Raising hygiene standards with dry steam vapour

 

Soft services and infection prevention experts discuss the working, implications, advantages and disadvantages of cleaning with dry steam vapour.

 

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Infection Control
 
June 21, 2022
 
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Raising hygiene standards with dry steam vapour
 

As the COVID-19 pandemic continues to shake the world, the face of environmental hygiene needs to adapt fast. We need to put standard cleaning practices under the microscope and raise the bar on what are called “standard hygiene practices.” When cleaning to achieve a sanitised, safe environment, understanding the difference between disinfection and decontamination is paramount, and how you can use Dry Steam Vapour (DSV) cleaning to tackle COVID-19 is useful in achieving this.

So we hear from soft services and infection prevention experts to understand the working, implications, advantages and disadvantages of cleaning with dry steam vapour. 

Stanley Azubuike Atammo, Head of Operations- Soft Services, Magnum Plus

Dry steam vapour acts like a natural disinfectant. It kills germs and bacteria thoroughly. Dry steam vapour cleaners create a low moisture vapour that carries heat to the surface of what is being cleaned. The heat combined with light agitation does all the work.

Dry steam vapour cleaners come with a variety of accessories that allow heated vapour to focus on the surface of what is being cleaned while applying a brushing action to release dirt. They are designed for an unlimited number of applications, from walls and floors to ovens and countertops.

Cleaning with vapour eliminates chemical residues while disinfecting the surface being treated. Because so little water is used, approximately 1.5 quarts per hour, cleaning with vapour is virtually "mess-free" and dries almost instantly.

Cleaning with dry steam vapour provides a faster, deeper clean than chemicals that threaten the health of your family and pets. Vapour steam cleaners are cited as examples of green cleaning since they do not require the use of chemical cleaning solutions

Advantages

  • The use of a dry steam vapour cleaner, in general, contributes directly to better indoor air quality by reducing chemical residuals and removing airborne particles
  • Cleaning with vapour is mess-free with temperatures hot enough to kill bacteria and germs
  • The vapour steam cleaner is also quiet and portable so it can be used anywhere at any time
  • Dry Steam Vapour integrated decontamination techniques play in creating a safe and clean environment, free from risks of infection.
  • Better penetration on porous surfaces
  • Safe for human inhalation
  • No residual chemical cost, just soft water, which is much more economical and accessible

Disadvantages

  • It's very hot. The equipment uses steam that can go at a really high temperature.
  • You have to clean more often. You may need to clean more often than usual compared to using other methods of cleaning. 
  • Warm-up time. There are machines that may take a bit longer to warm up. 
  • More expensive.
  • Causing electricity power tripping

rollinMichael Rollins, Consultant Infection Prevention

Advances in environmental surfaces mechanical ‘bio-cleaning’ – efficacy – efficiency - environmental sustainability of Superheated Dry Steam Vapour (DSV).

The physical act of ‘cleaning’ removes soil including contamination by micro-organisms biofilm and residues. The efficiency with which soil and microbes are removed from built environment surfaces has been studied utilising microbiological measures to investigate the efficacy of technology based on the application of controlled superheated Dry Steam Vapour (DSV).

Surface-mediated infectious disease transmission is a major concern in many settings, including healthcare, schools, hospitality and food-processing facilities. The impact of SARS CoV2 infection has expanded the focus to all environments where people congregate, interact, and share facilities, such as transportation, commercial office environments, retail and more. 

Chemical disinfectants are frequently used to reduce contamination, but many present significant risks to humans, surface compatibility, and environmental impact. Chemical disinfectants must be diligently applied in strict accordance with label instructions including wet contact time to be effective. In some cases, chemical exposure alone is insufficient and mechanical action is required to disrupt the protective dry biofilm and enable direct chemical contact disinfection.

During my role as Projects manager for Healthcare Environment Research at University College London Hospitals, we conducted an extensive study into steam cleaning for the Dept of Health in the UK. To evaluate its potential for reduction to healthcare associated Infection (HCAI), practicality and patient acceptance in use within the healthcare environment. We learned from Food manufacturing and kitchens that steam cleaning was very effective in removing a heavy soil burden which could be dried onto surfaces with heavy residues formed. The question, could steam cleaning work for healthcare disinfection?

At the outset we needed to understand steam in its various forms, how it can be applied to surfaces and safety factors including droplet dispersion and aerosol generation. Factors which could adversely impact the process, contributing to viable contaminant transfer and cross contamination risk.

The steam we see from a boiling appliance is saturated wet steam which is slightly above boiling point (100C / 212F) and would be hazardous in practical use. Superheated Dry Steam Vapour is water which has been heated under pressure to produce fine steam vapour particles when released from the boiler. This release under pressure creates strong mechanical action as the vapour rapidly expands and dissipates. We calculated a minimum of 5.5 – 6.0 bar pressure to achieve a consistent quality of dry steam vapour at 150C / 318F. The concentration of dry steam vapour was critical as we learned from the dispersion and aerosolization studies.  The optimum calibration was critical in achieving surface disinfection and mitigating the risk of viable contaminant transfer. The steam generated from One litre of water equated to 2000 cubic litres of DSV. The rapid expansion of the DSV when released from the surface contact tool created the mechanical action, which penetrated the surface profile, emulsified any surface contaminant, including dried on biofilm and made this available for efficient removal either my adsorption or vacuum extraction.

