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R-22: Monochlorodifluoromethane, a popular refrigerant for air conditioning systems. R-22 Refrigerant: R-22 is a single component HCFC refrigerant with low ozone depletion potential. It has long been used in a variety of air-conditioning and refrigeration applications in a variety of markets. Production of R-22 will cease in 2015 per the Montreal Protocol. 'R' Value:The thermal resistance to heat flow across a sample material of a unit area and known thickness caused by a temperature difference across it. This is often used to give a comparative value of the effect of different insulating materials. (m2.K/W) RA: Return air. Rabbet: A rectangular, longitudinal groove cut in the corner edge of a board or plank. RACM (Reasonably Available Control Measures): A broadly defined term referring to technologies and other measures that can be used to control pollution; includes Reasonably Available Control Technology and other measures. In the case of PM10 , it refers to approaches for controlling small or dispersed source categories such as road RACT (Reasonably Available Control Technology): An emission limitation on existing sources in non-attainment areas, defined by EPA in a Control Techniques guideline (CTG) and adopted and implemented by states. Under Title I of the CAAA, EPA will establish RACT standards for marginal, moderate and serious non-attainment areas. Rad: Unit of absorbed dose and the quantity of energy imparted by ionizing radiation to a unit mass of matter such as tissue, and equal to 0.01 joule per kilogram, or 0.01 gray. Radial Blade: Fan wheel design with blades positioned in straight radial direction from the hub. Radial Compressor: A compressor belonging to the group of dynamic compressors. Characterized by radial flow. (Centrifugal.) Radial Saw: A circular saw which hangs from a horizontal arm or beam and slides back and forth. The arm pivots from side to side to allow for angle cuts and bevels. When sawing finish plywood, the good side should face up as the saw cuts on the down stroke. Radiance of the Sky (Ls): The radiant flux emitted in a small solid angle from a specific area of the sky in the direction of the observer expressed as the flux received normal to the beam per unit solid angle. (W/m2.sr). Radiant Barrier: A foil sheet or coating designed to reflect heat producing sun rays. Radiant Ceiling Panels: Ceiling panels that contain electric resistance heating elements embedded within them to provide radiant heat to a room. Radiant Energy: Energy that transmits away from its source in all directions. Radiant Floor: A type of radiant heating system where the building floor contains channels or tubes through which hot fluids such as air or water are circulated. The whole floor is evenly heated. Thus, the room heats from the bottom up. Radiant floor heating eliminates the draft and dust problems associated with forced air heating systems. Radiant Floor Heating: Process of embedding tubing directly in a concrete floor so that hot water can be pumped through the tubing for the purpose of heating the floor and thus the building. Radiant Flux, Radiant Power: Power emitted, transmitted or received in the form of radiation. (Unit: W). Radiant Heating: A method of heating, usually consisting of a forced hot water system with pipes placed in the floor, wall, or ceiling, or with electrically heated panels. Radiant Heat Transfer: Radiant heat transfer occurs when there is a large difference between the temperatures of two surfaces that are exposed to each other, but are not touching. The transfer of heat energy from a location of higher temperature to a location of lower temperature by means of electromagnetic radiation. Radiant heating is due to infrared radiation and its use is very prevalent in passive systems. see also infra-red radiation. Radiant Heating System: HVAC term for a heating system where heat is supplied (radiated) into a room by means of heated surfaces, such as electric resistance elements, hot water (hydronic) radiators, etc. Radiant Temperature: The average reflective temperature of objects in a home, like walls, ceiling, floor, and furniture. Radiant Temperature Asymmetry: The difference between the plane radiant temperature of the two opposite sides of a small plane element. Radiation: Heat energy originating on a hot body like the sun and traveling from place to place through the air. Radiation Dose (or mrem): A generic term to describe the amount of radiation a person receives. Dose is measured in units of thousands of a roentegen equivalent man (rem) (called the millirem). The conventional unit used by federal and state agencies in the United States is the millirem (mrem). Dose is a general term used to assist in the management of exposure to radiation. The common international scientific (SI) unit for dose is the millisievert (mSv). One mSv is the same as 100 mrem. Radiation, Thermal: The transmission of heat through space by wave motion; the passage of heat from one object to another without warming the space between. Radiative Heat Transfer: Heat transfer by electromagnetic radiation. Often divided into short-wave radiation - generally taken as those wavelengths associated with the solar spectrum (300-3,000nm) and longwave radiation (>3,000nm). Radiator: Apparatus for heating of a room, which gives off heat to the space by radiation and convection. Radiator Vent: A device that releases pressure within a radiator when the pressure inside exceeds the operating limits of the vent. Radio Frequency: In the vacuum cleaner industry this terms refers to a wireless system whereby electromagnetic waves are used to control the power of the vacuum motor simply by pushing + or – buttons on the hose handle. This system, found on the Miele Galaxy series also includes a stand-by button that allows the user to conveniently turn the vacuum cleaner on or off. Radio Frequency Interference (RFI): EMI in electronic equipment caused by radio frequencies. Radioactive Decay: Spontaneous transformation of one radionuclide into a different nuclide (which may or may not be radioactive), or de-excitation to a lower energy state of the nucleus by emission of nuclear radiation, primarily alpha or beta particles, or gamma rays (photons). Radioactivity: Spontaneous emission of nuclear radiation, generally alpha or beta particles, or gamma rays, from the nucleus of an unstable isotope. Radioallergosorbent Test (RAST): A radioimmunoassay test to detect specific IgE antibodies responsible for hypersensitivity: the allergen is bound to insoluble material and the patient's serum is reacted with this conjugate; if the serum contains antibody to the allergen, it will be complexed to the allergen. Radiolabeled anti-human IgE antibody is added where it reacts with the bound IgE. The amount of radioactivity is proportional to the serum IgE. Radiological Monitoring: Radiological monitoring is the measurement of radiation levels or individual doses, and the use of the results to assess radiological hazards in the environment or workplace, or the potential and actual doses resulting from exposures to ionizing radiation. Radionuclide: Unstable nuclide. See nuclide and radioactivity. Radius of Diffusion: The horizontal distance in feet from the diffuser to a point where the terminal velocity of 50 feet per minute occurs. Radon (Rn) And Radon Decay Products: Radon: A colorless, odorless gas that occurs naturally in almost all soil and rock. Radon migrates through the soil and groundwater and can enter buildings through cracks or other openings in the foundation. Radon can also enter well water. Exposure to