Summary
• The draft structural timber strength grade standard EN14081 threatens complex individual marking of treated timber.
• A thought-out strategy is needed for the marking or labelling of treated timber.
• The UK will vote against the standard if it is not amended.

The UK Wood Protection Association (WPA) is arguing for the draft of a new European standard for strength graded sawn structural timber to be amended to avoid over complex and time-consuming marking of individual pieces.

The new standard EN 14081 is harmonised for the purposes of the Construction Products Directive (CPD). That means its provisions, affecting a large proportion of wood used in construction, will be mandatory.

The standard includes the requirement to mark each piece with a CE mark incorporating certain minimum information, such as producer’s name and the grade.

But in its original format it also demanded that each piece be marked: “If preservative treated, additional marking according to prEN 15228”.

The latter standard – like EN 14081 also drafted by the CEN/TC 124 committee – demands that information provided on the applied treatment includes preservative, penetration class, retention, charge number, target biological agents and the producer.

If when BS EN 14081 were published it required individual piece marking with treatment information, then a means would have to found – and the cost incurred – of doing this when pieces were already bundled together in groups of 500 or more. And currently the draft includes as a minimum a mark “PT” and either a list of the six PrEN 15228 treatment-related parameters, or a reference number identifying where the information can be found on accompanying documentation.

Committees like CEN/TC 124 decide for their product standards how to apply the CE marking requirements of the CPD. Marking each piece of graded timber is the norm and easily achieved given individual piece handling during the grading process. So it is not unexpected that CEN/TC 124 would go for piece marking for grade.

Optional marking
However, the CPD itself states that piece marking is optional and technical committees must take into account the implications of their decisions on marking, balancing technical need against other factors.

We have stated in the UK industry “position document” that, where preservative affects the strength grade already marked on individual pieces, a modification factor mark should also be added to each piece. No-one would argue against that.

But where a treatment does not affect grade, then the technical committee can be more relaxed about the marking requirement and should respect the position of the industry sector concerned and go for batch marking; providing preservative information on “accompanying documentation”.

Following information provided by the WPA, the draft standard does include a list of preservatives deemed not to affect strength and a general “deemed to satisfy” provision for all treatments of penetration class NP2 or less.

But if CEN/TC 124 rejects our arguments, we have indicated that the UK will vote against the standard when it comes up for formal approval.

Our stance, and the positions of other CEN members, were considered at a meeting of the CEN/TC 124 Working Group on October 8, attended by WPA technical committee chairman Andrew Hughes.

We were getting mixed messages on the position of other CEN members but, in the event, while full details of the meeting are not yet out, it is understood that the individual piece marking provisions in prEN 15228 were removed.

This is welcome news. But it does place greater emphasis on the “accompanying documentation’” option, so we will look at ways to make this perhaps more robust and reliable.

Since one of the options in the CPD is to make the CE mark information available electronically, we think this may be one of the key routes of ensuring ready access to the information.

One argument, used by those in favour of the piece marking requirement in prEN 15228, was that it resulted in other benefits, including better traceability for quality assurance purposes and, by identification of the preservative used, easier end of life management. But this is not necessarily a given. As treated wood can be cut to size on site or during service life, and considering we are looking at service lives in excess of 60 years, perhaps in wet conditions, it is clearly not just a matter of stapling a label onto the end of each piece.

While these issues should be addressed, it is clear that a standard on strength grading is not the place to do so. The industry is developing its thinking on these issues; what role piece marking could play in that and how marking is best achieved. A properly thought-out strategy is needed and not a ‘quick-fix’ answer.