1958 No. 878
CLEAN AIR
The Dark Smoke (Permitted Periods) (Vessels) Regulations, 1958
Made 22nd May 1958
Laid before Parliament 29th May 1958
Coming into Operation 1st June 1958

The Minister of Housing and Local Government, in exercise of his powers under subsection (2) of section 1 of the Clean Air Act, 1956, and of all other owers enabling him in that behalf, hereby makes the following regulations:—

1 These regulations may be cited as the Dark Smoke (Permitted Periods) (Vessels) Regulations, 1958, and shall come into operation on the 1st day of June, 1958.
2 The Interpretation Act, 1889, applies to the interpretation of these regulations as it applies to the interpretation of an Act of Parliament.
3 1 Emissions of dark smoke from a chimney of a vessel for not longer than the period specified in column (2) of the schedule to these regulations in respect of the class of case specified in column (1) shall be left out of account for the purposes of section 1 of the Clean Air Act, 1956:
Provided that—
(a) continuous emissions of dark smoke caused otherwise than by the soot blowing of a water tube boiler shall 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 shall black smoke be emitted for more than 3 minutes in the aggregate in any period of 30 minutes.
In this paragraph “black smoke” means smoke which, if compared in the appropriate manner with a chart of the type known at 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.
2 For the purposes of the said schedule 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 shall be deemed to be under way.
Given under the official seal of the Minister of Housing and Local Government this twenty-second day of May, nineteen hundred and fifty-eight.
Henry Brooke Minister of Housing and Local Government
SCHEDULE
(1)	(2)
Class of case	Permitted period for emission of dark smoke
1. Emissions from a forced draught oil-fired boiler furnace, or an oil engine.	10 minutes in the aggregate in any period of 2 hours.
2. Emissions from a natural draught oil-fired boiler furnace (except in the cases falling within class 4 below).	10 minutes in the aggregate in any period of 1 hour.
3. Emissions from a coal-fired boiler furnace:—
(a) when the vessel is not under way (except in the cases falling within class 4 below).	10 minutes in the aggregate in any period of 1 hour.
(b) when the vessel is under way	20 minutes in the aggregate in any period of 1 hour.
4. Emissions from a natural draught oil-fired boiler furnace or a coal-fired boiler furnace in the following cases:—
(a) a vessel with funnels shortened for the purpose of navigating the Manchester Ship Canal;
(b) a tug not under way, but preparing to get under way or supplying power to other vessels or to shore installations;	20 minutes in the aggregate in any period of 1 hour.
(c) a vessel not under way but using main power for the purpose of dredging, lifting, pumping or performing some other special operation for which the vessel is designed.
5. Emissions from any other source	5 minutes in the aggregate in any period of 1 hour.

EXPLANATORY NOTE
Section 1 of the Clean Air Act, 1956, as applied by section 20 of that Act, makes it an offence to emit dark smoke (as defined) from the chimney of a vessel, but provides that emissions of smoke lasting for not longer than such periods as may be specified by the Minister of Housing and Local Government by Regulations shall, in such classes of case and subject to such limitations as may be so specified, be left out of account for the purposes of the section. These Regulations specify the permitted emissions of smoke.