radon can cause lung cancer. Radon is a radioactive gas formed in the decay of uranium. The radon decay products (also called radon daughters or progeny) can be breathed into the lung where they continue to release radiation as they further decay. Rafter: A roof beam that follows the roof’s slope. Rafter Tail: The portion of a rafter that extends past the building to form the eaves. Rafter, Hip: A rafter that forms the intersection of an external roof angle. Rafter, Valley: A rafter that forms the intersection of an internal roof angle. The valley rafter is normally made of double 2-inch-thick members. Raggle Block: A specially designed masonry block having a slot or opening into which the top edge of the roof flashing is inserted and anchored. RAID: Redundant Array of Independent Disks. A new technology employing many smaller, independent hard disks logically coupled together to replace older, expensive single drive systems. Rail: Cross members of panel doors or of a sash. Also the upper and lower members of a balustrade or staircase extending from one vertical support, such as a post, to another. Railroad Tie: Black, tar and preservative impregnated, 6”x8” and 6’-8’ long wooden timber that was used to hold railroad track in place. Normally used as a member of a retaining wall. Rainwater Harvesting/Catchment: A method of collecting rain and snow melt in a cistern for reuse. Raised Floor: In underfloor air distribution systems, a platform structure typically consisting of concrete-filled steel floor panels supported on pedestals 8 to 18 inches above the concrete structural floor slab. Each panel can be independently removed for access to the underfloor plenum containing the air delivery system, electrical cables, and other services. Rake: Trim members that run parallel to the roof slope and form the finish between the wall and a gable roof extension. The angle of slope of a roof rafter, or the inclined portion of a cornice. Rake Edge: The overhang of an inclined roof plane beyond the vertical wall below it. Rake Fascia: The vertical face of the sloping end of a roof eave. Rake Siding: The practice of installing lap siding diagonally. Ranch: A single story, one level home. Random Noise: A sound that has an average amplitude and constantly changing frequency. Random-Tab Shingles: Shingles on which tabs vary in size and exposure. Rankin: Thermometer scale on which unit of measurement equals the Fahrenheit degree. Rapidly Renewable: Materials that are not depleted when used. These materials are typically harvested from fast growing sources and do not require unnecessary chemical support. Examples include bamboo, flax, wheat, wool and certain types of wood. Rarefication: A phenomenon related to negative pressure. When air is drawn out through resistance into a fan inlet, the air is stretched out, or rarefied, and becomes less dense than at the entry to the system. While negligible at low pressures and volumes, high-pressure fan selection must be based on rarefied inlet density. Rash: A skin swelling. Kinds of rashes are butterfly rash, diaper rash, drug rash, heat rash. RAST Testing: Radioallergosorbent test; a blood test for measuring antigen specific antibodies (allergic reactions). Used primarily where skin testing is impractical or unreliable (i.e. extreme sensitivity, dermatitis, children). Rated Airflow: The manufacturer’s assigned design airflow capacity of a HEPA filter at a “not to exceed” designated clean filter resistance. With a media velocity limit of 5 feet per minute, the rated airflow is obtained by multiplying the filtration velocity of 5 feet per minute by the effective area of filter media. Rated Airflow Volume: Specific quantity of air recommended by a filter manufacturer to be handled by a filter. (The volume of airflow at which the filter is tested). Rated Flow: Normal operating flow rate at which a product is passed through a housing; flow rate which a housing and medium are designed to accommodate. Raw Linseed Oil: The crude product processed from flaxseed and usually without much subsequent treatment. Raw Sludge: Untreated sewage sludge. RCRA: Resource Conservation and Recovery Act: federal environmental legislation, administered by EPA, aimed at controlling the generation and treatment of hazardous wastes. Reactive Metabolites: Substances that interfere with the body's ability to build up and break down complex molecules. ReadySpace®: A proprietary technology invented by Tennant Company, ReadySpace® uses substantially less water to effectively remove dirt and debris, leaving a superb carpet appearance with virtually no wick-back. As less water is used, less waste water is produced, creating cleaner, healthier environments by permitting more frequent cleanings and reducing odors and molds caused by excess water. Carpets cleaned with ReadySpace® are dry and ready for use in less than 30 minutes. Ready Mixed Concrete: Concrete mixed at a plant or in trucks en route to a job and delivered ready for placement. Reactivation: The removal of adsorbates from spent activated charcoal, which allows the carbon to be reused; also called regeneration. Reactive Organic Gas (ROG): A photochemically reactive chemical gas, composed of non-methane hydrocarbons, that may contribute to the formation of smog. Also sometimes referred to as Non-Methane Organic Gases (NMOGs). (See also Volatile Organic Compounds and Hydrocarbons.) Reactivity (or Hydrocarbon Photochemical Reactivity): A term used in the context of air quality management to describe a hydrocarbon's ability to react (participate in photochemical reactions) to form ozone in the atmosphere. Different hydrocarbons react at different rates. The more reactive a hydrocarbon, the greater potential it has to form ozone. Reagent: Solution or substance used in analytical testing purposes or procedures. Reasonably Available Control Measures (RACM): A broadly defined term referring to technologies and other measures that can be used to control pollution. They include Reasonably Available Control Technology and other measures. In the case of PM10, RACM refers to approaches for controlling small or dispersed source categories such as road dust, woodstoves, and open burning. Reasonably Available Control Technology (RACT): Control techniques defined in U.S. EPA guidelines for limiting emissions from existing sources in nonattainment areas. RACTs are adopted and implemented by states. Reasonably Available Retrofit Control Technology (RARCT): (See also Best Available Control Technology.) Rebar: Reinforcing bar used to increase the tensile strength of concrete. Rebound: The extension of an air actuator beyond its design height. Rebuilt: Product has been returned to mechanical specifications of a new machine. Parts may have been replaced with new ones if they did not meet new specifications. Receiver: A pressure vessel (as defined by CSA B51) used to store compressed air or compressed breathing air; refer to CSA Z180 for the definition. Receivers: Tanks used for the storage of air discharged from compressors. They serve also to damp discharge line pulsations. Receptacle: An electrical outlet. A typical household will have many 120 volt receptacles for plugging in lams and appliances and 240 volt receptacles for the range, clothes dryer, air conditioners, etc. Receptor: Any opening, which could admit asbestos fibers into a structure if not properly protected. Examples include but are not limited to operable windows, doors, vents, air intakes or exhausts of any mechanical device within a building or structure. Recharge Area: An area where rainfall can infiltrate into an aquifer. Reciprocating: In refrigeration, a