Leak testing is performed for four basic reasons, says John McLaren, product manager, leak detection at Agilent Technologies, Inc.

• Prevent material loss by leakage
• Avoid contamination of the product or the environment
• Maximize product or system performance and reliability
• Minimize product liability if leakage presents a hazard

All these factors promote improved quality, reduced downtime and lower warranty cost.

A control valve can be used to control pressure, pressure drop, flow and temperature in any system where there is a fluid flowing through a pipe that needs to be controlled. Control valves are commonly referred to as “final control elements,” which convert a signal from the process controller into the desired adjustment to the process. A control valve (with its associated actuator) does this by adjusting the size of its flow passage, based on the signal received.

Many parameters help determine which control valve to select for a given application. The choice, often complicated, can become even more so for control valves destined to handle severe flow conditions.

From time to time Valvemagazine.com likes to re-publish some of our most popular articles from years past. This one was originally published on March 2, 2016.

Normally, valves are pressure tested by the factory to check for leaks before they’re shipped. The type and method of testing conforms to one or more of many different standards. The purpose of these tests and the expected results are often misunderstood and misapplied, resulting in unnecessary delays and unanticipated costs.

This article identifies the most common mistakes. Its primary purpose is to inform and guide end users and engineers that write valve specifications so those parties can avoid some of the mistakes.

Pipelines represent an efficient, safe way to transport many kinds of liquids and gases. Other methods such as truck or rail transport are more expensive, have a larger carbon footprint and are more likely to experience leakage, theft or accident that may imperil people and the environment.

Pipelines can leak or break, too, of course. Good practice and regulatory requirements make leak detection a necessary part of pipeline operation.

Many different methods have been used to detect leaks. The options for leak detection include non-continuous methods, such as inspection by helicopter, smart pigging or even specially trained sniffer dogs, said Daniel Vogt, product manager at Krohne, in a presentation recorded at a NAMUR (User Association of Automation Technology in Process Industries) annual meeting.