Page 218 - Water Loss Control

Contr olling Appar ent Losses—Customer Meter Inaccuracy 191

easily tolerated by the residential customers supplied by the small meter. This is not
the case for large meter customers. Buildings serviced by large meters include facto-
ries, hospitals, military installations, shopping centers, and many important facilities
that cannot easily tolerate the lengthier water supply interruption that accompanies
the replacement of a large meter. Similarly many such buildings must be provided fire
service capability with minimal interruptions. Many large meter installations are
designed with a bypass line and valve that are used to allow continuous supply water
to the customer while the meter is being serviced or tested. For nonfire line meter
applications, the bypass should be sized one nominal size smaller than the meter being
tested down to the 2-in size. For fire line metering applications the bypass line size
should be the same nominal size. The bypass line provides the capability for a cus-
tomer with critical water supply needs to receive continuous service. Without bypass
lines the meters serving these customers cannot be tested or repaired which may result
in the loss of significant revenue. Typical bypass line configurations for large meters
are shown in Figs. 12.10, 12.11, and 12.12.
Preassembled meter packages are designed to provide the necessary equipment for
the complete meter installation and help provide for fast, easy installation. These pack-
ages are supplied by most meter manufacturers and are especially valuable to many
utilities that may not have the tools or equipment required to handle the installation of
large meters.
Most meter manufacturers recommend that a spool piece of piping be installed
downstream of the meter. The length of the spool piece should be at least twice the
diameter of the pipe. This feature is used to eliminate any turbulent flows on the exit

This coupling does not
restrain axial pipe movement
Smith-Blair coupling

Smith-Blair flange coupling
adaptor w/anchor studs Air bleed
(optional f/flexibility) screw

Flow
Downstream Upstream

Full-open
Sensus
Full-open As required for Sensus SRH strainer 5 Dia. minimum gate valve
gate valve gate valve, test built-in test straight pipe
outlet access outlet recommended
FIGURE 12.10 Installation recommendations for compound meters. (Source: Water Loss Control
Manual, 1st ed.)