TiO2 Coating

Maintenance and Diagnostics

Self-cleaning mechanisms drastically reduce the need for cleaning requirements. Even with reduced extent of dirt adhesion on surface, surfaces still needs to be cleaned. Maintainable facades can be achieved through proper maintenance strategies.

Regular Maintenance

Regular maintenance, cleaning of facades should take place at least once every 2 years for TiO₂ coatings. For glass façade, regular maintenance is necessary due to the characteristic of glass. Beside gondola, the cherry picker can be used for façade cleaning⁴⁴. Many consumers have the misconception that TiO₂ is a self-cleansing coating, which requires no maintenance efforts. This stands corrected as it is advised by suppliers that the TiO₂ coating to receive proper washing with water annually to make sure that the remnants of broken down dirt and dust on the surface is washed off thoroughly. It is also recommended to reapply the TiO₂ coating every few years, preferably 5 years to ensure that the TiO₂ coated surface remains effective⁴⁶.

Skilled Maintenance Team

Experienced workers have a careful attitude in handling maintenance in order not to damage the TiO₂ coating. Extra care is needed during the cleaning works so that scratches do not occur on the substrates. New workers are attached to an experienced worker so that they have sufficient guidance in maintaining TiO₂ coatings.

Cleaning Agents

TiO₂ coating still need maintenance and requires proper cleaning procedures, thus it prohibits the use of the wrong type of cleaning agents as it may damage the photocatalytic coating. Neutral cleaning agent are mainly used for glass, plastered wall and concrete substrates. While, special cleaning agents for aluminium cladding are used to leave a shiny surface and protect the cladding after the cleaning works. During cleaning works, to remove stains on substrates, the sequence of cleaning agent used for the removal is an important step to take note. Workers should try with neutral cleaning agents to remove the stains. For glass substrates, polish glass surface with glass polish compound to remove the dirt. Only if the stains are unable to be removed, then they should use mildly alkaline cleaning agent to remove the stains on the substrates. Usage of a stronger cleaning agent will result in damage to photocatalytic coating⁴⁴.

Proper cleaning tool

Lime wool cloth attached onto the T- bar for cleaning purpose is recommended. Figure 18 shows the T- bar handle used for cleaning of facades.

Figure 18 T- bar handle used for cleaning of facades
(Source: Law, 2016)

Recommended maintenance strategies for different substrates

Glass

Damp cloth to wipe glass surface and drying it with chamois to avoid overly wet surface. Avoidance of direct sunlight during cleaning to prevent streaking. The procedure for cleaning glazed surfaces begins by wringing a cloth, sponge or chamois until it is almost dry before wiping the glass surface. The wet surface is then dried with newspapers, paper towels, window wipes, or a chamois. Washing windows or glazed surfaces in direct sunlight is avoided as they tend to streak⁴².

Aluminium

There are many ways to clean metals, from using plain water to harsh abrasives. The mildest possible method should be used especially for anodized aluminium so as to prevent alteration on the appearance of the material surface⁴⁵. Chew and Tan (2003)⁴² recommends the following steps such as that cleaning solution is applied and rinsed thoroughly with water; as well as the drying of aluminium panel with a clean cloth is vital to prevent streaking. For very dirty surfaces where the dirt is very stubborn, the use of synthetic pads is considered together with the products. The cleaning procedure begins by applying the cleaning solution only to an area that can be conveniently cleaned⁴². The surface is thoroughly rinsed with clean water before applying the cleaner. Cleaner rundown is to be minimized on the lower portions of the building and such areas should be rinsed as soon and as long as it is practical. The metal pane should be dried with a clean cloth to prevent streaking. Concentration of the cleaner at the bottom edges of the aluminium should be avoided⁴².

Concrete

The application of neutral cleaning agent and then washed water is recommended, as well as the drying of the surface to avoid water spotting⁴³.