Gas Glossary of Terms 
 
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Appliance:
Any device that utilizes gas as a fuel to produce light, heat, power, refrigeration, or air conditioning.

 
Applicant:
A person who applies for Residential or Non-Residential service and/or who requests a service extension.

 
Approach Main:
Main extensions required to reach the boundary of a Residential and/or Non-Residential development or property.

 
Approved:
Acceptable to the authority having jurisdiction. See: Local Inspection Authority.

 
Automatic Meter Reading (AMR):
A system installed to read a utility meter remotely.

 
Backfill:
Earth, material or low strength flow-able material that has been replaced in an excavation or trench after pipe or other device has been installed.

 
Base Pressure:
The pressure used to define a standard cubic foot of gas. Base pressure is normally 14.73 psia which is also 0.25 psig or 7 inches water column.

 
Boiler, Primary-Backup:
Gas utilization equipment used to create steam to be used in a manufacturing process or for heating purposes. One appliance typically operates at various stages of the burner’s capacity while the second unit stands idle.

 
Boiler, Primary-Primary:
Gas utilization equipment used to create steam to be used in a manufacturing process or for heating purposes. The appliances typically operate in a series and each individual unit operates at a percentage of it’s burner’s capacity for a total of a 100 percent of one of the units burner capacity.

 
Bollard:
A concrete filled 4 inch diameter steel pipe installed by the customer to protect AmerenUE gas service riser and meter facilities.

 
Boring:
Installing pipe by drilling a route under an obstacle such as a railroad, driveway, or roadway.

 
British Thermal Unit (BTU):
Energy measurement. The amount of heat required to raise 1 pound of water 1 degree Fahrenheit at standard conditions. The average BTU content of natural gas is 1,000 BTU’s per cubic foot.

 
Building:
Any structure which is regularly or periodically occupied by people.

 
Burner:
A device for the final conveyance of gas, or a mixture of gas and air, to the combustion zone.

 
Codes:
Various government bodies have adopted minimum safety standards, or “codes” for the installation and operation of gas equipment and piping on customer’s premise (National Fuel Gas Code - NFPA 54).

 
Combustible Material:
Materials that are adjacent to or in contact with heat-producing appliances that are capable of being ignited and burned.

 
Commission:
The agency responsible for regulating the regulated portions of investor-owned public utilities. In Missouri, the Missouri Public Service Commission (PSC) or any duly constituted successor.

 
Company:
Refers to Ameren Missouri or its designated agent. The company may act through an inspector or another authorized representative.

 
Conduit:
A channel for holding and protecting gas pipe, made of metal or an insulating material, usually circular in cross section like a pipe.

 
Connected Load:
The total potential gas load of all natural gas appliances of the connected service.

 
Cook Stove
: Gas utilization equipment with multiple burners used in the preparation of food. The appliance may be a combination cook stove/oven or only a cook stove.

 
Corps of Engineers:
Refers to the United States Army Corps of Engineers.

 
Cubic foot (CF):
A three-dimensional volume one foot wide by one foot long, by one foot high.

 
Cubic feet per hour (CFH):
The volume of gas that passes through a point in one hour.

 
Customer:
Any person, developer, firm, organization, association, corporation or other entity legally receiving service at a Premise or whose facilities are connected for utilizing service at the Premises.

 
Delivery Pressure:
The regulated pressure through the gas meter (normally 7” w.c.)

 
Developer:
The entity responsible for constructing and making improvements to a tract of land (streets, sidewalks, storm sewers, utilities, etc.) for the creation of a Residential and/or Non-Residential development.

 
Development:
A lot, tract, or parcel of land divided into two or more lots, plots, sites or other divisions for use for two or more new buildings or the land on which is constructed new multiple-occupancy buildings per a recorded plat.

 
Diaphragm Meter:
A positive displacement meter in which gas passes through a series of chambers which records the volume of gas. Most domestic meters are diaphragm type meters.

 
Dig Rite:
Also known as Missouri One Call.

 
Distribution Main:
A non-transmission main.

 
Distribution System:
The non-transmission portion mains, service piping and equipment operated by a distribution company to deliver gas from a delivery station to the outlet of the customer meter.

 
Dryer:
A gas utilization appliance used to dry a product or clothes.

 
Duplex:
A Residential building consisting of two units that share a common wall.

 
Easement:
A formal permission granted by landowners for installation and maintenance of facilities. Easements are commonly referred to as right-of-way grants.

