Energy operators use mineral oil for the cooling and insulation of aggregates in switching and transformer plants. To avoid the penetration of oil into the ground in case of an accident and contamination, oil catch pans are usually arranged below the aggregates. Inflammation due to the relatively low flash point of the oil and the high operating temperature cannot be ruled out. Nowadays fire-retardant covers are used to limit and reduce the burn-up in the oil catch pans which in the past were covered with a 20 cm layer of gravel.
There are two different variations
In order to smother the flames in the catch pans in the case of a possible fire in a transformer, the Lichtgitter perforated metal plank type BP-H was developed with welded woven wire mesh and a foam glass granulate filling. The suitability of this cover system has been demonstrated in several in-house and external tests.
The fire retarding covering, type BN-OF, was developed as an alternative to conventional flame retardant covers. Lichtgitter has manufactured and sold this type for many years based on the well-known perforated metal plank type BN-O. The more advanced BN-OF type is ideally suited as a cover on tub-shaped catchment spaces under transformers. Through the limited air permeability, the flames are confined and delayed but not smothered in case of fire.