Stainless Steel

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Maintenance and Cleaning

Condition
Cleaning1
Remarks
Cleaning Frequency
Routine cleaning of light soiling Use high foaming jet with neutral to mild alkaline cleaner. Avoid chlorinated products.

Alternatively, can use soap, detergent or dilute (1%) ammonia solution in warm clean water. Apply with a clean sponge, soft cloth or soft-fibre brush then rinse in clean water and dry2

 Satisfactory on most surfaces Rain can wash well-designed facades quite effectively. However, it is usually recommended to supplement this natural process by washing the stainless steel once or twice a year. For instance, a stainless steel curtain wall may be washed at the same time as the windows.
Fingerprints

 

 Detergent and warm water. Alternatively, hydrocarbon solvent.

Avoid chlorinated products.

 Proprietary spray-applied polishes available to clean and minimize remarking
Oil and grease marks

 

 Hydrocarbon solvent

Avoid chlorinated products.

 Alkaline formulations are also available with surfactant additions3
Stubborn spots, stains and light discolouration. Water marking. Light rust-staining. Mild, non-scratching creams and polishes. Apply with soft cloth or soft sponge, rinse off residues with clean water and dry.

Avoid chlorinated products.

 Avoid cleaning pastes with abrasive additions. Cream cleaners are available with soft calcium carbonate additions. Avoid chloride containing solutions4
Localised rust stains caused by carbon steel contamination

 

 Proprietary gels, or 10% phosphoric acid solution (followed by ammonia and water rinses), or oxalic acid solution(followed by water rinse).

Avoid chlorinated products.

 Small areas may be treated with a rubbing block comprising fine abrasive in a hard rubber or plastic filler. Carbon steel wool should not be used, nor should pads that have previously been used on carbon steel. A test should be carried out to ensure that the original surface finish is not damaged.

Table 1: Cleaning methods for bare stainless steel

Notes:

  1. Cleaning agents should be approved for use under the national environmental regulations and should be prepared and used in accordance with the company or supplier’s health and safety and application instructions. Non-aromatic hydrocarbon solvents which are substitutes for 1,1,1-Trichloroethane are available for degreasing.
  2. Rinse water should be clean, equivalent to a reasonable quality potable water, and leave no deposits. To avoid drying marks, use an air blower or clean, soft, disposable wipers.
  3. When using potentially aggressive formulations, for example mortar cleaners and caustic, concentrated degreasants or paint strippers, a small hidden area of the surface should be cleaned first, to assess any changes in appearance. The products must be removed by thorough rinsing after application.
  4. Chloride-bearing solutions, including hydrochloric acid-based mortar cleaning agents and hypochlorite bleaches should not be used in contact with stainless steels, as they can cause unacceptable surface staining and pitting.

However, if in unusual circumstances, the use of a bleach solution cannot be avoided, it should be fully diluted, in accordance with supplier’s instructions, with contact times kept to a minimum and with thorough rinsing after use.

Under no circumstances should concentrated bleaches contact decorative stainless steel surfaces.

Condition
Cleaning1
Remarks
Adherent hard water scales and mortar/cement splashed

 

 10-15% volume solution of phosphoric acid. Use warm, neutralize with dilute ammonia solution, rinse with clean water and dry.
  • Proprietary formulations available with surfactant additions.
  • Avoid the use of hydrochloric acid-based mortar removers.
Heat tinting or heavy discolouration2 No-scratching cream or polish. Apply with soft cloth or soft sponge, rinse off residues with clear water and dry. Nylon-type pad3.
  • Suitable for most finishes.
  • Use on brushed and polished finishes along the grain.
Badly neglected surfaces with hardened, accumulated grime deposits A fine, abrasive paste as used for car body refinishing. Rinse clean to remove all paste material and dry. May brighten dull finishes. To avoid a patchy appearance, the whole surface may need to be treated.
Paint, graffiti Proprietary alkaline or solvent paint stripper depending upon paint type. Use soft, nylon or bristle brush on patterned material. Apply as directed by manufacturer4.

Table 2: Cleaning methods for bare stainless steel following vandalism, accident or neglect

Notes:

  1. See Note 1 in Table 1
  2. Heavy oxidation of stainless steel surfaces is unlikely to be encountered in normal architectural use. In exceptional cases, for example after a repair requiring welding, or after fire damage, it may be necessary to clean and repassivate areas using a nitric acid-hydrofluoric acid pickling paste pack. A change in surface appearance will result.
  3. Nylon abrasive pads should be adequate for dealing with most deposits. If a more severe treatment is needed to mask coarse scratches or physical damage on a surface, use the finest abrasive medium consistent with covering the damage marks. With directional brushed and polished finishes, align and blend the new scratch pattern with the original finish, checking that the resulting scratch pattern is aesthetically acceptable.
  4. Silicon carbide media may be used, especially for the final stages of finishing. Ensure that all abrasive media used are free from sources of contamination, for example iron and chlorides. If wire brushes are used, these should be made of a similar or better grade of stainless steel.