Back Pressure
Pressure against which a fluid is flowing. May be composed of friction in pipes, restrictions in pipes, valves, pressure in vessels to which fluid is flowing, hydrostatic head, or other resistance to fluid flow.
Earth or other material which has been used to refill a ditch or trench. Also, the act of refilling a ditch or trench.
A transaction that results in the transportation of gas in a direction opposite of the aggregate physical flow of gas in the pipeline. This is typically achieved when the transporting pipeline redelivers gas at a point(s) upstream from the point(s) of receipt. A backhaul condition will exist as long as the aggregate backhaul transactions total less than the aggregate forward haul transactions. A backhaul transaction can result in a delivery by non-delivery or cut back (reduction) of physical flow at a delivery point.
Badge, Meter
A permanent plate, affixed in a conspicuous place on a meter, containing basic meter information.
Plates, louvers, or screens placed in the path of fluid flow to cause change in the direction of flow; these are used to promote mixing of gases or to eliminate undesirable solid or liquid particles in the fluid stream. Sometimes baffles are inserted in a flue to lengthen the travel of flue gases and increase efficiency of operation.
Bag Hole
A hole cut into a main in preparation for a bag-off.
Inflatable bags and stoppers placed in a main to seal off gas flow.
A device used in cable tool drilling to remove drill cuttings from a well. It consists of a simple tube suspended on a cable, open at the top, with a foot-valve at the bottom. The foot-valve opens when the bailer touches the bottom of the drilled hole, permitting water with drill cuttings in suspension to enter the tube. When the bailer is raised to be emptied, the foot-valve closes instantly as it loses contact with the bottom of the hold and retains the water and drill cuttings.
Balance, Gas
An instrument used for determining the specific gravity of gases.
Making receipts and deliveries of gas into or withdrawals from a company equal. Balancing may be accomplished daily, monthly or seasonally, with penalties generally assessed for excessive imbalance.
Balancing Agreement
A contractual agreement between two or more legal entities to account for differences between chart measured quantities and the total confirmed nominated quantities at a point. They have been used to keep track of over/under production relative to entitlements between producers; over/under deliveries relative to confirmed nominations between operators of wells, pipelines and LDCs.
Balancing Penalty
A daily or monthly penalty assessed on the difference between volumes tendered and volumes received by the shipper. The purpose of balancing penalties is to prevent a shipper from tying up storage and line pack with excess deliveries of transportation gas, or from depleting storage and line pack by taking more gas off the system than it delivers, both of which disrupt other sales and transportation services.
Balancing Provisions
A requirement that gas entering a pipeline for transportation (receipts) must equal the amount leaving the pipeline (deliveries). This requirement is enforced by levying penalties on any difference between receipts and deliveries on an hourly, daily and monthly basis.
Balancing Units
The unit of measure used for the purpose of balancing the amount of gas received by transporter at the transporter receipt point(s) with the amount of gas delivered by transporter for shipper's account at the transporter delivery point(s). The Balancing Unit shall be reported in MMBtu's which shall be determined by multiplying each Mcf of dry gas so received or delivered by the dry heating value thereof.
Band Clamp
Bar Hole
Small diameter hole made in the ground in the vicinity of gas piping for the purpose of extracting a sample of the ground atmosphere for analysis such as when searching for leaks.
Bar Test Survey (For Gas Mains)
Leakage surveys made by driving or boring holes at regular intervals along the route of an underground gas pipe and testing the atmosphere in the holes with a combustible gas detector or other suitable device.
Instrument used for measuring atmospheric pressure.
Barrel (Oil)
A volumetric unit of measurement equivalent to 42 U.S. gallons, 9,702 cubic inches, 5.6146 cubic feet, 34.9722 Canadian Imperial gallons, 158.99 liters, or .15899 cubic meters. It is the unit of measurement commonly used to measure oil production and oil reserves within the U.S.
Base Conditions
The ANSI Z132 has established 60oF and 14.73 psia as the base temperature and pressure to which all volumes are commonly referred.
Base Contract Price
The stated per unit price for natural gas in a contract between a producer and a purchaser.
Base Cost of Gas
The component in the BASE TARIFF RATE which represents the average cost of purchased gas.
Base Gas
The gas required in a storage reservoir to provide the pressure to cycle the normal working storage volume. See also CUSHION GAS: STORAGE, UNDERGROUND.
Base Load
As applied to gas, a given consumption of gas remaining fairly constant over a period of time, usually not temperature-sensitive.
