Fire Resistance in Sandwich Panels

The largest fires in our country occur in industrial structures operating in organized industrial zones, causing significant material damage and loss of life. Additionally, fire spread through jumping threatens neighboring structures. However, when the correct products and proper details are used, the probability of fire spread can be minimized and the fire can be contained in the area of origin, ensuring losses are kept to a minimum. In this article, we will address 'fire resistance in industrial structures' from the perspective of sandwich panels. A significant portion of roof and façade systems in industrial structures and warehouses in our country utilize sandwich panel products. Unfortunately, when selecting these products, neither the toxic gas emissions that would threaten human life in case of fire are considered, nor the Building Fire Protection Regulation (*) requirements for fire resistance of walls and roofs constructed with sandwich panels are taken into account. When sandwich panels ignite, there are 2 elements that threaten human life. The first of these is toxic gas emissions, the other is fire resistance. Toxic Gas Emissions When sandwich panels burn, the panel filling material will also begin to burn. In this case, toxic gas emissions can occur and the gases can cause people in spaces with inadequate ventilation to become poisoned and lose their lives in a very short time. Such a situation is likely to occur, particularly in sandwich panel structural elements produced using polyurethane-based filling material. For this reason, if structural elements are to be created with sandwich panels, selecting non-combustible panel filling material would be the correct choice. Fire Resistance Fire resistance classifications for roof and façade systems used in industrial structures and warehouses are defined in BFPR Appendix 3-C as follows: • In industrial structures with building height up to 21.50 meters, if a sprinkler system is present, roof and façade systems must be fire-resistant for at least 60 minutes. If there is no sprinkler system, structural elements must be fire-resistant for at least 90 minutes. • In industrial structures with building height between 21.50 – 30.50 meters, if a sprinkler system is present, roof and façade systems must be fire-resistant for at least 90 minutes. If there is no sprinkler system, structural elements must be fire-resistant for at least 120 minutes.

• In industrial structures with building height exceeding 30.50 meters, a sprinkler system is mandatory. In these structures, roof and façade systems must be fire-resistant for at least 120 minutes if they are load-bearing, or at least 90 minutes if they are not load-bearing.

The fire resistance referred to in the Building Fire Protection Regulation means fire resistance meeting the stated duration in each of the load capacity (R), integrity (E), and insulation (I) criteria in load-bearing structural elements (for example, roofs). REI 60, REI 90 or REI 120, for example. In non-load-bearing structural elements (for example, walls), the fire resistance durations in question must be provided in both integrity and insulation criteria. EI 60, EI 90, EI 120, for example. We can say that the majority of industrial structures have building heights lower than 21.50 meters. For this reason, if we are to use sandwich panels, we need to use products that meet at least EI 60 criteria in façade products and at least REI 90 criteria in roof products. If the building has no sprinkler system, in this case EI 90 and REI 120 grade façade and roof panels should be used. Although many sandwich panel manufacturers claim to meet these criteria, preferring products with fire resistance documented in accredited laboratories is the safest approach. Fire resistance cannot be achieved by selecting only the correct product. Panels providing 60 minutes fire resistance may not withstand fire for even 10 minutes if incorrectly installed. The panel manufacturer must provide a correct application solution that ensures the declared fire resistance along with the product. This is a matter requiring experience. (*)BFPR: Building Fire Protection Regulation Hakan Uslu - Research and Development Specialist / İzocam Tic. ve San. A.Ş.