type of compressor which compresses refrigerant vapor by moving a piston up and down in a cylinder. Reciprocating Compressor: A compressor whose piston or pistons move back and forth in the cylinders. Reciprocating Internal Combustion Engine: An engine in which air and fuel are introduced into cylinders, compressed by pistons and ignited by a spark plug or by compression. Combustion in the cylinders pushes the pistons sequentially, transferring energy to the crankshaft, causing it to rotate. Recirculation: Ventilation system in which supply air includes air that has been previously removed from an interior space. Recirculation Air Cleanup System: An air cleaning system that recirculates the air of a contained space. Recirculated Air: Return air passed through the conditioner before being resupplied to the conditioned space. The air conditioning unit takes in outdoor air but also a part from the rooms. Re-circulated Air: Air that has been taken from a space, reconditioned (making necessary adjustments to temperature, humidity and cleanliness) and returned to the space. Reclaimed Water (also known as Recycled Water): Water which, as a result of treatment of waste, is suitable for direct beneficial use or a controlled use that would not otherwise occur. Reclaiming: Returning used refrigerant to the manufacturer for disposal/reuse. Reclamation: Restoration of materials found in the waste stream to a beneficial use that may be other than the original use. Recommended Exposure Limit (REL): A term for an exposure concentration to a given agent that is based on an evaluation of health effects data; see occupational exposure limit, threshold limit value. Recommended Practice: A published document that provides technical guidance, philosophy or preferred procedures regarding a given topic. Recommissioning: Also called Tuning, a re-calibration of a facility’s operating systems. Reconstituted Air: A gaseous mixture prepared from pure liquefied or gaseous oxygen and pure liquefied or gaseous nitrogen, suitable for breathing. Recording Fee: A charge for recording the transfer of a property, paid to a city, county, or other appropriate branch of government. Recovery: Ability of a filter to recover bacteria (or other defined particles) from a solution. Recovery Efficiency: A water heater’s efficiency at actually heating water to capacity level without regard to standby or distribution losses. Recovery Pressure: Is that pressure of either motive fluid or discharge at which an ejector returns to stable operation following a period of unstable operation due to having previously reached the breaking pressure. There are two recovery pressures, one for motive fluid and one for the discharge pressure. Recyclable: Commonly referred to as the ability of a product or material to be recovered from, or otherwise diverted from, the solid waste stream for the purposes of recycling. FTC guidelines indicate that a product may not be advertised as “recyclable” unless a viable, active reclamation system exists, that is available to a majority of end users, and collects and processes the product for recycling. Recyclable Content: Materials that have potential to be recovered from recycling. Recycled Content: Materials that have been recovered or otherwise diverted from the solid waste stream, either during the manufacturing process (pre-consumer), or after consumer use (post-consumer). Pre-consumer material does not include materials normally reused by industry within the original manufacturing process. Recycling: Process by which materials that would otherwise become solid waste are collected, separated or processed and returned to the economic mainstream to be reused in the form of raw materials or finished goods. Red Light Test: To accurately evaluate changes in the level of activity in rodents, the room lights can be turned off and using only a red light, their “normal” activity level will emerge after about 5 minutes. This is the “red light test.” Redline, Red Lined Prints: Blueprints that reflect changes and that are marked with red pencil. Red Mud: Filter cake in sodium aluminate filtration. Reduced Pressure: Ratio of the pressure of a gas to its critical pressure, in like units. Reduced Temperature: Is the ratio in absolute units of the actual gas temperature to the critical temperature. Reducer: See bushing. Reducing Agent: Any substance, such as base metal (iron) or the sulfide ion (S2-), that will readily donate (give up) electrons. The opposite is an oxidizing agent. Reduction: Reduction is the addition of hydrogen, removal of oxygen, or the addition of electrons to an element or compound. Under anaerobic conditions (no dissolved oxygen present), sulfur compounds are reduced to odor-producing hydrogen sulfide (H 2S and other com- pounds. The opposite of oxidation. Redundant Unit or System: An additional and independent unit or system, which is capable of achieving the objectives of the basic system and is brought online in the event of failure of the basic system. Red Zone: This is an emergency!! The red zone is a measurement on the peak flow meter that indicates that you are having a serious asthma episode. Get help. When you are in the red zone, your peak flow is below 50% of your personal best. You may be coughing, very short of breath, and/or the skin between your ribs and neck may be pulled in tight. Reentrainment: Process of rendering particles airborne again after they have been once deposited from an air stream. Re-Entrainment: Situation that occurs when the air being exhausted from a building is immediately brought back into the system through the air intake and other openings in the building envelope. Re-Entry : Situation that occurs when the air being exhausted from a building is immediately brought back into the system through the air intake and other openings in the building envelope. Reference Design: A detailed specification of the passive solar features of a hypothetical passive solar building used as the subject of performance analysis. Reference Dose (RfD): An estimate delivered by the U.S. EPA (with uncertainty spanning perhaps an order of magnitude) of the daily exposure to the human population, (including sensitive subpopulations) that is likely to be without deleterious effects during a lifetime. The RfD is reported in units of mg of substance/kg body weight / day for oral exposures. Reference Exposure Concentration (RfC): An estimate, derived by the U.S. EPA with an uncertainty spanning perhaps an order of magnitude) of a daily exposure to the human population, (including sensitive subgroups) that is likely to be without appreciable risk of deleterious effects during a lifetime of exposure. The RfC is derived from a no or lowest observed adverse effect level from human or animal exposures, to which uncertainty or “safety” factors are applied. Reference Exposure Level (REL): A term used in risk assessment. It is the concentration at or below which no adverse health effects are anticipated for a specified exposure period. Reference Temperature: A fixed indoor temperature in the definition of the net reference load. Also the fixed indoor temperature in the reference nonsolar building used in the definition of solar savings. Reflectance: Ratio of the reflected radiant or luminance flux to the incident flux in the given conditions. Can be defined for a incident radiatior of given spectral composition polarization and geometrical distribution). Reflectance (visible): The ratio or percentage of the amount of light reflected by surface to the amount incident upon it. Good light reflectors are not necessarily good heat reflectors. Reflective Glass: Radiant