750
Cost and Time Analysis: First Cost
The cost of the non-system components in the example design is only
.95/OGSF (the sum of .18 and
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.77 from Table 750-1), whereas
the average cost of the equivalent portion of the six hospitals in the cost
base was .05. (See Table 530-1.) Thus the non-integrated
subsystems account for only 39% of the total cost of the example
schematic design as compared to 47% in the cost base. Even when
adjusted to dollars per programmed net square foot, the non-system
portion of the building would cost 17% less in the system example than in
the cost base.
Cost base:
.05/OGSF x 1.6 = .88/PNSF
Example design:
.95/OGSF x 1.9 = .30/PNSF
Difference:
.58/PNSF
Unfortunately, the cost base figure was not obtained by direct estimate; it
is simply the result of subtracting the estimates for the integrated
subsystems from the contract cost in each case. The example design
figure, on the other hand, is based on a direct estimate, as indicated by
the breakdown in Table 750-1, which in turn is based on a scope assumed
to be approximately the same as that included in the non-system portion
of the contract costs of the six cost-base hospitals. The considerable
discrepancy in the two figures seems to challenge this assumption of
equivalent scope.
We can introduce an additional safety factor into our comparisons by
examining the effect of arbitrarily adding the .58/PNSF difference to the
total estimate for the example design, on the theory that this figure
represents an actual discrepancy in the assumed scope. The "adjusted"
figure would then be .50 + .58 = .08/PNSF, which puts the
example design now 8% higher than the .76 computed for the cost
base. (See Section 751.1.3 above.) It can be shown that even if this was
in fact the marginal extra cost of a systems building, the difference can be
easily recovered by anticipated savings in maintenance and alterations.
(See Sections 752.2 and 752.6 below.)
If the difference in non-system estimates is taken directly in dollars per
outside gross square foot and added to the total figure for the example
schematic design from Table 750-1, the result is still about 1.5% less than
the basic construction cost given by the cost base.
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