Base Load, Residential
The gas consumed by clothes dryers, water heaters, ranges and cooling. Base load does not vary with heating degree-days.
Base Period
Recently available 12 consecutive months of actual experience. Not always the most recent 12 months. In a rate proceeding, 12 months of actual operations ending no more than 4 months before the date a rate change application is filed. In reference to the EQUITABLE SHARING MECHANISM, a representative base period must reflect a representative level of purchases by a pipeline's firm customers during a period preceding the onset of changed conditions which resulted in reduced purchases and growth of the take-or-pay problem. See EQUITABLE SHARING MECHANISM, DEFICIENCY PERIOD, PURCHASE DEFICIENCY METHODOLOGY and TEST PERIOD.
Base Pressure
The pressure used as a standard in determining gas volume. Volumes are measured at operating pressures and then corrected to base pressure volume. Base pressure is normally defined in any gas measurement contract. The standard value for natural gas in the United States is 14.73 psia, established by the American National Standards Institute as standard Z-132.1 in 1969.
Base Pressure Index
A device which continuously and automatically compensates to correct gas volume at operating pressure to volume at base pressure, without regard for any correction for temperature.
Base Tariff Rate
The effective rate on file with the Commission, excluding adjustments. It is the rate level established in a general Section 4 rate proceeding or Section 154.303(e) base rate restatement proceeding.
Base Volume Index
A device which continuously and automatically compensates to correct gas volumes measured at operating temperature and pressure to volume at a specified base temperature and pressure.
Baseboard Radiator
A heat disseminating unit located at the lower perimeter of a room. Heat is supplied to these units by hot water, warm air, steam, or hot flue gases.
Basic Air or Gas Time
The time required to pass one cubic foot of air or gas through a given orifice in a flow prover at stated base conditions. This time is stamped on the prover orifice in seconds.
Beam Loading
The application of a load to a pipe between two points of support.
Behind the Pipe
Potentially producing reserves of oil or gas that have been penetrated by a well bore but are separated from the well bore by casing (pipe) and cement and hence cannot be produced without recompleting the well. If the zone penetrated is known to be productive (by tests or production elsewhere) the reserves are classified as proven but non-producing.
Bell Hole
A hole dug to allow room for workmen to make a repair or connection in buried pipe, such as caulking bell-and-spigot pipe or welding steel pipe. In the broad sense, any hole other than a continuous trench opened for working on a buried facility.
Bell Joint Clamp
A sealing device attached at the joint of bell-and-spigot pipe to prevent leakage.
Bell-and-Spigot Pipe
Pipe made with a cup-like flare at one end (the bell) and plain at the other end (the spigot). The spigot fits into the bell and the joint is sealed with a solvent cement or adhesive (in the case of plastic pipe) or packed with caulking, lead, and/or other material in the cast iron pipe annulus.
Below the Line vs Above the Line
A decision that is made to determine whether an item should be included in cost of service for establishing rates (above the line) or should not be included (below the line). The "line" referred to is utility net operating income on the income statement. "Above the Line" refers to revenues collected for and costs included in providing utility service.
Benefit-Cost Ratio
The ratio of the value of a measure's savings to its cost.
Best Available Control Technology (BACT)
A concept taken from the Clean Air Act designed to preserve air quality from degradation by requiring that emissions from new facilities, temporary facilities, and even existing facilities in some instances be controlled to the extent possible using the best available technology.
Best Efforts
An agreement by a contracting party to do its best to complete some specified result. In a gas transportation contract, it might represent a pledge by the transporter to use best efforts to transport the shipper's gas. BESS is the acronym for best efforts storage service.
A substantial enlargement or improvement of existing structures, facilities, or equipment by the replacement or improvement of parts, which has the effect of extending the useful life of the property, increasing its capacity, lowering its operating cost, or otherwise adding to the worth through the benefit it can yield.
Beveled pipe ends are for welding purposes. Pipe which is cut at an inclination so that two ends form an angle other than a right angle.
Bi-Monthly Billing
A customer billing procedure in a distribution company where bills are rendered every month, but meters are read every other month. An estimate is made of the volume of gas used in months when meters are not read.
Bill Frequency Analysis
A tabulation of bills by size (consumption) and type of service rendered.
Billing Cycle
The regular, periodic interval used by a utility for reading the meters of customers for billing purposes. Usually billing cycles are monthly or bi-monthly.
Billing Determinant
The demand which is used to determine demand charges in accordance with the provisions of a rate schedule or contract. It does not necessarily coincide with the actual measured demand of the billing period.
