B of M:  Bureau of Mines (USA).

B Surg:  Base Surgeon.

BA:  ACRONYM – Breathing air.

Bacillus:  A rod-shaped bacterium.

Back-draft Damper:  A damper, installed near a fan that allows air to flow in only one direction.  Damper used in a system to relieve air pressure in one direction and to prevent airflow in the opposite direction. 

Back-drafting:  Continuous spillage of combustion gases from a combustion appliances.  Potentially hazardous condition in which the exhaust from combustion appliances does not properly exit the building.  This can be due to a number of factors including a blocked flue or a pressure difference within the home. 

Backer Rod:  Polyethylene foam rope used as a backer for caulking.  Also, in glazing, a polyethylene or polyurethane foam material installed under compression and used to control sealant joint depth, provide a surface for sealant tooling, serve as a bond breaker to prevent three-sided adhesion, and provide an hour-glass contour of the finished bead.

Backfill:  The word is used in two contexts; to refill an excavated area with uncontaminated soils; and the material used to refill an excavated area. The slope of the ground adjacent to the house. In any previously excavated area, i.e., the replacement of excavated earth into a trench around and against a basement foundation. In carpentry, the process of fastening together two pieces of board by gluing blocks of wood in the interior angle.  

Backflow: Movement of water (or other liquid) in any direction other than that intended.  

Backflow Preventer: A device or means to prevent backflow into the potable water supply.  

Background:  The concentrations or measures of indicator parameters in water, air or other media that have not been affected by waste discharges.

Background Air Sampling:  A method used to determine airborne fiber concentrations in the area where abatement work is to be conducted, prior to starting Phase II A of the asbestos project.

Background Concentration:  The level of a containment present before the introduction of a new store.

Background Level:  The average presence of a chemical substance or microorganism in the environment, originally referring to naturally occurring phenomena.

Background Radiation:  The average person in the United States receives about 3.6 mSv (360 mrem) of ionizing radiation every year. About 3 mSv (300 mrem) per year comes from natural background radiation including cosmic radiation, radiation emitted by naturally occurring radionuclides in air, water, soil and rock, and radiation emitted by natural radionuclides deposited in tissues of organs; and about 0.60 mSv (60 mrem) from man-made sources such as exposures to diagnostic X-rays and consumer products (e.g., from smoking tobacco). The general worldwide contribution from radioactive fallout contamination is <0.3% of the average total annual dose. Exposures to natural background radiation vary depending on the geographic area, diet and other factors such as the composition of materials used in the construction of homes. The natural background radiation dose in the Marshall Islands is around 1.4 mSv (140 mrem) per year and is significantly less than what most people receive around the world.

Backhand: A simple molding sometimes used around the outer edge of plain rectangular casing as a decorative feature.  

Backhoe: Self-powered excavation equipment that digs by pulling a boom mounted bucket towards itself. It is used to dig basements and/or footings and to install drainage or sewer systems.

Back Nailing: The practice of nailing roofing felts to the deck under the overlap, in addition to hot mopping, to prevent slippage of felts.

Backout: Work the framing contractor does after the mechanical subcontractors (Heating-Plumbing-Electrical) finish their phase of work at the rough (before insulation) stage to get the home ready for a municipal frame inspection. Generally, the framing contractor repairs anything disturbed by others and completes all framing necessary to pass a rough Frame Inspection.  

Back Pressure:  Resistance to air flow; usually stated in inches H2O or PSI.  This is the refrigerant pressure in the low side of the system also called low side pressure or suction pressure.

Backpressure:  A backward surge of pressure from downstream to upstream of the filter. Can be the result of closing a valve or air entrapped in a liquid system.  

Backsplash: A raised integral portion of a wall mount sink or lavatory located at the rear to protect the wall.

Backward Compatible:  All Angstrom Technology cleanrooms can be repaired or expanded with new materials that match the aesthetics and performance of the original. No purchase is ever outdated or wasted because you can improve, expand, improve cleanliness, increase classification or upgrade discreet zones at any time.

Backwash:  Reversal of a fluid flow through the filtration media to remove solids from the filter. To clean or regenerate a filter.  

BACT (Best Available Control Technology): An emission limitation based on the maximum degree of emission reduction achievable under Title 1 of the CAAA. EPA will establish BACT standards for serious, severe and extreme nonattainment areas.  An emission limitation based on the maximum degree of emission reduction (considering energy, environmental, and economic impacts) achievable through application of production processes and available methods, systems, and techniques. BACT does not permit emissions in excess of those allowed under any applicable Clean Air Act provisions. Use of the BACT concept is allowable on a case-by-case basis for major new or modified emissions sources in attainment areas and applies to each regulated pollutant.

Bacteria:  Any of a division (Bacteria) of typically one-celled microorganisms that have no chlorophyll, multiply by simple division, and can be seen only with a microscope.  They occur in three main forms, spherical (cocci), rod shaped (bacilli), and spiral (spirilla).  Some bacteria can cause disease and others are necessary for fermentation, nitrogen fixation, etc. Free living simple celled, microscopic organisms having a cell wall, lacking a defined nucleus, shape and round, rod-like, spiral or filamentous.  Microorganisms with prokaryotic cell organization (lacking membrane-bounded nucleus and other specialized features); bacteria are also typically much smaller than fungi (molds).  Infectious organisms (germs) that may cause bronchitis or pneumonia.  Bacteria are everywhere. They are on everything we see and touch, and even in the air we breathe. In fact, right now, the bacterial cells on (and in) your body actually outnumber your own cells. Much of these bacteria are beneficial, helping us to digest our food, fight off sickness, and even keep our breath fresh. “Good bacteria” also helps to displace, or crowd out, the bad bacteria that can cause things like pneumonia, syphilis, cholera, and infections like Strep and Staph.  You can significantly reduce the amount of airborne bacteria in your home with a high quality air filter. Nordic Pure’s MERV 12, electrostatically charged, pleat design filters are effective at capturing even the smallest bacteria, and the unique filtering medial won’t support the growth of bacteria once it’s trapped in the filter.  Bacteria are removed by Nordic Pure’s MERV 12, electrostatically charged, pleat design air filters.  Singular: Bacterium.  Bacteria are microscopic, single-celled organisms that have a cell wall and a specific shape depending on the type of bacteria. Bacteria have no easily identifiable nucleus. There are many types of bacteria, and although many are harmful to humans there are some that actually help.

Bacterial Challenge:  Testing the bacterial retention of a filter.  

Bactericidal:  Able to kill bacteria.

Bactericide:  Any agent (chemical or physical) that is able to kill bacteria.

Bacteriophage:  Any virus that infects bacteria.

Baffle:  Plate or vane used to direct or control movement of air within a confined area.  Also, a plate or strip designed to retard or redirect the flow of flue gases.  Screen that controls the direction of the airflow in a heating appliance.  Balance point: The outdoor temperature at which no heating is needed.

Bag: The customary form of filter element. Also known as tube, stocking, etc. Can be unsupported (dust on inside) or used on the outside of a grid (cage) support (dust on outside).

Bag Blinding:  A condition where the particles (dust) becomes embedded in the fabric filter over time and are not removed by the bag cleaning process.

Bag Filter:  A fabric bag through which a gas stream is passed for the removal of particulate matter.

Bag House (or Baghouse):  A dust-collection chamber containing numerous permeable fabric filters through which the exhaust gases pass. Finer particulates entrained in the exhaust gas stream are collected in the filters for subsequent treatment/disposal.  An air pollution control device that traps particulates by forcing gas streams through large permeable bags usually made of glass fibers. An air filtration structure utilizing fabric filter bags for the purpose of removing solid particulate from the gas stream.An air pollution abatement device that traps gas-borne particulates by forcing the gas through filter bags.

Baghouse Filter: Large fabric bag, usually made of glass fibers, used to eliminate intermediate and large (greater than PM20 in diameter) particles. This device operates like the bag of an electric vacuum cleaner, passing the air and smaller particles while entrapping the larger.

Bag In, Bag Out: A method of introducing and removing items from a contaminated enclosure that prevents the spread of contamination or opening of the contaminated space to the atmosphere through the use of plastic bagging material.

Baghouse Filter:  Large fabric bag, usually made of glass fibers, used to eliminate intermediate and large (greater than PM20 in diameter) particles. This device operates like the bag of an electric vacuum cleaner, passing the air and smaller particles while entrapping the larger ones.

Bag Life:  Time a bag filter performs effectively.

Bake-out:  Process by which a building is heated in an attempt to accelerate VOC emissions from furniture and materials. 

Bakeout:  A technique for reducing the exposure of occupants to emissions of new construction. The building temperature is raised to a high level (to enhance emissions of volatile compounds from new materials) for several days before occupancy, while running the ventilation system at full capacity to exhaust the emissions.  A technique for reducing emissions of new construction materials and furnishings, in which the building temperature is raised (usually to at least 90 degrees F) for several days to enhance emissions of volatile compounds from new materials, while running the ventilation system at full capacity to exhaust the emissions.

Balance Heating:  This is the result of balancing the airflow of the central heating distribution system so that intake and output air exists at levels to maximize efficiency. The balancing of the distribution system assures that all areas of the home being served by the same heating or cooling system or any zone within the system receive approximately equal heated or cooled air.   

Balance Point:  The outdoor temperature at which no heating is needed.  The lowest outdoor temperature at which the refrigeration cycle of a heat pump will supply the heating requirements without the aid of a supplementary heat source.  An outdoor temperature, usually between 30° F and 45° F, at which a heat pump’s output exactly equals the heating needs of the home. Below the balance point, supplementary electric resistance heat is needed to maintain indoor comfort.The outdoor temperature at which a building’s heat loss to the environment is equal to internal heat gains from people, lights, and equipment.

Balanced Pressure:  When the both the inside and outside pressure of a container equal each other.

Balancing:  Process of adjusting the flow of air in duct systems, or water flow in hot-water heating systems.(1.) On a fan, the process of adding (or removing) weight on a rotor to move the center of gravity toward the axis of rotation. (2.) In a ventilation system, it’s the process of measuring or calculating the airflow at a branch and altering duct size or a valve to attain desired airflow at that branch.

