2-PSIG Gas Piping System	:A gas piping system that utilizes 2-psig pressure downstream of the point of delivery. This type of gas piping system allows greater versatility in the design of branch systems and in a multi-family building that could reduce the cost of installing the piping system when compared to the traditional 1/4 psig system.
Abandoned Well	:A well not in use because it was a dry hole originally, or because it has ceased to produce. Statutes and regulations in many states require the plugging of abandoned wells to prevent the seepage of oil, gas, or water from one stratum to another.
Abandonment	: Regulatory authorization for a utility to cease provision of a particular service and/or to shut down a particular facility.
Abandonment Costs	: Costs associated with the abandonment of facilities or services, including costs for the removal of facilities and restoration of the land.
Abbreviated Application	: An abbreviated application for a certificate of public convenience and necessity that may be filed under Section 7 of the NGA whenever the proposed action does not require all of the data and information normally filed in a certificate application in order to disclose fully the nature and extent of the proposed undertaking.
Above the Line	: See BELOW THE LINE.
Absolute Open Flow (AOF)	: The number of cubic feet of gas per 24 hours that would be produced by a well if the only pressure against the face of the producing sand in the well bore were atmospheric pressure.
Absolute Pressure	: Gauge pressure plus barométrie pressure. Absolute pressure can be zero only in a perfect vacuum.
Absolute Viscosity	: The measure of a fluid's tendency to resist flow, without regard to its density. By definition, the product of a fluid's kinematic viscosity times its density.
Absolute Zero	:The zero point on the absolute temperature scale. It is equal to -273.16 degrees C, or 0 degrees K (Kelvin), or -459.69 degrees F, or 0 degrees R (Rankine).
Absorbent	:A material which, due to an affinity for certain substances, extracts one or more such substances from a liquid or gaseous medium with which it contacts, and which changes physically, or both, during the process.
Absorption	: The extraction of one or more components from a mixture of gases when gases and liquids are brought into contact. The assimilation or extraction process causes (or is accompanied by) a physical or chemical change, or both, in the sorbent material. Compare ADSORPTION.
Absorption Plant	: A device that removes hydrocarbon compounds from natural gas, especially casinghead gas. The gas is run through oil of proper character, which absorbs the liquid constituents, which are then recovered by distillation.
Absorption Refrigerating System	: See REFRIGERATING SYSTEM, ABSORPTION.
Absorption Type Air Conditioner, Direct Fired	: A self-contained device which provides cooling by direct application of heat.
Accelerated Cost Recovery System (ACRS)	: A depreciation system enacted as part of the Economic Recovery Tax Act of 1981 that allows rapid depreciation of assets for tax purposes. It was repealed in the Tax Reform Act of 1986.
Acceptance for Filing (of a Rate Schedule)	: Commission action by which a rate schedule is accepted for filing and becomes a legal rate schedule when made effective by the Commission.
Acceptance Test	: An investigation performed on an individual lot of a previously qualified product (e.g., plastic pipe) by, or under the observation of, the purchaser to establish conformity with a purchase agreement stipulating specified requirements.
Accrual	: The recording on the books of account, in a given period, of expenses or charges incurred and/or of income earned for the period, to reflect the matching of income and expenses to the fullest extent possible, independent of the dates on which settlements of such items are made.
Accumulated Deferred Income Taxes	: Account(s) shown on a corporation's balance sheet, typically a net liability, that represents a future (deferred) claim by the government against the corporation's assets. Deferred income taxes arise from the use of accelerated or liberalized depreciation for tax purposes instead of straight-line or other non-liberalized depreciation methods used for book purposes, and from other temporary differences in the recognition of revenue and expense items for income tax purposes and for financial reporting purposes.
Accumulated Provision for Depletion	: The net accumulated credit resulting from offsetting charges to income for the pro-rata cost of extracted depletable natural resources such as coal, gas, oil, etc.
