Background radiation, The naturally-occurring ionizing radiation which every person is exposed to, arising from the earth's crust (including radon) and from cosmic radiation.
Backup fuel, In a central heat pump system, the fuel used in the furnace that takes over the space heating when the outdoor temperature drops below that which is feasible to operate a heat pump.
Backup Generator, A generator that is used only for test purposes, or in the event of an emergency, such as a shortage of power needed to meet customer load requirements.
Backup power, Electric energy supplied by a utility to replace power and energy lost during an unscheduled equipment outage.
Baffle A plate or wall for deflecting gases or liquids.
Baffle Tile A tile for deflecting gases.
Bag Filter A device containing one or more cloth bags for recovering particles from the dust laden gas or air which is blown through it.
Baffle-Type Collector, A device in gas paths utilizing baffles so arranged as to deflect dust particles out of the gas stream.
Bag-Type Collector, A filter in which the cloth filtering medium is made in the form of cylindrical bags.
Ballast, An operation during which the ship is not laden with cargo. Also, a substance, usually water, used to improve the stability and control the draft of a ship. A vessel is said to be “in ballast” when it is steaming without cargo and carrying water as Ballast.
Ballast tanks, Tanks carried in various parts of a ship for water ballast, to keep the vessel on an even keel.
Band gap In a semiconductor, the energy difference between the highest valence band and the lowest conduction band.
Band gap energy (EG), The amount of energy (in electron volts) required to free an outer shell electron from its orbit about the nucleus to a free state and, thus, to promote it from the valence level to the conduction level.
Bareboat Charter, A charter of a ship under which the shipowner is usually paid a fixed amount of charterhire for a certain period of time during which the charterer is responsible for the operating and voyage costs of the ship, as well as for the management of the ship, including crewing. A bareboat charter is also known as a 'demise charter' or a 'time charter by demise. see also time charter and voyage charter.
Bare Conductor A conductor not covered with insulating material.
Barge, a non self propelled marine vessel used as cargo tankers, as equipment and supply carriers, crane plattform and support and accommodation bases in offshore drilling, and as submarine pipe laying vessels. Se also accommodation barge, crane barge, barge for sale.
Barometric Pressure, atmospheric pressure as determined by a barometer usually expressed in inches of mercury.
Barrel Bbl In the energy industry, a barrel is 42 U.S. gallons measured at 60 º Fahrenheit.
Barricade A physical obstruction such as tapes, cones, or A-frame type wood or metal structures intended to provide a warning about and to limit access to a hazardous area.
Barrier A physical obstruction which is intended to prevent contact with energized lines or equipment or to prevent unauthorized access to a work area.
Barrier energy The energy given up by an electron in penetrating the cell barrier; a measure of the electrostatic potential of the barrier.
Base Line A horizontal level line at the lowest point of the mold lines and the top of the keel plate.
Base load That part of electricity demand which is continuous, and does not vary over a 24-hour period. Approximately equivalent to the minimum daily load. Se also peak load.
Base load (Heat plant) is also the term applied to that portion of a station or boiler load that is practically constant for long period. se also peak load.
Base load capacity The generating equipment normally operated to serve loads on an around-the-clock basis.
Base load plant A plant, usually housing high-efficiency steam-electric units, which is normally operated to take all or part of the minimum load of a system, and which consequently produces electricity at an essentially constant rate and runs continuously.
Base power, power generated by a utility unit that operates at a very high capacity factor.
Battery energy storage The three main applications for battery energy storage systems include spinning reserve at generating stations, load leveling at substations, and peak shaving on the customer side of the meter.
Bayonet Coupling A quick coupling device for plug and receptacle connectors, accomplished by rotation of a cam operating device designed to bring the connector halves together.
Beaded Tube End The rounded exposed end of a rolled tube when the tube metal is formed over against the sheet in which the tube is rolled.
Beam The extreme width of a ship. Also a transverse horizontal member supporting a deck.
Becquerel The SI unit of intrinsic radioactivity in a material. One Bq measures one disintegration per second and is thus the activity of a quantity of radioactive material which averages one decay per second.
Bed plate A structure fitted for support of the engine columns, as well as to provide support for crankshaft bearings. It also helps distribute engine weight and stresses to the ship's structure.
Beryllium Copper (BeCu) A relatively expensive contact material with properties superior to brass and phosphor bronze. It is recommended for contact applications requiring repeated extraction and reinsertion because of its resistance to fatigue at high operating temperatures.
Beta Rating is the method of comparing filter performance based on efficiency. This is done using the Multi-Pass Test which counts the number of particles of a given size before and after fluid passes through a filter.
Blind Nipple A nipple, or a short piece of pipe or tube, closed at one end.
Bilge The rounded portion of a vessel's shell that connects the bottom with the sides.
Bilge keel A fin fitted on the bottom of a ship at the bilge to reduce rolling. It commonly consists of a plate running fore and aft attached to the shell plating by angle bars.
Biodiesel Any liquid biofuel suitable as a diesel fuel substitute or diesel fuel additive or extender. Biodiesel fuels are typically made from oils such as soybeans, rapeseed, or sunflowers, or from animal tallow.
Biogas Methane and other gases produced during the decomposition of biomass.
Biomass fuels Organic nonfossil material of biological origin constituting a renewable energy source, (i.e. wood, vegetation or waste from food) that are collected and used as fuel for electricity production.
Blocking diode A diode used to restrict or block reverse current from flowing backward through a module. Alternatively, diode connected in series to a Photovoltaic string; it protects its modules from a reverse power flow and, thus, against the risk of thermal destruction of solar cells.