Balancing By Static Pressure:  Method of designing local exhaust system ducts by selecting the duct diameters that generate the static pressure to distribute airflow without dampers.

Balancing Damper: Baffle or plate used to control the volume of flowing air in a confined area.

Ballast:  A coil of wire or electronic device that provides a high starting voltage for a lamp and limits the current flowing through it.  

Balloon Framing: In carpentry, the lightest and most economical form of construction in which the studding and corner plates are set up in continuous lengths from the first floor line or sill to the roof plate to which all floor joists are fastened.

Balusters: Usually small vertical members in a railing used between a top rail and the stair treads or a bottom rail. ~

Balustrade: A railing made up of balusters, top rail, and sometimes bottom rail, used on the edge of stairs, teal conies, and porches. ~

BAMT: Blood assay test for Mycobacterium tuberculosis. This is a general term which refers to recently developed in vitro (iv) diagnostic tests that assess for the presence of infection with M. tuberculosis, the term includes but is not limited to IGRA’s.  QuantiFERON®-TB Gold is the IGRA that was approved by the FDA in 2005 and is approved by the CDC as a diagnostic test for TB infection.

Band Joist:  A board that rests on the sill and covers the outside surface of the joists and the space between them.  Also referred to as header or rim joist.  See:  Rim Joist. 

Bank Full Capacity:  The rate of water flow that completely fills a channel (i.e.: the rate at which the water surface is level with the flood plain). The bank full state is the most effective or dominate channel-forming flow.

Banking: A provision in air district permit regulations that allows a facility to accumulate credits for reducing emissions beyond regulatory limits (emission reduction credits) and then use or sell those credits at a later date.  A provision in air district permit regulations that allows a facility to accumulate credits for reducing emissions beyond regulatory limits (emission reduction credits) and then use or sell those credits at a later date.

BAQ:   Building Air Quality.  

Bar:  Unit of pressure. 1 bar = 14.5 psi.

Bara:  The pressure of a system or device measured from absolute zero.

Barbiturates:  Barbiturates are a group of sedative/anesthetic drugs. Some of these have a high potential for abuse, and all are controlled drugs.

Barcad:  Device that samples water in a well in which water, collected in a discrete water-bearing zone, is forced to the surface by pressurized nitrogen.

Bare Floor Brush:  Used to clean bare floors.  Brush is skirted around the nozzle.  Performs well on tile and is effective on grout lines. Can also be used on walls or hardwood.

Bare Floor Nozzle:  Used to clean bare floors.  Hard nozzle is designed to increase airflow directly under the nozzle to suck up particles.  Performs well on hardwood and linoleum.  Cannot be used on walls or on tile very well.

Bare Floor Option/Selector:  Selector on the base of an upright that stops the agitator from rotating to go onto flooring.  A rotating agitator will not work well on bare floors.
Barg:  Bar gauge (similar to the acronym “psig”).

Barge: Horizontal beam rafter that supports shorter rafters.

Barge Board: A decorative board covering the projecting rafter (fly rafter) of the gable end. At the cornice, this member is a facie board.

Barometer: Instrument for measuring atmospheric pressure

Barometric Damper:  Also called draft damper, is a device installed in a chimney to allow for the adjustment of dilution air.

Barometric Pressure:  Is the absolute atmospheric pressure existing at any given point in the atmosphere. It is the weight of a unit column of gas directly above the point of measurement. It varies with altitude, moisture and weather conditions.  A measure of the atmospheric air pressure using an instrument called a barometer.

Barrel Roof: A roof design which in a cross section is arched.

Barren Liquor:  Liquor for cake washing, which contains little to no valuable liquor; as barren cyanide solution in gold cake slimes washing.

Base:  A compound that reacts with an acid to form a salt. It is another term for alkali.

Baseboard: Usually wood or vinyl installed around the perimeter of a room to cover the space where the wall and floor meet. A board placed against the wall around a room next to the floor to properly finish between the floor and the plaster. 

Baseboard Heat: A heating system with the heating unit located along the perimeter of the wall where the baseboard would normally be located. It can be either an electric or hot water system. 

Base Flashing: The upturned edge of a watertight membrane formed at a roof termination point by the extension of the felts vertically over the cant strip and up the wall for a varying distance where they are secured with mechanical fasteners.

Base Flow:  The part of stream flow contributed by ground water that seeps into surface streams.

Baseline:  We have all been exposed to some level of worldwide fallout contamination.  In the United States, the general population receives up to 0.015 mSv (1.5 mrem) (0.3% of the average total annual dose) from exposure to worldwide fallout contamination from atmospheric nuclear weapons testing and about 0.005 mSv (0.5 mrem) (or 0.1% of the average total annual dose) from operations related nuclear power generation. Similarly, people living in the Marshall Islands will have very small quantities of internally deposited fallout radionuclides such as cesium-137, strontium-90 and plutonium in their bodies from worldwide contamination of food, air, water and soil. Assessments of possible increases in radiation exposure from elevated levels of fallout contamination in the northern Marshall Islands can only be made on the basis of comparisons with residual systematic burdens of radionuclides acquired from previous exposures to global fallout contamination. Under the Marshall Islands Radiological Surveillance Program, efforts are being made to improve on the reliability of measurements of background urinary excretion rates of plutonium from Marshallese populations against which the results of future bioassay measurements can be compared to accurately assess the impacts of resettlement on radiation exposure and dose.

Basement Window Inserts: The window frame and glass unit that is installed in the window buck.

Base Molding: Molding used to trim the upper edge of interior baseboard. 

Base Plate:  A metallic structure on which a compressor or other machine is mounted.

Base Ply: An asphalt-saturated and/or coated felt installed as the first ply with 4 inch laps in a built-up roof system under the following felts which can be installed in a shingle-like fashion.

Base Shoe: Molding used next to the floor on interior base board. Sometimes called a carpet strip.

Base Temperature:  A fixed temperature in the definition of degree-days.  

Basin Plan:  See Water Quality Control Plan.

Basket:  Element of a basket strainer. Normally uses a screen as a medium for removal of course bulk solids.

Basket Strainer: Basket shaped strainer with holes allowing water to drain while catching food or other solids. Can also be closed to fill the sink with water.

Batt:  A narrow blanket of fiberglass insulation, generally 14.5" or 22.5" wide.

Batt Insulation: Strips of insulation, usually fiberglass, that fit between studs or other framing. 

Batten: Narrow strips of wood used to cover joints or as decorative vertical members over plywood or wide boards.

Batten Plate: A formed piece of metal designed to cover the joint between two lengths of metal edge.

Batter Board: One of a pair of horizontal boards nailed to posts set at the corners of an excavation, used to indicate the desired level, also used as a fastening for stretched strings to indicate outlines of foundation walls. Temporary structure that holds strings used to locate and square the corners of a building.

Bay Area Air Quality Management District (BAAQMD):  Local agency responsible for regulating stationary air emission sources (including the LLNL Livermore site) in the San Francisco Bay Area.

Bay Window: Any window space projecting outward from the walls of a building, either square or polygonal in plan.

BCEO:  Base Construction Engineering Officer.

Bead: In glazing, an applied sealant in a joint irrespective of the method of application, such as caulking bead, glazing bead, etc. Also a molding or stop used to hold glass or panels in position.

Bead Blast:  A preparatory step for concrete sealing. Steel pellets are shot at the concrete at high velocity, similar to sandblasting. The process removes old paint, flooring adhesives, etc., and roughens the concrete for better seal adhesion.

Bead Ring:  A ring used to attach certain bellow type flexible members of an air actuators to the mounting surface.

Beam:  A strong horizontal building support used to carry the weight of a floor or roof.  A supporting member either of wood or steel. Structural support member (steel, concrete, lumber) transversely supporting a load that transfers weight from one location to another.

Beam or Direct Radiation:  The solar radiation directly from the sun without changed angle or diffusion. Instruments for measuring direct radiation require for practical reasons a wider aperture so the measured radiation also contains radiation from the immediate region of the sky around the sun (called circum solar; see also diffuse radiation).  

Bear Furnace Filters:  You will be able to find that filter that is right for your Trion Air Bear™ whole house air cleaner at NordicPure.com. There are only 4 cabinet sizes in the Air Bear™ air cleaner family, so if you know the general dimensions of the air cleaner, you can find what you need by choosing 1 of the following four sizes: 20x25x5, 20x20x5, 16x25x5, or 16x25x3.  Nordic Pure carries Honeywell filters in sizes 16x25x5 and 20x25x5 and, as always, shipping is free!

Bearing:  Mechanical device for decreasing friction in a machine in which a moving part bears—that is, slides or rolls while exerting force—on another part. Usually in a bearing the support must allow the moving part one type of motion, for example, rotation, while preventing it from moving in any other way, for example, sidewise. The commonest bearings are found at the rigid supports of rotating shafts where friction is the greatest.

Bearing Header: (a) A beam placed perpendicular to joists and to which joists are nailed in framing for a chimney, stairway, or other opening. (b) A wood lintel. (c) The horizontal structural member over an opening (for example over a door or window).

Bearing Partition: A partition that supports any vertical load in addition to its own weight.

Bearing Point: A point where a bearing or structural weight is concentrated and transferred to the foundation.

Bearing Wall: A wall that supports any vertical load in addition to its own weight.

Beater Bar:  A component of a revolving brush roll that beats the carpet to bring up fine dust and soils from deep in the pile where it can be brushed from the surface and removed by the suction of the vacuum cleaner. Beater bars can be actual metal or plastic bars that are inserted into the revolving brush roll just like agitator brushes or they may be molded into the revolving brush roll in a wide variety of configurations. Stiff bristled agitator brushes can also produce a beating action.

Beckett Burner:  A burner assembly within your oil furnace, manufactured by Beckett to exact specifications of Carrier. This burner provides good combustion of heating oil.

Becquerel (Bq):  A Becquerel (abbreviated as Bq) is the International System (SI) unit for activity of radioactive material. One Bq of radioactive material is that amount of material in which one atom is transformed or undergoes one disintegration every second. Whole body counting and plutonium bioassay measurements are usually reported in activity units of kBq (kiloBecquerel) (1000 x 1 Bq) and µBq (microBecquerel) (1x10-6 x 1 Bq), respectively.  SI unit of activity of a radionuclide, equal to the activity of a radionuclide having one spontaneous nuclear transition per second.

