Gas 2 Flashcards
Generally speaking, the closer natural gas gets to a customer, the
smaller the pipe diameter is and the lower the pressure is.
From the gate station, natural gas moves into distribution lines or “mains” that range from _________ to _________ in diameter.
2 inches to more than 24
Distribution lines typically operate at
less than one-fifth of their design pressure.
As gas flows through the system, regulators control the flow from
higher to lower pressures.
If a regulator senses that the pressure has dropped below a set point it will
open accordingly to allow more gas to flow. Conversely, when pressure rises above a set point, the regulator will close to adjust.
As an added safety feature, _________are installed on pipelines to vent gas harmlessly, if a line becomes overpressured and the regulators malfunction.
relief valves
Natural gas runs from the main into a home or business in what’s called a
service line.
Today, this service line is likely to be a
small-diameter plastic line an inch or less in diameter, with gas flowing at a pressure range of over 60 pounds to as low as ¼ pound.
When the gas passes through a customer’s gas meter,
it becomes the property of the customer.
When the gas reaches a customer’s meter, it passes through another regulator to reduce its pressure to
under ¼ pound, if this is necessary. (Some services lines carry gas that is already at very low pressure.)
1/4 pound pressure is the normal pressure for natural gas within a household piping system, and is less than
the pressure created by a child blowing bubbles through a straw in a glass of milk.
When a gas furnace or stove is turned on, the gas pressure is slightly higher than
the air pressure, so the gas flows out of the burner and ignites in its familiar clean blue flame.
