Steam sterilisation’s energy and water footprintForbes McGain A D , Graham Moore B and Jim Black C
A Departments of Anaesthesia and Intensive Care, Western Health, Footscray Hospital, Gordon Street, Footscray, Vic. 3054, Australia.
B Department of Infrastructure Engineering, Melbourne School of Engineering, The University of Melbourne, Vic. 3010, Australia. Email: firstname.lastname@example.org
C Nossal Institute for Global Health, Melbourne School of Population and Global Health, University of Melbourne, Vic. 3010, Australia. Email: email@example.com
D Corresponding author. Email: firstname.lastname@example.org
Australian Health Review - http://dx.doi.org/10.1071/AH15142
Submitted: 3 August 2015 Accepted: 1 February 2016 Published online: 14 April 2016
Objective The aim of the present study was to quantify hospital steam steriliser resource consumption to provide baseline environmental data and identify possible efficiency gains. We sought to find the amount of steriliser electricity and water used for active cycles and for idling (standby), and the relationship between the electricity and water consumption and the mass and type of items sterilised.
Methods We logged a hospital steam steriliser’s electricity and water meters every 5 min for up to 1 year. We obtained details of all active cycles (standard 134°C and accessory or ‘test’ cycles), recording item masses and types. Relationships were investigated for both the weight and type of items sterilised with electricity and water consumption.
Results Over 304 days there were 2173 active cycles, including 1343 standard 134°C cycles that had an average load mass of 21.2 kg, with 32% of cycles <15 kg. Electricity used for active cycles was 32 652 kWh (60% of total), whereas the water used was 1 243 495 L (79%). Standby used 21 457 kWh (40%) electricity and 329 200 L (21%) water. Total electricity and water consumption per mass sterilised was 1.9 kWh kg–1 and 58 L kg–1, respectively. The linear regression model predicting electricity use was: kWh = 15.7+ 0.14 × mass (in kg; R2 = 0.58, P < 0.01). Models for water and item type were poor. Electricity and water use fell from 3 kWh kg–1 and 200 L kg–1, respectively, for 5-kg loads to 0.5 kWh kg–1 and 20 L kg–1, respectively, for 40-kg loads.
Conclusions Considerable electricity and water use occurred during standby, load mass was only moderately predictive of electricity consumption and light loads were common yet inefficient. The findings of the present study are a baseline for steam sterilisation’s environmental footprint and identify areas to improve efficiencies.
What is known about the topic? There is increasing interest in the environmental effects of healthcare. Life cycle assessment (‘cradle to grave’) provides a scientific method of analysing environmental effects. Although data of the effects of steam sterilisation are integral to the life cycles of reusable items and procedures using such items, there are few data available. Further, there is scant information regarding the efficiency of the long-term in-hospital use of sterilisers.
What does this paper add? We quantified, for the first time, long-term electricity and water use of a hospital steam steriliser. We provide useful input data for future life cycle assessments of all reusable, steam-sterilised equipment. Further, we identified opportunities for improved steriliser efficiencies, including rotating off idle sterilisers and reducing the number of light steriliser loads. Finally, others could use our methods to examine steam sterilisers and many other energy-intensive items of hospital equipment.
What are the implications for practitioners? We provide useful input data for all researchers examining the environmental footprint of reusable hospital equipment and procedures using such equipment. As a result of the present study, staff in the hospital sterile supply department have reduced steam steriliser electricity and water use considerably without impeding sterilisation throughput (and reduced time inefficiencies). Many other hospitals could benefit from similar methods to improve steam steriliser and other hospital equipment efficiencies.
References Costello A, Abbas M, Allen A, Bell S, Bellamy R, Friel S, Groce N, Johnson A, Kett M. Managing the health effects of climate change. Lancet 2009; 373 1693–733.
| Managing the health effects of climate change.CrossRef | 19447250PubMed |
 Sustainable Development Unit, UK National Health Service. Carbon footprint update for the NHS England. 2013. Available at: http://www.sduhealth.org.uk/policy-strategy/reporting/nhs-carbon-footprint.aspx [verified 12 May 2015].
