Additional Guidance from the Department for Environment, Food and Rural Affairs and Welsh Assembly Government
AQ10(04)
Addendum to SG7: Secretary of State's guidance for the A2 Ceramics sector including heavy clay, refractories, calcining clay and whiteware
In the sector guidance note for the ceramics sector (SG7), published in March 2004, operators of certain types of kilns were, due to their size and simple design, extended dispensations so as not to be subject to the same level of process controls as other ceramics processes. This note extends the provisions given in the SG note for "clamps" to "scotch kilns".
Scotch kilns, like clamps, have no chimney so it is impossible to monitor pollutant concentrations in the emissions which are direct to atmosphere. Ambient air quality standards are used to assess the acceptability of the process, as well as the requirements of the Clean Air Act 1993.
The text attached to this AQ note should be read in conjunction with SG7.
AEQ/Defra
17 May 2004
Text changes
To clarify SG7 as it applies to scotch kilns, the following changes are made to SG7.
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In Table 5, to the end of the subtitle " Heavy clay and refractory goods except clamps" add the words "and scotch kilns"
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In Table 5, to the end of the 5 subtitle " Heavy clay goods - clamps" add the words "and scotch kilns"
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In the text in Table 5 in the cell titled "Heavy clay goods - clamps"
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Delete the words "A clamp does not have a chimney, "
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Insert the words "Clamps and scotch kilns do not have chimneys "
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Between the words "clamp" and "operations", insert the words "and scotch kiln"
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In Paragraph 3.9, at the end of the list called "Firing of ware", add a new bullet "scotch kilns"
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To the title preceding paragraph 3.42 add the words "and scotch kilns"
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Between that title and paragraph 3.42 add a subtitle "Clamps"
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Immediately after paragraph 3.49 add a subtitle "Scotch kilns" and the following paragraphs:
"A scotch kiln has no chimney so it is impossible to monitor pollutant concentrations in the emissions which are direct to atmosphere.
There are thought to be around 16 scotch kilns at four sites in the Chilterns and Suffolk, producing traditional bricks in the local style.
Scotch kilns, like clamps, have no chimney. Scotch kilns do have walls of refractory brick, typically three feet thick reinforced with steel girders, and firing ports along each long side. Increasingly the fuel used is gas oil, although recovered waste oil has been used. They have a dismountable roof of planks. Capacity is typically 60,000 to 100,000 bricks per kiln.
The unfired brick body contains colourant, (the colourant is typically 3% anthracite with a sulphur content typically 0.25 - 0.65%).
The unfired bricks are stacked in the kiln, and covered with partly fired bricks (splatter bricks). The stacking pattern and position in the kiln largely determine the brick colour. Firing with oil starts gradually and builds up to maximum input after about 24 hours. At this stage the oil burners are removed and the fire holes stopped up. The rising heat transferring from brick to brick completes the firing over a further 2 days or so, and then they start to cool. Three or more days after this the bricks can be unstacked.
The exhaust from the kiln is direct to atmosphere and ambient air quality standards are used to assess the acceptability of the process, as well as the requirements of the Clean Air Act 1993.
Controls include limiting the sulphur in the colourant and the fuel."
- To the BAT Box for clamps, immediately after "clamps" add the words "and scotch kilns"
This amendment constitutes guidance under regulation 37 of the PPC Regulations.
Page published: 18 May 2004