energy is reflected from both inside and outside surfaces of a sheet of parallel sided glazing. Multiple inter-reflections occur within the glazing. The ratio of the overall reflected radiant energy to the incident radiant energy is known a the reflectance. Its value depends on the angle of incidence. Energy inter-reflected from the inside face is dependent on the absorbability of the material and so is also dependent on wavelength. For any wavelength and angle of incidence, absorptance reflectance + transmittance = 1. The solar heat gain coefficient of reflective glass ranges from 0.10 to 0.40. Reflective Insulation: Sheet material with one or both sun faces of comparatively low heat emissivity, such as aluminum foil. When used in building construction the surfaces face air spaces, reducing the radiation across the air space. Reflectance of Opaque Materials: The proportion of radiation reflected by surface. the reflectance varies for different wavelengths and angles of incidence: for instance white paint has an average reflectance of 0.71 for normal incidence solar radiation and 0.11 for long-wave (thermal) radiation. For any wavelength and angle of incidence, absorbance + reflectance = 1. Reflected (global) Solar Radiation: Radiation that results from reflection of the global solar radiation by the surface of the Earth and by any surface intercepting that radiation. Reflex: Reflex usually describes an immediate involuntary response evoked by a stimulus, for example the cough reflex. Reformulated Gasoline (RFG): Also called Cleaner Burning Gasoline (CBG). Gasoline with a different composition from conventional gasoline (e.g., lower aromatics content) that results in the production of lower levels of air pollutants. Reformulated Gasoline Predictive Model: A set of mathematical equations that predict the emissions likely to occur from the combustion of a given formulation of gasoline. Refractive Index: A property of glazing materials that determines the reflection/refraction characteristics of the glazing. Refrigerant: A special fluid used in air conditioners and heat pumps that heats air when it condenses from a gas to a liquid and cools air when it evaporates from a liquid to a gas. R410A Refrigerant: A chlorine-free refrigerant that meets the EPA's newest, most stringent environmental guidelines. Refrigerant charge: This is the amount of refrigerant required by a particular system. Refrigerant Lines: Two copper lines connecting the outdoor condenser to the indoor evaporator coil. Refrigerant Recovery: To remove refrigerant in any condition from a system and store it in an external container without necessary testing of processing it in any way. Refrigerant Recycling: To clean the refrigerant by oil separation and single or multiple passes through devices, such as replaceable core filter-driers, which reduce moisture, acidity and particulate matter. This term usually applies to procedures implemented at the job site or at a local service shop. Refrigeration: The process of the absorption of heat from one location and its transfer to another for rejection or recuperation. Refrigeration Capacity: A measure of the effective cooling capacity of a refrigerator, expressed in Btu per hour or in tons, where one (1) ton of capacity is equal to the heat required to melt 2,000 pounds of ice in 24 hours or 12,000 Btu per hour. Refrigeration Dryer: A device consisting of a heat transfer system, a moisture elimination system and a refrigeration system designed to improve the quality of the air and reduce the temperature of the air. Regeneration: The process of desiccants being regenerated by water being driven off the desiccant. Hot air or gas passes through the desiccant bed, heating it. As a result, the partial pressure of the water vapor becomes higher than that in the regenerating air. Water is therefore released from the desiccant and carried away with the air stream (purge air) until a new state of equilibrium is reached. Regenerative Cooling: Process of utilizing heat which is rejected or absorbed in one part of the cycle to function usefully in another part of the cycle by heat transfer . Regenrated Cellulose: Those rayon’s in which the cellulose raw material is changed physically, but not chemically. Viscose, cuprammonium and nitrocellulose rayon’s are of this type. Regional Greenhouse Gas Initiative (RGGI): A cooperative effort by Northeastern and Mid-Atlantic states to reduce carbon dioxide emissions. The RGGI states will develop a regional strategy by April 2005 for controlling emissions. This strategy will more effectively control interstate transport and international transport of greenhouse gases, and will require electric power generators in participating states to reduce carbon dioxide emissions. Regional Haze: The haze produced by a multitude of sources and activities, which emit fine particles and their precursors across a broad geographic area. The U.S. regulations require states to develop plans to reduce the regional haze that impairs visibility in Class I areas. Regional Water Quality Control Board (RWQCB): Any California regional water quality control board for a region as specified in Porter- Cologne Water Quality Control Act, Section13200. Register: The grille cover over a duct outlet for warm air distribution or cold air return. Reglaze: To replace a broken window. Reglet: A horizontal slot, formed or cut in a parapet or other masonry wall, into which the top edge of counter-flashing can be inserted and anchored. In glazing, a reglet is typically a pocket or keyway extruded into the framing for installing the glazing gaskets. Regression (linear) : A statistical technique by which the variation of a dependent variable can be predicted from the value of an independent variable (or variables) through a Regression Coefficient (or coefficients) plus a constant term. (y = a.x + b). Regulated Abatement Work Area: The portion of the restricted area where abatement work actually occurs. For tent work areas, the interior of each tent is a regulated abatement work area. For OSHA Class I and Class II asbestos abatement, the interior of the restricted area containment enclosure is the regulated abatement work area. For exterior non-friable asbestos abatement conducted without the establishment of negative air ventilation systems or containment enclosures, the entire restricted area surrounding the abatement location is considered to be the regulated abatement work area. Regulator: An automatic or manual device designed to control pressure, flow or temperature. Regulatory Authority: An agency established by a provincial, federal, or territorial government that has the authority to make or enforce (or both), regulations regarding occupational health and safety. Reheat: A coil placed after the cooling coil, used to raise the air temperature; the process of raising the cooled air temperature. Used mainly with DX coil dehumidification. Reheaters: Heat exchangers for raising the temperature of compressed air to increase its volume. Reheating of Air: In an air conditioning system, the final step in treatment in the event the temperature is too low. Reinforced Concrete: A combination of steel and concrete using the best properties of each. The steel consists of rebar or reinforcing bars varying from 3/8” to 2 ¼” in diameter and is placed before concrete is poured. Reinforced Masonry: Masonry units, reinforcing steel, grout and/or mortar combined to act together to strengthen the masonry structure. Reinforcing: Steel rods or metal fabric placed in concrete slabs, beams, or columns to increase their strength. RELs: Recommended Exposure Limits (recommendations