Bed or Bedding: In glazing, the bead compound or sealant applied between a light of glass or panel and the stationary stop or sight bar of the sash or frame. It is usually the first bead of compound or sealant to be applied when setting glass or panels.

Bedbug:  Small, nocturnal, blood-sucking insects that live on humans or other live hosts.

Bed Depth:  The amount of adsorbent, expressed as units of length, parallel to the air stream, through which the air stream passes.

Bedford Scale:  A set of seven descriptors of subjective thermal response from Much Too Warm (7), Too Warm (6), Comfortably Warm (5), Comfortable, neither warm nor cool (4), Comfortably Cool (3), Too Cool (2), Much Too Cool (1). This differs from the ASHRAE scale in defining the central three categories as Comfortable.  

Bedload:  The particles in a stream channel that mainly move by jumping, sliding or rolling on or near the bottom of the stream.

Bed Molding: A molding in an angle, as between the over hanging cornice or eaves of a building and the side walls.

Bedrock: A subsurface layer of earth that is suitable to support a structure.

BEES:  See “Building for Environmental and Economic Sustainability.”

Bell Reducer: In plumbing, a fitting shaped like a bell which has one opening of a smaller diameter used to reduce the size of the pipe in the line, and the opposite opening of larger diameter. 

Bellows:  A corrugated cylindrical container which moves with a pressure change.

Below Grade: The portion of a building that is below ground level. 

Belt:  A rubber like, continuous loop placed between two or more pulleys to transfer a rotary motion.

Belt Filter Press:  Akin to a rotary drum and belt filter is an automatic pressure filter, where sludge is compressed on an endless rotating belt, dewatering and providing for very dry cake for discharge.

Beneficial Uses of Water:  Water used for the following purposes: domestic (homes, human consumption, etc.), irrigation (crops, lawns), power (hydroelectric), municipal (water supply of a city or town), mining (hydraulic, drilling), industrial (commerce, trade, industry), fish and wildlife preservation, aquaculture (raising fish etc. for commercial purposes), recreational (boating, swimming), stock watering (for commercial livestock), water quality, frost protection (misting or spraying crops to prevent frost damage), heat control (water crops to prevent heat damage), ground water recharge, agriculture, etc.

Benefit/Cost Analysis:  An economic method for assessing the benefits and costs of achieving alternative health-based standards at given levels of health protection.

Benign:  Not malignant. A benign tumor is one which does not metastasize or invade tissue. Benign tumors may still be lethal, due to pressure on vital organs.

Bent Glass:  Flat glass that has been shaped while hot into curved shapes. 

Benzene:  A clear, colorless, highly refractive flammable liquid derived from petroleum and used in or to manufacture a wide variety of chemical products, including DDT, insecticides, and motor fuels. Also called benzine.  A major organic intermediate and solvent derived from coal or petroleum. The simplest member of the aromatic series of hydrocarbons.

Benzocaine Hydrochloride:  Benzocaine is a local anesthetic, often used topically in human medicine. It is also used to kill amphibians and fish.

Bernoulli’s Principle:  In physics, the concept that as the speed of a moving fluid (liquid or gas) increases, the pressure within that fluid decreases. Originally formulated in 1738 by the Swiss mathematician and physicist Daniel Bernoulli, it states that the total energy in a steadily flowing fluid system is a constant along the flow path. An increase in the fluid’s speed must therefore be matched by a decrease in its pressure. 
Bernoulli’s principle applies in nozzles, where flow accelerates and pressure drops as the tube diameter is reduced. It is also the principle behind orifice or Venturi flow meters. These meters measure the pressure difference between a low-speed fluid in an approach pipe and the high-speed fluid at the smaller orifice diameter to determine flow velocities and thus to meter the flow rate. Bernoulli’s principle is sometimes mistakenly used to explain the net force in a system that includes a moving fluid, such as lift on an airplane wing, thrust of a ship’s propeller, or drifting of a spinning baseball. The principle, however, only applies to systems that do not produce a net force.  In stream of liquid, the sum of elevation head, head pressure, and velocity remains constant along any line of flow, provided no work is done by or upon liquid on course of its flow; decreases in portion to energy lost in flow. 

Beryl:  A silicate of beryllium and aluminum.

Best Air Conditioner (ac) or Furnace Filter(s):  We at Nordic Pure feel we offer the very best air conditioner filter(s) on the market today.  Our Electrostatic Pleated Air Filters come with a MERV 12 rating.  In addition to a higher quality media filter material and pleats for increased surface area for filtration, Electrostatic Pleated Air Filters are also electrostatic meaning that the filter media material is electrically charged so that the media material acts much like a magnet to draw more particulate into the media filter material for more efficient filtration.  Another benefit of the electrostatic material is that it does not permit the growth of bacteria, often a problem with other filters.  Nordic manufactures and sells only Electrostatic Pleated Air Filters in a wide variety of lengths and widths with thicknesses from 1" to 5".
Best Air Filter for Allergies:  Any substance (allergen) that causes an allergic reaction when you are exposed to it is an allergy trigger.  In your home you want a filter that will remove as much dust and particles from the air as possible.  Our Nordic Pure MERV 12 electrostatically-charged air filters are rated as providing the highest efficiency of an air filter while not overtaxing the HVAC system.  MERV12 requires 80% or better air filter efficiency on 1 - 3 micron particles and a greater than 90% air filter efficiency on 3 -10 micron airborne particles when tested in accordance with ASHRAE Test Standard 52.2 used in testing air filters and air filter efficiency.  Our air filters measured 97.8% air filter efficiency in removing airborne particles 3-10 microns in size and 84.1% air filter efficiency in removing airborne 1-3 microns in size and 60% air filter efficiency for smaller particles.

Best Air Filter for Home:  Most people are aware that outdoor air pollution can damage their health but may not know that indoor air pollution can also have significant effects. EPA studies of human exposure to air pollutants indicate that indoor air levels of many pollutants may be 2-5 times, and occasion more than 100 times, higher than outdoor levels. These levels of indoor air pollutants are of particular concern because it is estimated that most people spend as much as 90% of their time indoors.  Unlike outdoor air, indoor air is recycled again and again. This causes it to trap and build up pollutants. Common pollutants include dust, mold and spores, pollen, pet dander and smoke.  We at Nordic Pure want to ensure that you and your family are breathing air that is as clean as possible.  Therefore, you can trust Nordic Pure to provide an air filter for your home that has a rating of MERV 12 – minimizing the invasion of life-robbing air pollutants like dust, dirt, pollen and other airborne particulates.  We give the same consideration to the quality of the air passing through the cooling and heating system and into the living area of your home as we do to our own.
Best Air Filtration System:  According to the Department of Health and Human Services, Centers for Disease Control and Prevention, and the National Institute for Occupational Safety and Health (NIOSH), there are many factors to keep in mind when determining the best filtration system for your needs.  See their website http://www.cdc.gov/niosh/docs/2003-136/pdfs/2003-136.pdf for a complete, thorough report.

Best Air Purifier(s):  Look at the chart below to see Air Purifier Performance Test Results.  Test done by Air Purifiers America, Inc.  Overview:  We tested models from 6 manufacturers at our offices with a high-tech particle counter to measure the ability to remove particles from the air which are 0.3 microns and larger.  This represents all pollen, mold spores, pet dander and most of the dust in a home.  Recommendations: We highly recommend the IQAir, Alen or BlueAir air purifiers as these units remove over 95% of all air borne particles. We do not recommend the Friedrich C-90, Ionic Breeze or Oreck XL air cleaners as they generate ozone which is harmful to the body according to laboratory research conducted by California DHS' Indoor Air Quality Program. A detailed review of each of these units are listed below.

IQAir HealthPro ($699):  The IQAir model was the top performer and removed 100% of the particles when measured at the air output and removed 98% of the particles in the room after running for 20 minutes. The IQAir uses only HEPA filters and performed equally well at each fan speed.
Alen A350 ($399) and Alen A375UV ($499):  Both Alen air purifier units removed 98% of the particles at the unit and 97% of the particles in the room.  Both units use the same HEPA technology and the difference is the A375UV has a carbon filter plus 2 UV lamps.  These two units perform as well as the more expensive units like IQAir and BlueAir in dust and pollen removal, but cost half as much.  The other advantage to these units is the low filter replacement cost which is economical to own and operate.  These two units are available from Nordic Pure, and as always, shipping is free!

Best Available Control Measure (BACM): A term used to describe the “best” measures (according to U.S. EPA guidance) for controlling small or dispersed sources of particulate matter and other emissions from sources such as roadway dust, woodstoves, and open burning.  

Best Available Control Technology (BACT): The most up-to-date methods, systems, techniques, and production processes available to achieve the greatest feasible emission reductions for given regulated air pollutants and processes. BACT is a requirement of NSR (New Source Review) and PSD (Prevention of Significant Deterioration). An emission limitation based on the maximum degree of emission reduction (considering energy, environmental, and economic impacts) achievable through application of production processes and available methods, systems, and techniques. BACT does not permit emissions in excess of those allowed under any applicable Clean Air Act provisions. Use of the BACT concept is allowable on a case-by-case basis for major new or modified emissions sources in attainment areas and applies to each regulated pollutant.

Best Available Retrofit Technology (BART): Under NAAQS, EPA requires states to make a BART analysis to predict the effect of forcing all plants to install scrubbers. States must then either carry out the forced scrubbing program, or create a state cap and trade system.

Best Available Retrofit Control Technology (BARCT): An air emission limitation that applies to existing sources and is based on the maximum degree of reduction achievable, taking into account environmental, energy, and economic impacts by each class or category of source. (See also Best Available Control Technology.)  Under NAAQS, EPA requires states to make a BART analysis to predict the effect of forcing all plants to install scrubbers. States must then either carry out the forced scrubbing program, or create a state cap and trade system. 

