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Control and Instrumentation Glossary

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The relative movement of interlocked mechanical parts that occurs when motion is reversed.
Occasionally observed in valve actuators
Further Reading


Balance Ring
Similar to a Mono Flange but without the transition. It incorporates either a drain valve or a drain vent.
Often used to simplify Diaphragm seal installations.
Further Reading


Data carrying capacity.

Further Reading


BASEEFA (2001)
British Approvals Service for Electrical Equipment in Flammable Atmospheres - UK based testing institute and Notified Body.

Further Reading


Baud Rate
Serial communications data transmission rate expressed in bits per second.

Further Reading


bbl - Barrel
A volumetric unit of measure for crude oil and petroleum products. Derived by the original use of spent whiskey barrels to hold oil in the 1800s.
One barrel equals 42 U.S. gallons, equivalent to 158.978 litres.
Further Reading


A signal range that includes both positive and negative values e.g -5 V to +5 V

Further Reading


BOD - BiologicaL Oxygen Demand
The amount of oxygen used for biochemical oxidation by a unit volume of water at a given temperature and for a given time.
Used as an index of the degree of organic pollution in water.
Further Reading
Chemical Oxygen Demand

BoE - Barrel of Oil Equivalent
A measure of gas. A BoE has similar energy content as a barrel of Oil. Approx 167 MMscf depending on calorific value of the gas.

Further Reading


Bill Of Materials
A listing of materials for a job. The result of a Material Take Off.
Further Reading


BOPD - Barrels of Oil per Day
Unit of measurement of crude oil produced by a well or a field. The volume of a barrel is equivalent to 42 US gallons (0.16 metres cubed).

Further Reading


Barrels per Stream Day - A unit of flow measurement used on refineries.

Further Reading


Breakdown Voltage
The voltage at which circuit components begin to be damaged.

Further Reading


BSI - British Standards Institution
Responsible for the preparation of UK National Standards prefixed BS *** and publication of harmonised standards in the UK prefixed BS EN ***.

Further Reading
British Standards Website

BTU - British Thermal Unit
A unit of energy i.e. the amount of energy required to raise the temperature of 1 pound of water 1 degree Fahrenheit when the water is near 39.2 degrees Fahrenheit.

Further Reading


Bursting Disc
A non-reclosing element designed to burst or rupture at a predetermined pressure to protect systems or individual plant from unacceptable levels of pressure or vacuum.
Bursting discs are sometimes called rupture discs.
Further Reading


Bus Bar
A conducting bar that carries heavy current to supply several electric circuits.

Further Reading


Eight related bits of data or an eight-bit binary number.
Also denotes the amount of memory required to store one byte of data.
Further Reading


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