White Paper

Minimising Water and Energy Waste in Bedpan Washer-Disinfector Cycles

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.

Introduction

Bedpan washer-disinfectors (WDs) empty, clean and thermally disinfect human waste containers such as bedpans, urine bottles and commode pans. AS 5369:2023 lists bedpans, urinals, sponge bowls and commodes as non-critical items that may require thermal disinfection in a WD to ISO 15883-3 or ISO 15883-6. This paper quantifies water and energy use per cycle and sets out measures that reduce it without reducing the validated disinfection dose or cleaning efficacy.

Cycle Optimisation: Time, Temperature and Detergent

Resource baseline: The following illustrative build-up assumes 20 cycles per day, 25 L [6.6 US gal] of water per cycle, 0.5 kg [1.1 lb] of steam per cycle generated at atmospheric pressure from feedwater at 15 deg C [59 deg F], and a steam generator standby loss of 60 W [205 BTU/h]. Generating the steam requires 2,610 kJ per kg [1,123 BTU per lb], or 0.36 kWh per cycle. Tariffs are A$0.30 per kWh and A$5 per kL [A$18.93 per 1,000 US gal] for water and wastewater combined.

At these assumptions a cycle costs about A$0.23 in water and energy, and water costs more than energy. Fit a water meter and a kWh meter to the WD supply, record use per cycle by programme, and replace the assumptions with measured values.

Disinfection dose: ISO 15883-3 requires the thermal disinfection stage to deliver an A0 value of at least 60, equivalent to 80 deg C [176 deg F] for 1 min. Program a higher A0 value, e.g. A0 600, equivalent to 90 deg C [194 deg F] for 1 min, where the infection prevention risk assessment requires it. The energy difference is small. Heating an assumed 20 kg [44 lb] of chamber, rack and load steel a further 10 deg C [18 deg F] requires about 100 kJ [95 BTU], or 0.03 kWh per cycle, about A$61 per year at 7,300 cycles. Set the A0 value by risk, not by energy cost.

Spores: Thermal disinfection at these A0 values does not inactivate bacterial spores, including Clostridioides difficile. Spore load is reduced by cleaning. A programme intended for C. difficile must increase cleaning action, e.g. wash time or additional wash stages, not disinfection temperature.

Programme selection: Use reduced-water or short programmes only where they are validated programmes in the IFU that deliver the same A0 value and pass cleaning efficacy checks for the items processed. Take savings from flush, wash or cooling water volume or from cycle time, never from the disinfection stage. Any programme change requires operational and performance qualification before use.

Cooling stage: Many bedpan WDs cool the load with a cold water spray after disinfection. Measure this stage separately. Where the IFU offers air cooling or a reduced cooling volume, use it for items that are not handled immediately.

Cleaning agent: Use the cleaning agent specified in the IFU. Cleaning agents for reusable medical devices must be included in the ARTG. Confirm the dosage on the process record each cycle and verify the dosed volume at requalification. Under-dosing causes cleaning failures and repeat cycles. Over-dosing causes foaming and residue.

Loading: Load to the configurations validated during performance qualification. Overloading shields surfaces from the spray and causes repeat cycles. Combine items in one cycle only within validated configurations and the facility's infection prevention policy. At about A$0.23 per cycle, do not hold soiled containers to build a full load, as delay lets soil dry and increases cleaning failures.

Supply water: AS 5369:2023 limits water for all stages before the final rinse to a hardness of 150 mg/L or less and chloride of 120 mg/L or less, and notes this quality may suit the final rinse of ISO 15883-3 WDs. Test the supply before installation. Soften water near the hardness limit to protect the steam generator, valves and spray nozzles. Keep supply pressure within the IFU range, because low pressure reduces spray action and extends fill time.

Scale: Scale on electric immersion elements raises sheath temperature and shortens element life. It has little effect on energy efficiency, because element heat still enters the water. Scale on nozzles and spray arms reduces spray coverage and causes cleaning failures. Descale at the interval in the IFU, shortened where supply hardness is high.