Best Dust Collector:  One of the five principle types of dust collectors are electrostatic precipitators.  Electrostatic filters contain electrostatically enhanced fibers, which
actually attract the particles to the fibers, in addition to retaining them.  Electrostatic filters rely on charged fibers to dramatically increase collection efficiency for a given pressure drop across the filter.  Nordic Pure’s filters are not only a MERV 12 rating, but are also electrostatically-charged, pleated filters which mean they not only attract and retain air particulates, but the pleats provide a larger surface on which to contain the pollutants.

Key Features:
• Pre-filter/Allergy-HEPA Filter/Enhanced Activated Carbon Filter all-in-one makes filter changing easy
• Effectively removes smoke, pollen, dust, animal dander, dust mites, molds, bacteria and viruses
• Enhanced activated carbon for even greater odor removal
• 2 UV lamps for bacteria removal
• 4-speed settings & 12 hour timer
• Dust sensor and Odor sensor
• Wall-mountable space saving design
• Built-in Ionizer
• Filter replacement indicator
• Digital display with simple and intuitive touch button control
• Unique safety feature has power auto-off protection when front cover removed
• Remote control

Specifications:
• Type: Allergy-HEPA air filter
• Power: 120V
• Noise: ≤65dB
• Room Size: Up to 800 square feet; 400 square feet
  for best performance
• Unit Size: 18.5" x 8.23" x 17.48"
• Unit Packaging: 21.42" x 9.92" x 20.24"
• Unit Weight: 19 lbs

Best Home Air Filter(s):  We at Nordic Pure feel we offer the very best product on the market today when it comes to home air filters.  Our MERV 12 Electrostatic Pleated Air Filters are a more highly evolved version of the pleated air filter. In addition to a higher quality media filter material and pleats for increased surface area for filtration, Electrostatic Pleated Air Filters are also electrostatic meaning that the filter media material is electrically charged so that the media material acts much like a magnet to draw more particulate into the media filter material for more efficient filtration. Another benefit of the electrostatic material is that it does not permit the growth of bacteria, often a problem with other filters. Nordic manufactures and sells only Electrostatic Pleated Air Filters in a wide variety of lengths and widths with thickness from 1" to 5".
Best Management Practices (BMP):  A practice which is determined to be the most effective and practicable method of preventing or reducing the amount of pollution generated by pollution sources. Determination is made after public participation and review of all other alternatives (From the Federal Water Pollution Control Act).

Best Rated Air Filters:  HEPA filters can remove at least 99.97% of airborne particles 0.3 micrometers (µm) in diameter. Particles of this size are the most difficult to filter and are thus considered the most penetrating particle size (MPPS). Particles that are larger or smaller are filtered with even higher efficiency.
HEPA filters are composed of a mat of randomly arranged fibers. Key metrics affecting function are fiber density and diameter, and filter thickness. The air space between HEPA filter fibers is much greater than 0.3 μm. The common assumption that a HEPA filter acts like a sieve where particles smaller than the largest opening can pass through is incorrect. Just as for membrane filters, particles so large that they are as wide as the largest opening or distance between fibers can not pass in between them at all. But HEPA filters are designed to target much smaller pollutants and particles are mainly trapped (they stick to a fiber) by one of the following three mechanisms:

1. Interception, where particles following a line of flow in the air stream come within one radius of a fiber and adhere to it.
2. Impaction, where larger particles are unable to avoid fibers by following the curving contours of the air stream and are forced to embed in one of them directly; this increases with diminishing fiber separation and higher air flow velocity.
3. Diffusion, an enhancing mechanism is a result of the collision with gas molecules by the smallest particles, especially those below 0.1 µm in diameter, which are thereby impeded and delayed in their path through the filter; this behavior is similar to Brownian motion and raises the probability that a particle will be stopped by either of the two mechanisms above; it becomes dominant at lower air flow velocities.

Diffusion predominates below the 0.1 μm diameter particle size. Impaction and interception predominate above 0.4 μm. In between, near the 0.3 μm MPPS, diffusion and interception predominate.
The initial filter air flow resistance and final filter air flow resistance are typically measured as pressure drop across the filters.
Best Way to Remove Dust:  The National Institute of Allergy and Infectious Diseases says:  If you are dust-sensitive, especially if you have allergies and/or asthma, you can reduce some of your misery by creating a “dust-free” bedroom. Dust may contain molds, fibers, and dander from dogs, cats, and other animals, as well as tiny dust mites. These mites, which live in bedding, upholstered furniture, and carpets, thrive in the summer and die in the winter. They will, however, continue to thrive in the winter if the house is warm and humid. The particles seen floating in a shaft of sunlight include dead mites and their waste products. The waste products actually provoke the allergic reaction.
The routine cleaning necessary to maintain a dust-free bedroom also can help reduce exposure to cockroaches, another important cause of asthma in some allergic people.
You probably cannot control dust conditions under which you work or spend your daylight hours. To a large extent, however, you can eliminate dust from your bedroom. To create a dust-free bedroom, you must reduce the number of surfaces on which dust can collect.
In addition to getting medical care for your dust allergy and/or asthma, the National Institute of Allergy and Infectious Diseases suggests the following guidelines.

• Completely empty the room, just as if you were moving.
• Empty and clean all closets and, if possible, store contents elsewhere and seal closets.
• Keep clothing in zippered plastic bags and shoes in boxes off the floor, if you cannot store them elsewhere.
• Remove carpeting, if possible.
• Clean and scrub the woodwork and floors thoroughly to remove all traces of dust.
• Wipe wood, tile, or linoleum floors with water, wax, or oil.
• Cement any linoleum to the floor.
• Close the doors and windows until the dust-sensitive person is ready to use the room.

• Wear a filter mask when cleaning.
• Clean the room thoroughly and completely once a week.
• Clean floors, furniture, tops of doors, window frames and sills, etc., with a damp cloth or oil mop.
• Carefully vacuum carpet and upholstery regularly.
• Use a special filter in the vacuum.
• Wash curtains often at 130 degrees Fahrenheit.
• Air the room thoroughly.

Carpeting makes dust control impossible. Although shag carpets are the worst type to have if you are dust sensitive, all carpets trap dust. Therefore, health care experts recommend hardwood, tile, or linoleum floors. Treating carpets with tannic acid eliminates some dust mite allergen. Tannic acid, however, is

• Not as effective as removing the carpet
• Is irritating to some people
• Must be applied repeatedly

Keep only one bed in the bedroom. Most importantly, encase box springs and mattress in a zippered dust-proof or allergen-proof cover. Scrub bed springs outside the room. If you must have a second bed in the room, prepare it in the same manner.
Use only washable materials on the bed. Sheets, blankets, and other bedclothes should be washed frequently in water that is at least 130 degrees Fahrenheit.

• Lower temperatures will not kill dust mites.
• If you set your hot water temperature lower (commonly done to prevent children from scalding themselves), wash items at a laundromat which uses high wash temperatures.

Use a synthetic, such as Dacron, mattress pad and pillow. Avoid fuzzy wool blankets or feather- or wool-stuffed comforters and mattress pads.

• Keep furniture and furnishings to a minimum.
• Avoid upholstered furniture and blinds.
• Use only a wooden or metal chair that you can scrub.
• Use only plain, lightweight curtains on the windows.

Air filters-either added to a furnace or a room unit-can reduce the levels of allergens. Electrostatic and HEPA (high-efficiency particulate absorption) filters can effectively remove many allergens from the air. If they don’t function right, however, electrostatic filters may give off ozone, which can be harmful to your lungs if you have asthma.
A dehumidifier may help because house dust mites need high humidity to live and grow. You should take special care to clean the unit frequently with a weak bleach solution (1 cup bleach in 1 gallon water) or a commercial product to prevent mold growth. Although low humidity may reduce dust mite levels, it might irritate your nose and lungs.

In addition to the above guidelines, if you are caring for a child who is dust-sensitive

• Keep toys that will accumulate dust out of the child’s bedroom
• Avoid stuffed toys
• Use only washable toys of wood, rubber, metal, or plastic
• Store toys in a closed toy box or chest

Keep all animals with fur or feathers out of the bedroom. If you are allergic to dust mites, you could also be allergic or develop an allergy to cats, dogs, or other animals.
Although these steps may seem difficult at first, experience plus habit will make them easier. The results – better breathing, fewer medicines, and greater freedom from allergy and asthma attacks – will be well worth your effort.

Bet Method:  A method used to measure the surface area of granular activated carbon.

Betamesh®:                   A type of dutch weave wire cloth. 

Beta Particle:  Negatively charged particle emitted from the nucleus of an atom, having charge, mass, and other properties of an electron.

Beta Ratio:  Efficiency measurement of any filter expressed by the number of particles of a given size upstream of the filter, divided by the number of particles of that size downstream of the filter.  

Better Air:  Air that is void of airborne dust, pollen, mold spores, pet dander, bacteria and particulates carrying bacteria and viruses in the air.

Better Air Filters:  HEPA filters can remove at least 99.97% of airborne particles 0.3 micrometers (µm) in diameter. Particles of this size are the most difficult to filter and are thus considered the most penetrating particle size (MPPS). Particles that are larger or smaller are filtered with even higher efficiency.
HEPA filters are composed of a mat of randomly arranged fibers. Key metrics affecting function are fiber density and diameter, and filter thickness. The air space between HEPA filter fibers is much greater than 0.3 μm. The common assumption that a HEPA filter acts like a sieve where particles smaller than the largest opening can pass through is incorrect. Just as for membrane filters, particles so large that they are as wide as the largest opening or distance between fibers can not pass in between them at all. But HEPA filters are designed to target much smaller pollutants and particles are mainly trapped (they stick to a fiber) by one of the following three mechanisms:

4. Interception, where particles following a line of flow in the air stream come within one radius of a fiber and adhere to it.
5. Impaction, where larger particles are unable to avoid fibers by following the curving contours of the air stream and are forced to embed in one of them directly; this increases with diminishing fiber separation and higher air flow velocity.
6. Diffusion, an enhancing mechanism is a result of the collision with gas molecules by the smallest particles, especially those below 0.1 µm in diameter, which are thereby impeded and delayed in their path through the filter; this behavior is similar to Brownian motion and raises the probability that a particle will be stopped by either of the two mechanisms above; it becomes dominant at lower air flow velocities.