 Sneyd J, Montgomery H, Pencheon D. The anaesthetist and the environment. Anaesthesia 2010; 65 435–7.
| The anaesthetist and the environment.CrossRef | 1:STN:280:DC%2BC3czps1Wnug%3D%3D&md5=f8ccbc8884b2f8526db5aae669f652dbCAS | 20522026PubMed |
 Sherman JD, Ryan S. Ecological responsibility in anesthesia practice. Int Anesthesiol Clin 2010; 48 139–51.
| Ecological responsibility in anesthesia practice.CrossRef | 20616643PubMed |
 Haines A, Dora C. How the low carbon economy can improve health. BMJ 2012; 344 e1018
| How the low carbon economy can improve health.CrossRef | 22431656PubMed |
 Frischknecht R, Jungbluth N, Althaus H-J, Doka G, Dones R, Heck T, Hellweg S, Hischier R, Nemeck T, Rebitzer G. The ecoinvent database: overview and methodological framework. Int J Life Cycle Assess 2005; 10 3–9.
| The ecoinvent database: overview and methodological framework.CrossRef | 1:CAS:528:DC%2BD2MXmsFektw%3D%3D&md5=2cb090d96ad3196dfe647981504aa67aCAS |
 Weidema BP, Bauer C, Hischier R, Mutel C, Nemeck T, Reinhard J, Vadenbo C, Wernet G. Ecoinvent centre. Swiss centre for life cycle inventories. Data quality guideline for the ecoinvent database version 3. 2014. Available at: http://www.ecoinvent.org/files/dataqualityguideline_ecoinvent_3_20130506.pdf [verified 21 June 2015].
 The International Organization for Standardization. ISO-14040. 2006. Available at: http://www.iso.org/iso/catalogue_detail?csnumber=37456 [verified 20 March 2015].
 Overcash M. A comparison of reusable and disposable perioperative textiles: sustainability state-of-the-art 2012. Anesth Analg 2012; 114 1055–66.
| A comparison of reusable and disposable perioperative textiles: sustainability state-of-the-art 2012.CrossRef | 22492184PubMed |
 Adler S, Scherrer M, Rückauer K, Daschner F. Comparison of economic and environmental impacts between disposable and reusable instruments used for laparoscopic cholecystectomy. Surg Endo Intervent Tech 2005; 19 268–72.
| Comparison of economic and environmental impacts between disposable and reusable instruments used for laparoscopic cholecystectomy.CrossRef | 1:STN:280:DC%2BD2M3js1SksA%3D%3D&md5=d5d2c6bc8585eb6fede3979b9325faecCAS |
 Eckelman M, Mosher M, Gonzalez A, Sherman J. Comparative life cycle assessment of disposable and reusable laryngeal mask airways. Anesth Analg 2012; 114 1067–72.
| Comparative life cycle assessment of disposable and reusable laryngeal mask airways.CrossRef | 22492190PubMed |
 McGain F, McAlister S, McGavin A, Story D. The financial and environmental costs of reusable and single-use plastic anaesthetic drug trays. Anaesth Intensive Care 2010; 38 538–44.
| 1:STN:280:DC%2BC3cznvVSgtA%3D%3D&md5=dc46bad15c2286f68a78d1b503615ae0CAS | 20514965PubMed |
 Morris D, Wright T, Somner J, Connor A. The carbon footprint of cataract surgery. Eye (Lond) 2013; 27 495–501.
| The carbon footprint of cataract surgery.CrossRef | 1:CAS:528:DC%2BC3sXlvVertr0%3D&md5=f688741fcf28783049ef44f113b19ebeCAS | 23429413PubMed |
 Campion N, Thiel CL, DeBlois J, Woods NC, Landis AE, Bilec MM. Life cycle assessment perspectives on delivering an infant in the US. Sci Total Environ 2012; 425 191–8.
