Date: 03/07/2024
Read Time: 2 minutes
Author: Dr Surani McCaw, B.E. (Chemical), Ph.D.

Engineers using paper plans on a table.

Key points:

  • Proper design and implementation of RO systems in hospitals are essential for maintaining compliance and ensuring high standards of patient care, particularly in CSSD and dialysis units.
  • Robust disinfection processes, such as maintaining water temperature at 80°C for at least 60 minutes, are crucial to prevent bacterial colonisation and ensure effective thermal disinfection outcomes.
  • Correcting false beliefs about operating temperatures, ringmain length, and the heat retention properties of thermoplastics versus stainless steel is vital for optimal RO system performance and microbial compliance.

The integration of reverse osmosis (RO) plants in hospitals, particularly in CSSD and dialysis units, has become standard practice to uphold compliance and elevate patient care standards. However, the prevalence of ambiguous and misleading information has led to flawed approaches in RO system design, compromising adherence to essential standards.

Effective RO system design must meet critical requisites to ensure sustained compliance. A pivotal aspect involves implementing robust disinfection processes, such as thermal disinfection, to safeguard both patient and staff wellbeing. Correcting common misconceptions is crucial for proper practices. Here are corrections to some common misconceptions:

Misconception 1: operating CSSD RO systems at 65°C eliminates the need to maintain temperatures between 80°C and 90°C during disinfection.  

Correction: While operating at 65°C, bacteria can still colonise piping networks. Therefore, maintaining water temperature at 80°C for a minimum of 60 minutes is essential for achieving effective disinfection outcomes

Misconception 2: Achieving the required A0 value of 12,000 for dialysis does not depend on the overall length of the ringmain. 

Correction: Even with insulated pipes, temperature loss varies with ringmain length. Bacteria in biofilm matrices can adapt to lower temperatures and build resistance over time, leading to microbial non-compliance. 

Misconception 3: Stainless steel acts as a heat sink, therefore thermoplastics are more beneficial in achieving good thermal disinfection outcomes than stainless steel. 

Correction: Stainless steel’s higher thermal conductivity enables more effective heat penetration into the biofilm matrix during thermal disinfection processes compared to thermoplastics. This ensures thorough heating of the entire system, including the biofilm on pipe surfaces, to the required temperature for disinfection.
Moreover, the energy required to increase water temperature by one unit remains consistent regardless of the piping material used. It’s crucial to emphasise that thermodynamic heating efficiency within an RO system cannot be compromised solely by selecting the piping material. 

Precision in these processes is paramount for mitigating costs associated with risks to patient health, operational downtime, reputational damage, and premature RO system replacement.

I have authored several white papers aimed at empowering healthcare facilities and personnel with essential knowledge and insights. These resources are designed to ensure the effective and sustainable operation of RO systems in alignment with healthcare standards:

Final Rinse Water – Assessing Design Challenges

Legionella Safety in Building Water Systems

Disinfection, Sterilisation and Inactivation – Not knowing the difference could cost you a life (co-authored with D2K Information)

Purification Processes to Meet AS/NZS 5369:2023 (Formerly AS/NZS 4187:2014)

Focused on enhancing patient care outcomes and organisational efficiency, we at Southland aim to provide clarity and actionable strategies. The importance of correct RO system design and operation cannot be overstated in maintaining long-term compliance and futureproofing our healthcare systems.

Need Expert Guidance?

For personalised assistance in achieving AS5369:2023 compliance, reach out to our experienced team. We’re here to guide you through optimal sampling practices and effective testing methodologies.


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