In a reinforced plastic, the continuous phase which holds together the reinforcement. NOTE: During fabrication, the binder which may be either thermoplastic or thermoset, usually undergoes a change in state.
Methane produced by the decomposition or processing of organic matter.
Biologically produced organic matter.
Biomass Conversion
Process by which biomass materials are burned for direct energy or by which such materials are converted to synthetic fuels.
Bit, Drilling
A drilling tool that cuts the hole in the earth when drilling a well. Bits are designed on two basic and different principles; the cable tool bit, which moves up and down to pulverize; and the rotary bit which rotates to cut or grind.
Bituminous Coal
Ranking of soft coal generally having a heating value of 11,000-13,000 Btu/lb., high in volatile matter and ash.
Black Steel Pipe
Ordinary steel pipe, not galvanized.
Blanket Certificate
Authorizes open access transportation by interstate pipeline companies on behalf of others and certain services by local distribution companies and Hinshaw companies under blanket certificates (of public convenience and necessity) subject to certain conditions and reporting requirements. Blanket certificates pre-grant authority for abandonment of the transportation service upon expiration of the contractual term.
Blanket Transportation Certificate
A certificate that allows a pipeline to undertake individual transportation transactions without prior FERC approval. The pipeline is required to file periodic reports with respect to each such transaction.
Insertion of a solid metal disc between the companion flanges of a flanged joint.
Blind Flange
A solid plate used to close off the end of a piping system or a device constructed with flanged ends.
Block Valve
Main transmission line valve designed to close in or shut down gas flow.
Blow Down
The process of reducing gas pressures by means of releasing such pressures to atmosphere.
Blow Joint
Perforated joint of line pipe designed to capture "pig" after pigging and cleaning operations.
Blow-off Valve
Valve used to blow pressure off the pipeline. Also used in purge.
A device for forcing air or gas to flow in the desired direction at the required pressure. It may be either fan, centrifugal, or positive displacement type.
Blue Gas
Boil Off
A natural phenomenon which occurs when liquefied natural gas in a storage vessel warms to its boiling point and gases evolve.
A closed vessel in which a liquid is heated and/or vaporized. Often classified as to steam or hot water, low pressure or high pressure, capable of burning one fuel or a number of fuels.
Boiler Efficiency
The ratio of the useful heat output to the heat input, multiplied by 100 and expressed in percent.
Boiler Fuel Gas
Natural gas used as a fuel for the generation of steam (or hot water).
Boiler Pressure
The pressure of the steam of water in a boiler, depending on type, generally expressed in pounds per square inch gauge and corresponding temperature.
Boiler Rating
The rating of a steam boiler expressed as the total heat transferred by the heating surfaces in Btu per hour. Sometimes expressed in horsepower or pounds of steam per hour.
Boiler, High Pressure
A boiler furnishing hot water at pressures in excess of 160 pounds per square inch (psi) and at temperatures in excess of 250oF (121oC) or steam at pressures in excess of 15 psi.
Boiler, Low Pressure
A boiler furnishing hot water at pressures not exceeding 160 pounds per square inch (psi) and at temperatures not more than 250oF (121oC) or steam at pressures not more than 15 psi.
Boiling Point
The highest temperature that can be reached by a liquid, under a given pressure, when heat is applied externally and evaporation occurs freely from the surface.
Bond Ratings
Rating systems which provide investors with a simple series of gradations by which the relative investment qualities or risks of bonds are indicated. Moody's Investors Service and Standard & Poor's Corporation are two principal bond rating agencies.
Bond Yield Risk Differential (BYRD)
Bonds (Mortgage)
Certificates of indebtedness representing long-term borrowing of capital funds, the terms of which contain an indenture pledging the property as security for the loan and providing for the appointment of a trustee to represent the bondholders. If the lien of the mortgage is limited to specific property owned at the time the mortgage was created and to replacements thereof, the mortgage is described as "closed." If the lien extends to "after acquired" property which may be used as the basis for issuance of additional bonds under the terms and provisions of the indenture, the mortgage is referred to as an "open-end" mortgage.
Book Cost
The amount at which property is recorded in plant accounts without deduction of related provisions for accrued depreciation, depletion, amortization, or for other purposes.
Book Value
The recorded plant cost less the accumulated depreciation.
Book Value per Share of Common Stock
Common stock equity divided by the number of common shares outstanding at the date of the computation.
