White Paper

Recommended Replacement Frequency for Medical Sterilisation and Disinfection Equipment in Australia

October 2026

Disclaimer

This content is provided for information only. The authors make no representation or warranty regarding the accuracy, completeness or currency of the content. No information in this whitepaper should be construed as medical advice. Readers should seek appropriate professional guidance before acting on any information contained in this document. The authors expressly disclaim all liability for any direct or indirect loss or damage arising from the use of or reliance on this information.

Abstract

This paper sets out how to determine when to replace washer-disinfectors and steam sterilisers in Australian health facilities. No Australian standard or regulation sets a replacement interval. Replacement follows from compliance with AS 5369:2023 and the applicable equipment standard, the results of routine monitoring, maintenance and requalification, pressure equipment inspection, parts and service support, capacity and whole-of-life cost. The paper lists the AS 5369:2023 maintenance, testing and record requirements, gives reference lives for capital planning and defines objective replacement triggers.

Overview of Sterilisation and Disinfection Equipment

Scope: Washer-disinfectors (WDs) and steam sterilisers used to reprocess reusable medical devices (RMDs) in hospitals, day procedure services and office-based practices. The same replacement method applies to low temperature sterilisers, with performance testing to the instructions for use (IFU).

Washer-Disinfectors: WDs clean and thermally disinfect RMDs before inspection, packaging and sterilisation. Wear components include circulation and drain pumps, heating elements, solenoid valves, spray arms, dosing pumps, door seals and temperature sensors. Scale from hard supply water and chemical exposure accelerate wear. Bedpan WDs disinfect human waste containers at ward level.

Steam Sterilisers: Steam sterilisers operate at sterilisation temperatures of 121 deg C [250 deg F] to 134 deg C [273 deg F]. AS 5369:2023 classifies sterilisers with a chamber volume of 60 L [2.1 cu ft] and above as large and those not exceeding 60 L [2.1 cu ft] as small. Wear components include vacuum pumps, door seals, valves, steam generator elements, steam traps and pressure and temperature sensors. The chamber, jacket and steam generator are pressure equipment.

Small Steriliser Cycles: EN 13060 defines type B, N and S cycles. Type N cycles sterilise unwrapped solid products only. Wrapped, porous and hollow loads require a type B cycle, or a type S cycle where the IFU specifies that load.

Equipment Standards: AS 5369:2023 requires reprocessing equipment to conform to the following standards.

Use Intensity: Wear components fail by cycle count and operating hours rather than calendar age. Record cycles per year for each unit.

Regulatory Standards and Compliance in Australia

AS 5369:2023: Published on 15 December 2023, AS 5369:2023 supersedes AS/NZS 4187:2014 and AS/NZS 4815:2006 and applies to hospital and office-based settings. It contains no compliance timeframes and no replacement interval for reprocessing equipment.

NSQHS Standards: Action 3.17 requires reprocessing processes consistent with relevant national and international standards, in conjunction with manufacturers' guidelines. It also requires a traceability process for critical and semi-critical devices that identifies the patient, the procedure and the devices used.

Advisory AS24/01: The Australian Commission on Safety and Quality in Health Care issued Advisory AS24/01 on 11 November 2024. It rescinds Advisory AS18/07 and removes compliance deadlines. Health service organisations were to complete a gap analysis against AS 5369:2023 by 30 June 2025 and must hold a compliance plan with timeframes. Assessors rate Action 3.17 not met where the gap analysis was not complete by July 2025 or the plan is not implemented on schedule. The economically useful life of reprocessing equipment and water filtration systems is to be detailed in the asset register. Infection risk and the IFU inform when equipment is declared inoperable or obsolete. Replacement equipment is to meet the relevant national or international standards, and previously used replacement equipment should operate as originally intended and conform to those standards. Assessors review evidence of conformance for replaced equipment.

Therapeutic Goods: Reprocessing equipment supplied in Australia must be included in the Australian Register of Therapeutic Goods (ARTG). Confirm the ARTG entry before purchasing new or used equipment.

