View report page

minutes' emission in one continuous period of half an hour.
Smoke from domestic chimneys is expressly exempted. If
proceedings are taken in respect of a smoke nuisance, the
defendant may plead that he has taken the best practicable
means for preventing the nuisance. The expression "smoke"
includes soot, ash, grit and gritty particles.
The "Beaver" Report states that: "By 'smoke' we mean
suspended particles or droplets of carbonaceous matter, grit and
dust arising from the combustion of fuel", and "by 'dark smoke'
we mean smoke of density equivalent to or greater than shade 2
on the Ringelman Chart." In making recommendations, the
Committee are satisfied that with few exceptions no industrial
chimney need normally emit more than a light haze of smoke,
but as it will be necessary to make allowance for short discharges
of dark smoke, it would be proper to permit a total upper limit of
six minutes of dark smoke in any period of four hours, but that
no single burst of dark smoke should last more than three minutes;
the only defence being that the emission of dark smoke is due to
lighting up the furnace from cold, or to temporary and unforeseen
mechanical failure.
Nearly half of all the smoke in the air comes from domestic
chimneys, and, consequently, the proportion is greater where
houses predominate. Most of the domestic smoke is produced
during the winter months when atmospheric conditions are
most likely to give rise to fog. Although the smoke from these
chimneys is less dense than that from industrial chimneys, it is
discharged at a low level, and its harmful effects may be accentuated.
The problem of domestic smoke must be tackled.
It is advocated, therefore, that the extension of smokeless zones
is an admirable and effective method of securing smokelessness
where local conditions permit. The scope is limited, however,
since complete smokelessness is not practicable in areas which
include industry as well as houses. In that case, a second type of
area—a "smoke control area" in which concurrently with the
measures to reduce industrial smoke, domestic users would be
required to use only smokeless fuels such as bituminous coal
containing not more than 20 per cent, of volatile matter (and in
consequence substantially smokeless) or manufactured fuels
having similar smokeless qualities. The available solid smokeless
fuels are natural smokeless coal, manufactured fuels such as
"Phurnacite", low temperature cokes ("Coalite" and "Rexeo"),
coke from coke ovens and gas works coke.
Both in "smokeless zones" and in "smoke control areas,"
however, house owners will be obliged to install the necessary
improved appliances, where they are at present lacking, in
which to burn smokeless fuels. It is already the practice of many
Local Authorities at the instance of Central Government to install