Firm fibrous mastic based on mineral fillers, organic fibres and water displacing materials.

Densoseal 16A is packed into the ends of the duct by hand and moulded firmly around cables and against the duct to ensure there are no gaps or fissures. The mastic should be packed to a depth of at least equal to the diameter of the duct. Surfaces should be free from loose rust, scale, dirt or previous sealants.