Page 54

RCI Feb 2018

All round roof solutions Tony Ryan, head of fire engineering services at Kingspan Insulated Panels, highlights a case study at Clifton Comprehensive School, which showed how cored insulated panels In the December issue of RCI, we looked at how large-scale insurer-backed testing can provide a good indication of how insulated panel systems will behave in a fire. The real fire case studies examined specifically related to how well Loss Prevention Certification Board (LPCB) and FM-approved insulated panel systems performed when installed on buildings. However, it is every bit as important to understand how effectively a roofing system can perform, and not just in terms of fire safety. Thermal efficiency, structural strength, durability and ease of installation are all important considerations. Testing, testing, testing Let’s take fire performance first. Once again, tests that have been developed by the LPCB and FM Approvals can be the contractors’ friend by providing a clear indication of the level of performance that has been attained by certified products. The relevant standards for roofing are LPS 1181 Part 1: Requirements and tests for built up cladding and sandwich panel systems for use as the external envelope of buildings, which was looked at in some detail in the December article, or FM 4471. The requirements of FM 4471 are stated by FM Approvals to “measure and describe the performance of Class 1 panel roofs in response to exposure from heat, wind, foot traffic, and hail...”, and include tests to measure combustibility from below the roof assembly and combustibility from above the roof assembly. The tests enshrined within LPCB and FM standards are credible allowing designers and contractors to understand the fire performance of insulated panel systems. Case study An internal fire at Clifton Comprehensive School demonstrated the performance of LPCB-approved PIR (polyisocyanurate) cored insulated panels as part of a compartmentalised construction. The area associated with the fire was part of a development at the school nearing completion at the time of the incident. A passageway had been constructed to provide an escape corridor between two flat roofs. The floor of the passageway was of concrete slab construction. Blockwork walls, that formed the corridors on the ground and first floors, had been carried to 1,370mm above the concrete slab of the passageway to form the lower walls of the passageway. The upper walls of the passageway consisted of partitioning between the top of the blockwork walls and the underside of the insulated roof panels. The partitioning was constructed using a 70mm stud partition system consisting of metal studding fixed to the top of the blockwork wall. The top of the vertical studding terminated in an inverted ‘U’ channel that ran the full length of the roof. Fire resisting board, approximately 25mm thick, had been installed between the top of the inverted ‘U’ channel and the underside of the insulated roof panels. The roof was constructed using a PIR cored insulated roof panel system approved to LPS 1181 Part 1. The insulated roof panels had not been cut into, and the panels passed over the top of the partition system. Each side of the partition system had been clad with fire resisting board, approximately 15mm thick. The fire was reported at 7.37pm when smoke was seen to be coming from the centre of the new roof section. From subsequent investigation, it was believed that the fire occurred in a drum of roof sealant, containing solvents that was accidentally or purposely ignited with a naked flame. The roof sealant was both the material that was first ignited and the material mainly responsible for the development of the fire. The fire burned fiercely with flames impinging on the left-hand blockwork wall, the partition, and the insulated panels above. Flame and hot smoke travelled down the passageway at a high level in both directions. The deformation of the purlins immediately above the seat of the fire shows that this was a very hot fire. The internal faces of eight roof panels in the immediate area of the fire had delaminated and deformed, exposing the insulation. A report from independent fire safety engineering consultant, Tenos, concluded that the insulated roofing panels did not contribute to the cause or spread of the fire. What about the rest? Insulated panels themselves carry many benefits, but it is when they are employed as part of a full system that these benefits can really be maximised. The beauty of a system-based approach is that the different components are designed to work together, aiding ease of installation and helping to ensure that ‘as-built’ meets the designed levels of performance. It is even possible to integrate insulated panels with elements such as LPCB-certified insulated guttering to maintain both the fire and thermal integrity of the roof. From the perspective of health and safety on-site, insulated panel roofing systems help to reduce the amount of time working at height, and provide a safe, walkable platform as soon as they are fixed to the supporting steelwork. The rigid thermoset insulating core offers high levels of thermal efficiency, easily achieving desired U-values with minimal thickness and weight. The factory engineered joints can supply levels of air tightness below 1m3/hr/m2 at 50 Pa which, together with the integral insulation, helps to deliver energy savings throughout the life of the building. Performance without compromise Fire safety is paramount in any building being constructed or refurbished today, but that does not mean that other important factors, such as energy efficiency or site safety, need to suffer. LPCB or FM-approved insulated panel systems can tick all the boxes and provide all round roofing solutions. performed during fire tests The LPS 1181 Part 1 “Garage Test” includes specific pass fail criteria for flashover, external surface flaming, burning brands from the ceiling, concealed burning and damage Kingspan’s premium Membrane Lined Insulated Gutter System was the first gutter system to be approved to LPS 1181 by the Loss Prevention Certification Board INSULATION FEBRUARY 054 2018 RCIMAG.COM “Fire safety is paramount in any building being constructed or refurbished today, but that does not mean that other important factors, such as energy efficiency or site safety, need to suffer”


RCI Feb 2018
To see the actual publication please follow the link above