From pipeline leak and theft detection to simulation software, the world of pipeline technology is continuously evolving. With new innovations being introduced every day, it’s important to keep up to date on the language.

The Atmos Glossary provides maximum information in a consumable format for pipeline companies, pipeline operators and other stakeholders in the industry. To reflect our constant alignment with the pipeline industry, this glossary is regularly updated* based on our experience delivering pipeline solutions to customers in over 60 countries. Read the glossary below.

*Last updated on March 27 2024. The following definitions are in the context of pipeline leak detection, theft detection, simulation and optimization.


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


Acoustic sensing, Adaptive spatial mesh, American Petroleum Institute (API), Artificial intelligence (AI), Asset management plan (AMP)


Batch tracking, Bunkering, Basic offshore safety induction and emergency training (BOSIET), Benedict-Webb Rubin equation of state (BWRS EOS), Block valve, Box scheme


Canada Energy Regulator, Capacity evaluation, Carbon capture and storage (CCS), Centrifugal, Class location, Climate change, The cloud, Computational pipeline monitoring (CPM), Concentrator plant, Conference of the parties (COP), Control (philosophy, room), Corrosion, Crude oil


Data acquisition unit, Data manager, Decarbonization, (US) Department of Transportation (DOT), Desalination, Design specification, Distributed control system (DCS), Distribution network, Doppler flow meter, Double transient, Drag reducing agent, Drop-out


Elastic modulus (B), Electrolysis, Embrittlement, Emergency shut down (ESD), Enthalpy, Entropy, Estimated Time of Arrival (ETA), Equation of state


Factory acceptance test (FAT), Fatty acid methyl ester (FAME), Fiber optic, Finite difference method, Flash flood, Flow assurance, Flow balance (difference), Flow regime (laminar, turbulent), Flowsheeting, Fluid thermal model, Frozen look-ahead


Gap analysis, Gas composition, Gas distribution network, Gas transmission network, Gas venting, Gathering lines, GERG-2004 EOS, GERG-2008 EOS, Greenhouse gas, Ground thermal model, Groundwater contamination


Heat capacity (𝐶), Helmholtz free energy, High consequence area (HCA), Human machine interface (HMI), Hydraulic profile, Hydraulic simulation, Hydrocarbon, Hydrogen backbone, Hydrogen blend, Hydrogen colors, Hydrogen economy, Hydrogen fuel


Integrated factory acceptance test (IFAT), Isentropic bulk modulus (Bs)


Joukowsky equation, Joule-Thomson effect


Knot spacing


Lahar, Lateral scour, Leak detection, Linepack, Liquefied natural gas (LNG), Liquefied petroleum gas (LPG), Look ahead, Lowest allowable operating pressure (LAOP)


Machine learning, Management of Change (MOC), Maximum allowable operating pressure (MAOP), Maximum daily quantity (MDQ), Midstream, Model acceptance test (MAT), Moderate consequence area (MCA), Mono ethylene glycol (MEG), Multiphase


National Energy Board (NEB), Natural gas liquid (NGL), Navier-Stokes equation, Negative pressure wave, Network topology, Net-zero, Newton-Raphson iteration, Noise correlation, Nominal flow, Nominations look-ahead


Offshore, Onshore, Optimizer, Ore, Ore extraction


Parametric study, Pipeline and Hazardous Materials Safety Administration (PHMSA), Pipeline inspection gauge (PIG), Pipeline Integrity Management, Piping and instrumentation diagram, Position sensor, Positive displacement flow meter, Positive displacement pump or compressor, Potential impact circle (PIC), Potential impact radius (PIR)Predictive analysis, Pressure distribution analysis, Programmable Logic controller (PLC), Proportional integral derivative (PID) control


Quality tracking


Rapid transient, Real-time transient model (RTTM), Recommended practice, Recommended standard, Reid vapor pressure (RVP), Reliability centered maintenance (RCM), Restraint factor (ϕ), Retention pond, Reverse osmosis, Rich gas, Riverbed scour, Remote terminal unit (RTU), Rupture


