GME Supply is North America's Premier Outfitter of fall protection, safety equipment, and gear for at-height workers, industry, and construction.

1391 E Boone Industrial Blvd
Columbia, MO 65202
(718) 210-3913

Gear Expert® Glossary of Terms

# | A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z |


100 (Respirators) - A number class rating used for respirators that represents that the respirator filters 99.7% of all particles measuring 0.3 microns or larger in diameter. This class filter is typically an HE or HEPA quality filter.

100% Tie-Off - 100% Tie-Off means that while working at height you must have fall protection equipment connected to you and an anchorage point at all times.

3-Strand (Rope) - 3-Strand Rope is a rope that is constructed of 3 smaller ropes spun together. Most commonly used as a lifeline.

4-Point Suspension (Hard Hats) - A suspension, typically constructed from nylon webbing, which is attached to the inside shell of a safety helmet at 4 individual locations. This suspension typically consists of two straps, which cross perpendicularly at the top of the head, creating an X pattern to support the shell of the helmet off of the top of the head. The suspension also usually serves as the shock absorption for the helmet. 

95 (Respirators) - A number class rating used for respirators that represents that the respirator filters 95% of all particles measuring 0.3 microns or larger in diameter.

99 (Respirators) - A number class rating used for respirators that represents that the respirator filters 99% of all particles measuring 0.3 microns or larger in diameter.

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Abate - The act of significantly reducing or ending the risk of a hazard.

Above Ground Level (AGL) - Above ground level is a height measured with respect to the underlying ground surface.

Above Ground Wiring - Another name for overhead power and communications lines, such as telephone or cable television wiring. These wire are strung between utility poles which must be grounded, and can span great distances. 

Abrasion - The process of scraping or wearing away - often used in place of damaging.

Abrasion Guard - A treatment used on material to prevent the material from being damaged while in contact with other materials or equipment that might scrape or damage the material.

AC (Alternating Current) - An electric current which periodically reverses direction.

Acceleration Stress - The additional stress that is imposed on a wire rope as a result of an increase in the load velocity. The opposite of deceleration stress.

Access - The right to enter or use; typically a communications site or building.

Accessory Cord - A piece of rope that can be used for prusik cords, tag lines, and hauling.

Accessory Loop - A feature of a full body harness, tool belt, or pouch where a tool or piece of hardware can be stored when not being used. Typically located on the belt, or seat sling of a harness, an accessory loop provides a location to clip a carabiner, tool tether, or other piece of equipment that needs to be accessed during work at-height.

ACI - American Concrete Institute

Acid - A chemical substance that neutralizes alkalis, dissolves some metals, and turns litmus red.

Activation Distance - The distance traveled by a fall arrester  or the amount of line paid out by a self-retracting lifeline from the start of a fall to the point where the fall arrester or self-retracting lifeline begins to apply a braking or stopping force.

Active Fall Protection System - A fall protection system that requires authorized persons to wear or use fall protection equipment and that requires fall protection training.

Adjuster - A component that provides a means to vary the length of a strap, webbing, or rope.

Administrative Controls - Employer mandated safe work practices or procedures that are designed to prevent exposure to a fall by signaling or warning an authorized person to avoid approaching a fall hazard.

Aeolian Vibration - The high-frequency vibration of guy wires usually caused by tensions in excess of 15% of breaking strength.

Aerated - The process of introducing air into a material.

Aggregate Strength - The strength derived by totaling the individual breaking strengths of the elements of a strand or rope. This strength does not give recognition to the reduction in strength resulting from other factors that may affect efficiency like knots or termiation plates.

AGMA - American Gear Manufacturers Association

Air Circulation Blower - A piece of a ventilation system, often used in confined space work. Confined spaces require air circulation to ensure a safe work environment.

Air Tools - Tools operated by compressed air.

AISC - American Institue of Steel Construction

AISE - Association of Iron and Steel Engineers

Albert’s Lay - See Lang Lay Rope.

ALC - Automatic Level Control.

Alkalis - A chemical compound that neutralizes or effervesces with acids and turns litmus blue.

Alloy - A metal that is made by combining two or more different types of metals. Usually done to provide added strength and/or resistance to corrosion.

AM (Radio) - Amplitude modulation (AM) is a modulation technique used in electronic communication, most commonly for transmitting information via a radio carrier wave. In amplitude modulation, the amplitude (signal strength) of the carrier wave is varied in proportion to that of the message signal being transmitted.

