NEW TYPES OF FIRE RETARDANT MATERIALS AND THEIR APPLICATION TO FIRE PROTECTION OF CABLES.

The increasing need for preventing fire spreading through electric wire and cable lines has focused attention on the fire retardant material. Up to now, intumescent or nonintumescent coating compositions have been most widely used for that purpose. However, highly effective and economical fire prevention for electric lines was not found feasible with such coating compositions alone, without a suitable approach to handle the lines in accordance with the particular conditions involved. Taking account of various installation line of wire and cable, a new series of intumescent materials based on polymers and/or oligomes has been developed. These materials are in the form of a jacket, sheet, tube, self-bonding rubber-like tape, and a putty of nonhardening type for use in wall and floor penetrating bores and/or ducts for lines. Excellent fire-retardancy is experimentally observed on the cable covered with sheet, tube, tape or jacket, and on the cable installed in the penetrating bore where inlet and exit are sealed with the putty as a flame barrier. Effective and economical fire prevention can be assured by using the presently developed materials in suitable combination in accordance with line conditions.