In our last post we examined changes to Building Regulations Part Q and examined what test criteria was acceptable under Approved Document Q.
One of the most relevant tests for glass rooflights installed in a residential area on domestic dwellings is LPS 2081 Issue 1:2015.
Here we explore the performance of fixed modular glass rooflights when under manual attack by an opportunist intruder attempting to use a combination of physical bodily force, stealth and a selection of tools that are easily concealed about the person in order to gain entry.
What types of glass are used in secure rooflights?
LPS 2081 Issue 1:2015 security rating A involves a sustained attack on both glass, framework or mechanical fixings using hand tools for a period of up to one minute.
The glass can break, but should remain intact enough to prevent an intruder gaining entry into the building, so a laminated inner pane is required to maintain the structural integrity of the glass for the required time.
This video clip of a recent test demonstrates that although the outer toughened panel breaks quickly when the attack commences, the inner laminated pane can withstand an attack for much longer.
LPS 2081 Issue 1:2015 security rating B
Security rating A guarantees that the product tested can withstand an attack for up to one minute and is the only requirement under this test to satisfy Approved Document Q. But there is a further test, which prolongs that attack for up to three minutes and with an enhanced set of tools.
Any rooflight that is able to last the full three minutes is awarded a security rating B and can be considered a more secure product. There are no further prolonged tests under this standard.
How secure is the rooflight frame?
The tests are not only focused on the glass itself but also on the frame and how the glass is fixed into it; depending on the material and construction technique the rooflight frame can sometimes be vulnerable to attack.
In this case the glazing is structurally bonded into a powder coated aluminium frame on all sides providing improved structural integrity.
As depicted in the video clip, the frame is attacked with a number of tools with the intruder resorting to removing the mechanical fixings to the upstand and levering them out with a claw hammer.
Given enough time the rooflight can still be removed, but this takes over three minutes by which time it is commonly accepted that most attempts to gain forced entry into a building will have been abandoned, or the intruder risks raising the alarm or being discovered.
Security for larger modular style rooflights
In some cases glass rooflights will be specified and manufactured in modular sections, which include internal framework to support the joints between glazed panels.
It is important that these joints do not present a weak point in the structure, so you should ensure that the manufacturer has tested modular configurations of their product if these are available as part of their range.
In this example the joint between the glazed sections is supported by an aluminium back-to-back angle, which is welded to the main perimeter frame. This type of support provides enough strength to prevent the intruder gaining entry for up to three minutes, at which point the test is stopped and the product awarded a class B (highest) rating.
In our next post we take a look at security tests for opening rooflights.
Glazing Vision are pleased to announce that they have just released their new ‘secure and secure+’ range of Secured by Design rooflights, all of which are part Q compliant.