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34
Single stack plumbing.
Since the introduction of single stack plumbing in Borough Council flats
in the past five years, of over 1500 flats completed or in course of
erection, the single stack system of plumbing was provided in over 1300 of
them. The nett saving in capital cost therefore, as compared with
traditional plumbing designs, has been estimated to be in the region of
more than £20,000. These are striking figures. Economies have been
achieved by reducing labour costs by at least 50% fo and tho cost of materials
by over 30%. Experiments carried out by the Building Research Station in
1954/5 confirm these figures.
The latest development carried out in single stack plumbing by the
Shoreditch Borough Council has been in the drainage designs applied to
multi-storey blocks of flats of ten and eleven storeys. Three such blocks
have been occupied during 1958. four are in various stages of construction
and one is almost ready for occupation.
In the first two multi-storey blocks, duplicate 4" stacks were
incorporated in the design, one stack receiving roof water and all wastes
from W.C's, sinks, baths and washbasins up to a height of six storeys and
the other stack all such fitments from- the remaining storeys in addition
to roof water. No anti-siphonage system was provided and in practice full
efficiency has been maintained.
On the third multi-storey block, one 6" stack was provided receiving
the wastes of all W.C's, sinks, baths and washbasins together with roof
water in plaoe of the two 4" stacks provided in the previous two multistorey
blocks, further reducing the costs and speeding up the work. Again
no anti-siphonage system was provided and once again full efficiency has
been maintained. This latest method of drainage has been included in the
remaining three multi-storey blocks now in course of erection.
To sum up, whereas traditional plumbing required the provision of
three stacks, one for rainwater, one for sink, bath and basin wastes, and
one for soil from W.C'S, together with elaborate systems of anti-siphonage,
experiments carried out have enabled us to provide one stack to receive
all soil and waste water and to omit all anti-siphonage pipes without loss
of efficiency.
Detergent Foam.
The risk of the back flow of detergent has had to be taken into
consideration in the application of this design, but we are confident that
the increased size of the diameter of pipes used in the single stack system
will eliminate any risk of this happening. There has been up to the
present no evidence of any back flow of detergent foam in any single stack
construction.