Diffusion predominates below the 0.1 μm diameter particle size. Impaction and interception predominate above 0.4 μm. In between, near the 0.3 μm MPPS, diffusion and interception predominate.
The initial filter air flow resistance and final filter air flow resistance are typically measured as pressure drop across the filters.
Better Air Quality:  The cleaner the air, the better the air quality.

Bevel: The angle of the front edge of a door usually from 1/8" to 2".

Bevel Siding (or Lap Siding): Wedge-shaped boards used as horizontal siding in a lapped pattern. This siding varies in butt thickness from ½ to ¾ inch and in widths up to 12 inches. Normally used over some type of sheathing. 

BFC:  Base Fire Chief.

BHP:  ACRONYM – Break horse power.

BHR:   Bronchial hyper-responsiveness. Describes airways that narrow too easily or too much in response to a provoking stimulus.  

Biaxially Stretched Membrane:  A microporous membrane from either polypropylene or PTFE that has been stretched in both the MD and CD direction in a manner to form pores of a controlled size and possessing a narrow pore size distribution.

Bicarbonate:  An acid carbonate.

Bicycle Awareness Program: 
Bicycling is important to the health of Californians – and not just those doing the cycling.  Statewide, about seven tons per day of smog-forming gases and almost a ton of inhalable particles are spared from the air we breathe due to use of bicycles rather than motor vehicles.  People choosing to pedal rather than drive usually replace short automobile trips that are disproportionately high in pollutant emissions.  The ARB is attempting to increase public awareness of this alternative mode of transportation.

Improving California Air Quality Through Increased Bicycling: A Fact Sheet (revised April 2005)
 
California Bike Summit brochure (PDF –– 205 KB):  Presents the outcome of a statewide strategy meeting to chart ways to increase bicycle usage in California.  For printed hard copies of this brochure, please contact Tom Scheffelin at (916) 327-7847, or via email at tscheffe@arb.ca.gov..
Links:

Caltrans Bicycle Program
http://www.dot.ca.gov/hq/tpp/offices/bike/bicycle_prgm.htm

Caltrans Deputy Directive (DD-64) calls for the full consideration of the needs of bicyclists and pedestrians in all phases of transportation projects.
http://www.calbike.org/pdfs/Caltrans_DD-64.pdf

California Department of Motor Vehicles Bicycle Page
http://www.dmv.ca.gov/about/bicycle.htm

California Vehicle Code excerpts relating to the operation and equipping of bicycles.
http://www.bikelink.com/law_safety.asp

California Bicycle Coalition
http://www.calbike.org

Bikes Belong
http://bikesbelong.org/site/intro.cfm

Active Transportation
http://www.activetransportation.org

Bid: A formal offer by a contractor, in accordance with specifications for a project, to do all or a phase of the work at a certain price in accordance with the terms and conditions stated in the offer.

Bid Bond: A bond issued by a surety on behalf of a contractor that provides assurance to the recipient of the contractor’s bid that, if the bid is accepted, the contractor will execute a contract and provide a performance bond. Under the bond, the surety is obligated to pay the recipient of the bid the difference between the contractor’s bid and the bid of the next lowest responsible bidder if the bid is accepted and the contractor fails to execute a contract or to provide a performance bond. 

Bid Documents: Drawings, details, and specifications for a particular project. 

Bid Security: Funds or a bid bond submitted with a bid as a guarantee to the recipient of the bid that the contractor, if awarded the contract, will execute the contract in accordance with the bidding requirements of the contract documents.

Bid Shopping: A practice by which contractors, both before and after their bids are submitted, attempt to obtain prices from potential subcontractors and material suppliers that are lower than the contractors’ original estimates on which their bids are based, or after a contract is awarded, seek to induce subcontractors to reduce the subcontract price included in the bid.

Bidding Requirements: The procedures and conditions for the submission of bids. The requirements are included on documents, such as the notice to bidders, advertisements for bids, instructions to bidders, invitations to bid, and sample bid forms. 

Bi Fan: Centrifugal fan with backward inclined blades that move air more efficiently than straight blade fans. BI fans are usually on the clean side of a piece of control equipment as the blades are not especially abrasion resistant.

Bifold Door: Doors that are hinged in the middle to allow them to open in a smaller area than standard swing doors. Often used for closet doors.

Big Five Energy Sources:  Coal, oil, natural gas, large-scale hydroelectric, and nuclear power.

Bimetal:  A temperature regulating or indicating device which works on the principal that two dissimilar metals with unequal expansion rates, welded together and will bend as their temperature changes.

Bimetal Element:  A metal spring, lever, or disc made of two dissimilar metals that expand and contract at different rates as the temperature around them changes. This movement operates a switch in the control circuit of a heating or cooling device.  

Binder: A receipt for a deposit to secure the right to purchase a home at an agreed terms by a buyer and seller. 

Binding:  Water vapor or droplets that interfere with particulate capture.

Bioaccumulants:  Substances that increase in concentration in living organisms as they take in contaminated air, water, or food because the substances are very slowly metabolized or excreted.

Bioaccumulation:  The process by which the concentrations of some toxic chemicals gradually increase in living tissue, such as in plants, fish, or people as they breathe contaminated air, drink contaminated water, or eat contaminated food.

Bioactivation Enzymes: Produced in cells and are capable of speeding up chemical reactions necessary for life. When affected by toxins these enzymes can malfunction and produce reactive metabolites. 

Bioaerosol:  An airborne dispersion of particles containing whole or parts of biological entities, such as bacteria, viruses, dust mites, fungal hyphae, or fungal spores. 

Bioaerosols:  Microscopic living organisms suspended in the air that grow and multiply in warm, humid places.

Bio-Antibody Filter:  Airborne viruses are captured by the power of the bio-antibodies and then quickly removed. They work in the same way as an influenza vaccination. Bio-antibody filters are made using EGG antibody and excel in the removal of viruses.

Bioassay:  Laboratory analytical test in which the effects of a waste stream or effluent upon living organisms are measured.  Diverse sets of analytical methodologies, which utilize living organisms –applications range from assessment of water pollutants to screening pharmaceuticals.

Bioburden:  The load or level of microorganisms in a substance to be filtered.  

Biochemical:  Pertaining to chemical change resulting from biological action.

Biochemical Action:  Chemical change resulting from the metabolism of living organisms.

Biochemical Oxidation:  An oxidation brought about by biological activity that results in chemical combination of oxygen with organic material.

Biochemical (Biological) Oxygen Demand (BOD):  An empirical test in which standardized laboratory procedures are used to determine the relative oxygen requirements of wastewaters, effluents, and polluted waters.  Measure of the amount of dissolved oxygen that microorganisms need to break down organic matter in water, used as an indicator of water quality.

Biocide:   Any poison that kills a living organism.  Substances such as antibiotics, bacterialcides, or fungicides that are capable of destroying living organisms. 

Biocontaminant:  Contaminants that are either life forms (e.g., bacteria) or are derived from living things (e.g., rodent droppings).

Biodegradability:   The ability of an organic material to break down or change into a natural substance such as water or carbon dioxide.

Biodegradable:   Able to break down or decompose rapidly under natural conditions. Materials that can be decomposed when discarded by the normal action of bacteria and fungi. Typical examples are paper and wood products, natural fibers and starches.  Waste material composed primarily of constituent parts that occur naturally, are able to be decomposed by bacteria or fungi, and are absorbed into the ecosystem. Wood, for example, is biodegradable, while plastics are not.

Biodegradation:  The destruction or mineralization of either natural or synthetic organic materials by the microorganisms populating soils, natural bodies of water, or wastewater treatment system.

Biodiversity:  A large number and wide range of species of animals, plants, fungi and microorganisms. Ecologically, wide biodiversity is conducive to the development of all species.

Bioeffluent:  Any odorous volatile organic compound emitted by human beings, usually through perspiration or exhalation.

Bioengineering:  Creation of new organisms with specific attributes through the insertion of the appropriate genetic material into the original organisms genome.

Biogenic Source: Biological sources such as plants and animals that emit air pollutants such as volatile organic compounds. Examples of biogenic sources include animal management operations, and oak and pine tree forests. (See also natural sources.)  

Biohazard:  The term “Biohazard” is used to describe any time of biological waste. Often, this biological waste is pathogenic in nature or contaminated in some way.  A combination of the words biological hazard. Organisms or products of organisms that present a risk to humans. 

Biohazardous Materials: Infectious agents, the products of infectious agents, or the components of infectious agents presenting a risk of injury or illness.

Bio-HEPA Filter: High-efficiency media air filter designed to be 95% efficient on 0.3 micron and larger particles when clean.

Biokinectic:  The word ‘biokinectic’ is used here to describe the adsorption (uptake), distribution and retention of elements in humans.

Biological Contaminants:   Agents derived from or that are living organisms (e.g., viruses, bacteria, fungi, and mammal and bird antigens) that can be inhaled and can cause many types of health effects including allergic reactions, respiratory disorders, hypersensitivity diseases, and infectious diseases. Also referred to as “microbiologicals” or “microbials.”

Biological Impoverishment:  The loss of variety in the biosphere (even when species have not gone completely extinct).

Biological Monitoring:  Analysis of exhaled air, a biological fluid (e.g., urine, blood, perspiration), or a body component (e.g., hair, nails) to assess the extent to which an individual has been exposed.

Biological Oxidation:  The process whereby living organisms in the presence of oxygen convert the organic matter contained in wastewater into a more stable or a mineral form.

Biological Oxygen Demand (BOD):  A measure of the amount of oxygen consumed in the biological processes that break down organic matter in water. BOD is used as an indirect measure of the concentration of biologically degradable material present in organic wastes. It usually reflects the amount of oxygen consumed in five days by biological processes breaking down organic waste. BOD can also be used as an indicator of pollutant level, where the greater the BOD, the greater the degree of pollution. Also referred to as “biochemical oxygen demand.”

Biological Productivity:  Nature’s capability to reproduce and regenerate, thereby accumulating biomass.