Pressure Equipment: Steam sterilisers and dedicated steam generators are pressure equipment under the work health and safety regulations of each jurisdiction. The hazard level determined under AS 4343 sets design and item registration requirements. In-service inspection to AS/NZS 3788 determines whether the vessel remains fit for continued service.

Maintenance, Testing, and Reporting Requirements

AS 5369:2023 sets the following minimum requirements. The IFU and the facility's risk assessment add activities and set frequencies where AS 5369:2023 does not.

Water Quality: Test supply water before equipment installation and record the results. Water for pre-cleaning, cleaning and rinses before the final rinse must not exceed 150 mg/L hardness or 120 mg/L chloride. Final rinse water for WDs to ISO 15883-1 and ISO 15883-2 must meet limits that include conductivity not exceeding 30 µS/cm at 20 deg C [68 deg F], total hardness not exceeding 10 mg/L as CaCO3, total viable count less than 100 cfu per 100 mL and endotoxin less than 0.25 EU/mL. Test supply water hardness and chloride, final rinse conductivity and total viable count monthly, and endotoxin annually, adjusting frequency to the results.

Steam Quality: Test steam quality on installation or relocation of large steam sterilisers and after any change to the steam supply. Acceptance criteria are a dryness value greater than 0.95, non-condensable gases less than 3.5 % V/V and superheat not exceeding 25 deg C [45 deg F]. Test dedicated steam generator feedwater, or steam condensate from a non-dedicated supply, at IQ or OQ and annually thereafter. Dedicated generator feedwater conductivity must be less than 5 µS/cm at 20 deg C [68 deg F].

Return to Use: Do not reprocess devices on equipment until specified maintenance is complete and documented. Specify the maximum permitted delay for scheduled maintenance, e.g. 10 working days after the due date. Remove equipment from use immediately where a fault can affect device quality or safety, or operator safety.

Repairs and Changes: After repair, test the equipment against its original IQ and OQ specifications. Assess whether the repair, e.g. a controller, sensor or vacuum pump replacement, can affect process efficacy, and requalify where it can. Validate changes to control and monitoring software that affect operation. A designated competent person determines the extent of requalification and documents the rationale.

Maintenance Records: For each maintenance activity or repair, record the reason, date, model and serial number, location, work performed, parts replaced, person or company performing the work and person releasing the equipment to use. Process records may be paper or electronic. AS 5369:2023 recommends that all facilities work towards electronic tracking and process record systems. Retain records for the period set by the regulator or, where none is set, by facility policy.

Infrequently Used and Standby Equipment: Standby equipment requires the same maintenance, recalibration, electrical safety check and annual requalification as equipment in daily use. Where a cycle-based maintenance schedule would extend beyond 12 months at low use, service at 12 months. Follow the IFU for idle periods, including draining of reservoirs and steam generators. Before returning an idle unit to service, confirm that maintenance and requalification are current and complete the routine tests for that equipment type.

Trend Data: Routine test failures, aborted cycles, extended heat-up and vacuum times, rising leak rates and repair frequency indicate deterioration. Trend them for each unit and use them in the annual replacement assessment.

Equipment Lifespan and Replacement Frequency

No Mandated Interval: No Australian standard or regulation sets a replacement interval. Use planning lives for capital budgeting and replace on the triggers that follow.

Planning Lives: The following lives apply to high use, meaning daily operation at or near rated throughput with planned maintenance to the IFU. Actual life depends on cycles per year, water quality, load type, maintenance and build quality, and can differ from a planning estimate by a factor of two or more. Tax effective lives set by the Commissioner of Taxation are shown for comparison. They are depreciation estimates, not service life predictions.

Economic Life: The planning lives are economic lives, the age at which the equivalent annual cost of ownership is lowest. Capital cost per year falls with age while repair and downtime cost rises. Where repair and downtime cost rises by a constant amount G each year, the economic life is approximately the square root of 2C divided by G, where C is the installed cost. The following table gives the economic life for G as a share of C, with nil residual value.