 
Elevated Delivery Pressure:
The regulated pressure through the meter at a pressure above 7” w.c. Additional charges will be administered.

 
Excavation:
A cavity, trench, or depression in the earth’s surface, formed by earth removal.

 
Excess Flow Valve (EFV):
A valve designed to shut off the flow of gas when the flow rate exceeds the designed rate.

 
Food Equipment:
Gas utilization equipment used in the preparation of food. Does not include cook stove or cook stove/oven combinations (see cook stove).

 
Fuel Line:
The customer-owned gas piping downstream from the outlet of the customer meter or Ameren-owned pipe, which ever is further downstream.

 
Gang Meter Set:
See Multi-Meter.

 
Gas Utilization Equipment:
Appliances or equipment that utilize natural gas in the process.

 
Gauge Pressure (PSIG):
The pressure one would read on a typical spring gauge or recording chart. The pressure above atmospheric pressure.

 
Generator, Backup:
A piece of equipment used to generate electricity in the event of an electrical outage and may run on natural gas, diesel, or propane.

 
Hanging Unit Heater:
Gas heating appliances that are suspended from a ceiling and are fan assisted. These units are primarily used in a warehouse or garage area.

 
Inlet Pressure, Minimum:
The minimum pressure required at the appliance for the appliance to operate.

 
Input BTU’s:
The required volume of gas an appliance will use at maximum load, measured in BTU/Hr.

 
Inlet Pressure, Maximum:
The maximum pressure that can be put against the control valve without the installation of an appliance regulator.

 
Input BTU’s:
The required volume of gas an appliance will use at maximum load.

 
In. W.C.:
Inches water column.

 
Load:
The customer’s gas usage requirements in Btu’s/Hr, which must be supplied on the Company’s distribution system.

 
Load Information Sheet:
The data sheet used to collect the gas loads and characteristics required by a premise.

 
Local Inspection Authority
: The agency responsible for the inspection of a customer’s gas installations. The authority can be an agency of an incorporated city or town or of the County, State or Federal Government. The Ameren Companies are not inspection authorities.

 
Locating:
The process of finding and marking the location of an underground facility.

 
Main:
A distribution or transmission line that serves as a common source of supply.

 
Maximum Emergency Pressure (MEP):
The designated pressure that is allowed on a piping system under emergency conditions.

 
MCF:
A gas volume measure of 1,000 cubic feet.

 
MCFH:
1,000 cubic feet per hour.

 
MMBTU:
A supply term for a million BTU’s or approximately 1 MCF.

 
MMCF:
Million cubic feet.

 
Meter:
A mechanical device which measures the volume of gas delivered from the operator to the customer. Common types of meters are diaphragm and rotary.

 
Meter Loop:
A mechanical piping system in which a meter is attached.

 
Meter Pad:
A foundation used to support large meter sets.

 
Meter Set Assembly (also called a Meter Header or Meter Loop):
All components from the meter valve to the customers piping.

 
Missouri One Call:
The system established for making one telephone call to request locates for underground utilities. Commonly referred to as DIG RITE.

 
Missouri Public Service Commission (PSC):
See Commission.

 
Mobile/Modular Home:
A prefabricated home constructed to allow for movement from one location to another.

 
MoDOT:
Refers to the Missouri Department of Transportation.

 
Multi-Tenant (Multi-Plex):
A multiple occupancy building with three or more Customers who each qualify for Residential rate or two or more Customers who qualify for a Non-Residential rate.

 
Multi-Meter:
Two or more meters attached to a single service riser.

 
Natural Gas:
A hydrocarbon gas comprised mainly of methane.

 
NFPA:
National Fire Protection Association.

 
Non-Residential:
Service supplied primarily for commercial, industrial, and/or temporary construction purposes, for individual meters.

 
Pilot:
A small burning flame used to light an appliance.

 
Piping System:
Interconnected piping system used for the distribution of a produce.

 
Polyethylene Pipe (PE):
A pipe material made of a lightweight thermo-plastic that is resistant to chemicals and moisture.

 
Pool Heater:
An appliance designed for heating water for a swimming pool.

 
Premise:
The contiguous tract of land separated by nothing more than a highway, street, alley, or railroad right-of-way, where all buildings and/or electric consuming devices located thereon are owned or occupied by a single Customer or applicant for electric service, or where all electricity delivered thereto is utilized to supply one or more buildings and/or electrical loads which the Company considers as components of a unified operation.