Accumulated Provision for Depreciation and Amortiz	: The net accumulated credit balance arising from provisions for depreciation and/or amortization (both defined herein) of assets, usually utility plant and non-utility property. The net balance reflects current and prior credits less charges but is not a measure of actual depreciation.
Acetone test	: A process control test for PVC pipe which indicates how well the rigid vinyl compound has been fused together in the extruder. Improperly fused pipe will tend to flake when placed in anhydrous acetone.
Achievable Potential	: In DSM, an estimate of energy savings based on the assumption that all energy-efficient options will be adopted to the extent that they are cost-effective and possible through utility DSM programs. Compare ECONOMIC POTENTIAL, MARKET POTENTIAL and TECHNICAL POTENTIAL.
Acid Gases	: Gases that produce an acidic solution when dissolved in water. Examples of such compounds, often found in natural gas, are hydrogen sulfide and carbon dioxide.
Acid Rain	:Abnormally acidic rainfall, most often containing dilute concentrations of sulfuric acid or nitric acid.
Acidizing	: The practice of applying acids to the walls of oil and gas wells to remove any material which obstructs the entrance of fluids. Also used in carbonate formations, such as limestone, to increase porosity.
Acquisition Adjustments	:See ORIGINAL COST, HISTORICAL COST
Acre Feet of Water	: The volume of water that would cover one acre to a depth of one foot, or 43,560 cubic feet of water, or 325,841.1 gallons of water.
Acre Foot	: A unit of measurement applied to petroleum and natural gas reservoirs. It is equivalent to an acre of producing formation one foot thick.
Acrylonitrile-Butadiene-Styrene (ABS)	:Plastics containing polymers and/or blends of polymers, in which the minimum butadiene content is 6%, the minimum acrylonitrile content is 15%, the minimum styrene and/or substituted content is 15%, and the maximum content of all other monomers is not more than 5%, and lubricants, stabilizers, and colorants.
Acrylonitrile-Butadiene-Styrene (ABS) Pipe and Fit	:Plastics that contain more than 50% ABS polymers, more than 5% of other polymers, and lubricants, stabilizers, and colorants.
Action Plan	: A component of IRP, describing utility actions in the short-term (about two years) to meet the supply and demand objectives of the integrated resource plan.
Actual Cost	: In rate base determination. See ORIGINAL COST, HISTORICAL COST, WEIGHTED COST.
Ad Valorem	:Taxes imposed at a percent of a value.
Adaptor Plate, Instrument	:A specially designed plate mounted between a meter and an instrument to provide for a proper drive to the instrument.
Additions to Utility Plant	: a. Gross Additions - Expenditures for construction (including Allowance for Funds Used During Construction) and/or utility plant purchased and acquired. b. Net Additions - Gross additions less retirements and adjustments of utility plant. It is the net change in utility plant between two dates.
Adhesive	: A substance capable of holding materials together by surface attachment.
Adhesive, Solvent	: An adhesive having a volatile organic liquid as a vehicle. See SOLVENT CEMENTING.
Adiabatic	: A term indicating that no heat is lost or gained by a material being subjected to a thermodynamic process. An adiabatic process is one in which there is no exchange of heat with the surroundings.
Adjustment Clause	: See CLAUSE, ADJUSTMENT.
Administrative Law Judge (ALJ)	:The officer designated by the FERC to conduct the proceedings in a rate or other tariff filing.
Adsorption	:The extraction from a mixture of gases or liquids of one or more components, by surface adhesion to that material with which the gases or liquids come in contact. The adsorption or extraction process does not cause and is not accompanied by either a physical or chemical change in the sorbent material. Compare ABSORPTION.
Advance Payments	:Amounts paid by interstate gas pipelines to natural gas producers, including affiliated companies, for exploration, development, or production of natural gas, which amounts were to be repaid in cash or by future delivery of gas. During a brief period during the 1970s the Commission allowed such advances to be included in the pipeline's rate base (with adjustments when repaid) and hence to be recovered by the pipeline through its cost of service. The purpose of the advance payments was to induce producers to sell natural gas at regulated prices to the interstate pipelines, rather than at higher, unregulated prices to intrastate pipelines.