| Life cycle assessment perspectives on delivering an infant in the US.CrossRef | 1:CAS:528:DC%2BC38XlvFejt7o%3D&md5=ba58115007fa08a7ddd78d2fb5be75a7CAS | 22482785PubMed |
 Connor A, Lillywhite R, Cooke MW. The carbon footprints of home and in-center maintenance hemodialysis in the United Kingdom. Hemodial Int 2011; 15 39–51.
| The carbon footprints of home and in-center maintenance hemodialysis in the United Kingdom.CrossRef | 21231998PubMed |
 Thiel CL, Eckelman MJ, Guido R, Huddleston M, Landis AE, Sherman J, Shrake SO, Copley-Woods N, Bilec M. Environmental impacts of surgical procedures: life cycle assessment of hysterectomy in the US. Environ Sci Technol 2015; 49 1779–86.
| 1:CAS:528:DC%2BC2cXitFaqsbvK&md5=6b49b509498433253b2889c7275c3c03CAS | 25517602PubMed |
 Woods DL, McAndrew T, Nevadunsky N, et al Carbon footprint of robotically-assisted laparoscopy, laparoscopy and laparotomy: a comparison. Int J Med Robot Comp Assist Surg 2015; 11 406–12.
 Australian Government Department of the Environment. National greenhouse accounts factors. 2014. Available at: http://www.environment.gov.au/system/files/resources/b24f8db4-e55a-4deb-a0b3-32cf763a5dab/files/national-greenhouse-accounts-factors-2014.pdf [verified 13 June 2015].
 Rutala W, Weber D. Disinfection, sterilization, and control of hospital waste. In Mandell G, Bennett J, Dolin R, editors. Principles and practice of infectious diseases, 6th edn. Philadelphia, PA: Elsevier; 2005. pp. 3331–43.
 McGain F, McAlister S, McGavin A, Story D. A life cycle assessment of reusable and single-use central venous catheter insertion kits. Anesth Analg 2012; 114 1073–80.
| A life cycle assessment of reusable and single-use central venous catheter insertion kits.CrossRef | 22492185PubMed |
 Standards Australia. AS/NZS 4187 : 2014. Reprocessing of reusable medical devices in health service organisations. Sydney: SAI Global Standards; 2014.
 Levin M. Handbook of fiber chemistry, 3rd edn. Boca Raton, FL: CRC Press; 2006.
 The Engineering Toolbox. The specific heat of metals. 2008. Available at: http://www.engineeringtoolbox.com/specific-heat-metals-d_152.html [verified 12 March 2015].
 Australian Energy Market Operator. Estimated average daily consumption per household, 2013. Appendix B – energy efficiency. 2012. Available at: http://www.aemo.com.au/Electricity/Planning/Forecasting/NEFR-Archive/~/media/Files/Other/forecasting/2012%20National%20Electricity%20Forecasting%20Report.ashx [verified 20 February 2016].
 Melbourne Water. Water data: water use for Melbourne, 2014. 2014. Available at: http://www.melbournewater.com.au/waterdata/wateruse/Pages/default.aspx [verified 13 March 2015].
 Unger SR, Landis AE. Comparative life cycle assessment of reused versus disposable dental burs. Int J Life Cycle Assess 2014; 19 1623–31.
| Comparative life cycle assessment of reused versus disposable dental burs.CrossRef | 1:CAS:528:DC%2BC2cXhtFerur3N&md5=d6e92e67e5bf01a430a75a4b32582eecCAS |
 Schneider PM. New technologies and trends in sterilization and disinfection. Am J Infect Control 2013; 41 S81–6.
| New technologies and trends in sterilization and disinfection.CrossRef | 23622756PubMed |
 Esmaeili A, Twomey JM, Overcash MR, Soltani SA, McGuire C, Ali K. Scope for energy improvement for hospital imaging services in the USA. J Health Serv Res Policy 2015; 20 67–73.
| Scope for energy improvement for hospital imaging services in the USA.CrossRef | 25323087PubMed |