16. Eurocode 5 Part 1.1:- Design of timber structures. General rules and rules for building

EC5 will ultimately replace BS 5268 Part 2 for designing with timber and wood-based materials. This document provides the means for a designer to prove compliance with the requirements of the Construction Products Directive and the United Kingdom Building Regulations in the same way as does BS 5268.

APA plywood manufactured to PS1-95, PS2 and PRP-108 will comply with BS EN 636 Parts 1,2 and 3 and, therefore, will be eligible for consideration in EC5.

For timber designers, EC 5 represents a radical change because the basic design philosophy has altered. EC 5 is based on limit state design, whereas BS 5268 was based on permissible stress.

Under BS 5268 the grade value tables have already been reduced in value to take account of long term load duration and which already includes a safety factor. EC 5, on the other hand, uses characteristic values of materials as the starting point for the design. To these the designer applies factors to take account of the safety, load duration, environmental conditions etc. Thus these characteristic values are higher than the grade values given in BS 5268.

EC 5 has been published in each European country. Each country has in turn attached their own National Application Document (NAD). Individual countries are responsible for their own health and safety and other matters covered by the Essential Requirements of the Construction Products Directive.