Martin Bidewell of Sika discusses why supply chain accountability must be standardised across the industry for safer roof refurbishment
Two years after the Grenfell disaster and 18 months on from the Hackitt Report’s call for greater clarity of guidance and regulations for construction, safety has become a primary factor in specification decisions across all elements of a building. The tragedy and the subsequent report have been a catalyst for new safety legislation. Just as significantly, they have also nurtured a culture of safety that is prompting specifiers to consider products’ fire safety credentials throughout their lifecycle, including both the build and operational phases. Where legislation is not immediately forthcoming, it falls to industry bodies and product manufacturers to self-regulate and drive best practice to maximise safety for both contractors and the public during construction, and for end users following completion. One of the tangible ways that this is happening in the roofing sector is through the NFRC’s (National Federation of Roofing Contractors) Safe2Torch Guidelines, which are designed to manage the fire safety hazards associated with the specification and installation of bituminous roofing systems.
What are the guidelines?
Although they are not mandatory, the Safe2Torch guidelines have become the recognised industry standard for safer installation of bituminous roofing systems since they were introduced in 2017. They have also supported innovation in the sector and have also been instrumental in the product development process for some product manufacturers. The guidelines bring clarity to where it is safe to use flame-based hot works and where torch installation must be avoided, and using a self-adhesive bituminous membrane is a convenient and robust option. For specifiers, this means looking for a complete roofing system that includes both a torch-on membrane and a self-adhesive membrane or flame-free alternative. All elements of the system should offer the same level of guaranteed performance, in terms of both installation integrity and service-life. The specification should clearly set out the Safe2Torch zones and the torch-free areas where a self-adhesive membrane must be used, with the aid of hot air welding equipment where required to activate the adhesive.
What are torch-free zones?
It’s important to work with a roofing supply chain partner that offers a site survey to map the Safe2Torch and torch-free areas of roof for each project. This is because identifying all the Safe2Torch zones can often be complex and require an understanding of the existing roof build up, the layout of the roof, and the proximity and fire risk of surrounding structures. The supplier should then also ensure this information is written into the technical specification and procurement documentation, and that the installation is regularly inspected to ensure Safe2Torch compliance throughout the programme. The Safe2Torch guidelines provide a clear and detailed outline of areas that should be specified as torch-free zones. These include: timber roof decks and roof areas with timber upstands or fillets, hanging tiles, thatched roofs, rooflight kerbs and upstands, lantern rooflights, windowsills, and cladded areas. The guidelines also stipulate that torch-on systems should be avoided in any confined areas and for any areas that may contain concealed flammable materials, a full list of recommendations is available on the NFRC website. To maintain the safety of the installation team and any occupants in the building, and protect the fabric of the building from fire risk, the guidelines require a self-adhesive bitumen system to be used within 900 mm of any of these torch- free areas.
Other design & specification considerations
Bitumen roofing technology has advanced significantly over the past decade, not only in response to Safe2Torch Guidelines but also to provide increased durability, performance and service life. A membrane that combines the flexibility and tensile strength of SBS bitumen with the hardwearing performance and U/V resistance of APAO provides the ideal solution for the UK climate. The roofing membrane should be specified in combination with a suitable insulation to meet the required thermal performance, and the structural loading of the new roof build-up should be taken into account in the specification, particularly if the roof is being designed as an overlay. Similarly, if there will be rooftop plant or equipment, the compressive strength of the roof build up should also be factored into the specification. Wind uplift, fire safety, drainage and the safety of maintenance teams should also form part of the specification process for the Safe2Torch compliant roof.
The construction sector may still have some way to go to embed greater clarity in its specification processes but, for the roofing sector at least, the Safe2Torch guidelines provide an excellent best practice framework. It’s now up to manufacturers, specifiers and contractors to implement them.
Martin Bidewell is head of technical and product management – roofing at Sika