Biological Safety Cabinets – Installation:  Biological safety cabinets should be installed in accordance with AS 2647, with particular attention to selecting locations away from sources of air movements that could influence cabinet airflows.  A comprehensive Gelaire manual is available to assist with cabinet installations.

Biological Contamination:  Contamination of a building environment caused by bacteria, molds and their spores, pollen, viruses, and other biological materials. It is often linked to poorly designed and maintained HVAC systems. People exposed to biologically contaminated environments may display allergic-type responses or physical symptoms such as coughing, muscle aches and respiratory congestion.

Biomagnification:  The increasing concentration of a substance as it passes into higher trophic levels of a food web. Many bioaccumulants are also biomagnified.

Biomass:  Energy produced from biological sources, such as wood, grain and animal manure. Biomass energy can be released through combustion, gasification or conversion to alcohol.  Plant matter such as trees, grasses, agricultural crops or other biological material. It can provide a renewable source of electrical power, fuel, or chemical feedstocks.

Biome:  A large-scale category that includes many communities of a similar nature.

Bioremediation:  A process that uses microorganisms to change toxic compounds into non-toxic compounds.  The use of bacteria and other small organisms (such as single-celled and multicellular microbes and fungi) to clean up or reduce unwanted concentrations of certain substances: also known as biotreatment.

Biosafety:  Biological safety or non-toxicity of a substance to a living organism by passing tests as listed in the United States Pharmocopeia. Analogous to “chemically inert.”  For filters used in biological and health care application, Plastic Class-VI tests apply, which include Systemic Injection, Intracutaneous and Implantation Tests. 

Biosafety Cabinet 1: A ventilated cabinet which serves as a primary containment device for operations involving biohazard materials. The three classes of biosafety cabinets are described below:
Class I Biosafety Cabinet: The Class I biosafety cabinet is an open-fronted negativepressured ventilated cabinet with a minimum inward average face velocity at the work opening of at least 75 feet per minute. The exhaust air from the cabinet is filtered by a HEPA filter and discharged without recirculation.
Class II Biosafety Cabinet: The Class II biosafety cabinet is an open-fronted, ventilated cabinet. Exhaust air is filtered with a high efficiency particulate air filter (HEPA). This cabinet provides HEPA-filtered downward airflow within the workspace. Class II Cabinets are further classified as type A, type B1, type B2 and type B3. Class II, type A biosafety cabinets may have positive pressure contaminated internal ducts and may exhaust HEPA-filtered air back into the laboratory. Shall provide a minimum inward average face velocity of 75 feet per minute at the work opening.
Class II type B1 cabinets have all biologically contaminated internal ducts or plenums under negative pressure or surrounded by negative pressure ducts or plenums, exhaust HEPA filtered air through external ducts to space outside the laboratory, and have HEPA filtered downflow air composed largely of unrecirculated inflow air.
Class II type B2 cabinets (also know as “total exhaust” cabinets) have all biologically contaminated internal ducts or plenums under negative pressure or surrounded by negative pressure ducts or plenums, exhaust HEPA filtered air through external ducts to space outside the laboratory, and have HEPA filtered downflow air drawn from the laboratory or outside air.  Class II type B3 cabinets (also known as “convertible” cabinets) have all biologically contaminated internal ducts or plenums under negative pressure or surrounded by negative pressure ducts or plenums, exhaust HEPA filtered air through external ducts to space outside the laboratory, and have HEPA filtered downflow air that is a portion of the mixed downflow and inflow air from a common exhaust plenum.
Class III Biosafety Cabinet: The Class III biosafety cabinet is a totally enclosed, negative pressure, ventilated cabinet of gas-tight construction. Operations within the Class III cabinet are conducted through protective gloves. Supply air is drawn into the cabinet through high-efficiency particulate air filters. Exhaust air is filtered by two high efficiency particulate air filters placed in series or by high efficiency particulate air filtration and incineration, and discharged to the outdoor environment without recirculation.

Bio Safety Hood Classification:

• The Class I Biosafety cabinet is a ventilated cabinet with in inward airflow and outlet HEPA filters. It was previously referred to as the CDC Hood and served a valuable function in its time by protecting personnel and environment. Because it offers no product protection, it has been essentially obsolete for the past several decades.
• Class II (Types A and B) are Laminar Flow Biological Safety Cabinets that protect personnel, product and environment. They provide inward airflow to protect personnel, downflow HEPA filtered air to the rok area to protect the product and exhaust HEPA filtered air to protect the environment from particulate and aerosol hazards.
•  Class III cabinet is defined as a ventilated glovebox. This is a gas-tight chamger operated through sealed gloves which provide a complete barrier between the worker and hazardous material. The glovebox is maintained under negative pressure with HEPA filtered supply air and double HEPA filtered exhaust air.

Biosafety Level: Biosafety levels consist of laboratory practices and techniques, safety equipment, and a laboratory facility appropriate for the operations performed and the hazard posed by the particular biohazard material. The Centers for Disease Control (CDC) and the National Institute of Health (NIH) define the four biosafety levels in the publication, Biosafety in Microbiological and Biomedical Laboratories, 1988 and revisions, and recommend biosafety levels for particular pathogenic microorganisms.  Four biosafety levels (BSL 1, 2, 3, or 4), consist of combinations of laboratory practices and techniques, safety equipment and laboratory facilities. Each combination is specifically appropriate for the operations performed, the documented or suspected routes of transmission of the infectious agents and for the laboratory function or activity.

Biosolids:  Residuals generated by the treatment of wastewater with activated sludge. See Activated Sludge. Nutrient-rich organic materials that come from processing of domestic sewage in a treatment facility. When treated and processed, biosolids can be recycled and applied as fertilizer to improve and maintain productive soils and stimulate plant growth.

Biosphere:  (1.) The part of the earth and its atmosphere in which living organisms exist or that is capable of supporting life.  (2.) The ecosystem composed of the earth and the living organisms inhabiting it.

Biostimulatory:  Promote or enhance biologic activity.

Biostimulatory Substances:  Constituents (e.g. nutrients, temperature, etc.) that promote or enhance biologic activity.

Biota:  The plant and animal life of a region.

Bioterrorism:  Using living things, such as pathogenic organisms like anthrax, for terrorist activities.

Biotoxin:  In the cleaning industry this term typically refers to toxins produced by living organisms and may include toxic molds, toxins produced by bacteria, algaes, etc.

Biotransformation:  Transformation of one chemical to others by populations of microorganisms in the soil.

BIPAP (Bi-Level Positive Airway Pressure) Machine: A breathing machine that uses two pressure levels (inspiratory and expiratory) to provide breathing assistance. This machine is often used for patients with sleep apnea or respiratory failure.

Bipass Doors: Doors that slide by each other. Commonly used as closet doors.

Bipolar:  Have two (opposing) poles, (+) and (-) as applied to ionic charges or particles.

Bird’s-mouth Cut: A cutout in a rafter where it crosses the top plate of the wall providing a bearing surface for nailing.  Also called a heel cut.

Bite: The dimension by which the framing system overlaps the edge of the glazing infill.

Bitumen: Any of various mixtures of hydrocarbons occurring naturally or obtained through the distillation of coal or petroleum.  (See Coat Tar Pitch and Asphalt).

Bituminous Coal: The most common coal. It is dense and black (often with well-defined bands of bright and full material). Its moisture content usually is less than 20 percent. It is used for generating electricity, making coke, and space heating. Comprises five groups classified according to the following ASTM Specification D388-84.
LV = Low volatile bituminous coal
= Medium volatile bituminous coal
A = High volatile A bituminous coal
B = High volatile B bituminous coal
C = High volatile C bituminous coal

Black Body:  A perfect absorber and emitter of electromagnetic radiation (light, heat etc). A black body absorbs all radiation without any reflection (see also absorption). A cavity is a perfect black body. Lampblack is close to a black body, while aluminum (polished) is a poor absorber and emitter of radiation.

Black Pigment:  The material that gives damaged human lungs a black and sooty appearance.

Black Wall:  The Black Wall is an occurrence common with ionic air purifiers. The “Black Wall Effect” happens when the air around an ionic type air purifier becomes negatively charged. This negatively charged area causes airborne particles to stick to surrounding surfaces (often the wall behind the device) and cause a build up of dirt and bacteria. Black Wall can be a breeding ground for microscopic organisms.  

Blackwater:  Water that contains animal, human, or food waste.  Liquid and solid human body waste and the carriage water generated through toilet usage.  Wastewater from toilets and urinals, which contains pathogens that must be neutralized before the water can be safely reused. After neutralization, black water is typically used for non-potable purposes, such as flushing or irrigation.

Blankets:  Fiber-glass or rock-wool insulation that comes in long rolls 15 or 23 inches wide.

Blast Area: The fan outlet area less the projected area of the cut-off.

Blast Freezer:  A low -temperature evaporator that uses a fan to force air rapidly over a evaporator surface.

Blast Gate: Sliding damper in a duct used to balance airflow or to isolate a process from a system.

Blastomycosis: A disease caused by the fungus Blastomycosis dermatidis; may infect lungs, skin, mucous membranes, bones, internal organs, and joints.

BLDN:  ACRONYM – Blowdown.

Blebs and Bullae:  Localized destruction of portions of the lungs that may compress otherwise useful lung tissues.

Bleed: Particles of dust or fumes that are able to leak through filter media.

Bleed-Valve:  A valve with a small opening witch permits a minimum fluid flow when the valve is closed.

Bleeder Valve:  See “Suction-Control Air Vent.”

Bleeding:  The migration of a liquid to the surface of a component or into/onto an adjacent material.

Blend:  A mixture consisting of two or more single components.

Blind (blinding): The blockage of filtration media by dust, fume or liquid covering the filter media and not being discharged by the cleaning mechanism. Once enough material has built up, airflow is severely restricted and the elements have to be cleaned or replaced.

Blind Nailing:  Nailing in such a way that the nail heads are not visible on the face of the work – usually at the tongue of matched boards. 

Blind Stop:  A rectangular molding, usually ¾ by 1-3/8 inches or more in width, used in the assembly of a window frame.  Serves as a stop for storm and screen or combination windows and to resist air infiltration. 

