6. PERFORMANCE OF LVL IN FIRE 6.4.4 LVL-C panel as a protection against fire exposure When the LVL-C panel thickness is according to Table 6.3, the panel protects a wooden structure behind it for a certain fire resistance time t [min]. Other fire design calculations of the remaining wooden structure are not needed unless the panel is a part of the load-bearing system also in the structural fire design. In the case of timber frame assemblies, the LVL-C protection panel thickness hp1 [mm] can be calculated for the required fire protection time t based on EN1995-1-2, equation (4.1) and (C.7) or (D.3): Minimum panel thickness hp1 = β0 ∙ (t+4min)+7mm (6.5) When the protection panel is applied directly on beams or columns, the protection panel thickness hp2 [mm] is calculated for the required protection time t based on EN1995-1-2 equations (4.1) and (3.10): Minimum panel thickness hp2 = β0 ∙ t+7mm (6.6) 6.4.5 Summary of LVL-C panels for fire protection Table 6.10 specifies the minimum thickness hp of LVL-C panel when used as a covering with fire protection ability for the underlying materials (column A), fire protection of the structures (column B) or when used as a ceiling structure which has a fire resistance requirement EI (column C). All of the different fire protection specifications also have requirements for the detailing of, e.g., joints between the panels. Figure 6.10. Minimum LVL 36 C panel thicknesses in fire protection applications. A) The fire protection ability K2 class requirement for protecting the underlying material is that behind the protection panel the average temperature rise over the whole of the unexposed surface is limited to 250 °C and the maximum temperature rise at any point of that surface does not exceed 270 °C. Note that in some cases there can be additional requirements to use only non-combustible materials for the covering. B) LVL panel as fire protection. When the panel thickness hp = dchar,0 + k0 ∙7 mm, it protects the underlying structure for a required fire resistance time t and the effective cross-section in the resistance calculation is the entire underlying structure. C) The separating function (EI) is assumed to be satisfied when integrity (E) and insulation (I) are maintained. When LVL-C panel is used as a ceiling structure and has a fire resistance requirement of (EI), the required panel thicknesses hp can be determined according to EN19951-2 Annex E based on the insulation time tins. In addition, the requirements for the detailing of joints shall be fulfilled. Note: An advanced calculation method for separating function is presented in the publication Fire safety in timber buildings –Technical guideline for Europe, chapter 5.5 40 LVL 06, Figure 6.10 K2 10, when hp ≥ 15 mm Fire protection for 15 min, when hp ≥ 18 mm Insulation time tins = 15 min, when hp ≥ 18 mm K2 30, when hp ≥ 26 mm Fire protection for 30 min, when hp ≥ 29 mm Insulation time tins = 30 min, when hp ≥ 33 mm K2 60, when hp ≥ 52 mm Fire protection for 60 min, when hp ≥ 49 mm Insulation time tins = 60 min, when hp ≥ 66 mm A B C Panel as K2 classified covering Panel as fire protection Panel as ceiling with El requirement Increase 250°C (max 270°C) Increase 140°C (max 180°C) Underlying structure hp hp hp LVL Handbook Europe 165
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