EWPAA Structural Plywood and LVL Design Manual - Engineered ...

where:Note:T p(16.3)T pt it m= t i + t m= fire resistance period of a timber memberprotected with resistant insulation, in minutes;= fire resistance period appropriate to the protectiveinsulating systems, in minutes;= fire resistance period of the structural timber member● For protected timber c of Equation 16.1 is multiplied by 1.1;●T p of Equation 16.3 is a conservative estimate of the FRP and can be modified ifacceptable test data is available, through reference to manufacturers’ productcatalogues, technical reports and reports on tests performed in accordance with AS1530.4.16.8 Fire Protection of Joints with Metal ConnectorsThere are two possible scenarios in which joints having metal connectors can occur in a fire within astructure. These are as:1. Unprotected connectors whereby structural adequacy can be established by test or isnegligible if test data does not exist.2. Protected connectors which can be achieved by:● embedding, which results in the connectors being embedded into the member to a depthequal to the calculated effective depth of charring as shown in FIGURE 16.5. The resultingholes must be plugged, using timber, glued into place;● cladding which is effected by covering the joint, e.g. a nailed plywood gusseted moment joint,covered with fire-resistant claddings.FIGURE 16.5: Fire protected connectorsTABLE 16.1 provides comparative data for fire resistance levels for structural stability between Douglas firplywood as published in the Fire Protection Handbook published by the National Fire Protection Association,USA and radiata pine plywood as published by Carter Holt Harvey in their Technical Note 95/3/14, March,1995.252