Scraper, Separator, Sequential probability ratio test (SPRT), Shutdown, Simulation, Single phase, Site acceptance test (SAT), Slack, Slash and grab, Slugging, Slurry, Solver, Sour gas, Sparse matrix, Spill or Spillage, Standard flow, Statistical volume balance system, Steady state, Steam reforming, Supercritical phase fluid (sCO2, ethylene), Supervisory control and data acquisition (SCADA), Surge (analysis, scenario), Survival time


Tailing, Tapping point, Technical Report (TR) standards, Theft detection, Tightness monitoring, Time of flight, Time profile, Transient, True vapor pressure (TVP), Try and remain hidden, Tuning assistant


Underground erosion


Valve, Vertical scour, Volume balance, Vortex-induced vibration (VIV)


Wall thickness (δ), Wastewater, Waste water, Water Services Regulation Authority (Ofwat), Wet gas, What-if look-ahead




Young’s modulus (E)




Acoustic sensing

Also known as noise correlation, acoustic sensing is a leak detection method which listens to the sound of existing leaks to provide diagnosis. It can be used externally or internally. Learn more.

Adaptive spatial mesh

A feature in pipeline simulation software like Atmos SIM. It enables the user to decide simulation accuracy desired and calculate knot spacing automatically. Learn more.

American Petroleum Institute (API)

National Trade Association representing all segments of America’s oil and natural gas industry to provide Recommended Practice (RP) and Technical Report (TR) standards for pipeline leak detection and incident response. Learn more.

Artificial intelligence (AI)

The intelligence of machines and software which can learn from experience and perform human-like tasks. It is widely used by different industries. In pipeline simulation AI can benefit from large amounts of site data and simulation results. Learn more.

Asset management plan (AMP)

Performance commitments set by the Water Services Regulation Authority (Ofwat) in five-year planning cycles called asset management plan periods. Learn more.


Batch tracking

A technique for ensuring pipeline operators know the head and tail location of every batch in a pipeline with products of different characteristics and the Estimated Time of Arrival. Learn more.


A style of pipeline theft involving the resupply of fuel for use by ships. Learn more.

Basic offshore safety induction and emergency training (BOSIET)

A popular course in the oil and gas industry involving a helicopter safety and escape, dry compressed air breathing system, in water rebreather, sea survival and firefighting and self-rescue training. Learn more.

Benedict-Webb Rubin equation of state (BWRS EOS)

An equation of state used mainly in fluid dynamics. Learn more.

Block valve

An equation of state used mainly in fluid dynamics. Learn more.

Box scheme

An approach used in pipeline simulation, in particular gas pipelines, to achieve a given accuracy. Learn more.


Canada Energy Regulator

Formerly the National Energy Board, the Canada Energy Regulator enforces safety and environmental standards in the region. Learn more.

Capacity evaluation

A technique used to provide operational support to pipeline network operators. Atmos SIM can calculate the accurate capacity of complex gas networks saving time, cost and resource needed to perform the capacity evaluation manually. Learn more.

Carbon capture and storage (CCS)

A way of reducing carbon emissions from industrial processes that would otherwise release large amounts of carbon dioxide (CO2) into the atmosphere. Learn more.


A type of pump or compressor designed to move a fluid by means of the transfer of rotational energy from one or more driven rotors, called impellers. Fluid enters the rapidly rotating impeller along its axis and is cast out by centrifugal force along its circumference through the impeller's vane tips. Learn more.

Class location

An onshore area that covers 200 meters (660 feet) on either side of the centerline of any continuous 1.6 kilometer (1 mile) length of pipeline. Learn more.

Climate change

The long term increase in global average temperature, in part due to human activities. Learn more.

The cloud

The availability of computer system resources which is on-demand. The Cloud can run complex pipeline simulations quickly. Learn more.