Blinding:  Blockage by dust, fume or liquid not being discharged by the cleaning mechanism, results in a reduced gas or liquid flow of increased pressure drop across the filter media.

Blister: An enclosed raised spot evident on the surface of a building. They are mainly caused by the expansion of trapped air, water vapor, moisture or other gases.

Block Out:  To install a box or barrier within a foundation wall to prevent the concrete from entering an area. For example, foundation walls are sometimes “blocked” in order for mechanical pipes to pass through the wall, to install a crawl space door, or to depress the concrete at a garage door location.

Blocked (Door Blocking): Wood shims used between the door frame and the vertical structural wall framing members. 

Blocked (Rafters): Short 2x4s used to keep rafters from twisting, and installed at the ends and at mid-span. 

Blocking: In carpentry, the process of fastening together two pieces of board by gluing blocks of wood in the interior angle. 

Block Out: To install a box or barrier within a foundation wall to prevent the concrete from entering an area. For example, foundation walls are sometimes “blocked” in order for mechanical pipes to pass through the wall, to install a crawl space door, or to depress the concrete at a garage door location. 

BLogO:  Base Logistics Officer.

Blow Down:  The water discharged from a boiler or cooling tower to dispose of accumulated salts.  The act of removing water from a boiler to remove sediment and suspended particles.

Blowdown (BLDN):  The difference in pressure between the opening pressure and reclose pressure of a valve. May be expressed in percentage of set pressure or “psig.” Also, the use of pressure to remove liquids and/or solids from a vessel.  Water discharged from cooling towers in order to control total dissolved solids concentrations by a make-up water to replenish cooling apparatus.

Blower (BLWR):  A fan used to move air under pressure.  A compressor that is designed to operate at lower pressures. Usually a blower is an air compressor that operates below 2 barg, although this figure depends upon the respective manufacturer.  In HVAC the device in an air conditioner that distributes the filtered air from the return duct over the coil/heat exchanger. This circulated air is cooled/heated and then sent through the supply duct, past dampers, and through supply diffusers to the living/working space.  Redirects the airflow by 90 degrees towards one or more exit points.  Similar to a fan used to push air. 

Blower or Blower Wheel or Squirrel-cage Blower:  An air moving device typically used to move air against medium to high static pressure systems. Blowers are designed to operate against higher static pressures than fans. Packaged blowers provide compact, filtered, rack-mounted cooling in a variety of airflow configurations. 

Blower Call:  A signal from the thermostat to turn on the fan of the air handler or furnace. A blower call does not provide heating or cooling to the home, but circulates the air, providing additional operation time for an air cleaner or other accessories.

Blower Door:  A blower door is a diagnostic tool used to locate the points of infiltration in the building envelope and help prioritize the air sealing protocols. This device can be mounted in an exterior door or window opening. The blower door uses a calibrated, powerful, variable speed fan to pressurize or depressurize the dwelling. Its adjustable frame allows the fan assembly to fit snugly in most frames. Air movement and pressure differentials are measured using a set of gauges attached to the frame and fan. These calculations of air movement allow technician to quantify the level of leakage. Such leakage measurements are usually expressed in terms of equivalent leakage area (ELA), air changes per hour (ACH), and cubic feet per minute of airflow (CFM). Any one or more of these measurements can help determine levels of air leakage, indoor air quality, and amount of sealing work to be performed. In addition to measuring air movement, the blower door will exaggerate the leakage points in the building shell for easy identification. This diagnostic tool, when used in conjunction with an infrared scanner, produces even more accurate results.  A large fan placed in an exterior doorway to pressurize or depressurize a building to determine its air leakage rate expressed in air changes per hour or cubic feet per minute. 

Blower Fan: The squirrel-cage fan in a furnace or air handler.

Blowers (Variable Speed): The optimum open-cycle system for use in contaminated environments combines appropriate air filters and cooling-effect detectors with a variable speed blower that adjusts its operating speed to provide the desired cabinet air temperature, as sensed at some point within the enclosure. Since blower air delivery is directly proportional to motor shaft speed, airflow rate can be adjusted to a minimum compatible with a clean air filter and low ambient temperature. Should ambient temperature increase or the filter clog with contaminants, the sensor and controls would demand an increase in motor speed until the new conditions were satisfied.  The variable speed blower is self-adaptive to changes in ambient temperature, air density, line voltage, power dissipation in the enclosure, and to the degree of filter-loading. Since the blower operates at the minimum speed and air delivery compatible with cooling, both power consumption and the rate of contaminant accumulation on filter surfaces is greatly reduced, compared to a constant speed blower designed to satisfy worst-case conditions. This increases filter life and reduces filter maintenance to a minimum. Conversely, as the filter loads, blower air delivery could increase to levels beyond those that would be obtained under constant speed conditions. However, cost must be considered.

Blow-down:  The act of removing water from a boiler to remove sediment and suspended particles.  
Blower Fan:  The squirrel-cage fan in a furnace or air handler.
Blow Insulation: Fiber insulation in loose form used to insulate attics and existing walls where framing members are not exposed.

Blow Off Control:  The compressor continuously compresses, however, when the maximum pressure is reached, the delivered air is blown off to the atmosphere instead of being fed to the receiver.

Blow-Pipe: See manifold.

Blue Prints: Architectural plans for a building or construction project, which likely include floor plans, footing and foundation plans, elevations, plot plans, and various schedules and or details.

Blue Smoke: A descriptive term for the gaseous hydrocarbons that escape from hot asphalt and other sources of VOC.

Blue Stain: A bluish or grayish discoloration of the sapwood caused the growth of certain mold like fungi on the surface and in the interior of a piece, made possible by the same conditions that favor the growth of other fungi.

Blue Stake: Also Utility Notification. When a utility company (telephone, gas, electric, cable TV, sewer and water, etc) comes to the job site and locates and spray paints the ground and/or installs small flags to show where their service is located underground.

BMS (Building Management System): A system designed for the control, monitoring and optimization of mechanical operations within a building.  

Board and Batten: A method of siding in which the joints between vertically placed boards or plywood are covered by narrow strips of wood.

Board Foot: The volume of a piece of wood measuring 12 inches square and in inch thick. A piece of lumber ½" thick and 6 inches wide and 24 inches long is equal to one board foot. 

Boards: Yard lumber less than 2 inches thick and 2 or more inches wide.

BOCA:   Building Officials and Code Administrators.

Bodied Linseed Oil:  Linseed oil that has been thickened in viscosity by suitable processing with heat or chemicals. Bodied oils are obtainable in a great range in viscosity from a little greater than that of raw oil to just short of a jellied condition.

Body:  The stationary seating surface, the inlet of a valve.

Boiled Linseed Oil: Linseed oil in which enough lead, manganese or cobalt salts have been incorporated to make the oil harden more rapidly when spread in thin coatings.

Boiler:  A vessel or tank where heat produced from the combustion of fuels such as natural gas, fuel oil, or coal is used to generate hot water or steam for applications ranging from building space heating to electric power production or industrial process heat.  Also, a fossil fuel appliance used for producing hot water or steam as the medium to distribute heat to the dwelling unit.  A device for generating steam for power, processing, or heating purposes or for producing hot water for heating purposes or hot water supply. Heat from an external combustion source is transmitted to a fluid contained within the tubes in the boiler shell. This fluid is delivered to an end-use at a desired pressure, temperature, and quality.

Boiler Pressure:  The pressure of the steam or water in a boiler as measured, usually expressed in pounds per square inch gauge (psig).

Boiler Rating:  The heating capacity of a steam boiler expressed in BTU per hour (BTU/H), horsepower, or pounds of steam per hour.

Boiling Point: The temperature at which the vapor pressure of a liquid equals the surrounding atmospheric pressure. For purposes of defining the boiling point, atmospheric pressure shall be considered to be 14.7 psia (760 mm Hg).  The temperature at which the vapor pressure of a liquid equals atmospheric pressure.  The point at which a substance will vaporize if anymore heat is added.

Boiling Points of Hydrocarbons: Differences in the size, shape and weight of hydrocarbons mean that they have different reaction properties, including the temperature at which they boil or the “boiling point.” Generally, the larger the hydrocarbon, the heavier it is and the more energy it will take to boil. Using these differences in boiling points and weights, fossil fuel can be separated into their various parts within distillation towers. (Also see absorption and adsorption). 

Boiling Temperature:  Temperature at witch a fluid changes from a liquid to a gas.

Bolster: A short horizontal timber or steel beam on top of a column to support and decrease the span of beams or girders.

Bolting Cloth (silk):  Screens woven of twisted multifilament natural silk.

Bolting Grade (wire cloth):  Uniformly woven of stainless steel to provide high strength and the largest possible openings.

BOMA:   Building Owners Management Association.

Bond or Bonding: An amount of money (usually $5,000-$10,000) which must be on deposit with a governmental agency in order to secure a contractor's license. The bond may be used to pay for the unpaid bills or disputed work of the contractor. Not to be confused with a performance bond. They are an insurance policy which guarantees proper completion of a project. Such bonds are rarely used in residential construction.

Bond Breaker: A substance or a tape applied between two adjoining materials to prevent adhesion between them. 

Bond Plaster: In addition to gypsum, bond plaster contains 2-5% lime by weight and chemical additives which improve the bond with dense non-porous surfaces such as concrete. It is used as a base coat. 

Bonding Strip (Electrical): A thin strip of metal inside armored or BX cable. This strip is meant to back up the primary ground. 

Bonnet:  The portion of a safety/relief valve that surrounds the spring. The spring housing.

Boolean Logic:  The logic of binary systems, such as control systems in which all operations may be reduced to on-off, open-closed, or similar dichotomous basis.

Boom: A truck used to hoist heavy material up and into place, to put trusses on a home or to set a heavy beam into place. 

Boosted Reaction: A positive reaction to a tuberculin skin test due to a boosted immune response from a skin test given up to a year earlier. Occurs in people who were infected a long time ago and whose ability to react to tuberculin has lessened.

Booster:  A machine which aspirates gas which has already been compressed and delivers the same at higher pressure.  A term used for the first stage compressor in a cascading system.

