PART 1 Dark smoke – permitted periods for emissions from vessels

2 Dark smoke – emissions from vessels
1 Emissions of dark smoke from a chimney of a vessel for not longer than the period specified in column 2 of Schedule 1 to these Regulations, in respect of the class of case specified in column 1 of that Schedule, are emissions to which section 1 (prohibition of dark smoke from chimneys) does not apply, provided that—
(a) continuous emissions of dark smoke caused otherwise than by the soot blowing of a water tube boiler do not exceed—
(i) in the case of classes 1 and 2, 4 minutes;
(ii) in the case of natural draught oil-fired boiler furnaces in class 4, 10 minutes; and
(b) in no case is black smoke emitted for more than 3 minutes in total in any period of 30 minutes.
2 In paragraph (1)(b), “black smoke” means smoke which, if compared in the appropriate manner with a chart of the type known on 5th July 1956 (the date of the passing of the Clean Air Act 1956) as the Ringelmann Chart, would appear to be as dark as or darker than shade 4 on the chart.
1956 c. 52, repealed by Schedule 6 to the Clean Air Act 1993.
The Ringelmann Chart British Standard 2742C:1957.
3 For the purposes of Schedule 1, a vessel is not under way when it is at anchor or made fast to the shore or bottom, and a vessel which is aground is deemed to be under way.