Computational pipeline monitoring (CPM)

A term from the American Petroleum Institute to refer to the software based leak detection systems. Learn more.

Concentrator plant

A point in the process of desalinating water where the water is used in mining and slurry operations. Learn more.

Conference of the parties (COP)

A group of nations who have signed the UN Framework Convention on Climate Change (UNFCCC). They typically meet every year to discuss climate change. Learn more.

Control philosophy

A control philosophy that defines the control of pipelines or processes so that they are operated within the boundaries. Pipeline simulators can be used to design the philosophy. Learn more.

Control room

The secure room where all operations are monitored and controlled. In the context of a pipeline operation, a control room is where operators make informed decisions that are critical to safe and efficient pipeline operations. Learn more.


The gradual degradation of metal in a pipeline. Corrosion can be caused by the environmental properties of soil, air and water or fluids transported. Learn more.

Crude oil

A mixture of liquid hydrocarbons. Learn more.


Data acquisition unit

A piece of hardware that collects and stores data from field instruments.

Data manager

The software that collects and manages data from different applications. For example, Atmos Data Manager secures and validates data from distributed control systems (DCSs) and supervisory control and data acquisition (SCADA) systems.


The removal or reduction of carbon dioxide released into the atmosphere.

(US) Department of Transportation (DOT)

A US Government department responsible for planning federal transportation projects. Learn more.


The process of removing mineral salts (or saline) from water. Learn more.

Design specification

A document used during the design phase of a pipeline or process. Learn more.

Distributed control system (DCS)

A computerized control system where controllers are distributed throughout the system. Learn more.

Distribution network

A pipeline system that transfers product from its source to demand areas. For example, a water distribution network is made up of pipelines pumps and storage facilities for water. Learn more.

Doppler flow meter

A flow meter that uses the doppler effect to measure the velocity of a fluid. Learn more.

Double transient

Two separate changes occurring simultaneously in a pipeline operation. Learn more.

Drag reducing agent

A material that reduces frictional pressure loss during fluid flow in a pipeline. Learn more.


When gas pressure drops, it could result in the formation of liquid. In a gas pipeline, increments of flow or a temperature decrease can result in liquid drop-out. Learn more.


Elastic modulus (B)

A metric that measures a material’s resistance to elastic deformation when pressure is applied to it. It can be used to calculate sound speed in a pipeline fluid. Learn more.


The technique of using electricity to convert water into hydrogen and oxygen. Learn more.


The degradation of metal inside a pipeline. For example, hydrogen molecules can be absorbed into pipeline cracks, causing embrittlement. Learn more.

Emergency shut down (ESD)

A procedure that aims to reduce the impact of an emergency by stopping operations. Learn more.


An energy measurement in thermodynamic systems. Learn more.


A measurement for energy degradation. Learn more.

Estimated Time of Arrival (ETA)

The calculated time for a batch or gas composition or gas quality parcel to arrive at a delivery location. It is usually referred to by online pipeline simulation software. Learn more.

Equation of state

A measurement relating a thermodynamic property to two others. In pipelines, the thermodynamic properties dealt with are density, pressure and temperature. Learn more.


Factory acceptance test (FAT)

A project milestone that helps verify the specifications are met within the factory environment. Learn more.

Fatty acid methyl ester (FAME)

A type of fatty acid ester that can be found in multi-product pipelines transporting a range of fuel, from jet-a1 to biodiesel. Learn more.

Fiber optic

A flexible transparent fiber with a range of uses in telecommunication and intruder detection. Fiber optic cables can be laid alongside the pipeline to detect the vibrations caused by human activities, and changes in the event when a theft causes a leak. Learn more.

Finite difference method

An approach used for the solver of a pipeline simulator. Learn more.

Flash flood

A geohazard typically caused by heavy rain that can impact pipeline integrity and lead to leaks. Flash floods are a common threat to pipeline integrity in Latin America. Learn more.