Boom Cat
A tractor equipped with a boom used in laying pipe.
A compressor used to raise pressure in a gas or oil pipeline.
Booster Station
A facility containing equipment which increases pressure on oil or gas in a pipeline.
Boston Box
A square box installed flush with the pavement.
A gas-tight container fabricated from pipe or plate with integral drawn, forged, or spun end closures, tested in the manufacturer's plant, used for storing or transporting gas.
Bottle, Cubic Foot
A specially constructed device for calibrating bell provers. The bottle is designed to displace exactly one cubic foot of air when immersed in a tank containing light oil.
Bottled Gas
In the industry, liquefied petroleum gas contained under moderate pressure in cylinders, sometimes referred to as bottles. Usually propane and/or butane.
Bottom Gas
The quantity of gas that is not normally recovered from storage field operation. The same as BASE GAS, or CUSHION GAS.
Bottom Hole (Rock) Pressure
The pressure at the bottom of a closed-in well.
Bottom Hole Contract
A contract providing for the payment of money or other consideration upon the drilling of a well to a specified depth.
Bottom-Cycle Plants
An energy system which produces heat first for process use and electricity as a by-product.
The liquid or other residual matter that is withdrawn from the bottom of a fractionator or other vessel during processing or while in storage; also, the heaviest product remaining in the liquid phase after distillation.
Bourdon Tube
An arc-shaped, spiral, or helical metal tube that is approximately elliptical in cross-section and has one end attached to a pressure indicating, controlling, or recording device, while the other end is fixed. Pressure changes inside the tube affect its shape and actuate the device to which it is attached.
Boyle's Law
A packer (or fitting) installed on a well at the surface that enables the use of one size pipe inside another, for the subsequent control of products being delivered from either one of the two pipes.
Bradenhead Gas
Branch Connection
The junction of one pipe with another, often a header.
Branch Line or Take Off
That portion of a supply line which takes off the main header from the location of a tee on the main header.
A passageway, usually constructed of sheet metal, to conduct the flue gases from the boiler to the chimney. Frequently referred to as "vent connectory". See VENT CONNECTOR.
A strong saline solution such as common salt and water cooled by a refrigerant and used for the transmission of heat without a change in its state, having no flash point or a flash point above 150 degrees Fahrenheit.
British Thermal Unit (Btu)
The quantity of heat necessary to raise the temperature of one pound of water one degree Fahrenheit from 58.5 to 59.5 degrees Fahrenheit under standard pressure of 30 inches of mercury at or near its point of maximum density. One Btu equals 252 calories, (gram), 778 foot-pounds, 1,055 joules or 0.293 watt hours.
In CAPACITY ASSIGNMENT/BROKERING, a broker is one who sells or assigns firm transportation (or storage) capacity rights on an interstate pipeline to another entity. Also, an individual or company that buys or sells stocks, commodities, or services for others for a fee. A broker provides the function of bringing a buyer and seller together. A lease broker leases oil and gas leases for others or for the broker's own account for later sale.
Brokerage of Gas
The term applies to the activities and compensation in arranging for the sale of gas between producers and buyers.
Btu Adjustment Clause
A clause in a gas purchase contract that may adjust the contract price if the heat content of the gas delivered does not fall within a specified range.
Btu Method
A method of allocating costs between different operations or between different products based upon the heat content of products produced in the various operations or of the various produced products.
Btu per Cubic Foot
A measure of the heat available or released when one cubic foot of gas is burned.
Btu, Dry
Heating value contained in cubic foot of natural gas measured and calculated free of moisture content. Contractually, dry may be defined as less than or equal to seven pounds of water per Mcf.
Btu, Saturated
The number of Btus contained in a cubic foot of natural gas fully saturated with water under actual delivery pressure, temperature and gravity conditions. See BTU, DRY.
Buddy Swap
An arrangement whereby, during a period of severe curtailment, one industrial or commercial customer that can use an alternate fuel agrees to do so temporarily and transfers that part of his gas allocation to another customer that cannot use an alternate fuel.
Budget-Type Certification
A budget-type application is an abbreviated, single certificate application filed under Section 7 of the NGA covering a number of minor or routine construction projects expected to be completed during the calendar year or fiscal year of the applicant, where the facilities proposed are to be used for miscellaneous rearrangements not resulting in any change in service or exceeding a specified dollar amount. Budget-type applications started with the Commission's Order No.185, issued February 8, 1956.
Building Envelope
The walls, doors, windows and roof that separates the inside of a building from the outside.
