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| POWDER PRE PAINTED |
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| LIQUID PRE PAINTED |
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| OTHER INFORMATION |
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| The product |
The newest product of Otefal group is Dfalz, a liquid pre painted aluminium sheet for coverings and roofing.
Dfalz pre-coated aluminium uses PVDF coatings with IR-reflecting pigments. While white and near white pigments are naturally IR-reflecting, darker pigments tend to have a high rate of IR absorption. The difference in surface temperature (and panel temperature) between a coating using standard pigments and on using special IR-reflecting pigments can range from app. 5°C for light colours to more than 10°C for dark colours (measured on north-facing roofing panels at an exterior temperature of 30°C).
On a surface such as a painted roof, the visible light is partly absorbed by the coating, and partly reflected as the radiation we perceive as the colour of the object.
The UV radiation is destructive to many substances, including coatings, and it follows that in order to maximise the life of a coating, it should be as transparent as possible to UV light. PVDF coatings have this characteristic.
The IR radiation is partly reflected and partly absorbed. Absorbed IR radiation heats the surface, and the substrate underneath. The consequences of this process are:
- Heat transferred to the building increases the cost of cooling the building
- Higher working temperatures of the panelling decreases the life of coatings, adhesives and insulation materials
- Higher temperature variation of the panels increases thermal expansion and contraction, and consequent wear on fixtures
- Higher surface temperature of roofing surfaces increases the formation of ozone (an important component of smog)
Dfalz pre-coated roofing panels will have:
- lower operating costs, due to less maintenance and air-conditioning
- lower installation costs, due to less insulation requirement
- longer service life In densely constructed areas, Dfalz IR-reflecting panels will also contribute less to ozone creation, thus improving the air quality for the occupants and neighbours.
angular lock welt |
double lock welt |
german method |
belgian method |
swiss method |
french method |
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