Flow assurance

Coined by Petrobas in the 1990s, flow assurance means “guarantee of flow”. Learn more.

Flow balance (difference)

On pipelines, flow balance is the difference between inlet and outlet flow. It is used to analyze if a pipeline is leaking.

Flow regime (laminar, turbulent)

The flow structure in a pipeline. In a laminar flow regime, pressure drop is proportional to flow rate, whereas in a turbulent flow regime pressure drop is roughly proportional to flow squared. Learn more.


A document used in process design that can help with laying out a pipeline network and finding operating conditions.

Fluid thermal model

A pipeline model that covers fluid flow and energy transfer. Learn more.

Frozen look-ahead

A type of look-ahead scenario that can run in the background of pipeline simulation, predicting survivability if everything in the scenario stays the same as it is in the initial state. Learn more.


Gap analysis

A method of assessing performance that can be used to identify improvement areas. It can be used for pipeline companies in relation to leak detection regulation compliance. Learn more.

Gas composition

Gas composition refers to the hydrocarbon mixture consisting primarily of saturated light paraffins such as methane and ethane. As gas quality is determined by its composition, gas composition tracking is an important feature that Atmos SIM provides. Learn more.

Gas distribution network

A low pressure pipeline network that delivers gas directly to businesses and consumers. 

Gas transmission network

A high pressure pipeline network that delivers gas to local distribution networks, where the product is delivered to businesses and consumers. Learn more.

Gas venting

The controlled release of gas into the atmosphere. Gas venting is one of the main sources of methane emissions and can be caused by purging for works, regular emissions of devices, starts and stops of compressors and unexpected incidents. Learn more.

Gathering lines

Pipelines that are used to transport crude oil, water or natural gas from production site facilities to a central collection point for further processing or distribution. Learn more.


A modern cubic equation of state that is explicitly fit for the behavior of mixtures like hydrogen blends. It is valid for wide ranges of temperature, pressure and composition, and covers mixtures consisting of 18 components: methane, nitrogen, carbon dioxide, ethane, propane, n-butane, isobutane, n-pentane, isopentane, n-hexane, n-heptane, n-octane, hydrogen, oxygen, carbon monoxide, water, helium, and argon. Learn more.


An expanded version of the GERG-2004 equation. The equation is based on 21 natural gas components:  methane, nitrogen, carbon dioxide, ethane, propane, n-butane, isobutane, n-pentane, isopentane, n-hexane, n-heptane, n-octane, n-nonane, n-decane, hydrogen, oxygen, carbon monoxide, water, hydrogen sulfide, helium, and argon.

Greenhouse gas

Greenhouse gases are gases in the earth’s atmosphere that trap heat. Learn more.

Ground thermal model

A pipeline simulation software model that calculates the heat transfer between a pipeline and the ground (ambient). It needs an inner temperature boundary condition at the outer diameter of the pipeline. Learn more.

Groundwater contamination

The result of pollutants entering the ground from a pipeline or process leak and making their way into the groundwater. Learn more.


Heat capacity (𝐶)

The energy it takes to raise the temperature of any substance by one unit. Learn more.

Helmholtz free energy

A thermodynamics concept that measures the useful work obtainable from a closed thermodynamic system. Learn more.

High consequence area (HCA)

The HCA is a location where a pipeline release, such as a leak or rupture, would have significantly more impact on the health and safety of the surrounding area than in other, lower risk locations. Learn more.

Human machine interface (HMI)

A set of screens and views that keep an operator informed, in control and are typically tailored for the pipeline operation team’s needs while complying with stringent standards. Learn more.

Hydraulic profile

The distribution of hydraulic head along a pipeline. A simulation software like Atmos SIM can calculate how the pressure and head varies throughout a pipeline network. Learn more.

