PG6/33(04) - Wood Coating Processes

  
 

The wood coating process guidance note applies to sites using >5 tonnes solvent p.a. The note distinguishes between small (5 to 15 tonnes) and large solvent users (>15 tonnes) and its controls can be split into two; “final compliance options” and “other clauses.”

Final compliance options

All authorised solvent users must choose one final compliance option. This should have been in place by April 1999 for sites using >15 tonnes of solvent, whilst 5 to 15 tonnes users have until 2007. The options are:

  • Compliant coatings – all coatings must have a solvent content not more than that specified in Clause 20, e.g. 435 g/l VOC for clear coatings applied by spray, roller or dipping techniques. The 2004 version of the guidance note states that this compliance option can only be used by larger solvent users until 31st October 2005. Thereafter, they must use an alternative approach.

  • Emission limits: use of abatement technology to reduce VOC emission levels below 50 mg/m3 (>15 tonnes) or to below 150 mg/m3 (5 to 15 tonnes). Larger users could only meet such limits via unrealistically expensive “bolt on” abatement plant.

  • Mass balance (or mass reduction) approach - sites must achieve a “target emission” related to the solids content of coatings:

  • 5 to 15 tonnes users can apply up to 1.6 times as much solvent as solids, i.e. 1.6:1 and they are allowed until 2007 to achieve such a ratio or better

  • 15 tonnes and upwards users can apply the same amount of solvent as solids, i.e. 1:1 -  to be achieved by April 1999.

The mass balance is the approach that the majority of sites favour due to its relative flexibility and cost effectiveness. It allows the use of low solvent coatings where they are practical with the retention of solvent borne coats where essential.

Changes in 2004

The 1997 version of the process guidance note was replaced by PG6/33 (04) in March 2004. The revised version contains a number of changes such as:

  •  The term “authorisations” will be replaced by “permits” for each site. Currently these are reviewed periodically but this frequency will change to every 6 years.

  • Solvents with risk phrases R45, R46, R49, R60 and R61 together with halogenated solvents labelled R40 must be phased out as soon as possible in response to the Solvent Emissions Directive (SED).

  • Compliant coatings will cease to be a compliance option for companies above the SED threshold (>15 tonnes) from 31st October 2005 – as they are not in line with the Directive. 5 to 15 tonne users are not subject to the European controls, so they can continue to pursue the compliant coatings route to their 2007 deadline and beyond. The allowable solvent content of “clear coatings applied by spray, curtain or dip techniques” i.e. the vast majority, has been raised from 435 to 475 g/l.

  • Monitoring and recording of solvent consumption must be undertaken against production levels

Changes following BFM representation

Representation by BFM Ltd succeeded in obtaining a number of alterations on behalf of member companies:

  • Monitoring of solvent consumption against each production run. This requirement would have been problematic for the majority of companies due to the large in-company variations in production run lengths and composition. Representation led to the change of wording to monitoring against production levels rather than against each production run.

  • Use of programmable scales for mixing. This requirement was removed as the vast majority of industry mixing occurs during the addition of catalyst to two pack coatings. The ratios are determined by volume rather than weight – so scales would not be  appropriate to most companies.

The note can be downloaded at: http://www.defra.gov.uk/environment/airquality/lapc/pgnotes/pdf/pg6-33.pdf