View report page

57
During the past 15 years there has been a gradual closing
of all open grid sewer ventilators in the streets of most towns,
owing, chiefly, to complaints from the public, but many difficulties
have been met with in endeavouring to replace such ventilators
by a sufficient number of shaft ventilators.
Under existing conditions the ideal to be arrived at is, in
each instance, to ventilate the house drains by a ventilating
shaft, of at least 4 inches diameter, carried up to 3 feet or more
above the eaves of the house, or highest window opening, from
the highest point of the drainage system, with an air inlet pipe
on the house side of the intercepting trap: and a ventilating
pipe carried up in a similar manner from the sewer side of the
intercepting trap so as to ventilate the sewer.
Some objections to existing conditions are:—
(a) The frequency of obstruction in the intercepting
trap from foreign substances such as paper, cloths, &c.,
and from solidified grease.
(b) The blowing off of the cap on the inspection eye
of such trip, thus, where there is an inspection chamber,
opening up a direct communication for sewer air between
the sewer and drains.
(c) No immediate evidence of the above defects.
(d) The inadequate ventilation of the sewers.
This is brought about by objections on the part of property
owners to the sewer ventilator being placed by the side of the
house and on the part of occupiers to ventilating shafts being
placed opposite the house in the street, and the difficulty of
placing shaft ventilators in the street sufficiently high so as to
avoid complaints from the public of bad smells, actual or
imaginative.
The objections to abolishing the intercepting trap in towns
of long standing are:—
(a) The process of change would have to be gradual,
hence for some time, an undue amount of sewer air