Hydraulic simulation

Simulation of flow, pressure, temperature in a pipeline or process. A simulation software like Atmos SIM performs hydraulic simulation in a pipeline. Learn more.


A chemical compound made up of carbon and hydrogen. Hydrocarbons are highly combustible and the main energy source of the world. Learn more.

Hydrogen backbone

The initiative of building a hydrogen infrastructure for decarbonization, based on existing and new pipelines. Learn more.

Hydrogen blend

The integration of hydrogen with natural gas. As hydrogen blends increase, pipeline operators need to be fully aware of the capacity constraints generated by the transportation of hydrogen. Learn more.

Hydrogen colors

Hydrogen colors refer to the type of hydrogen as a way of distinguishing between different production methods. So far there are black or brown, grey, blue, turquoise, pink, yellow, green and white hydrogen. Learn more.

Hydrogen economy

An economy that relies on hydrogen as the commercial fuel that would deliver a substantial fraction of a nation's energy and services. Learn more.

Hydrogen fuel

A clean energy source that can be produced from a variety of production methods (see hydrogen colors definition). Learn more.


Integrated factory acceptance test (IFAT)

A key milestone in projects that aligns components from different vendors to validate and test the connectivity and overall performance of a whole system in the factory. Learn more.

Isentropic bulk modulus (Bs)

A measure of a fluid's compressibility under pressure. It affects the amount of pressure rise that will occur from the fuel pump pulse. Learn more.


Joukowsky equation

Named after Nikolay Zhukovsky, the Joukowsky Equation is a method for performing surge calculations in a way that can be achieved by hand: ∆P = - ρ c ∆V. Learn more.

Joule-Thomson effect

A temperature change in gas caused by a pressure drop. Learn more.


Knot spacing

A pipeline simulation term referring to the minimal length used for hydraulic calculations. A simulation software like Atmos SIM uses adaptive spatial mesh that allows for automatic knot spacing calculations. Learn more.



A term for the geohazard of mud or debris violently flowing down from a volcano. This is a common threat to pipeline integrity in Latin America. Learn more.

Lateral scour

A type of riverbed scour that causes the erosion of the riverbed, which is a common threat to pipeline integrity in Latin America. Learn more.

Leak detection

A system or technology for detecting leaks on pipelines. To achieve maximum efficiency, leak detection systems should detect leaks quickly, locate them accurately, issue minimal false alarms, be easy to retrofit, work effectively under all operating conditions and use sensors with high reliability and low maintenance. Learn more.


The calculated total volume of gas contained inside a pipeline or a segment. Learn more.

Liquefied natural gas (LNG)

A gas that’s been cooled down into liquid form for transportation purposes. Learn more.

Liquefied petroleum gas (LPG)

A hydrocarbon gas that exists in a liquefied form. Learn more.

Look ahead

A simulation software feature that can predict the future of a pipeline system by simulating a variety of potential scenarios. Learn more.

Lowest allowable operating pressure (LAOP)

A stringent minimum pressure limit that pipeline operators are bound by. Learn more.


Machine learning

Computer systems that can learn without following explicit instructions. Atmos Intelligent Optimizer (AIO) applies machine learning (ML) to the accurate hydraulic simulation data from Atmos SIM based on real-time data. Learn more.

Management of Change (MOC)

The best practice and process used when a change is introduced. Learn more.

Maximum allowable operating pressure (MAOP)

A stringent maximum pressure limit that pipeline operators are bound by. Learn more.

Maximum daily quantity (MDQ)

The maximum total amount of oil or gas that is allowed to be delivered into a pipeline system in one day. Learn more.


A main stage in the oil and gas industry that falls between upstream and downstream. It typically involves processing, storage and transportation of petroleum products. Learn more.

Model acceptance test (MAT)

A milestone in a pipeline simulation project where the model is inspected in isolation. Learn more.

Moderate consequence area (MCA)

An area within a potential impact circle (PIC) which has the potential to affect people, property and the environment although not as severely as a high consequence area (HCA). Learn more.