Standby: A steam generator held at temperature loses heat continuously. At the assumed 60 W [205 BTU/h], standby is 17 % of annual electricity. Switching the generator off for 8 h per day saves 175 kWh, about A$53, per year. Use programmed standby where the IFU permits and the heat-up time suits ward demand.

Reuse Technologies: Recycled Water and Heat Recovery

Recycled water: Bedpan WDs spray water onto items after thermal disinfection during the cooling stage. Non-potable water in that stage recontaminates disinfected items. Supply bedpan WDs with potable water that meets the AS 5369:2023 hardness and chloride limits, unless the IFU, validation and the state recycled water regulator approve another source. Use recycled water for sanitary fixtures, e.g. toilet flushing, where the state regulator approves it under the Australian Guidelines for Water Recycling. Provide backflow prevention to the hazard rating required by AS/NZS 3500.1 and identify recycled water pipework.

Drain heat recovery: Cooling 1 m3 [264 US gal] of water by 25 deg C [45 deg F] releases 29 kWh. Bedpan WD effluent is intermittent, small in volume and contains faecal solids, so a drain heat exchanger needs storage to match discharge to the next fill and must tolerate fouling. Separate drain water from potable water with double-wall, vented heat exchanger construction. At the baseline assumptions, recovering 50 % of the steam energy saves 0.18 kWh per cycle, or 1,324 kWh and A$397 per year. Over a 10 year life at a 5 % discount rate, this justifies a retrofit costing no more than about A$3,070. Compare quoted retrofit costs with this limit, and consider integrated heat recovery on new machines where its incremental price falls within it.

Steam vapour: Steam released when the door opens adds heat and moisture to the sluice room. Specify machines with internal steam condensing or a vapour extraction connection, and size room exhaust for the residual load.

Hot water supply: Connect a hot water supply only where the IFU provides a hot water inlet and the initial flush remains cold to avoid fixing soil to surfaces. Preheating steam generator feedwater from 15 deg C [59 deg F] to 60 deg C [140 deg F] reduces steam generation energy by about 7 %.

Validation: Treat any change to water source, feedwater temperature or drain configuration as a change to services. Repeat the relevant installation and operational qualification tests and confirm the A0 value and cleaning efficacy before return to service.

Compliance with Australian Standards and Guidelines

AS 5369:2023: Superseded AS/NZS 4187:2014 and AS/NZS 4815:2006. It requires WDs to conform to the applicable parts of ISO 15883. Where facility policy or the device IFU requires disinfection of non-critical items, use a thermal process or an instrument grade disinfectant under a documented procedure. A disinfection process recommended in the device IFU must be followed. Perform installation, operational and performance qualification, requalify annually, and repeat operational qualification when equipment is modified to deliver a new process.

Routine monitoring: Check the process record at the end of every cycle. Confirm water pressure, flow and spray action, cleaning agent dosage, and the temperature and time at disinfection temperature against the validated limits.

ISO 15883-1:2024 and ISO 15883-3:2024: Second editions were published in October and November 2024. Require conformance to these editions when specifying new bedpan WDs.

Chemical disinfection: Use chemical disinfection only for thermolabile non-critical items, in a WD to ISO 15883-7 with an ARTG-included disinfectant. It is not an energy measure for thermally stable bedpans, as it adds chemical cost, rinse water and chemical handling controls.

Manual cleaning: Do not substitute manual cleaning for a WD cycle to save water. Manual cleaning cannot deliver a thermal disinfection A0 value and increases splash exposure.

Storage: AS 5369:2023 requires non-critical items to be stored in a clean, dry place. Where the drying stage is shortened or switched off, dry items on a rack before storage.

NSQHS Standards: Hospitals are assessed against Action 3.17 of the Preventing and Controlling Infections Standard, which requires reprocessing consistent with national and international standards and manufacturers' guidelines.

