Factors affecting durability - internal sufaces

Internal environments take many different forms and the aesthetics, performance and functionality of the environment will depend on the requirements of a specific project. Since the requirements will change from project to project, so the suitability of materials and systems will also change. Pre-finished steel products offer a unique solution for many indoor environments and with Colorcoat®, Corus have a range of products which have been engineered with specific internal environments in mind.

In many cases, the internal environment will provide few challenges to a pre-finished steel product. There are examples, however, where special considerations must be made. In choosing the correct pre-finished steel for a particular internal environment, the following factors should be borne in mind:

One of the most common problems with buildings is the likelihood of condensation. Water vapour is contained in the air as gas – the higher the temperature of the air, the more water vapour can be supported. Condensation is considered frequent when it can be detected on interior surfaces daily, but where the time of wetness is generally for less than 2 hours. In excess of this condensation is considered to be permanent.

Generally, water vapour in the atmosphere inside a building occurs as a result of:

• The process carried out in the building.
• The heating system.
• The occupants.
• The drying-out of a new building.

The combination of condensation and other water sources with aggressive chemicals can have an impact on the performance of the internal surfaces.

The 'aggressivity' of an internal environment is determined by the presence of corrosive chemicals and the microbial challenge of the internal atmosphere and also by the frequency of cleaning and aggressivity ofcleaner solutions. Five levels of aggressivity can be defined which help in the specification of the correct internal pre-finsihed steel product:

Cleaning of pre-finished steel products can be carried out with the use of a proprietary cleaner, provided there are no abrasive ingredients, no strong acid or bleach in it and that it is not a strong colour. The surface should be rinsed with cold water following cleaning.

In some environments, there is a high potential for damage from traffic such as movement of goods in a warehouse or from patient trolleys in a hospital. Pre-finished steel when used as part of a building system have very good resistance to damage. However, it is important that the correct pre-finished product is specified for the job. The damage potential of an indoor environment is low if there is very low traffic or if the resulting damage is not considered a problem for the safe operation of the building. The damage potential is considered medium or high if there is a potential for traffic or if the occurrence of damage to the surface would constitute a serious problem for maintaining the safe operation of the building. For example if damage occurred in a food-processing factory, which created a site that was difficult to clean.

For some applications, maintaining a hygienic environment is of critical importance. Examples of such environments include food production, pharmaceutical production and medical procedures. For these challenging environments, Corus has developed the Controlled Environment Surfaces CES range of products. These are designed to be easily cleaned, resistant to the harmful effects of conventional cleaning agents and safe for food contact. For added protection, CES can also be combined with Assure® which provides anti-bacterial protection, using Microban®. When an indoor environment is determined to have a medium or high hygiene requirement, CES and Assure by Corus should be specified.