Mono ethylene glycol (MEG)

A colorless, flammable, odorless liquid that is used to prevent formation of hydrates in pipelines. Learn more.


A mixture of fluids that commonly includes either two-phase (oil and water, oil and gas, water and gas) or three-phase (gas, oil and water). Learn more.


National Energy Board (NEB)

Now known as the Canada Energy Regulator (CER), the National Energy Board was an international regulatory agency that oversaw the oil, gas and electric industries. Learn more.

Natural gas liquid (NGL)

Components of natural gas that are separated from the gas state in the form of liquids. Learn more.

Navier-Stokes equation

A partial differential equation that expresses the movement of viscous fluids that can be used in the solver of a pipeline simulation software. Learn more.

Negative pressure wave

The impact of a leak on pipeline pressure. Negative pressure waves propagate in both directions of the pipeline after a leak occurs. Learn more.

Network topology

The geometrical and spatial relations of a pipeline network’s various connections. Learn more.

Net Zero

The push to cut greenhouse gas emissions to zero. Net Zero is a common theme in COP discussions, with COP28 recently discussing the introduction of a hydrogen economy to reduce emissions. Learn more.

Newton-Raphson iteration

A numerical analysis method named after Isaac Newton and Joseph Raphson that involves iteratively refining an initial guess to converge it toward the desired root. Learn more.

Noise correlation

Also known as acoustic sensing, noise correlation is a leak detection method which listens to the sound of existing leaks to provide diagnosis. Learn more.

Nominal flow

The usual flow rate in a pipeline. Nominal flow is typically used in the definition of leak size percentage. Learn more.

Nominations look-ahead

A look-ahead scenario that can provide a forecast of pipeline conditions in response to shippers’ nominations. It’s an exact method, often with varying upcoming flow rates over time. Learn more.



Positioned at sea or some distance away from the shore. Learn more.


Positioned on land. Learn more.


A software that provides optimal solutions for process or pipeline operations. It can recommend pumping schedules, control set-points to help plan operations in advance and ensure bookable capacity is never underestimated or overestimated, among other things. Learn more.


Natural rock containing valuable minerals. Learn more.

Ore extraction

A mining process that involves extracting ore from natural rock. Learn more.


Parametric study

A series of simulations with varying parameters where the parameter range and any constraints can be defined. Learn more.

Pipeline and Hazardous Materials Safety Administration (PHMSA)

A federal regulator for the energy sector in the United States that aims to ensure the safe transportation of pipeline product. Learn more.

Pipeline inspection gauge (PIG)

A solid device that’s inserted into a pipeline with various uses, from monitoring to cleaning and maintenance. Learn more.

Pipeline Integrity Management

A process, program or plan pipeline companies follow that considers all the stages of a pipeline’s lifecycle. Learn more.

Piping and instrumentation diagram

An illustration of the piping and process equipment in a pipeline. Learn more.

Position sensor

A sensor that detects a pipeline object’s location. Learn more.

Positive displacement flow meter

A positive displacement flow meter measures the fluid in discrete volumes.

Positive displacement pump or compressor

A positive displacement pump or compressor is a mechanical device which displaces a known quantity of liquid or gas for every revolution or cycle that the pump or compressor completes. Learn more.

Potential impact circle (PIC)

A circle or radius the same as the potential impact radius (PIR). Learn more.

Potential impact radius (PIR)

The radius of a circle within which the potential failure of a pipeline could have significant impact on people or property. Learn more.

Predictive analysis

An analytical approach that anticipates behavior of a pipeline network so efforts can be made to manage future operations effectively. Learn more.

Pressure distribution analysis

A leak detection method that involves using multiple pressure sensors along a pipeline so that small discrepancies in pressure can be used to identify background leakage. Learn more.

Programmable Logic controller (PLC)

A modular system with customized instructions for performing pipeline or process operations related tasks. Learn more.