AM Tower - A tower that is isolated from the ground and acts as an antenna itself. RF radiates from the entire structure instead of the antenna on the structure, which is how other towers work.

AMP (Amperage) - An ampere is the unit for measuring electrical current. The higher the amperage, the faster the electric current is flowing.

Amplifier - An electronic device for increasing the amplitude of electrical signals, used chiefly in sound reproduction.

Analog (Two-Way Radio) - An analog radio transmits the audio signal in the form of electrical signals resembling sound waves. In comparison, digital radios process the audio into a pattern of numbers, which are then re-encoded by the receiving radio into sound waves. 

Anchor Attachment - The act of a user who is wearing personal fall protection equipment, connecting directly or indirectly to an anchorage. It also means the condition of an employee being connected to an anchorage.

Anchor Guys - Guy Wires run from the top of a pole to the ground. Used as support to poles with angles, unstable soil of in line dead-ends. The guy transfers the unbalanced force on a pole or structure to the earth without intermediate support. 

Anchor Rods - The connecting link between a guy wire and an anchor.

Anchor Shaft - A steel shaft extending from a concrete anchor and used to attach guy wires.

Anchorage - A piece of equipment or structure that provides a secure attachment point for workers. Anchorage points must be rated for at-least 5,000 pounds.

Anchorage Connectors - A component or subsystem that functions as an interface between the anchorage and the fall protectionwork positioning, rope access, or rescue system for the purpose of coupling the system to the anchorage.

Anco - A type of locking nut. An Anco nut has a bit of a stiff wire protruding from one face. This piece of wire rides in the threads of the mating bolt, preventing any unintentional slippage. Note: Anco nuts should not be re-used. If they are removed, they should be replaced.

Anemometer - A device that measures the speed of any current of gas or wind.

Angle Factor - Angle in degrees of rope or cable entering and leaving a block.

Angle Indicator, Boom - An accessory that measures the angle of a boom or platform in reference to horizontal. 

Angle of Loading - The inclination of a leg or branch of a sling as measured from the horizontal or vertical plane.

Annular Cutter - A hollow, multiple cutting edges cutting tool used to make/drill holes in ferrous and non-ferrous metals. Also called a core drill, core cutter, broach cutter, trepanning drill hole saw, or cup-type cutter.

Anode - A positively charged electrode by which the electrons leave a device.

ANSI - American National Standards Institute.



ANSI/ASME B30.21 - Standards for Lever Hoists.

ANSI/ASME B30.23 - Standards for Personnel Lifting Systems.

ANSI/ASME B30.26 - Standards for Rigging Hardware.

ANSI/ASME B30.7 - Standards for Winches.

ANSI/ASME B30.9 - Standards for Slings.



ANSI/ASSE A10.28 - Standards for Work Platforms Suspended from Cranes or Derricks.


ANSI/ASSE A10.32 - Standards for Personal Fall Protection Systems for Construction and Demolition Operations.



ANSI/ASSE A10.33 - Requirements for Multi-Employer Projects.


ANSI/ASSE A10.34 - Protection of the Public on or Adjacent to Construction Sites.


ANSI/ASSE A10.4 - Standards for Personnel Hoists and Employee Elevators.


ANSI/ASSE A10.42 - Safety Requirements for Rigging Qualifications and Responsibilites.



ANSI/ASSE A10.44 - Control of Energy Sources (Lockout/Tagout) for Construction & Demolition.


ANSI/ASSE A10.48 - Criteria for Safety Practices with the Construction, Demolition, Modification and Maintenance of Communication Structures.


ANSI/ASSE A10.5 - Standards for Material Hoists.


ANSI/ASSE A10.6 - Safety Requirements for Demolition Operations.


ANSI/ASSE Z359.2 - Minimum Requirements for a Comprehensive Managed Fall Protection Program.


ANSI/ASSE Z490.1 - Criteria for Accepted Practices in Safety, Health and Environmental Training


ANSI/IEEE C95.1 - Standard for Safety Levels with Respect to Human Exposure to Electric Magnetic. and Electromagnetic Fields, 0 Hz to 300 GHz.


ANSI/TIA 1019-A - Standard for Installation Alteration and Maintenance of Antenna Supporting Structures and Antennas.

ANSI/TIA 222-G - The structural standards for steel antenna towers and antenna supporting structures. The objective of this standard is to provide minimum criteria for specifying and designing steel antenna towers and antenna supporting structures.


