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alkyd -- a synthetic binder used in oil base paint. Also another name for oil--based paint.
asbestos -- a mineral fiber used as insulation, fire proofing, reinforcing fiber, and other applications in construction materials. Asbestos fibers are now known to cause asbestosis and cancer.
asset -- any owned property. Specifically any equipment or building component.
BAC -- see building automation control.
bearing -- the supporting guide for a rotating or sliding machinery component.
best maintenance practice -- a commonly accepted industry maintenance practice that is used when the manufacturer's recommendations are not available.
binder -- the component of paint that polymerizes and develops into the final film of paint. Sometimes called the "solids" of the paint.
biological contaminants -- pollutants from living things such as pet dander, rodent droppings, mold, bacteria, etc.
bitumen -- asphalt or tar-based sealant and adhesive used between layers of roofing felt in many commercial roofs. Can be applied hot or mixed with solvents to make the bitumen liquid enough to mop onto the roofing layers.
BMP -- see best maintenance practice.
Btu -- British thermal unit. A measure of thermal energy. 1 Btu is the amount of heat required to raise one pound of water one degree Fahrenheit.
building automation control -- A heating and cooling control system where temperature, humidity and occupancy sensors send data to a central computer which directly controls all heating and cooling equipment in a building.
building envelope -- the outside surfaces of a building. Walls roofs windows doors etc.
built-up roof--a commercial roofing system consisting of several layers (usually 3 or 4) of roofing felt embedded in layers of asphalt or tar. (See also modified bitumen roof.)
BUR--see built-up roof
call back maintenance--maintenance work that needs to be done again often because it wasn't done right the first time.
CLAIR--clean, lubricate, adjust, inspect, repair. An acronym to help PM mechanics remember the proper procedure for performing PM.
CMMS--computerized maintenance management software.
cold galvanizing compound--zinc-based paint formulated to protect metal from rusting.
corrective maintenance--repair. Fixing something after it has broken.
DDC--see direct digital control.
deferred maintenance--maintenance work that is not being done at this time.
direct digital control--a heating and cooling control system where temperature, humidity, and occupancy sensors send data to a central computer which directly controls all heating and cooling equipment in a building.
direct expansion--a type of air conditioning equipment where the refrigerant exchanges heat directly with air via a cooling coil, e.g. "DX coil."
downtime--time that equipment is not working due to some equipment failure.
dust spot efficiency rating--method of testing and reporting how well air conditioning filters remove particles from the air.
dust weight arrestance rating--method of testing and reporting how well air conditioning filters remove particles from the air.
DX--see direct expansion.
EAC--see equivalent annual cost.
elastomeric wall coating--an architectural coating that forms a very thick flexible film.
emergency maintenance--maintenance work that needs to be done immediately.
envelope--see building envelope.
EPDM--ethylene propylene diene monomer. The type of rubber used in the majority of single-ply commercial roofs. Often referred to as a rubber roof.
equipment data sheet--a form used to record important information about each piece of equipment in a facility.
equivalent annual cost--used to compare the costs of repair vs. replacement options. Used as a tool in "life cycle costing."
EWC--see elastomeric wall coating.
flashing--roofing component that provides a water shedding transition between two different surfaces.
flat roof--a roof having a pitch of less than 1/4" rise for every 12" horizontally.
grease--lubricating oil mixed with a thickener. Used to lubricate slow moving equipment or rolling element bearings.
group re-lamping--replacing an entire section of fluorescent or HID lamps at one time as they reach the end of their expected life.
HID--see high intensity discharge lighting.
high intensity discharge lighting--type of lighting that is more efficient than traditional incandescent lights. Typically used for exterior or high bay lighting applications. Includes metal halide, mercury vapor, and high pressure sodium lighting.
HVAC--the trade involved in heating ventilation and air conditioning.
HVAC/R--heating ventilation air conditioning and refrigeration.
hydrodynamic pressure--fluid pressure generated from the rapid compression of a fluid. In fast rotating bearings hydrodynamic oil pressure keeps bearing surfaces from touching, eliminating surface to surface wear.
hydrostatic pressure--fluid pressure generated by a source outside of the fluid. In slow rotating or heavily loaded bearings, oil pumps may be used to create hydrostatic pressure.
IAQ--see indoor air quality.
indoor air quality--the presence or absence of airborne pollutants inside a building.
infant mortality--the concept that brand new equipment or parts are more likely to fail than those parts that have been in service for some time due to manufacturing defects.
infrared imaging--see thermal imaging.
inverted roof--a roofing system where insulation board is applied on top of the roofing membrane to protect the roof membrane from physical damage and temperature extremes.
JCAHO--Joint Commission on the Accreditation of Healthcare Organizations, organization that sets voluntary standards for healthcare centers that exceed state and federal standards.
latex paint--paint that uses water soluble plastic or polymer binders and water as the carrier.
lead--a toxic heavy metal once used extensively in architectural paints.
life cycle costing -- comparing the cost of various maintenance repair or replacement options over the life of the various options. Requires converting all options to one common unit of time.
low pitch roof--a roof having a pitch of less than 2" of rise for every 12" horizontally but more than 1/4" rise for every 12" horizontally.
lubrication--the application of grease or oil to a machine to reduce friction.