We also needed to understand the nature and characteristics of the surfaces we aim to clean and disinfect. Are all surfaces compatible?  What is the tolerance for heat transfer? Will the steam vapour penetrate into surface profiles or abraded areas where biofilm residues may reside?

The next step was to evaluate the steam delivery to the surface – the tool(s).  The early food industry steam tools were designed to clean in contact with flat surfaces. Not all surfaces are flat and in health care most are not. This laid down the challenge for the design of new healthcare tools which subsequently were developed and validated. The manufacturer’s design work was rewarded with the Dept of Health Award for Healthcare Cleanliness and Technology Innovation in 2008.

The validation work included microbiological assessment of this chemical-free decontamination technique evaluated against the standard disinfection test method range of pathogens of concern including bacteria, spores and fungi, applied to ten common types of hospital surface, including plastic laminates, stainless steel, woven mattress covers etc. All tests were conclusive, achieving a 6-Log reduction following the specified SOP method for each surface and tool selected. Subsequent studies have validated the inactivation of respiratory and gastrointestinal virus SARS, Influenza, norovirus.

DSV leaves the surface totally clean, free or residue. A factor which is vital for those surfaces which have antimicrobial properties, such as silver impregnated plastic, topical silane AM coating, copper etc. Surface contamination obviously inhibits the antimicrobial performance. 

The next generation of in-line steam cleaning machines are now found within the food manufacturing sector. Material conveyor belts are cleaned and disinfected, allergens removed in real time with each cycle. Robot steam cleaning systems have also been developed to automate in-line processes such as degreasing manufactured components or cleaning a patient bed. 

Superheated Dry Steam Vapour disinfection systems are chemical free, rapidly efficacious across a broad spectrum of bacteria, virus, fungi. DSV cleaned and maintained surfaces reduce surface-mediated infection risk. Dry Steam Vapour serves as a practical and sustainable alternative to chemical disinfectants. 

References

  1. Gillespie E, Williams N, Sloane T, Wright L, Kotsanas D, Stuart RL. Using microfiber and steam technology to improve cleaning outcomes in an intensive care unit. Am J Infect Control. 2015 Feb;43(2):177-9. DOI: 10.1016/j.ajic.2014.11.006 12. 
  2. Gillespie E, Brown R, Treagus D, James A, Jackson C. Improving operating room cleaning results with microfiber and steam technology. Am J Infect Control. 2016 Jan;44(1):120-2. DOI: 10.1016/j.ajic.2015.08.016 13. 
  3. Sexton JD, Tanner BD, Maxwell SL, Gerba CP. Reduction in the microbial load on high-touch surfaces in hospital rooms by treatment with a portable saturated steam vapor disinfection system. Am J Infect Control. 2011 Oct;39(8):655-62. DOI: 10.1016/j.ajic.2010.11.009 14. 
  4. White LF, Dancer SJ, Robertson C. A microbiological evaluation of hospital cleaning methods. Int J Environ Health Res. 2007 Aug;17(4):285-95. DOI: 10.1080/09603120701372433 15. 
  5. Gillespie E, Wilson J, Lovegrove A, Scott C, Abernethy M, Kotsanas D, Stuart RL. Environment cleaning without chemicals in clinical settings. Am J Infect Control. 2013 May;41(5):461-3. DOI: 10.1016/j.ajic.2012.07.003 16. 
  6. Isabella Marchesi, Arianna Sala, Giuseppina Frezza, Stefania Paduano, Sara Turchi, Annalisa Bargellini, Paola Borella & Claudio Cermelli. In-vitro virucidal efficacy of a dry steam disinfection system against Human Coronavirus, Human Influenza Virus, and Echovirus’. Journal of Occupational and Environmental Hygiene, 18:12, 541-546, 2021  DOI: 10.1080/15459624.2021.1989442 
  7. Gant VA, Rollins M, Wren M, Jeanes A, Rao G (2006). Microfibre cloth and steam cleaning technology: An investigation of cleaning and decontamination performance, and observations on practical implementation in the hospital environment. Study sponsored by the CNO Workstream BCS 205 (1); Department of Health  London, November 2006. Published  Department of Health Guideline (2007) An Integrated Approach To Hospital Cleaning: Microfibre Cloth and Steam Cleaning Technology, Dept of Health, London
  8. L.B.J van Boxtel; J. Kastelein; M. Rollins TNO Food and Nutrition report V7683 Date March 2008 Validation of Superheated Dry Steam Vapour Cleaning Technology in the Healthcare Environment
  9. Soo-Hwan Kim Sang-Hyun Park Sang-Soon Kim Dong-Hyun Kang  Inactivation of Staphylococcus aureus Biofilms on Food Contact Surfaces by Superheated Steam Treatment J Food Prot. 2019 Sep;82(9):1496-1500 doi: 10.4315/0362-028X.JFP-18-572