ANSI/TIA 222-H - Structural Standard for Antenna Supporting Structures, Antennas and Small Wind Turbine Support Structures

ANSI/TIA 322 - Loading Criteria, Analysis, and Design Related to the Installation, Alteration and Maintenance of Communication Structures

ANSI A1, A2, A3, A4, A5, A6, A7, A8, A9 (Gloves) - ANSI classification that denotes level of cut resistance.

Antenna - A specialized transducer that converts RF fields into AC or vice-versa.

Antenna Gain - The amount of amplification of a RF signal due to the design of the antenna.

Antenna Alignment - A tool that assists in the installation of antennas by providing extremely accurate readings of tilt, roll, and azimuth.

Antenna Array - A platform, typically three sided, where telecom carriers place equipment to provide signal transmission and reception to a specific area. The number of antennas in an array varies based on a number of factors, including the number of active subscribers for that carrier, the volume and type of network usage by subscribers, technology being used, and type of spectrum currently used by the carrier. 

Antenna Mount - A steel structure attached to a tower to which antennas are fastened to for broadcast of signals.

Antenna Supporting Structure - A structure, including guy assemblies, guy anchorages, and substructures that support antennas or antenna arrays.

Applicable - Appropriate or capable of being applied.

Application - What something is meant to be used for or how something is meant to be used.

Appurtenance - An addition to a major structure that extends outside the boundaries of that structure.

APR - The acronym for Air-Purifying Respirator. APR's can consist of a disposable respirator, reusable half-mask, full-face mask, or supplied air respirators.

Arborist - See Tree Care.

Arc Rating - A value representing the energy necessary to pass through any given fabric to cause, with 50% probability, a second or third degree burn. Typically measured in calories/cm2.

Arresting Distance - The distance that it takes for fall protection equipment to arrest the fall of a worker. This distance also includes the calculations for equipment stretch.

Arresting Force - The amount of force exerted on a worker when a fall protection system arrests a fall. Usually the highest peak forces experienced during a fall.

Armored Rope - See Steel-Clad Hoisting Rope.

Armor Rod - A covering used to protect a conductor from damage due to excessive vibration.

ASA - American Standards Association

Ascender - A progress capture device that allows the user to travel up a rope.

ASD - ASD, or allowable stress design, is a method of analysis in which the design strength of the structure is equivalent to its ultimate strength divided by a specified factor of safety.

ASM - American Society of Metals

ASME - American Society of Mechanical Engineers

ASME B30 - The American Society of Mechanical Engineers standard for lifting and rigging

ASNT - American Society of Nondestructive Testing

Assisted Rescue - A rescue requiring the assistance of others.

Athermal Effect - Any effect of electromagnetic energy absorption that is not associated with a measurable rise in temperature.

ASTM - The American Society for Testing and Materials - an international standards organization

At-Height - The name given to any kind of work that, if proper precautions are not taken, a person could fall from a distance high enough to cause personal injury.

ATPV (Arc Thermal Performance Value) - A value representing the energy necessary to pass through any given fabric to cause, with 50% probability, a second or third degree burn. Typically measured in calories/cm2. Also referred to as Arc Rating.

Attach - To fasten or connect.

Attachment Point - Any point on a piece of equipment, such as a harness, where another piece of equipment, like a carabiner, tool tether, SRL, etc. can be attached.

Authorized (Basic) Climber - An individual with the physical capabilities to climb who may or may not have previous climbing experience, but has training in fall protection regulations, the equipment that applies to the field including instruction for their proper use; able to climb designated fixed access routes equipped with safety climb devices.

Authorized Person - A person assigned by the employer to perform duties at a location where the person will be exposed to a fall hazard.

Authorized Rescuer - A person assigned by the employer to perform rescue from fall protection.

Auto-Lock (Carabiner) - A three stage designed gate on carabiners that will automatically shut and locked when the user lets go of the gate.

Auxiliary Hoist - Supplemental hoisting unit.

Average Power - The transmitter power available averaged over a modulation cycle. The power actually available to do work.

Average Time - The appropriate time period over which exposure is averaged for purposes of determining compliance with a Maximum Permissible Exposure (MPE).

Aviation Paint - A specially formulated industrial coating designed to meet the requirements for brightness and color accuracy according to FAA specifications for communication towers. Aviation paint also has greater durability and protective properties than standard exterior paint. 

AWG - American Wire Gage

AWS - American Welding Society


AWS D1.1/D1.1M - Structural Welding Code (Steel)

Axis of Rotation - The vertical axis around which a crane superstructure rotates. Also called center of rotation (obsolete) and swing axis.