made by the National Institute for Occupational Safety and Health (NIOSH)). Relamping : The replacement of an existing, standard light bulb with lower wattage energy efficient bulbs like compact fluorescent lamps. Relapse: The return of signs and symptoms of an illness after a period of improvement. Relative Clearance Volume: The ratio of clearance volume to the volume swept by the compressing element. Relative Heat Gain: The amount of heat gain through a glass product taking into consideration the effects of solar heat gain (shading coefficient) and conductive heat gain (U-value). Relative Humidity (RH) : The water vapour pressure in the air expressed as a proportion of the saturated water vapour pressure (ie the highest possible value) at the current air temperature. Air that is completely saturated has 100% relative humidity. Relative Risk: The ratio of health impact incidence among exposed individuals to incidence among unexposed individuals. Relative Sunshine Duration: Ratio of sunshine duration to possible sunshine duration within the same period. Relative Vapor Pressure: The ratio of the vapor pressure to the saturated vapor pressure at the temperature considered. Relay: An automatic, electrically-operated switch. Release Tape: A plastic or paper strip that is applied to the back of self-sealing shingles. This strip prevents the shingles from sticking together in the bundles, and need not be removed for application. Relief Device: A device designed to open under a high pressure. Relief Valve: A spring loaded pressure relief valve actuated by the static pressure upstream of the valve. The valve opens normally in proportion to the pressure increase over the opening pressure. RELs: Recommended Exposure Limits (recommendations made by the National Institute for Occupational Safety and Health (NIOSH)). Rem: Unit of radiation dose equivalent and effective dose equivalent describing the effectiveness of a type of radiation to produce biological effects; coined from the phrase “roentgen equivalent man,” and the product of the absorbed dose (rad), a quality factor (Q), a distribution factor, and other necessary modifying factors. 1 rem = 0.01 sievert. Remanufacturing: A recycling concept by which an existing product has its useful life extended through a secondary manufacturing or refurbishing process such as remanufactured systems furniture. Remediation: Cleanup of a site to levels determined to be health-protective for its intended use, or protective of beneficial uses of water. Remote: Remote electrical, gas, or water meter digital readouts that are installed near the front of the home in order for utility companies to easily read the home owners usage of the service. Remote Decontamination System Enclosure: Decontamination systems that are not attached to the regulated abatement work area but are within the work site. Remote Sensing: The collection and interpretation of information about an object without physical contact with the object; e.g., satellite imaging, aerial photography, and open path. Removal: Abatement, consisting of operations where ACM, PACM or asbestos material is removed or stripped from structures or substrates. This includes demolition operations. Renewable Energy: The term renewable energy generally refers to electricity supplied from renewable energy sources, such as wind and solar power, geothermal, hydropower, and various forms of biomass. These energy sources are considered renewable sources because they are continuously replenished on the Earth. Renovation: The altering of an existing building/structure, or a portion of building/structure components or systems, including the stripping, removal or abatement of ACM from a building or structure. Operations in which load-supporting structural members are wrecked or taken out are demolitions. Repack: Cylindrical element used in a single-stage filter separator for removal of one liquid and course solids from another liquid. May be used as a single element, a combination of wafers, or a cluster type. Medium may be excelsior, glass fiber or steel wool; or a combination of glass fibers and metal mesh. Repair (Asbestos): Abatement, consisting of corrective action for a Minor Asbestos Project using required work practices to control fiber release from damaged ACM, PACM or asbestos material. Repair: The replacement, overhaul, rebuilding, reconstructing or reconditioning of any part of a building/structure component or system with like or similar material or parts, due to damage or excessive wear. Repeat: The number of threads in a weave before the weave repeats or starts over again. The number of ends and picks in the repeat may be equal or unequal, but in every case the repeat must be in a rectangular form. Replacement Air: A ventilating term that refers to the replacement of air lost because of exhaust air requirements. Representative Sample: A portion of material or water that is as nearly identical in content and consistency as possible to that in the larger body of material or water being sampled. Repressuring Baghouse: Baghouse using bags that are cleaned by flowing air backwards through the cloth. Same as reverse air baghouse. Required Capacity: Cubic feet per minute (cfm) of air required at the inlet to the distribution system. Requirements and Submittals: LEED Green Building Rating System component that specifies the criteria to satisfy the prerequisites or credit, the total number of points available, and the documentation required for the LEED application. Reservoir: The environmental substrate, or source, of a particular organism. Reservoirs for indoor biocontaminants include stagnant water, moist surfaces, and dust collection sites. Reset: A process of automatically adjusting the control point of a given controller to compensate for changes in outdoor temperature. The hot deck control point is normally reset upward as the outdoor temperature drops. The cold deck control point is normally reset downward as the outdoor temperature increases. Reset Controller: Adjusts fluid temperature or pressure in a central heating system according to outdoor air temperature. Residential Wood Combustion (RWC): The process of burning wood for home heating purposes. Residual: Amount of a pollutant remaining in the environment after a natural or technological process has taken place. Residual Chlorine: The amount of free and/or available chlorine remaining after a given contact time under specified conditions. Residual Dirt Capacity: The dirt capacity remaining in a service loaded filter element after use, but before cleaning, measured under the same conditions as the dirt capacity of a new filter element. Residual Risk: The quantity of health risk remaining after application of the MACT (Maximum Achievable Control Technology). Residual Shrinkage: The amount of shrinkage remaining in a fabric after it has undergone all fabric weaving, washing and heat setting steps. Residue: Solids deposited upon the filter medium during filtration in sufficient thickness to be removed in sizeable pieces. Sometimes referred to as a cake or discharge solids. Resistance: The property of a material resisting the flow of electrical energy or heat energy. Resistance (Filter): See: Pressure Drop. Resistance value (RSI): Thermal resistance value. Measurement of the ability of a material to resist heat transfer. Resistivity: The thermal resistance of unit area of a material of unit thickness to heat flow caused by a temperature difference across the material. (m2K/W). Residential wood combustion (RWC): The process of burning wood for home heating purposes. Residual Chlorine : Chlorine remaining in water or wastewater