ROOFLIGHTS Working Safely With

Mark Wilcox, Safety Representative for NARM, the National Association of Rooflight Manufacturers, outlines current safety guidance in respect of working with rooflights.

NARM was formed in the late 1990s, to provide a unified voice for the UK’s rooflight industry and to support best practice in rooflight specification and installation. The Association plays an important role in commissioning research, liaising with industry bodies and informing government and standards bodies in respect of all aspects of rooflighting.

Over the years, a number of topics have remained central to NARM’s work, key among these being safety for roof workers. In my role as NARM’s safety representative and sitting on the UK’s Advisory Committee for Roofsafety* (ACR), I’m proud to be playing a part in this important work.

Rooflights and non-fragility

In the mid 1990s, the HSE (Health and Safety Executive) stated that all roofing products should be manufactured to be ‘non-fragile’ when fixed. However they did not define what was ‘non-fragile’. It was the rooflight industry that started discussions with the HSE to establish a universal test that to define non-fragility. All trade bodies associated with the manufacture of roofs and their components formed an organisation called the Advisory Committee for Roofsafety (ACR).

NARM works in close collaboration with ACR and has contributed to the widely referenced Red Book: ACR(M)001 “Test for Non-Fragility of Large Element Roofing Assemblies” This defines a test for non-fragility which can be applied to any roof assembly, intended to indicate whether the roof can support the instantaneous loads imposed on it by a person falling or stumbling on it. It is not a product test but products such as rooflights can be tested as part of a roof assembly.

NARM built on that excellent work by collating extensive test data from member companies, to create a Technical Document entitled NTD03 Application of ACR[M]001 ‘Test For Non-Fragility of Large Element Roofing Assemblies to GRP Profiled Rooflight Sheeting’. This provides comprehensive coverage of nonfragility requirements and ratings for industrial rooflights.

In the case of glass rooflights, there are specific safety issues which require a different testing standard. Glass may pass the ACR soft body impact test, but it is particularly susceptible to hard body impacts that do not form part of the ACR test. This has been recognised by the glass industry for some time and as a result the Centre for Window and Cladding Technology (CWCT) devised specific nonfragility tests for large area glazing.

These are referenced in the latest issue of ACR’s Red Book and NARM has published a document entitled Understanding CWCT Classifications of Rooflight Types, providing practical guidance for installers and specifiers.

Whatever CWCT classification is required for a given application, NARM strongly advocates the use of laminated inner panes on glass rooflights, to avoid the risk of glass shattering and falling on building occupants - as well as providing increased safety for roof workers.

It’s important to note that nonfragility of rooflights is a complex subject which can be influenced by many different factors, including material selection, design and the competence of the installer. For this reason, over the years, NARM has advocated that whatever the nonfragility rating or age of a rooflight, it should be considered as if it may be fragile and foot traffic on rooflights should always be avoided

In recent years, the increasing popularity of what have become termed ‘walk-on rooflights’ has created some confusion in this respect, but these are highly specialised products designed for intentional foot traffic on roof terraces and other applications, as outlined below.

Understanding the differences between ‘non-fragile’ and

‘walkon’ rooflights

The only suitable material for rooflights designed for deliberate foot traffic is glass. The outer pane must be both toughened and laminated, and must be specifically designed for the pane size and method of support. It will usually comprise 3 leaves laminated together, sometimes with an additional sacrificial annealed leaf on the outer surface, typically giving a total thickness of 30-40mm for the outer pane alone. This results in an extremely heavy product which must be correctly supported – and would not be suitable for many roof structures.

We have published guidance to clarify definitions of ‘walk-on’ rooflights, to avoid potentially dangerous specification errors. Our Technical Document NTD11 Understanding the differences between ‘non-fragile’ rooflights and ‘walk-on’ rooflights for deliberate foot traffic provides details and definitions.

Working at height – always put safety first

This article has focussed on safety guidelines and standards relating to rooflights. However, it’s vitally important to be aware of the wider picture relating to safe working practices when working at height. The ACR has published a suite of authoritative guidance documents covering this important subject. These can be accessed free of charge at www.the-acr.org or via the NARM website.

For free access to any of the documents outlined in this article, or for further information about our work, please visit www.narm.org.uk