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  • Writer's pictureNutrochem Bethal

Factors to consider for effective foam-cleaning best practices

Several factors play a role in creating the best practice for foaming and can be summarised as follows:

  • When applying foam, foam up (bottom to top) as far as possible and rinse down (top to bottom).

  • Use products that are well formulated to give the appropriate cleaning and retention times.

  • Use the best suited equipment for the cleaning task at hand.

  • Adjust concentrations and air to solution ratios to get a foam that gives good contact time. It can deliver the chemistry to the soil, but rinse easily.

  • Combining the above into one package and tailoring to local conditions will drive productivity for effective foam-cleaning.

Best foaming practices

A series of factors affect the benefits of foam cleaning. These factors can be grouped into the following categories:

  • Application technique It is essential to ensure that the foamed cleaning chemical is in contact with the soiled surface for a suitable amount of time. Vertical surfaces should be foamed in horizontal strokes, going from bottom to top—this provides a clear view of coverage in real-time, without the interference of foam drainage downwards. It also ensures that the soil is first contacted with the full strength of cleaning chemical. Rinsing of the cleaning chemical should be done from the top to bottom, to ensure the last water used on the cleaned surface is the rinse water rather than chemical and soil from above. This also takes advantage of the rinse-off from the upper surface, ultimately reducing the total amount of rinse water required. The nature of the cleaning chemical can help influence the rinsing process and minimise the rinse needed.

  • Product chemistry The formulation of the cleaning chemical is crucial, as it must contain the right proportions of surfactants, chelants and pH control (buffers). Surfactants produce a lower surface tension cleaning solution, allowing rapid penetration into micro-environments on the surface and adsorbed soils. Surfactants should also emulsify the soil particles, solubilising them in the cleaning solution to allow their fast rinse off. Chelants help solubilise mineral deposits and protect detergents from inactivation by water hardness. Buffers ensure the proper pH environment is maintained in the cleaning solution to ensure favourable chemical equilibrium conditions exist according to the cleaning task (e.g., acidity in scale removal and alkalinity in greasy soil removal).

  • Application equipment The application equipment should be simple and easy to set up, operate and break down when cleaning is completed. Training should be given and be easy to understand to avoid in-use mistakes. Select equipment that is simple to use and delivers the correct in-use solution, as preparation is prone to errors and wastage and poses a safety hazard.

  • Foam characteristics The nature of the foam is important. It should be of the proper consistency – bubble size, air content and effective viscosity so that gravity drag is not excessive and has good cling to vertical surfaces. It should be easy to rinse – i.e., rapid break-up on rinsing. It should not accumulate excessively at the bottom of vertical surfaces as this hampers rapid rinsing from the work area. It must provide the correct contact time to allow for removal and emulsification of the soils. The proper selection of equipment and cleaning chemicals and the right application procedure will realise the full benefit of foamed cleaning.

  • Productivity Foam-cleaning has the benefit of being a hands-off process, consisting of essentially two steps in its most basic form. The first step is the application of the foam, and the second step is the rinsing of the foam with an optimised application system such as a central foam station, cleaning chemistry and proper technique, foam can be applied at the rate as fast as 1 m2 per second. This allows the cleaning of large areas relatively quickly, particularly if a one-step cleaning/disinfection approach is viable. Rinsing off the cleaning chemicals can add significant time to the overall process. Thick or airy foams that are hard to rinse and tend to deposit and accumulate on the floor due to rapid run-off from vertical surfaces are time consuming and can be tough to deal with. The cleaning chemical must deliver a stable foam, with adequate cling time to vertical surfaces and bubble size and air content that enables rapid rinse-off. Equipment set-up and break-down can sometimes be an important contributor to total cleaning time. In this case, equipment that quick-connects to the water hose without tools, along with cleaning chemicals that do not need further preparation procedures (e.g., dilution, filling of a bottle, etc.), are helpful in aiding productivity.


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