at the end of a specified contact period as combined or free chlorine. Residual Fuel Oil: The topped crude of refinery operation, includes No. 5 and No. 6 fuel oils as defined in ASTM Specification D396 and Federal Specification VV-F-815C; Navy Special fuel oil as defined in Military Specification MIL-F-859E including Amendment 2 (NATO Symbol F-77); and Bunker C fuel oil. Residual fuel oil is used for the production of electric power, space heating, vessel bunkering, and various industrial purposes. Imports of residual fuel oil include imported crude oil burned as fuel. Residual Volume: The amount of air left in the lungs when someone exhales as much as possible. This is tested in a PFT. Residuum: Input definition. Resilient Flooring: A durable floor cover that has the ability to resume its original shape. Resistance: The internal structure of wires even in the best conductors opposes the flow of electric current and converts some current into heat. This internal friction-like effect is called resistance and is measured in ohms. Resistance equals Voltage divided by Amperage. Resistivity: The thermal resistance of unit area of a material of unit thickness to heat flow caused by a temperature difference across the material. (m2K/W). Resource Conservation: Practices that protect, preserve or renew natural resources in a manner that will ensure their highest economic or social benefits. Resource Conservation and Recovery Act (RCRA): A 1976 act to reduce or eliminate the generation of hazardous waste as expeditiously as possible. Waste that is generated should be treated, stored or disposed of to minimize the threat to the environment. Resource Efficiency: A practice in which the primary consideration of material use begins with the concept of “Reduce - Reuse - Recycle – Repair” stated in descending order of priority. Resorcinol Glue: A glue that is high in both wet and dry strength and resistant to high temperatures. It is used for gluing lumber or assembly joints that must withstand severe service conditions. Respirable: Particles or aerosols capable of being inhaled into the deep lung, < 3 microns in diameter. Respirable Dust: Airborne dust in sizes capable of passing throughout the upper respiratory system to reach the lower lung passages. Respirable Fraction: The size range of particles most hazardous to health. Includes those particles which are both small enough to pass through the human body’s biological filters and large enough to remain in the lungs rather than be expelled. The respirable fraction generally consists of particles between 0.3 and 5 microns. Respirable Particles: Respirable particles are those that penetrate into and are deposited in the nonciliated portion of the lung. Particles greater than 10 micrometers aerodynamic diameter are not respirable. Respirable Suspended Particles (RSP): Inhalable particulate matter in the air. Respiration: Production of carbon dioxide and heat by ripening of perishables in storage; also the breathing process of animals. Respirator: A device designed to protect the user from inhaling a hazardous atmosphere. Respiratory Disease: A disease affecting the respiratory system. Respiratory Failure: The sudden inability of the lungs to provide normal oxygen delivery or normal carbon dioxide removal. Respiratory Inlet Covering: The part of a respirator that envelops the area between the user’s respiratory tract and a breathing air source; for example, a facepiece, helmet, hood, or supplied-air suit. Respiratory Protection Program: A formal, documented, and enforceable plan for protecting respiratory health and safety in the workplace. Respiratory System: The parts of the body involved in breathing, including the nose, pharynx, larynx, trachea, bronchi, and the lungs, which contain alveoli and where an exchange of oxygen and carbon dioxide takes place. Respiratory Therapist: A health care professional who specializes in assessment, treatment and education for people with lung diseases. Respiratory Therapy Department: A hospital department that provides therapies and treatments to patients who have cardiopulmonary problems. Respiratory Tract: The Respiratory Tract includes the organs that are involved in breathing. These are the nose, throat, larynx, trachea, bronchi, and lungs. The respiratory tract is also known as the respiratory system. The upper respiratory tract includes the nose, sinuses, pharynx (throat), and larynx (voice box). The lower respiratory tract includes the trachea (windpipe), bronchial tubes (two branches from the windpipe), bronchioles (smaller bronchial tubes, and alveoli (tiny sacs in the lungs where the exchange of oxygen and carbon dioxide occurs). Responsible Party: An individual or corporate entity considered legally liable for contamination found at a property and, therefore, responsible for cleanup of the site. Retail Competition: In states with retail competition, consumers have the opportunity to choose their energy provider and purchase products based on the price or on the source of power supplied to their home or business. Retaining Wall: A structure that holds back a slope and prevents erosion. Retentate: Substance retained in the upstream side of a filter. Retention: Ability of a filter to retain particles suspended in a gas or liquid. A percentage of particles originally present. Retentions: Amounts withheld from progress billings until final and satisfactory project completion. Retention: Ability of a filter to retain particles (total number or those of a specific size) suspended in a gas or liquid. Expressed as a percent of particles originally present. Retention Volume: See “Hold-up Volume.” Retro-Commissioning: Commissioning performed on a facility that has been in service but not previously commissioned. Retrofit: An energy conservation measure applied to an existing building or the action of improving the thermal performance or maintenance of a building. Retrofitting: Installing modern pollution control devices on older power generating facilities without making major changes in plant design. Return: In heating and cooling systems, a vent that returns cold air to be warmed. In a hot air furnace system, it is located near an inside wall. Return Air: Air circulation back to the furnace from the house to be heated by the furnace and supplied to the rooms. Return Duct: The central heating or cooling system contains a fan that gets its air supply through these ducts, which ideally should be installed in every room of the house. The air from a room will move towards the lower pressure of the return duct. Return Ductwork: Ductwork that takes air from the home and brings it back to the HVAC system. Return Flow: Applied water that drains as surface flow from irrigated lands. Reusable Filters: Filters that are washed or cleaned of contaminate, either in-situ or off-line, for additional uses. Reuse: Using a product or component of municipal solid waste in its original form more than once. Reused Components: Structural or finish materials removed from old buildings and reused in new or remodeled buildings. Reverberation: The persistence of sound in an enclosed space after the sound source has stopped. In a reverberation room, it is characterized by the decay or dying away the sound. Reverberation Time: The reverberation time of an enclosed space is the number of seconds required, or that would be required were the decay rate to remain constant, for the sound pressure level to decrease by 60 decibels. Reverse Air Baghouse: Baghouse using bags that are cleaned by flowing air backwards through the cloth, to cause dust cake release. Reverse Jet: See Pulse Jet. Reverse Osmosis (RO): A