Advances for Construction	:A deferred credit account representing cash advances paid to the utility by customers requiring the construction of facilities in their behalf. These advances are refundable -- the time or extent of refund is dependent on the contract provisions of the advance (usually dependent on whether or not during a specified period the revenue from the installation warrants the refund). The unrefunded balance, if any, must be transferred to the appropriate plant account. Compare CONTRIBUTIONS IN AID OF CONSTRUCTION.
Affiliated Entities Test	:A test to determine if the amount paid for gas to an affiliate exceeds the amount paid in comparable first sales between non-affiliated entities.
Affiliated Marketer	:A marketer that is owned either by a distribution or transmission company, or by a corporation that also owns a distribution or transmission company.
After-Cooling	:The process of cooling a compressed air or gas immediately after compression.
AFUDC	:See ALLOWANCE FOR FUNDS USED DURING CONSTRUCTION.
Age Interval	:A standard period of time, usually one year. A series of such consecutive intervals facilitates observing the pattern of survivors and developing the survivor curve. Age interval should not be confused with calendar year.
Agent	:A legal representative of buyers, sellers or shippers of natural gas in negotiation or operations of contractual agreements.
Aging	: Effect on materials in service of exposure to an environment for an interval of time.
Agreement and Undertaking	: A document which an independent gas producer may be allowed to file, at the discretion of the Commission, in lieu of a bond, agreeing to refund that portion of an increased rate which has been made effective subject to refund and is ultimately found not justified by the Commission.
Agreement on Principles	:The Agreement between the United States of America and Canada on the ALASKA NATURAL GAS TRANSPORTATION SYSTEM (ANGTS). The agreement was signed by representatives of the two governments on September 20, 1977.
Air Change	:A method of expressing the amount of air infiltration and/or ventilation of a building or room in terms of the number of building volumes or room volumes exchanged per unit of time.
Air Conditioner, Room	: A factory-made encased assembly, designed as a unit for mounting in a window, through a wall, or as a console, for the purpose of delivering conditioned air to an enclosed space without ducts.
Air Conditioning	: The process of heating, cooling, humidifying, filtering, drying, deodorizing, or otherwise treating air in a room or building to maintain a specified temperature and/or relative humidity and to remove impurities.
Air Conditioning Central	:A mechanical system that is designed to provide air conditioning, which may include cooling, heating, dehumidifying, circulation and cleaning. The air is treated by the conditioner at one or more central locations outside the space served and conveyed to and from the space by means of fans and pumps through ducts and pipes.
Air Diffuser	: An air delivery device or louver so arranged as to promote mixing of the air introduced by it into a room with the room air, without causing objectionable drafts or noise.
Air Heater	: Combustion air (fed to burners) can be heated to approximately 500 degrees F by transferring heat from the flue gases to the air.
Air Receiver	: A storage tank for compressed air.
Air Shutter	: An adjustable device for varying the primary air inlet(s) regulating primary or secondary air.
Air-Gas Ratio	: The ratio of the air volume to the gas volume. A specified ratio is necessary to achieve a desired character of combustion.
Alaskan Natural Gas Transportation System (ANGTS)	: A proposed pipeline system to transport gas from the Prudhoe Bay field in Alaska to the vicinity of Chicago and San Francisco through Canada. Portions from Canada towards San Francisco (the Western Leg) and from Canada towards Chicago (Northern Border Pipeline) were "prebuilt" to import gas from Canada prior to the flow of Alaskan gas. The project was authorized by the ANGTA of 1976 and the President's Decision and Report to Congress in September 1977.
Aliphatic	:Hydrocarbon that does not contain an aromatic ring structure. See AROMATIC.
Allocated Pool	: A pool in which the total oil or natural gas production is restricted and allocated to various wells therein in accordance with proration schedules.
Allocation	: The process of determining ownership rights to the gas delivered to a meter.
Allocation Method	: A method of allocating volumes to affected parties when an imbalance occurs.
