Our customer had designed a harness that was very comfortable to wear, but it need to pass one of the most stringent flameproof tests in force. We were approached due to our extensive experience in developing fire resistant elastomeric materials.
The flame test qualification was severe – the completed harness should not catch light even when exposed to 1000°C heat for 30 seconds. This was a challenge in itself, but the customer also wanted to ensure that the harness remained comfortable to wear, was not heavy and would give many years’ service.
The Development Process
We worked closely with the customer to achieve the desired outcome. We combined rubber compound design with vulcanised sheet manufacturing methods to develop an elastomeric material with outstanding fire performance without being too thick or heavy. The elastomer, which was used as a coating for the fabric used in harness manufacture, also needed to be flexible so that it could be used as a binding to stitch over cut edges.
To achieve the required flame resistance we used a compound formula based on self-extinguishing chlorprene polymer, developed further to enhance the high temperature flame resistance properties.
Extensive product development testing and customer feedback established the minimum thickness of coating to guarantee the flame performance requirement could be met. This in turn managed the weight penalty imposed by such an enhancement to within acceptable limits.