water treatment method whereby water is forced through a semi-permeable membrane which filters out impurities, such as salt (NaCl) from seawater. Reversible Disassembly: Reverse manufacturing, in which the removal of screws, clips, and other fasteners permits refurbishment and reuse of some or all of the components and modules of a product. Reversible Process: An ideal process that may be stopped and made to retrace its steps and restore to the systems or surroundings all work and heat previously removed. It is frictionless. Reversing Heat Pump: A heat pump in which the condenser and evaporator coils of the unit reverse roles in response to a reverse in the direction of the flow of refrigerant in the machine. Reversing Valve: A device in a heat pump that reverses the flow of refrigerant as the system is switched from cooling to heating. Revetment: Facing (as of stone or concrete) to sustain an embankment. Re-Weatherized Unit: Any unit that received weatherization services prior to September 30, 1985 and has received additional services under subsequent grants or allowed by current DOE regulations. Reynold’s Number: A dimensionless flow parameter, ( Jnr/m), in which J is a significant dimension, often a diameter, n is the fluid velocity, r is mass density, and m is dynamic viscosity, all in consistent units. RF: Radio frequency; portion of electromagnetic spectrum. RFP (Request for Proposal): A public document outlining a particular business opportunity between a government entity and a private company. RF (radio frequency) Welding: Utilizes specific bands of radio frequency waves which are directed through specially constructed tooling to form localized melting/joining of certain dielectric thermoplastic materials. Can be used to form hermetic seals. Also known as high frequency or dielectric welding. RH: Relative humidity. Rhinitis: Inflammation of the lining of the nose. Ribbon (or Girt): Normally a 1”x4” board let into the studs horizontally to support ceiling or second-floor joists. Ridge: The horizontal line at the junction of the top edges of two sloping roof surfaces. Ridge Board: The board placed on edge at the ridge of the roof into which the upper ends of the rafters are fastened. Ridge Cut: The end cut on a rafter that fits to the ridgeboard. Ridgeboards: Horizontal support at the ridge of a roof to which opposing rafters are attached. Riello Burner: A burner assembly within your oil furnace, manufactured by Riello to exact specifications of Carrier. This burner provides a cleaner, higher quality combustion of heating oil to increase energy efficiency. Rigid Insulation: Rigid board material which provides thermal resistance. Foam plastic such as EPS, XPS, and polyisocyanurate are commonly used, polyurethane and may be found. Rigid Metal Conduit: This conduit resembles plumbing pipe, protecting wires from damage. Rim Joist: The outermost joist around the perimeter of the floor framing. Rings: Circular metallic elements that ride in the grooves of a piston and provide compression sealing during combustion. Also used to spread oil for lubrication. Ring Sticking: Freezing of a piston ring in its groove in a piston engine or reciprocating compressor due to heavy deposits in the piston ring zone. Ringtail: Ringtail in the rat is a condition in young suckling rats and mice, believed to be caused by low relative humidity (less than about 30%). There are annular constrictions on the tail that may progress to necrosis and sloughing of the tail tip. Ringtail can be prevented by maintaining relative humidity at approximately 50%. Ringelmann Chart: A series of charts, numbered 0 to 5, that simulate various smoke densities by presenting different percentages of black. A Ringelmann No. 1 is equivalent to 20 percent black; a Ringelmann No. 5 is 100 percent black. They are used for measuring the opacity or equivalent obscuration of smoke arising from stacks and other sources by matching the actual effluent with the various numbers, or densities, indicated by the charts. Ringworm: Fungal infections of the skin resulting in raised red swellings or lines that resemble burrowing worms; includes the diseases known as athlete’s foot, jock itch, and ringworm or the scalp. Riparian: Of, adjacent to, or living on the bank watercourse (e.g. stream, river, lake, etc.). Riparian Rights: Comes with ownership of land adjacent to a water source, ground water rights are held by those owning land over a ground water basin. Riparian Vegetation: The vegetation along a watercourse which is distinguished from other vegetation by its dependence on the combination of soil moisture and other environmental factors provided by a permanent or intermittent stream. Rise: In stairs, the vertical height of a step or flight of stairs. Riser: Each of the vertical boards closing the spaces between the treads of stairways. Riser Shaft: A vertical shaft designed to house electric cables, piping and ductwork. Risk: The probability of injury, disease, or death under specific circumstances. In quantitative terms, risk is expressed in values ranging from zero, which represents the certainty that harm will not occur, to one, which represents the certainty that harm will occur. Risk Assessment: A risk assessment looks at the chemicals detected at a site, the frequency and concentration of detected chemicals, the toxicity of the chemicals and how people can be exposed, and for how long. Routes of exposure to people are generally through ingestion, such as eating, contact with the skin, or inhalation. The most significant potential routes of exposure are trough ingestion and contact with the skin. Based on the standard risk assessment guidelines established for use nationwide by USEPA, exposures for an on-site resident are generally assumed to be daily contact over a 30-year period starting with children ages 0-6, and continuing from 6-30 years. The health risk assessment cannot predict health effects; it only describes the increased possibility of adverse health effects, based on the best scientific information available. Risk Communication: Exchange of information about health or environmental risks between risk assessors, risk managers, the general public, and other interest groups such as the news media. Risk Levels: 1. LOW RISK: risk level of agents and/or operations having minimal effect on personnel, other animal or plants under ordinary use. This classification is restricted to all etiologic agents designated as Biosafety Level 1 by the CDC. 2. MODERATE RISK: risk level of agents/or operations requiring special conditions for control or containment because of (a) known pathogenicity to personnel, other animals or plants; (b) concentration; or (c) genetic alteration (synergistic effect) with other materials. This classification includes all etiologic agents designated as Class 2 or 3 by the CDC (Biosafety level 2 or 3) and oncogenic viruses specified as moderate risk by the National Cancer Institute (NCI). 