
106 MATERIALS
Thermal Insulation
The boilers, cylinders, pipes, and other surfaces to be insulated, are
carefully measured from the drawings, and the Specification con-
sulted as to type and thickness of covering required.
Unless the heating contractor employs skilled coverers, as some
firms
do,
the estimator will obtain a quotation from a specialist
firm.
Before submitting his price the insulating contractor should if
possible examine the drawings and specification in order that he
may know exactly the conditions under which his men will work.
This applies especially to covering in ducts and trenches. Although
many such quotations are base