 
Premise Number:
A unique number assigned to Premise.

 
Pressure:
A force within an enclosed piping system (normally in pounds per square inch gauge - PSIG).

 
Pressure Drop:
The loss in pressure due to friction or obstruction in pipes, valves, fittings, regulators, and burners.

 
Pressure Test:
An operation performed to verify the gastight integrity of gas piping following installation or modification.

 
Primary Point of Contact (PPC)
: The Ameren Missouri representative assigned to help you manage your request through the construction process.

 
Process Heating:
Gas utilization equipment used in the manufacturing process.

 
PSI:
Internal pressure measurement in pounds per square inch.

 
PSIG:
Pressure measurement in pounds per square inch gauge. (PSI +14.65).

 
Purge:
To free a gas conduit of air or gas.

 
Radiant Tube Heaters:
Gas heating appliances that are suspended from a ceiling that are non fan assisted. The units are typically used at entrances to structures or in warehouses.

 
Regulator, Gas Appliance:
A pressure regulator for controlling pressure to the appliance manifold.

 
Regulator, Line Gas
: A pressure regulator placed in a gas line between the service regulator and the appliance regulator.

 
Regulator, Pressure:
Equipment placed in a gas line for reducing, controlling, and maintaining the pressure in that portion of the piping system downstream of the equipment.

 
Regulator, Service:
A pressure regulator installed to reduce and limit the service line gas line pressure to delivery pressure.

 
Regulator Vent:
An opening in a regulator to the atmosphere.

 
Relief Valve:
An emergency valve used to maintain system pressure to desired or safe level.

Residential Service: Service supplied primarily for domestic purposes, to individual metered residences and apartments.

 
Right-Of-Way (ROW):
A strip of land, granted by deed or easement, in which facilities are installed. Includes City, County and State owned roadway right-of-ways.

 
Rotary Meter:
A positive-displacement meter in which gas passes through a series of impellers which turns a rotor recording the volume of gas. Most rotary meters are commonly used for commercial or small industrial applications.

 
Safety Shutoff Device:
A mechanism, normally a valve, provided to stop the flow of gas in case of emergency.

 
SCFH:
Standard cubic feet per hour.

 
Service Line:
A pipe that transports gas from a common source of supply to a meter set assembly.

 
Service Regulator:
A mechanical device that controls the flow of gas at a constant pressure to meet downstream customers demand. Standard delivery pressure is normally 7 inches of water column.

 
Site Ready:
A point reached in the construction of a premise which is ready for natural gas service. (normally within 6” of final grade).

 
Source of Ignition:
Appliances or equipment that because of their intended modes of use or operations, are capable of providing sufficient thermal energy to ignite flammable gas-air mixtures.

 
Spoil:
The material, dirt, rock, soil, etc., removed or excavated from a trench or excavation.

 
SSN/FEIN:
An individual’s Social Security Number or a company’s Federal Employer Identification Number.

 
Subdivision:
A lot, tract, or parcel of land divided into two or more lots, plots, sites or other divisions for use for two or more new residential buildings or the land on which is constructed new multiple-occupancy residential buildings per a recorded plat.

 
Tariff:
Schedule of Ameren Missouri rates, charges, and General Rules and Regulations for providing gas service. Tariffs are available at www.ameren.com, and are on file with the Missouri Public Service Commission.

 
Taxing Area:
The geographical area where premise is located and where taxes are paid. Generally speaking, taxing areas are jurisdiction boundaries such as cities or towns and may have inspection authority jurisdiction.

 
Test Duration:
The amount of time (typically in minutes or hours) for which a pressure test should be held.

 
Test Medium:
The medium (air, nitrogen, carbon dioxide, or an inert gas) used to perform the required pressure test.

 
Therm:
A quantity of heat equivalent to 100,000 British Thermal Units (BTU). Approximately the same heat content as 100 cubic feet of natural gas.

 
Trench:
A narrow excavation in relation to its length made below the surface of the ground.

 
Vent:
A passageway used to convey flue gases from appliances or their vent connectors to the outdoors.

 
Villa:
A residential building consisting of two units that share a common wall.

 
Water Heater, Conventional:
An appliance with a storage tank that supplies hot water for domestic or commercial purposes.

 
Water Heater, On-Demand:
An appliance that supplies hot water instantaneously based on flow for domestic or commercial purposes. Also known as a tankless water heater.

 
W.C.:
Water column.

 
 
 
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