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73
The question as to the utility of fresh air inlets having been brought
up before a Board meeting, the subject was referred to the Building
and Drainage Committee. The two following reports were made by
the Surveyor and myself to the Committee, and were afterwards
presented to the Board :—
June iqth, 1895.
To the Chairman and Members of the Building and Drainage
Committee.
Gentlemen,
We your Surveyor and Medical Officer of the South District,
beg to report that we have experimented upon a "Fresh Air Inlet,"
to three houses, viz.:—122, 124 and 126, St. Leonards Road, the
combined drainage of which premises is entirely rear, and is 50 feet
in length. The Mica valve fitted on to a 4 inch pipe, is 21 feet from
the invert of the drain and the top of the upshaft also a 4 inch pipe,
is 39 feet from the invert of the drain. The distance from the intake
to the outlet being 110 feet. The Anemometer was allowed to
remain in the intake pipe on two separate occasions, for 74 and 72
hours respectively, on the first occasion (74 hours) it was found that
it registered a velocity of 2,557 lineal feet, and on the second occasion
(72 hours) it was found that the instrument registered a velocity
of 17,720 lineal feet. These figures do not take into consideration
the correction,—which for the instrument used, is to add "30 per
minute to the observed reading of the Air Meter."From these results
it is evident that a current of fresh air passed through the drain, and
the velocity of the current depended upon the speed of the wind
over the top of the upshaft. We think that the above observations,
prove conclusively in this particular case, the utility of the system of
house drainage ventilation.
We are Gentlemen,
Your obedient servants,
(Signed) G. F. HOLT, Surveyor.
FREDK. WM. ALEXANDER,
Medical Officer of Health. Poplar and Bromley.