30
Concrete Pens.
Tunnels.
These are above-ground concrete structures and will
resist blast and splinters from 500lb. high explosive
bombs falling 50 feet away. Each pen accommodatos 120
people, and at present 12 pons have been erected, giving
accommodation to approximately 1,440 people at a cost of
$7.80 per head.
The supply of blocks for the construction of the se
pons is limited, due to the lack of plant and to the fact
that only three firms would undertake to produce on a
mass-production scale.
At present our commitment amounts to $94; 200 and
this sum was provided out of the first million dollars,
but a further $507,000 has now been asked for in order to
extend protection to the central and western districts
to house approximately 66,400 people.
The advantage of pens is their comparative cheapness
and the case with which they can be erected. The money
expended on the production of concrete blocks will be
largely recoverable as they have been made in sizes
suitable for future building purposes.
It is proposed to accommodate in this way approx-
imately 213,930 people, and it will take approximately
12 months to erect at a cost of $1,657,710.
are:
The advantages of tunnels over all other systems
(a) Complete protection
(b) Accessibility
(c) Comfort.
Accessibility is important, especially in the
central and western districts, where there are few
spaces for the erection of concrete pens, construction
of trenches, or Dispersal Areas available, and the only
real solution to this problem is the construction of
tunnels.