3.3.1 Gas Utilities

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3.3.1 Gas Utilities

• Jesse Sopko, Don(Wilton) Jacobson, Brooke Adams,
  Hali Perkins, Chris Claypool

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History of Gas

• Natural gas formed over millions of years ago
  from decaying plant and animal matter. As plant
  and animals died, their remains mixed and layered
  with water, sand, and mud.  Over time, the mud
  and sand sediment built up and formed into rock,
  trapping the remains underground where the heat
  and pressure changed the matter within the rock
  into gas. 
• 1800s, natural gas was used almost exclusively as
  a fuel for lamps
• In 1855, Robert Bunsen invented a burner that
  mixed air with natural gas. The "Bunsen burner"
  showed how gas could be used to provide heat for
  cooking and warming buildings.
• It took the construction of pipelines to bring
  natural gas to new markets.
• First lengthy pipelines was built in 1891 -it was
  120 miles long and carried gas from fields in
  central Indiana to Chicago - there were very few
  pipelines built until after World War II in the
  1940s. 

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History of Gas Cont.

• Improvements in metals, welding techniques and
  pipe making during the War made pipeline
  construction more economically attractive.
• Industrial users use almost half of the gas
  produced in the U.S. A large portion is also used
  in homes for heating, lighting, and cooking.
• Naturally occurring natural gas was discovered
  and identified in America as early as 1626, when
  French explorers discovered natives igniting
  gases that were seeping into and around Lake
  Erie. In 1821, William Hart dug the first
  successful natural gas well in the U.S.
• In 1836, the City of Philadelphia created the
  first municipally owned natural gas distribution
  company. Today, U.S. public gas systems number
  more than 900, and the Philadelphia Gas Works is
  the largest and longest operating public gas
  system in the U.S.

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Providers
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Ways In
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Transmission/ Distribution

• Gas is transported by main lines across the
  country, and trucks by compressing the natural
  gas in tubes on the trailers.
• Gas lines can be from 1/2in for our house or 4ft.
  In diameter
• Many natural gas wells are on private property so
  a company pays a royalty and the owner gets an
  allowance per year of free gas.
• Many gas lines are at 200 to 1500psi (Pounds per
  Square Inch).
• There is many stations that check the gas
  pressure at several points in its journey.

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Measuring

• Normally measured in cubic feet.
• 1,000 cubic feet of natural gas is approximately
  enough to meet the natural gas needs of an
  average home (space-heating, water-heating,
  cooking, etc.) for four days.
• In 2009, the average American home consumed
  70,500 cubic feet of natural gas (or 72.6 million
  Btu). On a daily basis, the average U.S. home
  used 193 cubic feet of natural gas.
• Most natural gas household bills display the
  amount of natural gas consumed by the 'therm'
  (100,000 Btu) or in hundreds of cubic feet (100
  cubic feet - 1 Ccf).
• Looking at larger quantities, 1 billion cubic
  feet (Bcf) of natural gas is enough to meet the
  needs of approximately 10,000 - 11,000 American
  homes for one year.
• 5 trillion cubic feet of natural gas is enough to
  meet the needs of 5 million households for 15
  years.

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Typical Composition of Natural Gas Typical Composition of Natural Gas Typical Composition of Natural Gas
Methane CH4 70-90
Ethane C2H6 0-20
Propane C3H8 0-20
Butane C4H10 0-20
Carbon Dioxide CO2 0-8
Oxygen O2 0-0.2
Nitrogen N2 0-5
Hydrogen sulphide H2S 0-5
Rare gases A, He, Ne, Xe trace
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Sizing Requirements

• The top of the conduit must be buried deep enough
  to allow for PSEs required minimum depth of
  cover over the gas service line at final grade. A
  minimum of 24 inches of cover is required for
  commercial/industrial service lines that
  are1-1/4-inch or larger pipe.
• Use yellow or white Schedule 40 PVC for a gas
  service. You must use conduit that has a smooth
  wall and is not perforated. The markings on the
  conduit shall not contain any reference to any
  other utilities (such as water or sewer).
• It is preferable that directional changes in the
  service route be at 90 degrees. It is recommended
  that the combined degrees of bend do not exceed
  180 degrees.

Gas Service Size Min. Bending Radius Min. Conduit Diameter
1-1/4 Inches 48 Inches 3 Inches
2 Inches 60 Inches 4 Inches
4 Inches 113 Inches 6 Inches
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Sizing Requirements Cont.

• PVC conduit should extend to the work pits, but
  stop 4 feet shy of the building wall and 4 feet
  shy of the gas main stub at the front property
  line.
• Dig to within 1 foot of the gas stub marker at
  the front property line. Do not expose gas pipe
  or stub. If accidentally exposed, cover the gas
  line stub with a minimum of12 inches of sand.
• The trench should be left open at both ends for
  PSE to install the service. A 4-foot by 4-foot
  work pit opening is recommended .
• Conduit ends should be sealed shut and clearly
  marked using a piece of conduit or 2-inch by
  4-inch stake marked Gas.
• Use soil backfill that is free from construction
  debris, sharp rocks, glass, frozen clods, and
  rocks larger than 10 inches in diameter.

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Sources

• http//www.amerigas.com
• https//www.vectren.com/
• http//www.naturalgas.org
• http//www.tuckergas.com
• http//www.mesaaz.gov/energy/nghistory.aspx
• http//www.fossil.energy.gov/education/energylesso
  ns/gas/gas_history.html
• http//www.apga.org/i4a/pages/index.cfm?pageid332
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• http//pse.com/accountsandservices/Construction/Do
  cuments/2772.pdf