The Truth About Steam Cleaning
The cleaning industry has experienced a dramatic increase in the use of low pressure steam cleaners since the late 1990s – so much so that many cleaning experts often refer to the period as a “steam revolution!” However even though the use of dry steam as a cleaning tool has become much more commonplace in recent years, the technology is still very much confined to certain niche segments within the cleaning industry despite the fact it is far less aggressive than more conventional cleaning methods and does not damage any surfaces.
In addition dry steam has great “green biodegradable” credentials as it only uses clean cold tap water to achieve these high standards of cleanliness and the highest degree of bactericidal efficacy.
Initially the term “dry steam” may sound like a contradiction as steam is a by-product of water and therefore cannot possibly be dry. This is true of conventional steam such as that from a kettle but by applying further heat to conventional steam and super heating it to between 140°C and 200°C, the remaining water is vaporised resulting in “dry” steam. It is this dry steam that is ideal for use in both wet and dry environments alike and gives excellent cleaning and sanitation capability.
To explain further: dry steam technology heats the water within a boiler/heating coil to boiling point. The so called “Steam Curve” table or “Saturated Steam” table always refers to steam at a particular saturation point, also known as the boiling point. This is the point where water (liquid) and steam (gas) can coexist at the same temperature and pressure. At this temperature water is converted from its liquid state into a gas at an expansion rate of one litre of water converting to 1,650 litres of steam during the process.
Highest cleanliness standards
The Steam Curve table also states the correlation between boiler temperature and the pressure of steam. Dry steam machines start with a boiler temperature of between 120°C and 200°C approximately. Good quality dry steam is produced from about 145°C onwards. The hotter the steam, the smaller the water molecules within the dry steam will be and the safer in use the technology will be. Equally the hotter the steam temperature the better the bactericidal efficacy will be.
It is a fallacy to believe that bactericidal efficacy is achieved through the killing of pathogens as this method of sanitation only serves to encourage antimicrobial resistance over time. It is instead the safe removal of all debris which offers the highest levels of bactericidal efficacy whereby all pathogens are inevitably removed from any given surface.
Professional steam hygiene systems ensure that even the highest standards of cleanliness and bactericidal control can be exceeded. Utilising steam at temperatures above 140°C safely removes microbes and organisms living beneath their own protective biofilm, which normally can resist the most powerful of chemical agents for prolonged periods. Independent laboratory and hospital tests have verified the bactericidal efficacy of steam.
Heat alone ensures that the bonding between micro-organisms and the surface structure is broken down whilst the low pressure allows the steam to deeply penetrate into areas such as cracks, crevices and grouting which are normally inaccessible by any other cleaning process. The heat from the vapour saponifies the dirt, grease and grime whilst the pressure at which the steam is being released onto the surfaces ensures it quickly penetrates into the surface without causing surface damage or destruction as can happen with hazardous or aggressive cleaning chemicals.
The dry steam then works instantly to remove dirt and pathogens and their biofilm including MRSA, Acinetobacter and C. Difficile and any residue is left ready for instant removal either manually
using a microfibre cloth or via an inbuilt vacuum cleaner. The surfaces are left thoroughly deep cleaned, instantly ready for reuse and pathogen free. This method of cleaning has the added benefit of not requiring any contact time either.
Given the proven track record of dry steam, it is easy to see why it has become the chosen method of sanitation in high risk areas such as food production and preparation areas as well as other environments which require the highest standard of cleanliness and bactericidal efficacy including (but not limited to) hospitals, education facilities and hospitality and leisure environments. The focus in these areas is very often to achieve the highest degree of disinfection and/or sterilisation yet it is often forgotten that the prerequisite to achieving the highest standards of bactericidal cleanliness is good and through cleaning.
Unlike other technologies, dry steam is not concerned with killing pathogens but instead with achieving the highest degree of deep cleaning thereby inevitably removing most of the pathogens from any given surface – a 4-6 log can be achieved as reported in the OspreyDeepclean TNO validation report.
The benefits of steam have long been experienced within the health sector, specifically hospitals, nursing homes and care centres which are constantly confronted with the task to ensure the highest standards of cleanliness in their respective environments. Hygiene products, specifically disinfectants, have over the past decade provided effective protection with appropriate cleaning power.
The right selection of the correct hygiene products, however, becomes more and more complex. It is therefore imperative to employ a cleaning method which not only achieves the highest bactericidal efficacy against the most commonly known pathogens and microbes but one that also ensures a standard approach to cleaning and bactericidal control.
Dry steam is used within the daily cleaning regime by operatives and infection control nurses alike within the ward environment to
clean the patient environment and sanitary area. Additionally the technology is also deployed as a rapid response cleaning tool in case of outbreaks and during “terminal cleaning operation.” Dry steam is also widely used by for cleaning and decontamination of disability and mobility aids.
Food retailers and commercial kitchens have, for many years, reaped the benefits of dry steam for the deep cleaning of their respective environments as steam easily cleans, degreases and sanitises even the most difficult to reach areas without damaging any of the predominantly stainless steel surfaces. This has, in more recent times been further developed for the food manufacturing and processing Industry where the technology has achieved widespread acclaim for its deep cleaning performance and its bactericidal efficacy against specific pathogens such as listeria and salmonella.
In this environment, normally the larger three-phase technology is employed as it delivers a far greater volume of steam per minute than conventional 230 volt equipment. It is not uncommon today to find dry steam solutions from six kilowatt right up to 72 kilowatt in the food manufacturing and processing environments. The technology has also proven to be very effective in removing allergens whilst greatly reducing the volume of water being used on a daily basis which in turn reduces the effluent discharge.
major installations in food factories can save as much as six million litres of water per annum in comparison to traditional more water based hygiene solutions.
Many food manufacturers are also now looking to deploy the technology in conjunction with conveyor belt cleaning equipment in a quest to automise the cleaning of conveyor belts. Technological solutions are available for the various types of conveyor belts used in the food manufacturing industries either as
part of a periodic deep cleaning regime, during daily product changeovers or 24/7 sanitation during production.
Dry steam technology has also been long used to combat the plight of discarded chewing gum deposits on our streets and public places. In the chewing gum removal process, the steam is mixed with a chemical. Steam softens the gum while the chemical, in conjunction with light agitation with a brush, dissolves the chewing gum into a powder whereby it is simply brushed away. This technology is widely used throughout the world and has now seen the first development of non-electrical solutions in the form of gas powered machines or more recently, battery operated chewing gum removal steam machines.
The benefits of dry steam can therefore easily be qualified and quantified. The most obvious benefit is the potentially huge water usage reduction as well as a reduction in chemical usage. The risk of surface damage and surface degradation is greatly reduced and there is also the reduction in time and labour costs. Enhanced visual cleanliness is greatly increased as is bactericidal efficacy and dry steam offers a greater compliance with any applicable food and hygiene directives.
The applications where dry steam can be used and the associated benefits really are limitless. There are the essential, if a little mundane, applications such as vehicle cleaning which has seen a large increase over recent years in the use of dry steam as the chosen medium specifically because of the deep cleaning credentials and water-saving benefits.