LEAK DETECTION METHOD
MODE OF OPERATE
LEAK DETECTION CAPABILITY
APPLICABLE ON PARTIALLY
FLOW NO PRESSURE FLOW
RESPONSE TIME
APPLICATION FIELDS
FEED
LEAK LOCATION CAPABILITY
REMARKS
Acoustic/Negative wave
Acoustical method
(general)		 continuous/
intermittent		 from medium
to small leaks		 NO few minutes chemical plants and refinery potable water pipelines battery
or VAC		 until 0.05% of
pipeline length		 [I]
Acoustical method
(wave alert)		 continuous 1-3% of
flow rate		 NO seconds refinery and
storage plants		 battery
or VAC		 500 feet problems with leak
caused by corrosion
Acoustical method
(rarefraction wave)		 continuous 9-15 l/h NO seconds refinery, airport VAC 40 feet [I]
acoustic
reflectometric		 any large leaks (on line)
small leaks (shut down)		 the portable
version		 minutes refinery, storage plant, waterpipeline battery
or VAC		 within 1 Km no fixed system
Volume/Mass ballance
mass balance
(general)		 continuos until 0.2% flow rate
often >1% of flow rate [II]		 NO 30" big leaks
5' small leaks		 oil pipelines low powered
(solar panel or VAC)		 none [III]
modified volume
balance		 continuos it depends on the correction applied NO realtime oil pipelines it depends on relief system none small leaks are not detectable
Pressure/Flow monitoring
pressure drop
(general)		 intermittent large leaks (on line)
small leaks (shut down)		 NO realtime oil pipelines VAC between block valve  
pressure drop
(pipeline shut down)		 intermittent small leaks NO 24 hours oil pipelines VAC between block valve  
pressure drop
(temp. dependance)		 intermittent very small leaks NO 3 hours test airports VAC between block valve  
Others
real time
transient model		 continuous API 1155 [IV] NO real time chemical plants and raffinery potable water pipelines it depends on relief system small leaks  
statistical analisys continuous it depends on the model ~0.5% flow rate NO real time chemical plants and refinery potable water pipelines it depends on relief system small leaks  
ultrasonic leak
detection pig		 intermittent 50 l/h NO depends on piggin frequency oil pipelines unknown within 100 m  

[I] - the system cannot find leaks that ooze, seep, ...
[II] - more often 1% or more of flow rate because of technical problems.
[III] - these system are the more used in long oil pipelines, but cannot detect small leaks
[IV] - API 1155 is the most sophisticated method of Computational Pipeline Monitoring

 

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