Concerns, however, have been voiced with regards to some of the requirements of EN45545-2, as consequences of emissions during and after a fire become equally as important as flame retardancy in the new standard.
“Our customers are concerned that these new standards show partially opposed requirements,” said Jorg Stumbaum, technical marketing manager, high performance elastomers business line CR/EVM at Lanxess.
A rubber part, he explained, has to have good flame retardancy, good high-temperature resistance (for long service time), good low temperature flexibility (to be used in colder regions of Europe), good physical properties (high tensile strength, low abrasion), sometimes good oil resistance and of course it must be cheap.
The difficulty, Stumbaum added, is to find the best compromise between all requirements.
It is not one size fits all, as Hubert Butterwegge, head of marketing and sales EMEA/Asia/Pacific at ContiTech Industrial Fluid Systems put it.
“We experience time and again that customers are searching for products that fulfil – in all their component parts – the European fire safety standard EN 45545. But it is quite difficult to meet all criteria because some flame retardants release toxins, for example,” he said.
According to Butterwegge rubber products need to fulfil their actual functions in addition to the fire standards. And for the “actual functions” it is important to meet other standards too.
For example, explains Butterwegge, hydraulic standards and the requirements from the International Union of Railways (UIC) are often a particular difficulty.
Another point of frustration for ContiTech is that customers do not appreciate problems with conflicting requirements.
“That is to say, they still don’t see a conflict with competing parameters like low-temperature flexibility, predetermined dimensions and elongation properties from the material; and the EN 45545-2,” he explained.