Boot:  A duct section that connects between a duct and a register or between round and square ducts.  

BOPP-SI™:  Precision woven wire screens woven by G. Bopp & Co., Switzerland.

Boring:  Usually, a vertical hole drilled into the ground from which soil samples can be collected and analyzed to determine the presence of chemicals and the physical characteristics of the soil.

Boston Ridge: A method of applying asphalt or wood shingles at the ridge or at the hips of a roof as a finish. 

Bottled Gas:  A generic term for liquefied and pressurized gas, ordinarily butane, propane, or a mixture of the two, contained in a cylinder for domestic use.

Bottom Chord: The lower or bottom horizontal member of a truss. 

Bottom Plate: The 2x4s or 6s that lay on the subfloor upon which the vertical studs are installed. Also called the sole plate.

Bottom-Up Approach:  The development and encouragement of sustainable uses of biodiversity that provides incentives to save species while also respecting the right of all people to support their families and have a decent quality of life.

Bow: A curve, bend, warping or other deviation from flatness in glass or wood.

Box Cornice: A cornice completely closed with trim work.

Box Fan Air Filter(s):  Nordic Pure’s Merv 8 pleated box fan air filters have an anti-microbial layer and do not support the growth of bacteria, fungi, mildew or mold. Our box fan filter media has a permanent electrostatic charge which will attract and trap the dust and stop it from being blown through your box fan and back into your home or office.  Attach to the BACK of your 20x20 box fan with included Velcro tabs. Place so wire mesh side is against the fan and the air flow arrows point towards the box fan.  When used in conjunction with our furnace and air condition Merv 12 air filters you will reduce the dust, dust mites, mold spores, pet dander, pollen, smoke particles, and other airborne particulates by up to 97.8%.
Box Fan with Filter:  Simplest air cleaner on the market!  Cleans the air of lung damaging dust size particles (0.5 - 7 microns).  Reduces trigger particles that bring on asthma attacks.  Cleans the air in 15' x 15' x 8' (225 sq ft) room.  Operating costs is only 1 - 2 cents an hour.  30 cents/day on low speed.

Box Filter(s):  Nordic Pure carries the following box filters:  20x20x1, Actual Size of Filter: 19 1/2 x 19 1/2 x ¾, Price for a box of 6 - ($6.33 per Box Fan Air Filter) $37.97 per box and 20 x 20 x 1/8, Actual Size of Filter: 19 7/8 x 20 x  1/8, Price for a box of 12 - ($2.91 per Box Fan Air Filter) $34.97 per box.  And as always, price includes FREE SHIPPING.
Boyle’s Law:  Boyle’s law states that the volume of a given amount of gas varies inversely with its pressure, if temperature is constant. This means that at a constant temperature, the pressure of a gas will increase as the volume of the gas is decreased. 

BP:  ACRONYM - Back pressure.

Brace: An inclined piece of framing lumber applied to wall or floor to stifle the structure. Often used on walls as temporary bracing until framing has been completed. 

Bracing: Ties and rods used for supporting and strengthening various parts of a building used for lateral stability for columns and beams. 

Brackish Water:  Water containing more than 1,000 mg/L (1,000 parts per million) of dissolved solids.

Bradycardia:  Slowing of the heart rate.

Bradykinin:  One of a group of small proteins that actively affect smooth muscle contraction in blood vessel walls, and so have effects on blood pressure. Bradykinin dilates blood vessels, and also stimulates pain receptors.

Brake Horse Power (BHP):  The maximum rate at which an engine can do work as measured by the resistance of an applied brake. Expressed in horsepower.  The horsepower actually required to drive a fan. This includes the energy losses in the fan and can be determined only by actual tests of the fan (this does not include the drive losses between motor and fan).

Brake Metal: Sheet metal that has been bent to the desired configuration. 

Branch Circuit (Electrical):  Wiring that runs from a service panel or sub-panel to outlets. Branch circuits are protected by fuses or breakers at the panel.  An electrical circuit used to power outlets and lights within a home.  

Branch Duct: Duct used to transport contaminants from a collection point to a main duct or air cleaner.

Branch Lines:  Are lines that supply equipment from sub headers.

Brazing:  A method of joining two metal surfaces by using nonferrous filler metal heated to above 430° C (800° F), but below the melting point of the metals to be joined.

Breakdown Maintenance:  Maintenance performed after a machine has failed to return it to an operating state.

Breaker:  A hand held pneumatic tool.  Designed for light demolition work, digging, making holes etc.

Breaker Box: A metal box that contains circuit breakers or fuses that control the electrical current in a home.

Breaker Panel: The electrical box that distributes electric power entering the home to each branch circuit (each plug and switch) and composed of circuit breakers.

Breaking Pressure:  Is that pressure of either the motive fluid or of the ejector gas discharge which causes an ejector to become unstable.

Breakthrough:  Used to describe the passing of solids through the cake build up of a filter medium.  Also called breakpoint.

Breakthrough Time:  The time for initial chemical contact to detection.

Breakthrough Volume:  The sampling volume for which a significant amount (usually more than 1 %) of a VOC being drawn through a sorbent tube appears in the tube effluent, i.e., the volume that is sufficient for sampling but for which there will be no significant loss of analytes; also called retention volume.

Breath Sounds:  Sounds heard through a stethoscope.  The intensity of the sound of air moving in and out of the lungs may indicate the amount of obstruction.

Breather:  A filtering unit for vented enclosures installed to prevent dirt and foreign matter from entering the enclosure.

Breathing Air:  Specialty compressed air treatment meeting OSHA Grade D breathing air requirements.

Breathing Gas:  A respirable gas, such as oxygen or air, as defined in the relevant standard.

Breathing Rate:  The number of breaths per minute.

Breathing Zone:  Area of a room in which occupants breathe as they stand, sit, or lie down.  The area of a room in which occupants breathe as the stand, sit and lie down, generally considered to be about 3-72 inches above the floor.

Breeze Way: A roofed, open-sided passageway connecting two structures, such as a house and a garage.

BRI:   Building-related illness: a recognized disease that can be attributed to airborne building bioaerosols or chemical pollutants.

Brick Ledge: Part of the foundation wall where brick (veneer) will rest.

Brick Lintel: The metal angle iron that brick rests on, especially above a window, door, or other opening.

Brick Mold: Trim used around an exterior door jamb onto which siding butts. 

Brick Tie:  A small, corrugated metal strip (1" x 6"-8" long) nailed to wall sheeting or studs.  They are inserted into the grout mortar joint of the veneer brick, and hold the veneer wall to the sheeted wall behind it.

Brick Veneer:  A facing of brick laid against and fastened to the sheathing of a frame wall or tile wall construction.

Bridge Rectifier:  A full-wave rectifier in which there are four arms - each containing a diode.

Bridge: Material building across an opening (such as a screw conveyor) and blocking off that opening.

Bridging:  A condition of filter element loading in which contaminant spans the space between adjacent sections of a filter element, thus blocking a portion of the useful filtration.  Small wood or metal members that are inserted in a diagonal position between the floor joists at midspan to act as both tension and compression members for the purpose of bracing the joists a spreading the action of loads.  Material or particulate blockage across an opening, often of a pore or filter medium.

Bright Sunshine: Sunshine above a certain level sufficient to be registered on a Campbell-Stokes sunshine recorder .The threshold is imprecisely defined and varies according to the type of recorder, but generally refers to sunshine bright enough to cast a shadow. Burning typically starts when the beam intensity is 200W /m2.g.  

Brightness: The intensity of the sensation derived from viewing a lit surface. Measured in footlamberts, it is also called luminance or luminous intensity. 

Brine:  Highly saline water.  A salt water mixture commonly used as a secondary refrigerant.

British Allergy Foundation:  The British Allergy Foundation was formed as a registered charity in 1991 by a group of leading medical specialists determined to improve awareness, management and treatment of allergy. In May 2002 the operational name of the Foundation was changed to Allergy UK.

British Thermal Unit:  BTU. The amount of heat required to raise the temperature of one pound of water one degree Fahrenheit under set conditions of temperature and pressure.

BRMA:  Business Recovery Managers Association. BRMA is Northern California’s largest business recovery association.  (www.brma.com)

Broker: One that acts as an agent for others, as in negotiating contracts, purchases, or sales in return for a fee or commission.

Bronchi:  A part of the respiratory system; two air passages that branch off from the trachea to the bronchioles.  The airways that lead from the trachea to each lung, and then subdivide into smaller and smaller branches.  They connect to the bronchioles.  They have many mucus producing glands.  Singular: Bronchus.

Bronchial Tubes:  Bronchial tubes are the airways into the lungs. These airways branch from the trachea (windpipe). When a person has an asthma attack these airways may become constricted.

Bronchioles:  A part of the respiratory system; very small airways that extend from the bronchi to the alveoli.  The tiny (<1mm in diameter) branching airways that lead from the bronchi to the alveoli. They also produce mucus.

Bronchitis:  An inflammation of the bronchi (lung airways), resulting in persistent cough that produces consideration quantities of sputum (phlegm).

Bronchitis, Chronic: Irritation and inflammation of the lining of the bronchial tubes. The irritation causes coughing and excess amounts of mucus in the airways which can lead to difficulty breathing. Bronchitis is considered chronic when the person has a productive cough (coughs up mucus) and shortness of breath that lasts at least three months each year for at least two years in a row.

Bronchoconstriction: The reduction in the diameter of the bronchi, usually because of squeezing of the smooth muscles in the walls. This reduces the space for air to go through and can make breathing difficult.

Bronchodilator:  Pronunciation (brong′kō-dī-lā′ter, -tōr).  A medicine that relaxes the smooth muscles of the airways. This allows the airway to open up, or dilate, because the muscles are not squeezing it shut.  Medication used to relax the muscle bands that tighten around the airways to increase air flow. Bronchodilators also help clear mucus from the lungs.  (1.)  Causing an increase in caliber of a bronchus or bronchial tube.  (2.) An agent that possesses this power (e.g., epinephrine, albuterol).  

Bronchodilators, Long-Acting: (Also called “maintenance” med