Proportional integral derivative (PID) control

A control algorithm used in the process and pipeline industry consisting of three coefficients: proportional, integral and derivative. Learn more.


Quality tracking

The process for monitoring pipeline product quality over time. Simulation software can improve operations planning and efficiency via quality tracking. Learn more.


Rapid transient

Big changes happening in significantly short timescales. Learn more.

Real-time transient model (RTTM)

An online simulation model that calculates flow, pressure and temperature anywhere in a pipeline network based on the measurements of actual flow, pressure and temperature at supply, delivery points and stations. Learn more.

Recommended practice

A document related to pipeline operations that is optional in nature. Learn more.

Recommended standard

A document related to pipeline operations that contains mandatory requirements. Learn more.

Reid vapor pressure (RVP)

A measurement of the volatility of petroleum products in a pipeline. Learn more.

Reliability centered maintenance (RCM)

A highly customized process with a unique approach for each asset tailored to its usage, key component parts, and unique threats to usability. The ultimate goal is to maximize equipment availability while reducing the need to replace assets, thereby reducing costs.

Restraint factor (ϕ)

A metric related to pipe properties in the sound speed calculation for a pipeline fluid. Learn more.

Retention pond

A key location in mining and slurry pipeline operations where wastewater is deposited. Learn more.

Reverse osmosis

The most common desalination process which involves using high pressure to pass seawater over a membrane which filters out the minerals and other contaminants, creating desalinated water. Learn more.

Rich gas

Natural gas containing heavy hydrocarbons. Learn more.

Riverbed scour

Riverbed scour is the erosion of the riverbed (vertical scour) or riverbanks (lateral scour) by flowing water. Learn more.

Remote terminal unit (RTU)

A remote terminal unit collects and distributes data in the field to a SCADA system. Learn more.


A pipeline burst or a large leak. Learn more.



Similar to a pipeline inspection gauge (PIG), this is a solid device that’s inserted into a pipeline with various uses, from monitoring to cleaning and maintenance. Learn more.


A process that can be used to separate products. Learn more.

Sequential probability ratio test (SPRT)

A hypothesis testing method on the inventory compensated volume balance data, to decide between a leak and no-leak scenario on a pipeline. The SPRT calculates the ratio of the probability of a leak over the probability of no-leak and decides if the corrected volume balance has increased with a predetermined probability. Learn more.


When a pipeline operation stops, usually for a temporary period due to maintenance. Learn more.


The process for modeling the hydraulic behavior of gas and liquid in pipelines so pipeline operators can respond to changes quickly and the pipelines are run safely and cost effectively. Learn more.

Single phase

Pipeline fluid containing only one product. Learn more.

Site acceptance test (SAT)

A project milestone where it’s verified that a system meets the requirements of the customer after site installation. Learn more.


A pipeline operating condition where vapor is formed when the pressure falls below vapor pressure of the liquid. Learn more.

Slash and grab

A common type of pipeline theft, which is characterized by poor installations of tapping points, angle grinding the pipeline, larger diameter taps, hitting the pipeline once and not returning and a high risk of pipeline rupture. Learn more.


The buildup of liquid in a gas or multiphase pipeline. Learn more.


Dense solids suspended in liquid in a pipeline. Learn more.


A technique used in simulation software to find a solution to equations numerically. Learn more.

Sour gas

A gas containing substantial amounts of hydrogen sulfide. Learn more.

Sparse matrix

A matrix where most of the values are zero. Learn more.

Spill or Spillage

The release of pipeline or process fluid into the environment. Learn more.

Standard flow

A term for the standard volumetric flow rate used in the pipeline and process industry. Learn more.

Statistical volume balance system

A leak detection solution that detects leaks in pipelines reliably. In 1995, Atmos Pipe was the first statistical volume balance system to be created. Learn more.

Steady state

When the condition of a pipeline or process is unchanged or the changes are minimal over a period of time. Learn more.

