Eurocode 5 & CE Marking
Eurocode 5 (EN 1995-1-1:2004 Design of timber structures) has been in force since March 2010, making significant changes to the way that calculations are made and components chosen. In some cases this will significantly change some design decisions. ITW Industry has worked hard to ensure that all fasteners meet the requirements of the new rules.
Eurocode 5 is one of ten Eurocodes aimed at harmonising the standards for all construction products across Europe, simplifying the choice between competing products and opening up the market, encouraging the spread of knowledge and best practice. It also sets minimum acceptable performance criteria.
The objective of Eurocode 5 is that all construction products will be CE marked to show that they are safe and fit for purpose in terms of:
- Mechanical resistance and stability
- Safety in case of fire
- Hygiene, health and the environment
- Safety in use
- Protection against noise
- Energy economy and heat retention
The CE mark will supersede national standards.
Whilst a deadline of March 2010 has been set, Eurocode is essentially an ongoing process which will be implemented as the component European standards and ETAGs (European Technical Approval Guidelines) are agreed. Several standards or ETAGs affect fasteners for timber construction, roof truss design, and open web joist design, including;-
- EN14592 Dowel Type Fasteners (nails, staples, screws)
- EN14566 Gypsum Fasteners
- EN14545 2D nailing plates
- ETAG 015 3D connectors
- ETAG 011 Light composite wood based beams and columns
- ETAG 007 Timber frame building kits
- ETAG 001 Metal anchors for use in concrete (where fixing sole plates or wall plates to masonry structures)
The detail of these is all subsidiary to the calculation and performance criteria of Eurocode 5 and the permitted variations of the National Annex. In particular 3 Service Classes cover the variety of conditions to which building components are exposed:
- Service Class 1 = Internal fixings and fasteners, protected from cold and damp.
- Service Class 2 = Fixing of sheathing, battens etc., which are outside the thermal insulation, but not directly exposed to weather.
- Service Class 3 = Exposed directly to weather.
These service classes essentially deal with the moisture contained within the timber and additional consideration needs to be made of the local environment. It is fundamental to Eurocode 5 that the minimum design life of most buildings is 50 years and this should always be born in mind by the engineer.
EN14592 concerns fasteners not covered by more specific approvals (e.g. fasteners for non-structural plasterboard or fasteners for attaching 3D connectors). The applications it relates to include timber frames and sheathing, external cladding, roof construction. It stipulates the requirements for factory production control and for the independent testing of characteristic strength values for withdrawal, head pull through and yield moment.
ETAG 011 covers the design and manufacture of ‘Light composite wood-based beams and columns’. These products are not covered by specific Euro Norm standards but can be CE marked by obtaining an ETA (European Technical Approval). The ETAG generally uses a mixture of design and testing to substantiate the values that should be used for the product. The evaluation of the product is done by a Notified Body who then applies to EOTA for the issue of the ETA (for example, ITW’s SpaceJoist was evaluated by BM TRADA with TRADA Technology carrying out the physical testing).