Temperature Ratings and their Ambiguity

Temperature Ratings are referred to repeatedly for good reason given that different fibres exhibit different behaviours at different temperatures. Therefore, for many industrial applications where heat is present, the choice of fibre can be crucial.

Often fibre producers have differing opinions on how temperature ratings ought to be marketed because the point at which the fibre stops being useful is very much subjective and down to the the application.

Textile Technologies rate E Glass to 550°C but we always caveat this rating with the words ‘in optimal conditions’ because we know that the fibre becomes weaker and more brittle at lower temperatures. However, this does not matter for the majority of static applications where E Glass is acting as an insulation medium only. If we factor in repeated aggressive hot and cold heat cycles as well as mechanical abrasion or vibration; Textile Technologies believe E Glass will deteriorate far more quickly from 400°C onwards at least.

Another issue which we come across regularly is the temptation for engineers and specifiers to over exaggerate the temperatures involved, believing that by doing so they are playing it safe. An example would be insisting on using silica textiles instead of E Glass textiles given textiles with high silica content are rated to higher temperatures. Whilst this is true, it is also true that E Glass has higher strength than silica and so if the temperatures do not in fact exceed the limitations of E Glass, E Glass is not only more economical, but the better choice all round.  

There are also different types of heat. Radiant Heat, Convective Heat, Ambient Heat, Contact Heat and so on, all of which are often mistaken for being one or the same thing and they are not.

For expert help on fibre choice in applications where heat is involved Textile Technologies Europe Ltd are able to offer sound solid advice.

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