MIL-HDBK-1133
The process described here involves inputs of estimated
and known water use. The calculation assistance presented
earlier in this section can be used to prepare many of the inputs
required. The forms and sample reconciliation displayed in
Tables 19 through 23 were completed by following these steps:
a) Define a consumption period and group of buildings
and/or other water uses (e.g., one-month time period and entire
installation).
b) Collect and enter the total billing (usually
utility metered) water consumption values for that time period in
Table 19 as Billed Total. It is important to verify that these
values relate directly to the group of buildings and other water
uses under consideration as well as to the appropriate time
period being considered.
c) Identify all metered and otherwise known water
consumption quantities for buildings, ships, and other processes
and enter in Table 19.
d) In the appropriate component spaces, enter
estimated total consumption values for buildings, ships,
maintenance, and losses that are not metered.
e) Sum the water component estimates and known
consumption values to derive the Estimated Total. Compare these
to the Billed Total consumption value entered in Step (b). If
either of the summed totals do not match, an adjustment or
correction is required.
Differences may be attributable to weather and
operational factors that vary from installation to installation
and are not always accurately represented by the estimation
process. One large source of variance at many activities is
water loss due to undetected leaks.
f) The final reconciliation step eliminates any
remaining difference between the actual total consumption and the
summed estimates and metered values. This difference is
apportioned to water use components by a percentage Adjustment
Factor calculated in Table 19. The Adjustment Factor is
determined by dividing the Difference (Billed - Estimated) by the
sum of selected Water Use Components to which the difference is
to be apportioned (see equation in Table 19). For the example
provided in Table 19, if the difference is to be apportioned
among estimated (nonmetered) housing, ships, maintenance and
losses, then the factor is one plus the difference (16.3) divided
by the sum of all Estimated Domestic Water (6), Estimated Ship
Water (1.7), and Maintenance Use and Losses (8.0) which is equal
to 2.04.
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