Azimuth (Antenna Alignment) - The direction of a celestial object from the observer, expressed as the angular distance from the north or south point of the horizon at which a vertical circle passing through the object intersects the horizon. A calculation important for installing antennasAntenna aligners often calculate this measurement.

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Back Stay - Wire rope or guy wire used to support a boom, mast, or section of a main rope, as on a suspension bridge or cableway leading from the tower to the anchorage.

Back SupportA piece of personal protective equipment designed to provide ergonomic support for the back of the wearer.

Back-Hitch Gantry - A fixed-or adjustable-height structure that forms part of the upper structure of a mobile crane, to which the lower spreader (carrying live boom-suspension ropes) is anchored.

Balaclava - A piece of personal protective equipment that is a close-fitting garment covering the whole head and neck except for parts of the face.

Ballast - Weight added to a crane base to create additional stability; it does not rotate when the crane swings.

Barrel - The lagging or body part of a rope drum in a drum hoist.

BarricadeA piece of equipment used to separate areas of danger from safe zones. Barricades can be used to help regulate traffic, vehicular and pedestrian, away from dangerous construction areas and situations. Barricades can consist of cones, bollards, fencing, netting, rope flags, and more.

Barrier - A physical obstruction, which is intended to prevent contact with energized lines or equipment.

Base (Hoist) - The mounting flanges or feet used to attach a hoist to its supporting structure or foundation.

Base Curve - A measure of the flatter curvature of the front surface of the lens on a pair of safety glasses.

Base Insulator - A ceramic insulator typically at the bottom of an AM tower. It is designed to electrically insulate the tower from the ground.

Base Mounting - The structure forming the lowest element of a crane or derrick; it transmits loads to the ground or other supporting surfaces. For mobile cranes, this is synonymous with carrier or crawler mounting. For tower cranes, the term includes a travel base, knee frame base, or fixed base (footing).

Base Section - The lowermost section of a telescopic boom; it does not telescope but contains the boom foot pin mountings and the boom hoist cylinder upper end mountings.

Basic Boom - The minimum length of sectional latticed boom that can be mounted and operated. This usually consists of a boom base and tip section only.

Basket (Sling Configuration) - A configuration for rigging slings or fall arrest anchorage where the sling cradles the load or anchor with both ends of the sling function as if they were two separate slings. The capacity of this configuration can be up to twice that of the same sling in a vertical hitch, but only if the sling angle of each leg is 90 degrees. 

Basket Support (Gin pole) - The lower support for a gin pole once in position. The basket support provides vertical and lateral support for the gin pole.

Bearing - A part of a machine that bears friction, especially between a rotating part and its housing.

Bearing Life - The number of revolutions or the number of hours at a constant speed that 90 percent of an apparently identical group of bearings will complete or exceed before the first evidence of fatigue develops; i.e., 10 out of 100 bearings will fail before rated life. Minimum life and L10 life are also used to mean rated life.

Beater - Slang for a sledgehammer. Usually preceded by its weight: “six-pound beater”.

Becket (Pulley) - An extra rigging hook or eye on a pulley, or block, where a rope can be anchored. Often used in a mechanical advantage or haul system. A becket is on the other side of the pulley from the fixed anchorage point. 

Becket Line - The part of the rope in a multiply reeving system that is dead-ended on one of the blocks.

Becket Loop - A loop of a small rope or strand fastened to the end of a large wire rope. Its function is to facilitate wire rope installation.

Belay - To secure a person at the end of a rope. A term often used when talking about recreational climbing, but sometimes used in at-height industries.

Below Grade - The act of being below ground level.

Bend Radius - The distance from the center of a pulley to the edge, which should be considered based on rope diameter, construction, and use. The smaller the bend radius, the more flexible the rope should be. The larger the bend radius, the less stress is placed on the rope while running through the sheave of the block or pulley.

Bending Stress - Stress that is imposed on the wires of a strand or rope by a bending or curving action.

Birdcage - An informal description of the appearance of a wire rope forced into compression. The outer strands form a "cage" and at times, displace the core.

Bleeding Line - A condition caused when wire rope is overloaded, forcing the lubricant in the cable to be squeezed out and run excessively.

Block - A nickname for a rigging pulley or snatch block.

Block and Tackle - The primary parts of rigging. Consists of the block and the line attached through the block.

Blow Torch - A device that produces a hot flame that is directed onto a surface. Often used in welding.