Allocation-Capacity	:A process by which capacity available in a pipeline is distributed to parties in the event requests for volume (i.e., nominations) are in excess of the available space. Typically the allocation is based on service type, contract type and a company's tariff provisions. Also called NOMINATION ALLOCATION.
Allocation-Measurement	:The assignment of a total measured quantity of gas at a point to the various contracts active at that point during a specific period of time.
Allocation-Supplies	: The process by which supply is assigned to purchasers in accordance with a given priority during periods when total sales requests exceed the seller's total supply.
Allocation-Supplies to End-Use Customers	:The amount of gas supply available to the customer in accordance with a given priority during periods of curtailment. See COST OF SERVICE, DESIGN DAY AVAILABILITY.
Allowable Working Stress	:The maximum hoop stress permitted by code for the design of a piping system. See HOOP STRESS.
Allowables	: The permitted rate of production from a well or group of wells that is allowed by a particular state or governing body. The rate is set by rules which vary among the various states or governing bodies.
Allowance for Funds Used During Construction (AFUD	:AFUDC is a component of construction costs representing net cost of borrowed funds and a reasonable rate on other funds used during the period of construction. AFUDC is capitalized until the project is placed in operation by concurrent credits to the income statement and charges to utility plant, based generally on the amount expended to date on the particular project. Effective January 1, 1977, FERC amended the Uniform System of Accounts establishing formulas for maximum allowable AFUDC rates.
Allowed Rate of Return	:The rate of return that a regulatory commission allows on a rate base in establishing just and reasonable rates for a utility. It is usually based on the composite cost of financing rate base from debt, preferred stock, and common equity. See RATE OF RETURN.
Alternate Fuel Capability	: The ability to use an alternate fuel whether or not the facilities for such use have actually been installed.
Alternate Fuels	:Other fuels that can be substituted for the fuel in use. In the case of natural gas, the most common alternative fuels are distillate fuel oils, residual fuel oils, coal and wood.
Amagat's Law	:See LAWS.
Ambient Vaporizer	:A vaporizer which derives energy for vaporizing and heating LNG from storage conditions to send out conditions from naturally occurring sources such as the atmosphere, sea water, or geothermal waters.
American Gas Association (AGA)	:Trade group representing natural gas distributors and pipelines.
Amorphous	:Devoid of crystallinity. Most plastics are in the amorphous state at processing temperatures; many retain this state under normal conditions.
Amortization	:The gradual extinguishment (or accumulated provision or reserve therefor) of an amount in an account by pro-rating such amount over a predetermined period, such as
Anemometer	:An instrument for measuring the velocity of wind.
Annealing	:A process involving controlled heating and subsequent controlled, generally slow, cooling applied usually to induce ductility in metals. The term also is used to cover treatments intended to remove internal stresses, alter mechanical or physical properties, produce a definite microstructure, and remove gases.
Annealing, Bright	:A process which is usually carried out in a controlled furnace atmosphere so that metal surface oxidation is eliminated or reduced to a minimum, and the surface remains relatively bright.
Annual Fuel Utilization Efficiency (AFUE)	:AFUE measures average annual seasonal efficiency of a gas furnace or boiler and may be expressed as total heating output divided by total energy (fuel) input. AFUE's for furnaces can range from 55% to 97%.
Annual Gas Consumption (Sales) Per Customer (By Cl	:Average annual sales used per customer in Btu's or therms by class of service; annual Btu's or therms sales to a class divided by the average number of customers for that class of service.
Annual Gas Revenue Per Customer	:Annual revenue exclusive of forfeited discounts and penalties from a class of service, divided by the average number of customers in that class of service.
Annual Volume Method	:A method to allocate commodity costs by function to customer classes based on the Test Period volume level for that customer. See COST OF SERVICE.
Annualization	: To adjust to a full-year basis any item not included in the Base Period or included in the Base Period for less than a full year. Also called KNOWN CHANGE ADJUSTMENTS.
Anode, Sacrificial