Determination of flexibility of roofingmaterials at low temperatures.

About the BDA Bending Tester

The standard equipment is the BDA Bending Tester®, type G, and has a built-in cryostat and adequate insulation, which reduces heat losses to the minimum. Temperatures as low as -40 °C can be achieved rather quickly: from 0 °C down to -10 °C within 20 minutes, from -10 °C down to -20 °C in 35 minutes. With the aid of a built-in heating unit (controlled independently) it is also possible to return quickly to a higher temperature.

In the machine, each time five test specimens of a roofing sheet having a width of 50 mm can be mechanically bent around a cylindrical bending mandrel, 30 mm wide, according to EN 1109:2013 - Flexible sheets for waterproofing - Bitumen sheets for roof waterproofing - Determination of flexibility at low temperature. It is also possible to test according to other standards and therefore choose other mandrels, for instance 10 mm wide, 20 mm, 50 mm or other diameters. The bending mandrels can easily be exchanged. The bending mandrel is self-centring and it is suspended between two round supports of Ø 20 mm. The distance between these supports is adjustable.
On request it is possible to supply sets of supports with fixed distances, which can be very useful for routine tests.

A special option is a set of rotating outer supports (Ø 20 mm) combined with the action of two springs, positioned at the end of the set. The intention of this method is to regulate the friction forces to a certain extent. This system offers a better workability because the sets of outer supports need not be exchanged and possible mistakes are prevented (e.g. taking the wrong distance between the supports).

The average cold bending temperature of bitumen sheets is about 4 K lower in comparison with the former method.
The machine is manufactured out of stainless steel and equipped with an insulated lid. The bending speed is adjustable between circa 100 mm.min-1 and 400 mm.min-1. The bending unit is provided with a safety pin to prevent the machine against overload.
220/230 V with 50 Hz electrical supply is needed.


The approximate dimensions are (l x w x h) = 0,9 m x 0,7 m x 1,3 m. The equipment stands on a table and shall be accessible from at least one direction.

References

EN 1109:2013