Figure 9-4.-Sample Bill of Material (BM) sheet.
This loss may occur during shipping, handling,
storage, or from the weather. Waste is inevitable
where material is subject to cutting or final fitting
before installation. Frequently, material, such as
lumber, conduit, or pipe, has a standard issue length
longer than required. More often than not, however,
the excess is too short for use and ends up as waste.
Waste and loss factors vary depending on the
individual item and should be checked against the
conversion and waste factors found in NAVFAC
P-405, appendix C.
CHECKLISTS. Use checklists to eliminate
any omissions from the material estimates. Prepare a
list for each individual project when you examine the
drawings, specifications, and activity estimates. This
is the practical way to prepare a listing for the variety
of material used in a project. The listing applies only
to the project for which it has been prepared. If no
mistakes or omissions have been made in either the
checklist or estimate, the material estimate will
contain a quantity for each item on the list.
LONG LEAD TIMES. Long lead items are not
readily available through the normal supply system.
They require your special attention to ensure timely
delivery. Items requiring a long lead time are
nonshelf items, such as steam boilers, special door
and window frames, items larger than the standard
issue, and electrical transformers for power distribu-
tion systems. Identify and order these items early.
Make periodic status checks of the orders to avoid
delays in completing the project.
PREPARING MATERIAL ESTIMATES.
There are several steps for preparing a material
estimate. First, determine the activity by using the
activity description with the detailed information
furnished by the drawings and plans to provide a
quantity of work.
Convert this quantity to the
Next, enter the conversion on a
work sheet to show how each quantity was computed,
as shown in figure 9-2. Include sufficient detail; work
sheets need to be self-explanatory. Anyone examin-
ing them should be able to determine how the
quantities were computed without having to consult
the estimator. Allowances for waste and loss are
added after determining the total requirement. All
computations should appear on the estimate work
sheet, as must all notes relative to the reuse of the
project are entered
quantities for similar items of a
on the Material Takeoff Sheet or