A difference is made between internal and external monitoring. The internal monitoring to be conducted by the manufacturer is subject to strict regulations, and it is additionally controlled by an external testing institution. Every manufacturer applying for the award of the RAL quality label must subject to these controls not only the finished multi-pane insulating glass product, but also the production and the choice of raw and process materials used.
When a manufacturer applies to an external testing centre for the award of the RAL quality label, a system description is laid down in accordance with the quality and testing standards containing information on
Every insulating glass unit with assured quality produced by the manufacturer must comply with this system description.
Needless to say, all materials used have a high quality standard. Before the RAL quality label is awarded, a simulated long-term test of the insulating glass product is conducted by the independent testing institution. By measuring the dew point temperature at the beginning and at the end of the test, conclusions may be drawn regarding the product's expected life-cycle and, hence, its quality.
Furthermore, twice a year the monitoring institution takes random samples from the ongoing production without prior notification to the manufacturer, and tests these samples in its own facility.
Where these samples do not comply with the requirements, the test of the entire system is repeated. If the system test is failed as well, the manufacturer loses the right to use the RAL quality label and to display it on the products.