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Infection Control

Steam Vapor Systems: What To Look For

February 01, 2011
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Steam vapor systems use low-moisture, high-temperature steam to clean, deodorize, sanitize and, in some cases, disinfect surfaces.

The units provide a portable, effective, "clean in place" process that is especially helpful when working in an indoor environment.

Since its introduction to the United States in the late 1980s, steam vapor''s growing popularity has resulted in systems in a variety of sizes, shapes and functionalities.

But, no matter their intended purpose, when evaluating equipment involving high temperatures, water and electricity, there are several key features to keep in mind.


Aluminum boilers are sometimes used and hold heat well but require a good deal of metal to construct and have a short operational life if regularly used with water containing a lot of calcium or other minerals.

Stainless steel boilers of adequate thickness — 1 millimeter to 1.5 millimeters — have been shown to provide good service and longevity.

Stainless steel comes in different grades, and the boiler should be produced from a grade that will resist corrosion and flex without cracking or breaking.

The heating element should be submersible so that the water comes in direct contact with its surface: This is the most efficient way for the water to be heated.

The boiler, the valves and the heating element should all be made to resist or be protected from the scale produced by the machine; copper and brass components resist corrosion well.

Acids and other options do exist to clean the internal components; the downside is that some portion of the cleaning solution always remains.

The leftover solution may corrode or eat away at the different surfaces in the system, which may lead to failures or greatly reduce the life of the unit.

To help avoid this, the operator should be able to drain the boiler completely.

Some units do not have boiler drains or the drain is the same point at which the solution is added, which can limit the boiler''s ability to be completely drained.

It''s important to have redundant safety measures engineered into the boiler system to prevent overheating, over-pressurization or any other situation that might arise as a result of using a portable pressure vessel.


The reservoir holds the system''s water supply and, in a single-tank system, the boiler also serves as the reservoir.

A drawback to this design is that the unit requires a cool-down period before it can be refilled and the operator must wait for the unit to again reach operating temperatures and pressures — up to 30 minutes, depending on the boiler''s characteristics — before work can continue.

In two-tank systems, a separate reservoir feeds the boiler automatically, resulting in a constant, uninterrupted supply of steam vapor.

Two-tank systems allow water to be added any time during operation, eliminating the downtime experienced during the refill of a single-tank system.

Single-tank units require a high degree of care by the user, as adding water to a hot boiler during a refill operation can be problematic.

The system should be engineered so that if the water reservoir is empty, the operator cannot draw steam from the boiler.

This prevents situations where someone drains the boiler of all water and steam and then attempts to use the unit, which can create an overheating situation.

Heat And Hoses

A good steam vapor system will be able to achieve heat around 300 degrees Fahrenheit to 320 degrees Fahrenheit in the boiler, which will provide an appropriate water droplet size in the steam vapor and provide good energy transfer within the steam.

The steam curve is not linear; getting the boiler hotter does not necessarily make the steam hotter.

The optimal operational point is reached when the steam flow matches the capability of the boiler to produce steam; that is, when the amount of steam being produced matches the amount of steam being used.

A pressure gauge can be helpful and allows the operator to verify that the flow out is balanced with the production of steam in the boiler — assuming there is a steam volume control or that the volume is adjustable and built into the system.

Low boiler pressures result in cooler, wetter steam; higher pressure produces hotter, drier steam.

Systems able to achieve surface temperatures of 220 degrees Fahrenheit to 230 degrees Fahrenheit at the tool interface have been shown to deactivate bacteria and germs, as well as dust mites, bedbugs and fleas.

The hose assembly carries the steam from the boiler to the application tool and will be the most abused part of the system — perhaps its weakest link.

Hoses should be removable to allow for repair or replacement.

The hose should be lightweight enough to be convenient to use, flexible and user-friendly, yet durable enough to last.

A hose should be well-insulated, both to maintain higher steam heat levels between boiler and the application tool and for operator safety.

User-friendly Operation

Simple, straightforward controls dramatically shorten the learning curve and allow the new user to get up to speed quickly.

Steam volume controls allow the user to vary the amount of steam being dispersed, and controls located on the hose handle provide the operator with continuous command of the system.

Color-coded pressure gauges and well-placed warning lights or audible alarms help ensure machine and operator safety.

As with any cleaning process, the operator should expect to confront a variety of surface types and wide-ranging soil conditions; therefore, a variety of tools should be available to meet those special needs.

Tools and attachments should be easy to take on and off safely, as well as being easy to use and maintain.

The system should be able to adapt to a user''s requirements for a particular facility, area of use, etc.

Mobility and operational flexibility should be considered when evaluating different units.

Training And Support

New users will require instruction as to a system''s operation, its capabilities, etc.

In some industries such as health care, the unit may be used primarily for disinfection.

Users need to gain understanding about subjects like biofilm, how bacteria are spread, the ability of heat to penetrate pores and how improper practices may result in incomplete disinfection.

The systems are easy to use but are different from what many technicians are accustomed to using when cleaning and disinfecting surfaces.

Small yet crucial maintenance procedures should be laid out during initial instruction.

For example, the boiler should be drained once a month, both to combat scale buildup and because solutions other than plain water could be introduced to the boiler.

Draining the boiler water frequently can limit any undesired consequences from this or other actions.

Aftermarket technical service support, repairs, parts, etc., should be easy to access and customer service should be responsive.

As with most equipment purchases, good customer service and support cannot be overemphasized when it comes to selecting a steam vapor system.

Rick Hoverson is the principal of Advanced Vapor Technologies LLC, Edmonds, Washington. The simplified, water-only protocol for Advanced Vapor Technologies'' proprietary thermo accelerated nano-crystal sanitation (TANCS®) steam vapor cleaning and disinfection system means fewer consumables, less room for error and less mess. Reduced health risks than those associated with typical chemical cleaners mean a healthier, more comfortable work environment and fewer lost workdays for your staff and less risk for you. For more information, visit

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