Although robust, all grades of stainless steel will stain and discolour due to surface deposits and, as such, can never be accepted as completely maintenance free. In order to achieve maximum corrosion resistance, the surface of the stainless steel must be kept clean. Provided the grade of stainless steel and the surface finish are correctly selected, and cleaning schedules carried out on a regular basis, excellent performance and long service life are assured.

Factors Affecting Maintenance
Surface contamination and the formation of deposits must be prevented in order to maintain a durable and hygienic surface.

These deposits may be minute particles of iron or rust from other sources used on the building of new premises and not removed until after the stainless steel drainage products have been installed. Wire brushes and wire wool must not be used to remove marks and cement spillages as this will only serve to introduce iron impurities to the material surface. Care must also be taken when storing, erecting or cutting carbon steel near to stainless steel.

Industrial and even naturally occurring atmospheric conditions can produce deposits which can be equally corrosive, e.g. salt deposits from marine conditions.

The working environment can offer more aggressive conditions, for example the high humidity found in swimming pools increases the speed of discolouration and therefore requires maintenance on a more frequent basis.

Modern processes use many cleaners, sterilisers and bleaches for hygienic purposes. All these proprietary solutions, when used in accordance with makers instructions are safe, but if used incorrectly (e.g.warm or concentrated) can cause discolouration and corrosion on the surface of any quality of stainless steel.

Strong acid solutions are sometimes used to clean masonry and tiling of buildings but they should never be permitted to come into contact with metals, including stainless steel. If this should happen the acid solution must be removed immediately by copious applications of water.

Maintenance Programme
With care taken during fabrication and installation, cleaning before handing over to the client should present no special problems, although more attention may be required if the installation period has been prolonged.

Where surface contamination is suspected, immediate attention to cleaning after site fixing will encourage a trouble free product.

Food and beverage handling, pharmaceutical and chemical industry applications require extremely high levels of cleanliness applicable to each industry.

Advice is often sought concerning the frequency of cleaning stainless steel and the answer is quite simple: clean the metal when it is dirty in order to restore its original appearance. This may vary from once to four times a year for external applications or it may be once a day for an item in hygienic or aggressive situations.

Frequency and cost of cleaning is lower with stainless steel than with many other materials, and will often outweigh the initial higher cost of this superior product.

Cleaning Methods
Stainless steel is easy to clean. Washing with soap or a mild detergent and warm water followed by a clear water rinse is usually quite adequate for many industrial applications. An enhanced aesthetic appearance will be achieved if the cleaned surface is finally wiped dry.

Precautions
Acids should only be used for on-site cleaning when all other methods have been proved unsatisfactory. Rubber gloves should be used and care taken to see that acid cleaners are not spilt over adjacent areas.

Special precautions are necessary with oxalic acid. Solvents should not be used in closed places without adequate ventilation. Smoking must be avoided when using solvent. Manufacturer’s directions should be followed.

Conclusion
If all the suggestions and actions in the table below have been attempted, stainless steel has the facility to be mechanically cleaned by specialists on site. Please contact ACO for further assistance.