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89
connected to an inspection chamber by 6in. stoneware pipes. In some
cases these pipes run under the floors of the buildings.
The rain water from the roofs is conveyed by 3in. iron pipes to 4in.
stoneware trapped gullies. From these it is carried to the inspection
chamber by 4in. stoneware pipes, which also in some cases run under the
floors of the buildings. There are heads on the rain water pipes at each
floor level to take the waste from the sinks, each pipe taking five sinks.
The inspection chambers are connected by 6in. stoneware pipes to a
9in. stoneware main drain from which they are trapped in every case,
except the one from the inspection chamber, marked R on drawing A,
which has no trap. The traps used are of an ordinary intercepting type
with an "eye" for cleaning as shown on figure 3, but the stoppers have
been removed in every case as shown by figure 4, so that the object of
trapping is not fulfilled.
I applied water tests and also smoke tests to several of the blocks of
tenements, and will deal with each test in detail.
Water test made on November 13th to Block Nos. 81 to 100.
I applied a water test to the 6in. stoneware drains marked C and D,
on drawing A, which pass under the floor of the building. A section on
drawing B. shows the fall between the w.c. pan on the ground floor
(where the water was put in) and the inspection chamber. The head
was 2.92 feet, giving a pressure of about 1½ lbs. per square inch. The
amount of water which each length of drain would contain, provided no
leaks occurred, would be about 34½ gallons. I had the water for the
tests put into the pipes in pails of 3 gallon capacity, by which the leakage
could be calculated, and it was found to be at the rate of 240 gallons per
hour from the pipe marked C., and practically the same leakage occurred
from pipe D.
The inspection chamber for this block (marked R. on drawing A.)
was in a very bad state of repair, large cracks being found in the cement
rendering on the floor, and in the benching between the channels.
The joints between the pipes entering the chamber and the
channelling were in some cases open, liquid could be seen running freely
down these cracks. I had some colouring matter introduced into these
two pipes in order to trace if there was any connection through the
subsoil between the pipes. I established such a connection between the
pipes marked B. and D1., on drawing A., the latter being the 4in. pipe
from the rain water gulley. This occurred close to the chamber, and was
discovered when the stopper was removed, the coloured liquid flowing
freely from the 4in. pipe.