To support the industry and stakeholders in the use of consistent terminology, Ipieca, IOGP, GIE and MARCOGAZ prepared this methane emissions glossary covering the whole natural gas value chain.

Intended for policymakers and regulators working on methane regulation in Europe, this glossary will be updated to reflect new legislation and technologies.

All | # A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
There are currently 4 names in this directory beginning with the letter B.

The process of measuring a leak rate by enclosing an equipment piece in a bag or tent to determine the actual mass emission rate of the leak to determine an emission flow rate. (Note: typically consists of a suction pump combined with a calibrated flow and concentration measurement.)

Block valve
A valve used to isolate a piece of pressurized equipment or a section of a pipeline for tie-in or maintenance purposes. (Note – Block valves typically are located to limit the volume of gas that may need to be depressurized for tie-ins and maintenance, and to reduce the amount of gas that would be lost in an event.)

Blowdown open ended line (BD-OEL)
A pipeline to evacuate a pressurized section of the network from gas. [12]

Bottom-up emission approach/inventory
Method based on direct measurements, engineering calculations, manufacturer data and emissions factors for emissions sources/activities, compiled to develop an account of emissions discharged to the atmosphere from an asset (e.g. compressor station) or a geographic area (e.g. basin, state, region). (Note - The bottom-up approach is a source-specific quantification approach: the emissions from each identified source are individually quantified. Total emissions on a given perimeter are calculated by adding each type of emission source data.)


[1] Directive 2009/73/EC of the European Parliament and of the Council of 13 July 2009

[2] EN-12186 – Gas infrastructure – Gas pressure regulating stations for transmission and distribution – Functional requirements

[3] EN-12327 – Gas infrastructure – Pressure testing, commissioning and decommissioning procedures – Functional requirements

[4] EN-12583 – Gas Infrastructure – Compressor stations – Functional requirements

[5] EN-15446 – Fugitive and diffuse emissions of common concern to industry sectors – Measurement of fugitive emission of vapours generating equipment and piping leaks

[6] GIE & MARCOGAZ Report “Potential ways the gas industry can contribute to the reduction of methane emissions”

[7] IPIECA/API/IOGP (2020). Oil and gas industry guidance on voluntary sustainability reporting

[8] IPIECA Methane Glossary

[9] ISO 14532 – Natural gas — Vocabulary

[10] JCGM-100 – Evaluation of measurement data – Guide to the expression of uncertainty in measurement. s.l.: Committee for Guides in Metrology (JCGM/WG 1), 2008

[11] MARCOGAZ – Assessment of methane emissions for gas Transmission and Distribution system operators, 2019 Assessment+of+methane+emissions+for+gas+Transmission+and+Distribution+system+ operator.pdf?t=1602849054

[12] MARCOGAZ – Guidance for using the MARCOGAZ methane emissions reporting template – DSO, TSO, LNG receiving terminals and UGS

[13] MGP Reducing methane emissions: Equipment leaks

[14] MGP Reducing methane emissions: Identification, detection, measurement and quantification

[15] MGP Reducing methane emissions: Transmission, storage, LNG terminals and distribution

[16] Oil and Gas Methane Partnership Technical Guidance Documents

[17] Regulation (EC) No 715/2009 of the European Parliament and of the Council of 13 July 2009

[18] US EPA – ‘Method 21: Determination of volatile organic compound leaks’