Not just skin deep

Simply increasing the door’s GRP skin thickness – in order to achieve PAS24:2016 – could have a negative impact on the performance of the door, Distinction Doors has announced.

Dave Walker, technical director at Distinction Doors, said: “We are very proud of our door’s credentials and its ability to meet the most demanding technical requirements. What is particularly important to us is that Distinction Doors meets all these performance standards because of the overall quality and innovation in our doors.

“For example, a demanding PAS 24: 2016 test element gives composite doors three minutes to survive an attack by Ukas laboratory engineers using a 6mm, 25mm chisel and or a Stanley knife in creating a 50mm diameter hole. This hole size is considered large enough to get an arm through and open the door and therefore constitutes a failure. Certain suppliers of composite doors might think the best way to protect against this was to increase the thickness of the door’s GRP skin. We believe there are better ways to do it.”

Dave said out that by increasing the GRP skin thickness there are four potential detrimental issues which fabricators should consider.
Firstly, the thermal performance/efficiency of the door will be compromised because the insulating foam core is reduced in thickness. Secondly is that GRP is an extremely hard material, and by increasing the amount used in the door leaf, it will have adverse effects in the CNC machining process of apertures, resulting in reduced tooling yield.

Thirdly, any future changes to the PAS24 standard could result in pressing tools being de-commissioned in order to carry out modifications, which could affect the supply of goods for an unspecified period of time.

Finally, by only increasing the depth of a part of the skin, there is danger that this could affect the long-term aesthetics of the door. As tooling wears through continuous use, it could start exhibiting witness/shadow lines that become evident on the skin’s surface at the junction where skins increase/reduce. This was something that Nan Ya’s technical and manufacturing teams felt strongly about and were therefore very much against, Dave said.

It is also important to be aware that if the GRP skins have only been increased in part of the area, then it must be within the 800mm banded area (400mm above and below of the positioning of the cylinder) of Zone 1 of the attack. Should this not be the case then a sizeable proportion of door styles will be compromised and not compliant.