Aged care: AS 5369:2023 applies wherever reusable medical devices are reprocessed. The ACSQHC Aged Care Infection Prevention and Control Guide checks whether reprocessing practices comply with current Australian Standards. Write programme selection and loading rules into local procedures so that casual and agency staff apply them.

Equipment Specification

Specify the following when procuring bedpan WDs:

• Conformance: ISO 15883-1 and ISO 15883-3, current editions, with type testing that covers every container type and rack configuration to be used, and ARTG inclusion.
• Resource data: Water per cycle by programme and stage (L), energy per cycle (kWh), standby power (W) and cycle time. Compare offers on cost per cycle at the facility's cycle count.
• Steam generation: Insulated generator with programmable standby, or on-demand generation.
• Vapour control: Internal steam condensing or a vapour extraction connection.
• Cooling: Air cooling or adjustable cooling water volume.
• Racks: Holders that match the facility's container mix, so that validated loads use the chamber capacity.
• Records: Electronic cycle records that include water and energy per cycle. Set alerts for drift, e.g. rising fill time from low pressure or blocked strainers, and rising heat-up time from scale or element faults.
• Adaptive programmes: Where a programme adjusts to load or soil, every control path must be validated.
• Lifecycle cost: Compare purchase price plus 10 years of water, energy, cleaning agent and maintenance cost.

Accept alternative technologies, e.g. ultrasonic, ultraviolet or ozone stages, only as additions to a WD that conforms to ISO 15883-3 and holds ARTG inclusion. Thermal disinfection remains the ISO 15883-3 process.

Practical Recommendations for Facility Managers and Clinicians

1. Measure: Meter water and electricity at each WD and record use per cycle by programme. Use measured values in all savings estimates.
2. Set the dose: Set the A0 value by infection prevention risk assessment. Use only validated programmes and qualify any programme change before use.
3. Write the procedure: Specify programme selection, validated load configurations, prompt processing and the prohibition on manual cleaning in place of a WD cycle.
4. Train: Train and assess staff on the procedure, including loading and reading the cycle record.
5. Maintain: Clean strainers and nozzles, descale, verify dosing and supply pressure at the IFU intervals, and review cycle records for drift in fill time, heat-up time and water use.
6. Control water quality: Test supply hardness and chloride, and soften where hardness approaches 150 mg/L.
7. Reduce standby: Program standby or off periods outside peak use where the IFU permits.
8. Evaluate reuse: Assess heat recovery against the break-even capital at the measured cycle count. Keep recycled water out of WD supplies unless the IFU, validation and the regulator approve it.
9. Procure on cost per cycle: Require per-cycle water and energy data, and compare lifecycle cost.

Conclusion

A bedpan WD cycle uses a small quantity of water and energy, about A$0.23 per cycle at the illustrative assumptions, with water the larger cost. The largest savings come from avoiding repeat and unnecessary cycles, controlling flush and cooling water volume, maintaining spray performance and water quality, and reducing steam generator standby. Raising or lowering the A0 value changes energy use little, so set it by risk. Heat recovery and recycled water require a measured business case, regulatory approval and revalidation, and recycled water must not contact disinfected items.

Sources

1. Standards Australia. AS 5369:2023 Reprocessing of reusable medical devices and other devices in health and non-health related facilities.
2. ISO 15883-1:2024 Washer-disinfectors, Part 1: General requirements, terms and definitions and tests.
3. ISO 15883-3:2024 Washer-disinfectors, Part 3: Requirements and tests for washer-disinfectors employing thermal disinfection for human waste containers.
4. Australian Commission on Safety and Quality in Health Care. National Safety and Quality Health Service Standards, Action 3.17.
5. Australian Commission on Safety and Quality in Health Care. The Aged Care Infection Prevention and Control Guide, 2024.
6. Natural Resource Management Ministerial Council, Environment Protection and Heritage Council, Australian Health Ministers' Conference. Australian Guidelines for Water Recycling: Managing Health and Environmental Risks (Phase 1), 2006.
7. AS/NZS 3500.1 Plumbing and drainage, Part 1: Water services.