Glossary of Natural Gas Terms
 

 
Arizona Blue Stake (ABS)  – A one-call notification system established by underground facility owners to assist excavators with the statutory requirements to notify them prior to excavation. It is a damage prevention service that is provided free of charge to any individual or company planning to excavate. ABS forwards the notification of proposed excavations to utility owners so that they can provide actual field locations of their facilities. Prior to any type of excavation it is required to notify ABS.

Arizona Corporation Commission (ACC) – Relative to natural gas distribution, the governing body responsible for the enforcement of the Code of Federal Regulations and State regulations. 

Base Pressure – A standard used in determining gas' volumes, expressed in PSIG, ounces of water column or ounces per square inch. 

British Thermal Unit (BTU) – A unit of heat measurement which is defined as the amount of heat required to raise one pound of water one degree Fahrenheit. Processed natural gas typically contains approximately 1,000 BTU/cubic foot.

BTU dry –  A measure of  the heating value of natural gas that is free of moisture, or containing less than 7 lbs. per Mcf of water vapor. Condition under which natural gas is usually delivered for first sales.

Burner Tip – The point at which natural gas is consumed in the customer’s home or business. 

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Cathodic Protection – A method of preventing the corrosion or deterioration of underground pipe and connected equipment, through the control of electrolysis.

Ccf – Abbreviation for 100 cubic feet of natural gas.

City Gate – The point or measuring station at which a gas distribution utility receives natural gas from the pipeline transmission company.

Commodity Charges – The charges for basic gas supply service which is sold by volume or heating value.   

Cubic Foot – The most common unit of measurement of gas volume. It represents an area one foot long, by one foot wide, by one foot deep. In the measurement of gas supplied and metered to customers at standard delivery pressure, a cubic foot of gas is the volume of gas which, at the temperature and pressure existing in the meter, occupies one cubic foot.  

Customer Charge – A monthly charge to cover the City of Mesa’s  operating and maintenance costs such as:  maintaining the gas lines, meter reading, and billing.  

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Dekatherm (Dth) – A measure of the heat content value of gas. Gas usage is determined by multiplying the Mcf used by the heat content value of the gas.

Department of Energy (DOE) – The main government agency responsible for regulating many energy sources, gas included. 

Department of Transportation (DOT) – The federal agency responsible for pipeline safety programs and rulemaking procedures.

Distribution Charges – The charges for the delivery of natural gas from the point of receipt on the El Paso Pipeline into the City of Mesa Distribution System.

Distribution System – The mains, service connections, and equipment operated by a distribution company to carry or control the supply of natural gas from the point of local supply to and including the gas meter.  

Federal Energy Regulatory Commission (FERC) – Federal commission that regulates the fairness and legalities of the pipelines and the pipeline companies across the United States. 

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Gas Cost Adjustment Charge – The amount billed or credited each month to account for differences between projected and actual gas supply costs of the City of Mesa Distribution System. 

Gas Main – A gas pipe owned, operated or maintained by a gas company. 

Gas Odor – All gas supplied to customers has a distinctive odor to act as an indicator to its presence. Any gas that does not naturally have such an odor must have an odorant added to it. See mercaptan. 

Gas Service Line – The piping and equipment that connect a gas main with the inlet connections of a gas meter on a customer’s premises. 

Generation –The process of producing electric energy by transforming other forms of energy such as steam, heat or falling water. Also, the amount of electric energy produced, expressed in kilowatt-hours (kWh) or megawatt-hours (mWh).

Gross Generation – The total amount of electric energy produced by the generating units at a generating station or stations, measured at the generator terminals.

Net Generation – Gross generation less the electric energy consumed at the generating station for station use.

Interstate Delivery – A national network of pipelines that bring natural gas into a particular region.  

Interstate Pipeline – A pipeline that transports gas across state lines. Interstate pipelines are regulated by the Federal Energy Regulatory Commission. 

Leakage – Volume of gas lost through holes in pipes or fittings, bad joints, or broken pipes or fittings. 

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Load – The rate of natural gas from one point to another. As contrasted with service piping, mains generally carry larger volumes for general or collective use.

Lower Explosive Limit (LEL) – The minimum percentage of fuel required for combustion. The LEL standard is 5% gas in air.

Local Distribution Company (LDC)  – A natural gas utility company that delivers natural gas directly to the consumer. The City of Mesa is an LDC. 

Maximum Allowable Operating Pressure (MAOP) – the maximum gas pressure at which a piping system is allowed to operate. 

Mcf – Abbreviation for 1,000 cubic feet of natural gas (See Dekatherm Dth).   

Mercaptan – the chemical odorant added to natural gas to create a distinct odor for identification purposes (See gas odor). 

Meters – Devices used to measure and record the usage of natural gas. Typical types are orifice, positive displacement, rotary and turbine. 

Methane (CH4) – the simplest hydrocarbon and the primary constituent of natural gas. It is colorless, odorless and flammable. 

Mmcf – Abbreviation for one million cubic feet of natural gas. 

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Natural Gas – A naturally occurring mixture of hydrocarbon and non-hydrocarbon gases found in porous geological formations beneath the earth’s surface. The principal component is methane. Often associated with petroleum.

Odorization – The placing of malodorant, such as mercaptan, in natural gas for the purpose of detecting its presence. This is especially helpful for reporting and investigating possible leakage. 

Pipeline – Piping designed to deliver larger volumes of natural gas over great distances. They are usually operated by gas transmission companies and often are larger diameter pipes operating at high pressure. The City of Mesa city gates receive natural gas from the El Paso Pipeline Company.

Pressure Regulator – Device used to reduce and maintain a constant pressure to a piping system.

Pressure Regulating System – Consists of equipment installed for the purpose of reducing and regulating pressure to natural gas mains. The City of Mesa has, at this time, 76 regulator stations in its system. 

Relief Valve – Over-pressure protection device designed to exhaust excess natural gas pressure to atmosphere and prevent piping from operating above the MAOP. 

Therm – A unit of heating value equivalent to 100,000 British thermal units (BTU). (.01 MMBtu)   

Unaccounted For Gas – The difference between the amount of natural gas delivered to a pipeline for transportation and that redelivered by the pipeline, taking into account fuel, plant shrinkage, and imbalances. Differences include leakage or other actual losses, discrepancies due to meter inaccuracies, variations of temperature and/or pressure, and other variants, particularly billing lag. Pipelines typically levy a charge of a portion of each shipper's natural gas to cover losses.

Upper Explosive Level (UEL) – The maximum percentage of fuel that will allow combustion. The UEL standard is 15% gas in air.   

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