Steam reforming

The reaction of hydrocarbons with water to produce hydrogen and carbon monoxide. Learn more.

Supercritical phase fluid (sCO2, ethylene)

A substance at a pressure and temperature higher than its critical point. Learn more.

Supervisory control and data acquisition (SCADA)

A system of hardware and software that assist in the monitoring, controlling and operation of a pipeline. Learn more.

Surge analysis

The process of analyzing the results and impacts of a surge scenario. Atmos SIM can automatically report on surge scenarios. Learn more.

Surge scenario

An incident where there is a pressure surge, such as during an emergency shut down when a valve is closed. Learn more.

Survival time

The length of time a pipeline operation could sustain itself for before the operating constraint is reached eg minimum pressure. Learn more.



Leftover materials after mining ore is processed. Learn more.

Tapping point

The area on a pipeline that has been drilled, either by the pipeline company or illegally by pipeline thieves. Learn more.

Technical Report (TR) standards

Commonly set by API, technical report standards provide guidance on best practices. Learn more.

Theft detection

Hardware and software solutions that are able to detect product theft on pipelines. Learn more.

Tightness monitoring

An aviation solution that monitors for hydrant leaks in airports. Learn more.

Time of flight

The amount of time taken for a product to travel a specified distance in the pipeline. Learn more.

Time profile

Process variable over a period of time defined by the pipeline operator. Learn more.


The result of a sudden interruption in a pipeline, such as during an emergency shut down procedure. Learn more.

True vapor pressure (TVP)

A measurement of liquid mixtures that can be used to simulate slack in a pipeline. It is the highest achievable vapor pressure possible at a specified temperature. Learn more.

Try and remain hidden

An approach to pipeline theft that is popular with organized crime groups. In contrast with the slash and grab approach, this technique is characterized by the slow opening and closing of valves for small pressure changes, using longer hoses, stealing smaller amounts of fuel over longer periods and more. Learn more.

Tuning assistant

A feature in Atmos SIM that can automatically find suitable values to calibrate a pipeline model. Learn more.


Underground erosion

A geohazard where soil is carried away by seeping ground water which causes significant stress changes around the pipeline, impacting the integrity and areas of weakness along the pipeline. Learn more.



A device that controls the movement of fluid in a pipeline. Learn more.

Vertical scour

A geohazard which causes erosion of the riverbed. Learn more.

Volume balance

A leak detection method that calculates the flow difference between inlet and outlet flow to determine if there is a leak. Learn more.

Vortex-induced vibration (VIV)

Pipeline vibrations caused by fast-flowing liquid. Learn more.


Wall thickness (δ)

A metric of the thickness of a pipeline wall. Learn more.


Not to be confused with waste water, wastewater generally refers to municipal wastewater, a focus of Atmos’ as we apply over 25 years’ experience in the oil and gas industry to a multimethod approach to leak detection for the UK water and wastewater industries. Learn more.

Waste water

Not to be confused with wastewater, waste water is concerned more with the industrial effluent or the used water after it’s been used in a manufacturing process. Learn more.

Water Services Regulation Authority (Ofwat)

A UK regulatory body responsible for the economic regulation of the privatized water and sewerage industry in England and Wales. They set performance commitments in five-year planning cycles called asset management plan (AMP) periods. Learn more.

Wet gas

Any gas containing a small amount of liquid. Learn more.

What-if look-ahead

A what if-look-ahead considers what would happen in the transition from current pipeline conditions to a new situation, asking questions around what the impact would be on a pipeline if an event took place, like a compressor tripping or an emergency shut-down. The simulation software provides the answers to the questions. Learn more.



Xylene (C8H10) is a colorless, flammable liquid with a sweet odor.


Young’s modulus (E)

Young's modulus (E) is a property of the material that tells us how easily it can stretch and deform and is defined as the ratio of tensile stress (σ) to tensile strain (ε).