Part I of the Environmental Protection Act (EPA) imposes controls on a variety of industrial processes when they exceed specified thresholds. Timber processors should be familiar with the resulting Air Pollution Control regimes which can impact upon wood dust generation, wood combustion and coating.

The APC regime is based upon the principle of applying BATNEEC to the process – the Best Available Techniques Not Entailing Excessive Cost. This is a balance between state-of-the-art technology and management techniques and what an industrial sector can afford. BATNEEC is documented in process guidance notes which should be revised every four years.

The current round of reviews is under way – albeit one to three years late. Details are provided below of the proposed changes to three of the most important notes for wood processing companies:

  • PG1/12(95) – Wood combustion.

  • PG6/2(95) – Manufacture of timber and wood based products.

  • PG6/33(97) – Wood coatings.

    • It should be remembered that the reviews are ongoing. This article is based upon the contents of the current drafts which will hopefully change for the better following the lobbying of a number of trade bodies on behalf of their member companies.

    The most recent review is that of the wood coatings guidance note – which commenced in February 2002. By way of reminder, sites likely to use more than five tonnes of organic solvent in any 12-month period are subject to control by PG6/33(97). This threshold roughly equates with five (25 litre) tins per week of traditional pre-catalysed coatings, solvent borne stains and thinners. The guidance note requires companies to minimise solvent use and switch to low solvent and/or high solids coatings.

    The two drafts of the revised wood coatings guidance note have been issued and two meetings of the relevant working group have taken place. This group comprises a mixture of regulators, trade bodies, process operators and the Department for Environment, Food and Rural Affairs (DEFRA).

    The most striking differences in the new draft note are the length (60 pages compared to 24 previously) and complexity. The latter is due to an attempt to integrate the requirements of the EU Solvent Emissions Directive within the UK regime. All members of the working group have been arguing for simplification and this has had some impact in the second draft. However, the draft note is far from satisfactory as process operators would need to set aside a day or two to try to understand it.

    Control threshold

    The EU Solvent Emissions Directive has a threshold for control of 15 tonnes for wood coating operations. However, DEFRA is retaining the five tonnes threshold for UK control. Therefore, the new guidance note clauses relating specifically to EU Directive requirements, will not apply to 5-15 tonnes users.

    There are also potential problems with some of the new clauses included in the note which relate to generic best practice. Many of these are sensible in principle but the manner of their associated wording could impose onerous requirements if regulators were to apply the guidance note to the letter.

    The main practical differences proposed by the guidance includes:

  • Use of self-closing containers for all solvents: while lids should always be placed on solvent containing tins, self-closing lids would not be an option in many areas, eg for 25-litre tins used with diaphragm pumps.

  • Monitoring of solvent consumption against each production run: again, the thought is correct – in that it is useful to compare the amount of solvent used on one batch of 100 chairs against the next. However, monitoring for each production run would not be appropriate because of the large in-company variations in production run lengths and composition.

  • Use of programmable scales for mixing: 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.

  • Use of solvent inventory based upon usage rather than purchases: most com-panies rely upon their suppliers to provide an annual summary of purchases. The new guidance note proposes that solvent inventories should be based upon use rather than purchases – thereby requiring stocktaking at the start of each year. Where stocks are low (eg two weeks of annual consumption), the guidance note reviewer has indicated that companies might still use purchases.

  • Empty drums to be stored sealed: the existing note allows companies to store empty containers with their lids off to allow any remaining solvent to evaporate. The new note states that lids must be used. However, this would prevent can crushing.

  • Discountable solvent definitions: the existing note defines discountable solvent as that which is sent off-site for reuse or recovery for reuse. The Directive allows any solvent sent off-site to be discounted.

  • Introduction of additional controls for solvents with specific risk phrases: due to the EU Directive, solvents with risk phrases R45, R46, R49, R60 and R61 – together with halogenated solvents labelled R40 – will have more stringent controls. None of these phrases are thought to impact on the industry at present, though there is of course the danger that substances will be reclassified in future. For example, if formaldehyde was given such a risk phrase, acid catalysed coatings could not be used. This seems a strange mixing of environmental, health and safety controls within a piece of environmental legislation. However, there is limited scope to change this clause as it stems from Europe.

  • Compliant coatings: these will cease to be a compliance option for larger solvent users (more than 15 tonnes) from 2005 – as they are not in line with the Directive. Naturally, such coatings could still form part of a mass balance compliance programme. Five to 15 tonne users are not subject to the European controls, so they can continue to pursue the compliant coatings route.

    • Review of PG6/2(95)

    The review of PG6/2(95) – Manufacture of timber and wood based products – has been under way for over a year. The current draft suggests only one significant change whereby extraction plant discharging to atmosphere would be required to install continuous indicative monitoring. As with all process guidance notes, some changes are being introduced to the terminology to implement the Pollution Prevent Control Act requirements.

    The second draft of the wood combustion guidance note (PG1/12(95)) introduces some significantly more onerous proposals. DEFRA is trying to impose a carbon monoxide (CO) limit of 150mg/m3 on all existing plant of more than 1MW.

    At present, CO limits for existing plant are agreed on a site specific basis according to the level achievable. Prior to 1995, the limit was 400mg/m³ but this was removed because of the costs that would be imposed.

    Research suggests that a limit of 150mg/m³ could not be met by nearly 70% of existing plants. Therefore, these companies would be expected to have been upgraded or replaced by December 1, 2005 unless their CO emission is less than 400mg/m³, in which case the deadline would be December 1, 2007.

    The full overhaul of a boiler plant and its associated extraction and heat distribution equipment will entail significant cost. A 1.4MW installation is likely to cost a total of £200,000-250,000, while a 3MW plant will be nearer £450,000.

    Consequently, if existing plant must be taken out of service, it is likely that many companies will either send the waste to landfill or buy in more finished product from abroad (thus avoiding the waste generation in the first place.