Have you ever wondered why the timers in our fire resistance test images exceed the typical 60- or 120-minute period?

This additional time isn’t just a coincidence; it’s a deliberate endeavour to achieve something very specific : a Category B overrun, as stipulated in the fire test standard EN 1634-1:2014+A1:2018. But what does that mean for you, our customers?

When we surpass the ’round’ classification time, it formally allows us to expand elements of scope beyond the door as tested through use of the Direct Field of Application (DiAp) or Extended field of Application (ExAp). 

For instance, the Direct field of Application permits us to increase the height and/or width of the test specimen by 15%, providing that we successfully achieved the Category B overrun. In any case, the approved body will specifically describe/outline the scope expansion permitted.

Now, here’s what makes the difference; when aiming for performance durations of 60, 120, or even 240 minutes, we set the Category B requirement time as our target benchmark. Not only does this ensure a solid base level of fire resistance, but it also meets bespoke project requirements while maintaining compliance. 

    Below is a table displaying the classification times with the corresponding overrun requirements:


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