3. HIGH RISK: risk level of agents and/or operations requiring additional control measures beyond those for moderate risk. This classification includes all etiologic agents designated Class 4 or 5 by the CDC and oncogenic viruses classified as high risk by the NCI. Risk Groups for Microorganisms: AS 2243.3 classifies infective microorganisms according to degree of risk. Class I and II biological safety cabinets are intended for work with microorganisms of Risk Groups 2 and 3. Risk Identification: Designation of the nature of the risk, source, manipulation, consequences. Risk Management: The process of evaluating alternative responses to risks and selecting among them. Includes consideration of technical, scientific, social, economic, and political information. Risk Source Characterization: Description of the characteristics of the risk source that have the potential for creating or increasing the risk. RMQA, 1998: A 1998 study led by the Regroupement Montréalais pour la qualité de l'air. The study assessed the impact of air pollution on health and the environment in the Greater Montreal area and identified wood combustion as a major source of air pollution. Road Base: An aggregate mixture of sand and stone. Rock 1, 2, 3: When referring to drywall, this means to install drywall to the walls and ceilings (with nails and screws), and before taping is performed. Rock Drill: A pneumatic percussive drill designed as a boring tool. Roentgen (R): Unit of measurement used to express radiation exposure in terms of the amount of ionization produced in a volume of air. Roll, Rolling: To install the floor joists or trusses in their correct place. (To “roll the floor” means to install the floor joists). Roll Roofing: Roofing material, composed of fiber and satin rated with asphalt, that is supplied in 36-inch wide rolls with 108 square feet of material. Weights are generally 45 to 90 pounds per roll. Rolling Element: A type of journal bearing in centrifugal air compressors. Rollout Switch: A heat-sensitive protective device that opens the circuit if flame migrates away from the burner box. Romex: A non-metallic sheathed cable consisting of two or more insulated conductors having an outer sheath of moisture resistant, non-metallic material. The conductor insulation is rubber, neoprene, thermoplastic or a moisture resistant flame retardant fibrous material. There are two types: NM and NMC - described earlier. Roof Deck: See deck. Roof Sheathing: The boards or sheet material fastened to the roof rafters on which the shingle or other roof covering is laid. Roof System: General term referring to the waterproof covering, roof insulation, vapor barrier, if used and roof deck as an entity. An asphalt-saturated tape used with asphalt cements for flashing and patching asphalt roofing. Room Criteria Curves (RC Curves): Curves similar to NC curves that represent a close approximation to a well balanced, bland-sounding spectrum. Room Dry Bulb: The actual temperature of the conditioned room or space as measured with an accurate thermometer. Room Pressure: See pressure drop and room pressure. Pressure differentials between cleanrooms and adjoining zones are typically specified as ≥ 15 Pa. Room Temperature: Used colloquially to mean the ordinary temperature one is accustomed to find in dwellings. Technically it can mean the temperature of (l) a room in which a refrigerator is being operated or tested; (2) a room being conditioned for the occupant's comfort. Room Velocity: The residual air velocity level in the occupied zone of the conditioned space (e.g. 65, 50, 35 fpm). Root Cellar: Food storage area with a dirt floor. Root Cyclone Technology: This is a patented Dyson technology that uses 100,000 G's of centrifugal force in cyclones to filter dust and remove dirt from the airflow efficiently. The Root CycloneÔ delivers higher suction power by making the air stream spin, subjecting it to centrifugal force, which throws the dirt and debris out of the air. Because the airflow is unobstructed and because there are no filters or bags to clog, the suction power remains constant. Rotameter: A flow meter, consisting of a precision-bored, tapered, transparent tube with a solid float inside. Used for calibrating instruments. Rotary Actuator: A pneumatic device with a rotary output. Typically of a vane or rack-and-pinion construction. Rotary Airlock: A valve with a rotating wheel generally located on the dust collector discharge hopper or at the end of a screw conveyor. It is designed to allow continuous discharge of the collected dust while maintaining a positive air seal. Rotary Blowers: A compressor belonging to the group of displacement rotary compressors, a type of valve less displacement machine. Also referred to as “Roots blower.” Rotary Compressors: Machines in which compression is effected by the positive action of rotating elements. Rotary Drum: Continuous liquid filter equipment consisting of a large rotating drum covered with a filter cloth and cake, which collects incoming particulate from a contaminated bath or flow. A washing and/or discharge device (scrapper) ultimately cleans the contaminate from the cake as the drum rotates. Rotary Sliding Vane Compressors: Machines in which axial vanes slide radially in an eccentrically mounted rotor. Rotor: The rotating element of a machine and, in the case of a compressor, is composed of the impeller (impellers) and shaft, and may include shaft sleeves and a thrust balancing device. Rough: In hardware, metal fastenings on cabinets which are usually concealed, like staples. Rough Flooring: Materials used to form an unfinished floor. Floor sheathing. Rough Opening: The opening in a wall into which a door or window is to be installed. Rough Plumbing: All plumbing that should be done before the finish trades (sheetrock, painting, etc), including all waste lines and supply water lines that are in the walls or framing of the building. See also: Plumbing, Sub Rough, and Finish Plumbing. Roughing Filter: A prefilter with high efficiency for large particles and fibers but low efficiency for small particles, usually of the panel type.  Route of Entry: The path by which chemicals can enter the body. There are three main routes of entry: inhalation, ingestion, and skin absorption. Route of Exposure: The means by which toxic agents gain access to an organism such as ingestion, inhalation, dermal exposures; and intravenous, subcutaneous, intermuscular administrations. RPD: Respiratory protection device. RPM: Revolutions per Minute. RPP: See Respiratory Protection Program. RPP CFTO CFTO-87-040-000/MS-001: Respiratory Protection Program. RPPA: Respiratory Protection Program Administrator. RSP: Respirable suspended particles. RTC: Room temperature catalyst; a catalyst that accelerates chemical reactions at room temperature rather than at the usually required higher temperature. RTECS (Registry of Toxic Effects of Chemical Substances): A database that lists an identification number, synonyms, Department of Transportation (DOT) hazard label information, EPA Toxic Substances Control Ad (TSCA) information, OSHA and Mine Safety and Health Administration (MSHA) air exposure limits and animal and human toxicologic data. RTU: Roof top unit; a packaged AHU unit on the roof. Rubber Emulsion Paint: Paint, the vehicle of which consists of rubber or synthetic rubber dispersed in fine droplets in water. Rubber-Tired Roller: A roller with rubber tires commonly used for compacting trimmed subgrade or aggregate base or clay type soils. Run (Roofing): The horizontal distance between the eaves and the ridge of the roof, being half the span for a symmetrical gable roof. Also, the net width of a step or the horizontal distance covered by a flight of stairs. Running Losses: Evaporation of motor vehicle fuel from the fuel tank while the vehicle is in use. Running Time: The percentage of time a refrigeration compressor runs. Runoff: Rainfall or snow melt which is not absorbed by soil, evaporated, or transpired by plants, but finds its way into streams as surface flow. Rust Prevention Test: (Turbine oils) – a test for determining the ability of an oil to aid in preventing the rusting of ferrous parts in the presence of water. R-Value: A measurement of thermal resistance for materials and related surfaces. |
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