In December of 2015, the American Petroleum Institute issued the first edition of Recommended Practice 1175; Pipeline Leak Detection Program. Over the next few weeks, this blog will explore the meaning of this new document that communicates proven industry practices in the development and management of a leak detection plan.

This document provides a broad stroke, high-level view to pipeline operators of liquid pipeline leak detection programs (LDPs). The recommendations satisfy current US pipeline regulations and encourage pipeline operators to “go beyond"; meaning that pipeline operators to strive for better optimization and utilization of LDPs in hazardous liquid pipelines. The overall goal is to detect leaks quickly and with certainty, facilitating quicker shutdown to minimizing negative consequences.1

The API and the Association of Oil Pipelines issued this document in response to the US Department of Transportation Pipeline and Hazardous Materials Safety Administration (PHMSA) appeal to further address pipeline leak detection effectiveness.

As previous API documents addressing pipeline leak detection are frequently cited or even adopted by numerous regulating authorities around the world to set pipeline leak detection standards, it is likely that this new RP will also influence leak detection regulation around the world.

Main sections of Recommended Practice 1175

This blog will explore the key sections of the practice in the coming weeks. Some of the main sections addressed in the document are as follows:

  • Definitions
  • Leak detection culture and strategy
  • Performance targets, metrics, and KPIs
  • Testing
  • Control center procedures
  • Response alarm management
  • Roles, responsibilities, and training
  • Maintenance
  • Performance evaluation of the leak detection plan
  • Management of change Improving planning and process


The key definitions will be useful in clarifying how the industry frames any leak detection discussion going forward. Here are a few examples.

Leak Detection Program (LDP)
A top level term that encompasses all the various leak detection systems (LDS) - which may include multiple techniques - employed by the pipeline operator and identifies all methods used to detect leaks and the policies, processes, and the human element.

Dynamic leak volume
The amount of hazardous liquid that is leaked after the onset of a leak prior to the shutdown of the pipeline (or another appropriate operational response is initiated). This is also known as pumped volume.

Independent means
That which may be a separate or complementary leak detection system that uses another technique, some verification method, separate calculations, leak detection specialists’ involvement, or other procedure or process.

Leak detection technique
Individual technology applications (eg real-time transient model, wetted cable, fiber optical cable, etc) used to actually detect or indicate a leak.

Leak detection system (LDS)
End-to-end application of one technique that may be internally based or externally based and continuous or non-continuous.

Leak detection system (LDS) operational classifications
1) Primary LDS
LDS designated by the pipeline operator as being the main primary LDS.

2) Complementary LDS
LDS that use a different technique has different metrics, and, if possible, is independent of the inputs for the primary technique.

3) Alternative LDS
LDS that is used when the primary and complementary are out of service.

4) Redundant LDS
LDS that immediately takes over if the running LDS fails.

5) Backup LDS
LDS that may be used to replace an LDS that has failed.

Leak indication
Alarm or another notifying event that suggests that present conditions indicate the possibility of a leak.
This refers to the occurrence of a leak smaller than a rupture. The RP notes that the industry also uses the word “triggers” for leak indications.

Leak verification
Analysis of pipeline operation and/or pipeline conditions triggered by the suspicion of the existence of a leak intended to provide sufficient confidence in order to make a formal determination of whether or not a leak exists.

NOTE 1: It may involve onsite investigation. The possibility of a leak is stronger if there is more than one indication.
NOTE 2: industry also uses the word "triggers" for leak indications.

Overall leak volume
Total leak volume that occurs from the time the pipeline leak begins until all leakage is stopped.
NOTE: It includes dynamic leak volume plus static leak volume.

Rupture monitoring
A form of pipeline leak detection that is intended to swiftly detect the occurrence of a rupture.
Remember that the size of a rupture is different for every pipeline. What constitutes a rupture is determined on a pipeline by pipeline basis and decided by a pipeline operator.

Technology maturity
Characteristic of a technology that has been in use for long enough that most of its initial faults and inherent problems have been removed or reduced by further development.
One key indicator is how easy the technology is to use.

Read Part 2


  1. American Petroleum Institute. (December 2015) Recommended Practice 1175, (First Edition), Washington, DC: Author
  2. American Petroleum Association. (2014). Recommended Practice 1175, Pipeline Leak Detection Program Management (2nd ed.). Washington, DC: Author

A Look Inside API Recommended Practice 1175 Series

Categories: Regulation compliance

By: Atmos International
Date: 17 April 2019