The Binderholz CLT BBS ceilings have received the general construction supervisory test certificate. The 150 5s CLT BBS ceiling element fulfils fire resistance class REI 90 without having to obtain further proof for it.

The standard primarily discerns the load-bearing capacity, the space-enclosing function and heat insulation to describe a component’s fire resistance. The performance time of each of these criteria is specified in minutes, which means for the classification REI 90 that the load-bearing capacity, the space-enclosing function and the heat insulation of the components will remain preserved for at least 90 minutes in the event of a fire.

Load-bearing, space-enclosing ceiling structures consisting of five panel layers glued crosswise, these five-layered cross-laminated timber elements of the prototype binderholz CLT BBS 125, with covering where required, were tested under fire load from the bottom side of the ceiling. The first longitudinal layer facing the fire, with a thickness of 40 mm, consists of two lamellas glued along the grain with a thickness of 20 mm each.

The ceiling width is optional, may contain the tested longitudinal joints of the elements, while also additional common layers of paint or coatings with a thickness of up to 0.5 mm or breathable membranes or vapour barriers do not affect the attribution of the classification. The cross-laminated timber element is manufactured here according to the European technical evaluation ETA-06/0009.