A WD life of 7 years corresponds to repair and downtime cost rising by about 4 % of installed cost per year, and a steriliser life of 10 years to about 2 % per year. WD wear components are exposed on every cycle to detergent chemistry, hot water and thermal cycling from ambient to disinfection temperature. Steriliser wear components, principally the vacuum pump, door seal and valves, are replaced in service, and life is limited by the chamber, jacket and steam generator, which are pressure equipment, and by control system obsolescence. Equivalent annual cost stays within 3.5 % of its minimum for 2 years either side of the economic life, so a planning range rather than a fixed age is appropriate. Estimate G for each unit from the maintenance records by fitting a straight line to annual repair and downtime cost against age, and recalculate the economic life annually.

Usage Adjustment: Where repair cost scales with cycles, halving annual cycles halves G and extends the economic life by a factor of about 1.4, e.g. from 7 to 10 years. Calendar ageing of seals, elastomers and electronics, control obsolescence and parts support limit life at low use. The WA Health Medical Equipment and Imaging Replacement Program Guidelines (version 1.2) give a useful life for medical equipment of 5 to 15 years, state that extending the recommended useful life is not common practice, and prioritise replacement by condition, including age, risk of failure, availability of parts and maintenance services, criticality and impact on service delivery.

Field Data: Survey data give life expectancies of 3 to 6 years for poor quality, poorly maintained sterilisers and 10 to 15 years for good quality, well maintained sterilisers. One UK health trust declared four large steam sterilisers end of life at 11 years after about 24,000 cycles each, an average of about 6 cycles per day.

Replacement Triggers: Assess each unit annually at requalification. Plan replacement when any of the following applies.

• Requalification: The unit fails its acceptance criteria, or requalification data show that performance no longer matches the original qualification, and repair cannot restore it.

• Routine Tests: Air removal, leak rate, air detector or process record failures recur after corrective maintenance.

• Pressure Equipment: In-service inspection finds the vessel unfit for continued service, and repair to its design code is not practicable.

• Non-Conformance: The unit does not conform to its equipment standard, cannot produce a process record for each cycle or has no cycle suited to the loads processed, and modification is not practicable.

• Support: The supplier cannot confirm in writing parts and technical support for the planned remaining life, or controllers, sensors or pressure components are no longer available.

• Capacity: Throughput no longer meets demand with the redundancy required for maintenance, requalification and unplanned downtime.

• Cost: The forecast cost of retaining the unit for one more year exceeds the equivalent annual cost of a replacement.

Cost Test: Calculate the equivalent annual cost of a replacement as installed cost multiplied by the capital recovery factor, plus annual operating cost. The capital recovery factor is r divided by (1 minus (1 + r) to the power of minus n), where r is the real discount rate and n is the service life in years. At 5 % over 10 years it is 0.1295, e.g. a unit costing A$200,000 installed carries a capital charge of A$25,901 per year. Compare the equivalent annual cost with the forecast cost of keeping the existing unit for one more year: operating cost, expected repairs, downtime cost, requalification and the fall in resale value.

Hospitals and CSSDs: Provide capacity with redundancy for planned maintenance, calibration, requalification and scheduled and unscheduled downtime, with allowance for growth in demand. Stagger replacement dates across units so that capacity is maintained during installation and qualification and capital is spread across budget years.

Office-Based Practices: Dental, general practice and other office-based practices typically operate one or two small steam sterilisers under the same AS 5369:2023 requirements. Where a practice has one steriliser, arrange loan equipment or sufficient instrument stock to cover requalification, repair and replacement.

Bedpan Washer-Disinfectors: Scale on heating elements, steam generators and nozzles and exposure to human waste drive failure. Monitor disinfection temperature and time on each cycle, and supply water hardness. Plan replacement where the unit cannot reliably achieve its specified A0 value or repair frequency rises.

