleaning, disinfecting and sterilising equipment. There are minimum water quality requirements for pre-cleaning, cleaning and the rinse(s) prior to final rinsing. These include water hardness no greater than 150 mg/L and chloride no greater than 120 mg/L. AS/NZS 4187:2014 also specifies water quality requirements for the final rinse stages of sterile processing across Tables 7.2, 7.3 and 7.4, including final rinse water for manual cleaning and washer-disinfectors, and feed water for a dedicated steam generator.

Despite the Australian water quality guidelines, water supplies are variable in chemical impurities and the microbiological purity may also be a challenge. Therefore, water used for the final rinse of the disinfection process and the generation of steam for sterilisation must undergo treatment to achieve the water quality requirements. Reverse osmosis technology delivers a solution to meet the physical, chemical and microbial water quality required for the final rinse.

Reverse osmosis (RO) is a water treatment process that uses a semi-permeable membrane and applied pressure as the final step to filter out ions, unwanted molecules and large particles. The process is effective for the removal of micro-organisms and both organic and inorganic chemical components. ASSDA Member and Accredited Fabricator J&T Mechanical Installation have delivered stainless steel bioprocessing equipment for over 25 hospitals across Queensland, New South Wales and Victoria to meet the new specification and requirements of AS/NZS 4187:2014. The ongoing work includes the fabrication and installation of new equipment and replacement of non-compliant ring mains, water distribution networks and RO water treatment systems.

The RO water treatment systems must accommodate the required regular thermal disinfection to mitigate bacterial endotoxins and deliver a high level of microbial water quality. The treated water is reticulated to central sterile services departments (CSSDs) where surgical instruments and other reusable medical devices are sterilised. Continuous bacteria control is critical to supplying the required microbial water quality and the use of ultraviolet (UV) light in the ring mains to treat return water delivers compliance with AS/NZS 4187:2014. UV sterilisation is 99.99% effective in killing microbiological substances, and  is a safe, chemical-free process.

Stainless steel is the standard material of construction in water treatment applications, offering hygienic properties, durability, and optimum long-term performance. With excellent corrosion resistance and hydraulic conductivity characteristics, stainless steel is the first-choice material for best overall water system design.  

In addition, plastic materials are not viable in high water purity applications due to potential leaching, and copper may also be an issue because of cupro-solvency in soft water. 

Grade 316 stainless steel material has been specified for works as per the standard, including the use of 51mm tube, 20mm three-piece ball valves,  and 45o and 90o bends as specified in AS 1528 and supplied by ASSDA Member Atlas Steels.

J&T Mechanical Installation’s expertise has ensured the highest quality of work continues to be delivered to meet the current and future requirements of water supply systems complying with AS/NZS 4187:2014. Orbital welding is used on site during installation, with bioprocessing equipment requiring high quality welds to ensure water supply remains free of bacteria, rust and other contaminants. Orbital welding ensures full penetration welds with no overheating occurring that could undermine the corrosion resistance of the final weld zone.

The J&T team also performs hydrostatic testing and weld traceability to confirm mechanical integrity, as part of AS/NZS 4187:2014’s requirement for all equipment to undergo installation qualification (IQ), operational qualification (OQ) and performance qualification (PQ) tests.

As the roll out of AS/NZS 4187:2014 continues across Australia, hospitals and other health organisations are required to have a documented plan for implementation in place by December 2021, with the deadline for full compliance by December 2022.  Critical hospital infrastructure demands long-term compliance, structural integrity and quality fabrication, all of which are being delivered using stainless steel and superior workmanship by J&T Mechanical Installation.

  

Photo credits: J & T Mechanical Installation

This article is featured in Australian Stainless Magazine issue 73, 2021. 

Tina Belesis