MBR--see modified bitumen roof.
MERV--see minimum efficiency reporting value.
minimum efficiency reporting value--method of testing and reporting how well air conditioning filters remove particles from the air.
modified bitumen roof--commercial roofing system consisting of several layers (often 4) of roofing felt that is factory impregnated with asphalt or tar bitumens. Modified bitumen roofs get their name from additives (modifiers) that are added to the tar or asphalt to improve roof performance. See also built--up roof.
mold -- microscopic fungi that feed and grow on organic material. Often associated with poor indoor air quality within buildings.
neutral axis--the imaginary line through a drive belt where no compression or expansion of the material occurs when the belt flexes. Usually located where the reinforcing cords are located.
oil analysis--laboratory analysis of used lubricating oil to determine the condition of the equipment the oil sample was taken from. Often used as part of a predictive maintenance program.
oil-based paint--paint that uses petroleum--based solvents, usually mineral spirits as the paint carrier or solvent.
orifice--type of refrigerant expansion device consisting of a disk with a small hole to allow a metered amount of refrigerant to pass.
paint--a thin film coating of polymer applied as a liquid.
pathway--the route of travel of a pollutant. Specifically related to indoor air quality.
PDA--personal data assistant. A small hand held computer.
PdM--predictive maintenance. Maintenance that is performed when indicated by some measurable wear factor.
pesticides--chemicals used to kill pests.
pigment--the component of paint that provides the color or rust inhibitive properties to paint.
pitch--a measurement of the slope of a roof given in inches of rise for every 12" horizontally.
pitch pocket--a roofing component that is filled with asphalt or tar pitch to seal around pipes conduit or other penetrations.
pollutant--an airborne contaminant. Related specifically to indoor air quality.
ponding--standing water on a flat or nearly flat roof.
predictive maintenance--maintenance that is performed when indicated by some measurable wear factor.
preventive maintenance--a scheduled program of regular inspections adjustments lubrication or replacement of worn or failing parts in order to maintain an asset's function and efficiency.
primer--a type of paint engineered to work as an undercoat to improve adhesion and appearance of a top coat.
PTAC--package terminal air conditioner. Small self contained air conditioner units that are installed in a sleeve through a wall. Often found in hotel rooms.
pulley--wheel that drives or is driven by a drive belt. See also sheave.
pulley misalignment--when two pulleys are parallel but not in the same plane. Causes excessive heating and premature wear of drive belts.
purlin--a roof framing member applied on top of and perpendicular to the rafters.
radon--a colorless odorless radioactive gas that results form radioactive decay of uranium in rock. Radon can infiltrate buildings where it can be a cause of cancer.
reactive maintenance--see corrective maintenance.
reliability engineering--a field of engineering focusing on predictive maintenance and machinery reliability.
retro--commissioning--having a building and particularly the HVAC systems tested, inspected, and adjusted to maintain the energy savings designed into the system when it was new.
return on investment--financial term for the ratio of money invested to money earned from the investment given as a percentage.
ROI--see return on investment.
RPM--rotations per minute.
RTU--rooftop air conditioning unit.
run to failure--operating a piece of equipment with no intention of doing any maintenance until the equipment breaks down. Often used for inexpensive, easily replaced equipment.
rust convertor--a protective coating including tannic acid which converts rust to a hard protective stable compound.
shaft misalignment--when two pulleys are not parallel or in the same plane. Causes excessive heating and premature wear of drive belts.
sheave--wheel that drives or is driven by a drive belt. See also pulley.
sick building syndrome--phenomenon where building occupants suffer health symptoms while in a building that leave when the person is not in the building.
solvent -- the component of paint that evaporates away leaving a film made of the binder and pigments.
thermal imaging -- a non destructive method of testing equipment using thermal imaging cameras that can see and measure temperature. Often used as a predictive maintenance tool.
thermoplastic -- a plastic material that can be softened by heat. Several of these plastics are used as single--ply membrane roofing materials. A common example would be PVC (polyvinyl chloride).
thermostatic expansion device--a type of refrigerant expansion device.
Uses a temperature sensing bulb to adjust the size of the expansion orifice to maintain a constant refrigerant temperature at the evaporator coil.
ton -- a measure of cooling capacity. A ton of cooling is the amount of cooling required to produce one ton of ice in a 24--hour period. The same as 12,000 Btu.
TXV--see Thermostatic Expansion Device.
ultrasonic testing -- a non destructive method of inspecting machinery components, such as motor bearings, by using a listening device to hear sounds normally out of the range of human hearing.
urethane -- a group of architectural coatings based on reacting urethane with a catalyst to harden.
vibration analysis--a non destructive method of testing machinery components such as motor bearings by measuring and analyzing component vibrations.
viscosity -- a measurement of a fluids resistance to flow.
VOC -- see volatile organic compound.
volatile organic compound--organic materials that vaporize readily at normal temperatures. Often a component of paints, solvents and other maintenance products. VOCs can contribute to respiratory or environ mental problems.
work order -- a written or computerized request for maintenance work to be completed.
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