Bulk Plants for LP Gas
A distributing point with permanently installed pressure tanks and required accessory equipment for storing large volumes of liquid petroleum gas and, in dealer's plants, withdrawing it for refilling bottles, delivery trucks, and trailers; in consumer's plants, withdrawing it for vaporization and utilization.
A wall installed along a coastline or waterway to protect a pipeline from washout or soil erosion.
Bull Plug
A plug that is inserted into the end of an unfinished pipeline to keep out dirt and moisture; also a plug of a particular shape with a male thread on one end and considerable length to the closed end for convenient use of a wrench.
Bundled Sales Service
Natural gas sold on an as-needed basis, without prior scheduling, to the local distribution company at FERC-approved rates. Prior to implementation of various transportation programs, this constituted all gas delivered to an LDC.
Bunker "C" Fuel Oil
A heavy residual fuel oil used by ships, industry, and for large scale heating installations. The United States Navy calls it "Navy heavy"; in industry, it is often referred to as No. 6 fuel oil.
A pit, usually earthen and of shallow depth used to burn-off and dispose of petroleum distillates.
Burner Capacity
The maximum Btu per hour that can be released by a burner while burning with a stable flame and satisfactory combustion. Also called burner rating.
Burner Head
The portion of the burner beyond the outlet end of the mixer tube which contains the ports.
Burner Port
Burner Tip
An attachment for a burner head which forms a burner port modified for a specific application. Also, a generic term that refers to the ultimate point of consumption for natural gas.
Burner Unit
An assembly of one or more burner heads receiving gas through a single set of control valves.
Burner, Automatically Lighted
Where fuel to the main burner is normally turned on and ignited automatically.
Burner, Conversion
A burner designed to supply gaseous fuel to an appliance originally designed to utilize another fuel. a. Firing Door Type - a conversion burner designed specifically for boiler or furnace firing door installation. b. Inshot Type - a conversion burner normally designed for boiler or furnace ash pit installation and fired in a horizontal position. c. Upshot Type - a conversion burner normally designed for boiler or furnace ash pit installation and fired in a vertical position at approximately grate level.
Burner, Gas
A device for the final release of air/gas, or oxygen/gas mixtures, or air and gas separately into the combustion zone. Gas burners may be classed as atmospheric burners or blast (pressure) burners.
Burner, Manually Lighted
Where fuel to the main burner is turned on only by hand and ignited under supervision.
Burst Strength
The internal pressure required to cause a pipe or fitting to fail. NOTE: This pressure will vary with the rate of buildup of the pressure and the time during which the pressure is held.
Burst Test
Method of hydrostatic testing plastic pipe by a uniformly increasing internal pressure so that the pipe fails in 60 to 70 seconds. See ASTM D 1599. Also called quick burst test.
Butane (C4H10)
A low-boiling paraffin hydrocarbon generally stored and delivered in liquefied form and used as a fuel in gaseous form, obtained by processing natural gas as produced and also from a process in petroleum refining. Contains approximately 3,260 Btu per cubic foot.
Butane-Air Plant
A gasification plant where liquid butane is vaporized and mixed with air and delivered into a gas distribution system for the use of consumers.
The joining of two pieces of pipe or other material by full penetration welds.
Butylene Plastics
Plastics based on resins made by the polymerization of butene or copolymerization of butene with one or more unsaturated compounds, the butene being in greatest amount by weight.
Buy-Out Costs (Buy-Down Costs)
Payments made by pipelines to producers to extinguish (buy-out) outstanding take-or-pay liabilities under existing contracts, or to reform (buy-down) the contracts.
Buyer Protection Clause
A provision in a gas purchase contract permitting the buyer, under certain circumstances, to reduce the price below the amount specified in the contract.
Buyer's Right of First Refusal
In negotiating situations where the seller of gas has the right to solicit third-party bids for his gas, a right of first refusal provision gives the buyer of the gas the option of meeting the third party bid price and continuing the contract on such terms.
An auxiliary piping arrangement, generally to carry gas around specific equipment or an integral section of a piping system. A by-pass is usually installed to permit passage through the line while adjustments or repairs are made on the section which is by-passed.
By-Products (Residuals)
Secondary products which are obtained from the processing of a raw material and have commercial value. They may be the residues of the gas production process, such as coke, tar, and ammonia, or they may be the result of further processing of such residues, such as ammonium sulphate.
Obtaining service from a new supplier without utilizing the facility of the former supplier.


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