Page 311 - Water Loss Control

280 Cha pte r S i x tee n

Impact on Awareness Impact on Location
Technique Duration Duration Most Appropriate for
Permanent Reduces AT down to a Requires additional Due to high capital
noise logger couple of days— pin-pointing. Therefore cost it is difficult to
AT depends on how depends on availability justify permanent
often noise logger of staff and priority installation.
data is retrieved, given to the leakage
e.g., AT can be 1/2 event.
day if noise logger
data is transmitted or
collected every day.
Step testing Requires additional Rural distribution
pin-pointing. Therefore networks with high
depends on availability level of excessive
of staff and priority leakage.
given to the leakage
event.
General survey AT depends on Leak is pinpointed Areas where leaks
frequency of general immediately after it is occur mainly on the
survey. localized—very short distribution network
location time. and the mains and
services are of
metallic material.
Comprehensive AT depends on Leak is pinpointed Areas where high
survey frequency of immediately after it is level of service
comprehensive survey. localized—very short connections leaks
location time. exist and where a
significant portion
of nonmetallic
pipework exists.
Most appropriate
technique to detect
all leaks and remove
the backlog of hidden
leaks.
Leak noise Awareness time Leak is pinpointed In areas with high
mapping depends on frequency immediately after it is density of fire
of surveys. localized—very short hydrants.
location time—plus
all other noise picked
up during survey
by equipment has
to be noted down
and followed up and
verified.

Source: Ref. 1.

TABLE 16.1B Matrix of Leak Detection Techniques—Part Two (Continued)