Impact of Recent Australian Standard Changes on Equipment Replacement

Risk-Managed Timeframes: AS 5369:2023 and Advisory AS24/01 set no compliance deadline. Each gap requires a timeframe in the compliance plan, which is assessed under Action 3.17. For each non-conforming unit, record the gap, the risk controls in place and the planned replacement date.

Common Equipment Gaps: The following conditions place a unit in the gap analysis.

• No Process Record: AS 5369:2023 requires the process record to be checked at the completion of each sterilisation and WD cycle. Equipment specifications must describe the control, monitoring and recording instrumentation, including the means that prevent a failed process being recorded as effective. Equipment without a process record cannot meet these requirements.

• Equipment Standard: WDs that do not conform to ISO 15883 and steam sterilisers that do not conform to EN 285 or EN 13060.

• Cycle Type: Small steam sterilisers with only type N cycles used for wrapped, porous or hollow loads.

• Water Supply: Supply, final rinse or feedwater that does not meet AS 5369:2023 limits. Budget water treatment with the equipment replacement.

• Software: Control and monitoring software that can no longer be supported, or changes that cannot be validated.

• Standby Units: Standby units without current maintenance and requalification. Requalify them or retire them.

Conclusion and Recommendations

No Australian standard sets a replacement interval for WDs or steam sterilisers. For high use, plan replacement of WDs at 7 to 10 years, large steam sterilisers at 10 to 15 years and small steam sterilisers at 5 to 10 years, adjusted for cycles per year and repair cost history. Replacement is set by objective triggers: requalification or routine test failure that repair cannot correct, pressure vessel condition, non-conformance with AS 5369:2023 or the equipment standard, loss of parts and technical support, capacity and an equivalent annual cost comparison.

• Asset Register: Record for each unit the installation date, economically useful life, cycles per year, equipment standard, ARTG entry, pressure equipment hazard level and inspection dates, maintenance and requalification history, and the supplier's confirmed support period.

• Capital Plan: Update a 10-year replacement plan after each annual assessment, and keep the AS 5369:2023 gap analysis and compliance plan current.

• Procurement: Specify conformance to the applicable equipment standard, ARTG inclusion, process recording with electronic export, compatibility with the traceability system, and parts and technical support for the planned service life. Apply the same specification to previously used equipment.

• Installation: Before installation, specify the location, confirm that environmental conditions and services meet the equipment specification, test water quality and obtain specifications, calibration documentation and operating instructions. Complete IQ, OQ and PQ before clinical use.

Sources

1. Standards Australia. AS 5369:2023 Reprocessing of reusable medical devices and other devices in health and non-health related facilities.
2. Australian Commission on Safety and Quality in Health Care. Advisory AS24/01: National Safety and Quality Health Service Standards requirements for reprocessing of reusable medical devices in health service organisations, version 1.0, 11 November 2024.
3. Australian Commission on Safety and Quality in Health Care. National Safety and Quality Health Service Standards, 2nd edition, version 2, 2021. Action 3.17.
4. Commissioner of Taxation. Income Tax Assessment (Effective Life of Depreciating Assets) Determination 2025 (F2025L01097), Health care and social assistance. Effective lives previously published in TR 2022/1.
5. Department of Health, Western Australia. Medical Equipment and Imaging Replacement Program Guidelines, version 1.2 (MP 0179/23).
6. GTZ. Maintenance and the life expectancy of healthcare equipment in developing economies. Health Estate Journal, March 2000.
7. Prowse P, Kelso S, Austman R. Implementation of a Useful Life Reference for Medical Devices in Canada. CMBEC41 Conference, 2018.
8. Northern Health and Social Care Trust. Antrim Sterilisers Briefing Paper, 2026.
9. ISO 15883 Washer-disinfectors. EN 285 Sterilization, Steam sterilizers, Large sterilizers. EN 13060 Small steam sterilizers. ISO/TS 22421 Sterilization of health care products, Common requirements for sterilizers for terminal sterilization of medical devices in health care facilities.
10. AS 4343 Pressure equipment, Hazard levels. AS/NZS 3788:2024 Pressure equipment, In-service inspection.