Blow Off Valve A specially designed, manually operated, valve that connects to the boiler for the purpose of reducing the concentration of solids in the boiler or for draining purposes. (Often called bottom blowdown.).
Blow Down A procedure using steam pressure to discharge the contents of the boiler through low level vents in order to clear sediment from the mud drums.
Blowdown Valve A valve generally used to continuously regulate concentration of solids in the boiler, not a drain valve.
Blowdown Safety Valve The difference between the pressure at which a safety valve opens and at which it closes.
Blower A fan used to force air under pressure.
Boiler A closed vessel in which water is heated, steam is generated, steam is superheated, or any combination thereof, under pressure or vacuum by the application of heat from combustible fuels, electricity or nuclear energy. Common forms are "fire tube" and water tube". Each can be "horizontal" or "vertical" according to the orientation of the main drum.
Boiler Efficiency is often substituted for combustion or thermal efficiency. True boiler efficiency is the measure of fuel to steam efficiency.
Boiler fuel An energy source to produce heat that is transferred to the boiler vessel in order to generate steam or hot water. Fossil fuel is the primary energy source used to produce heat for boilers.
Boiler Horsepower The evaporation of 34-1/2 lbs of water per hour from a temperature of 212 °F into dry saturated steam at the same temperature. Equivalent to 33,475 Btu/hr.
Boiler Rating The heating capacity of a boiler expressed in boiler horsepower, Btu/hour, or pounds of steam/hour.
Boiler Shell The outer cylindrical portion of a pressure vessel (boiler).
Boiler Stays Rods inside a boiler restraining flat surfaces such as the end caps against steam pressure.
Boiling The conversion of a liquid into vapor with the formation of bubbles.
Boiling out The boiling of highly alkaline water in boiler pressure parts for the removal of oils, greases, etc.
Boiler room (ship) That part of the ship where the boilers are placed, connected with boiler hatch to top deck.
Boom rest (on ship) A saddle in which the cargo boom is lashed down and made fast.
Bonding Jumper A bare or insulated conductor used to ensure the required electrical conductivity between metal parts required to be electrically connected. Frequently used from a bonding bushing to the service equipment enclosure to provide a path around concentric knockouts in an enclosure wall - also used to bond one raceway to another.
Bone coal A coal with a high ash content; it is dull in appearance, hard, and compact.
Booster Fan A device for increasing the pressure or flow of a gas.
Bottom ash Residue mainly from the coal burning process that falls to the bottom of the boiler for removal and disposal.
Bottoming cycle A waste-heat recovery boiler recaptures the unused energy and uses it to produce steam to drive a steam turbine generator to produce electricity.
Brasses The plain bearings in the ends of the connecting rod. Originally made from brass now more commonly bronze or "white metal".
Breakdown Voltage The voltage at which an insulator or dielectric ruptures, or at which ionization and conduction take place in a gas or vapor.
Breeching A duct that transports the products of combustion between parts of a steam generating unit or to the stack.
Bridgewall A wall in a furnace over which the products of combustion pass.
British thermal unit Btu The amount of heat energy required to raise the temperature of one pound of water from 60 degrees F to 61 degrees F at one atmosphere pressure. A Btu is essentially 252 calories.
Boss (ship) Any protuberance on parts. For example: The boss on the stern casting is the part that the propeller shaft runs through.
Boss frame A frame bent to allow room for the stern tube, or tail shafts in the case of twin-screwships.
Boss plate A curved plate covering (one on each side) the boss of a propeller post and the curved portion of frames in way of the stern tube of a screw steamer. This plate is of extra thickness.
Bounding bar An angle which surrounds a plate in a frame or a bulkhead to make connections.
Bow The front or forward end of a ship.
Bow Plate Any of the shell plates in the bow of a ship.
Boyancy The capacity for floating which a vessel possesses.
Buckstay A structural member placed against a furnace or boiler wall to restrain the motion of the wall.
Bulk Unpackaged solid cargo such as coal, ore and grain.
Bulkhead A watertight partition extending from the double bottom to the top main deck, ao constructed that in case of accident in one compartment, damage is confined to that compartment.
Bulkwark A term applied to the strake of shell plat ing above a weather or shelter deck. It helps to keep the deck dry and also serves as a guard against losing cargo or men.
Bunker C Oil Residual fuel oil of high viscosity commonly used in marine and stationary steam power plants.
Bunkers Heavy fuel and diesel oil used to power a ship's engines.
Burnable poison A neutron absorber included in the fuel which progressively disappears and compensates for the loss of reactivity as the fuel is consumed. Gadolinium is commonly used.
Burner A device for the introduction of fuel and air into a furnace at the desired velocities, turbulence and concentration.
Burner Windbox A plenum chamber around a burner that maintains an air pressure sufficient for proper distribution and discharge of secondary air.
Burner Windbox Pressure The air pressure maintained in the windbox or plenum chamber measured above atmospheric pressure.
Bushing An insulating structure, including a through conductor or providing a passageway for such a conductor, with provision for mounting on a barrier, conducting or otherwise, for the purposes of insulating the conductor from the barrier and conducting current from one side of the barrier to the other.
By Pass A passage for a fluid, permitting a portion of the fluid to flow around its normal pass flow channel.
Bypass diode A diode connected across one or more solar cells in a photovoltaic module such that the diode will conduct if the cell(s) become reverse biased. Alternatively, diode connected anti-parallel across a part of the solar cells of a Photovoltaic module. It protects these solar cells from thermal destruction in case of total or partial shading of individual solar cells while other cells are exposed to full light.