Blue (Safety Can) - Color that denotes that the safety can has been designed to hold kerosene.

Body Extension (Tower) - The tower section that goes between the leg extension and the main tower body to adjust the tower height.

Body Harness - An integral part of a personal fall protection system. A body harness, also known as a full body harness, provides an anchorage point to safely secure a worker to a structure. In the event of a fall, a harness must be able to withstand the forces of the fall and support the victim until rescue arrives. 

Body Support - See Body Harness.

Body Wear - A term used to describe either a body belt or body harness.

Bolt Bag - A tool pouch, typically worn on a tool belt or waist belt of a harness, what a worker uses to store tools, hardware, construction components, and other accessories required for a job. Bolt Bags are available in a variety of sizes, configurations, and materials. Duck canvas is a popular construction material, but recently synthetic materials like nylonpolyester, and tarpaulin have replaced traditional canvas.

Bolt Cutters - Bolt cutters, also referred to as bow bits, is a cutting tool with a large, straight base designed to cut thicker cable.

Bolt Type Shackle - A type of shackle where the pin has a male threaded end, which is fed through the body of the shackle, and secured with a bolt on the outside of the shackle. This is different from a screw type shackle, where the pin threads into a female thread in the body of the shackle.

Bond (Electrical) - An electrical connection from one conductive element to another for the purpose of minimizing potential differences, providing suitable conductivity for fault current, or for mitigation of leakage current and electrolytic action.

Boom (Crane) - A member, in compression, hinged to the rotating superstructure and used for supporting the hoisting tackle and load.

Boom Base - A boom base is the lowermost section of a sectional latticed boom having the attachment or boom foot pins mounted at its lower end; also called boom butt or butt section.

Boom Gate - An antenna mounting bracket that positions the antenna away from the tower structure. This often resembles a fence gate.

Boom Guy Line - A fixed-length rope forming part of the boom suspension system; also called hog line, boom stay, standing line, or stay rope.

Boom Head - The portion of a boom that houses the upper load sheaves.

Boom Hoist - The rope drum(s), drive(s), and reeving that controls the lifting motion of the boom.

Boom Hoist Cylinder - A hydraulic ram used instead of a rope boom suspension, it's the most common means of derricking telescopic booms.

Boom Hoist Line - A wire rope that operates the boom hoist system of equipment such as derricks, cranes, deadlines, and shovels.

Boom Inserts - Center sections of a sectional latticed boom usually having all four chords parallel.

Boom Pendant - A non-operating rope or strand with end terminations to support the boom.

Boom Stop - A device intended to limit the maximum angle to which a boom can be raised.

Boom Suspension - A system of rope fittings, either fixed or variable in length that supports the boom and controls the boom angle.

Bosun's Chair - Also referred to as a boatswain's chair. This device is used to suspend a person from a rope while working at-height.

Bow Bits - See Bolt Cutters.

Bracing - The act of adding material to something to provide additional strength and rigidity.

Brake - A device used for reducing or stopping motion by friction or power means.

Breaking Strength - The greatest stress that a material or piece of equipment is capable of withstanding without rupture.

Breast Guy - A guy wire attached to the leg at the same elevation as a torque arm/stabilizer guy station. This is used when large structural guys are used/needed but only minimal torque exists.

Bridge Cable - The all-metallic wire rope or strand used as the catenary and suspenders on a suspension bridge or curtain antenna.

Bridge Strand - Bridge strand is a form of heavy galvanized steel cable. It is used frequently for the guy wires of large structures.

Bridle Slings - Sometimes called Bridle Supports, these are anchorage swings that are attached to the uppermost support point of a gin pole and secured to the tower. They restrict the pole from moving horizontally.

Bright Rope - Wire rope fabricated from wires that are not coated.

Broadcast - The transmission of sound, signals, or images by radio waves.

Broadcasting Company - Also known as a broadcaster. A potential customer in the radio or TV business. They typically use taller towers than others in the industry, but most broadcasting companies have fewer towers.

Brooming - Unlaying and straightening of strands and wires in the end of wire ropes during the process of installing a wire rope socket.

Brushed Motor - An internally commutated motor, ran on direct current. Brushed DC motors are varied in speed by changing the voltage or strength of the magnetic field, which rotates the axis of the motor. 

Brushless Motor - Also known as electronically commutated motors, brushless motors use a switching power supply which produces an AC electrical current to drive each phase of the motor. These motors have a high power to weight ratio, high speed, and are being used more in more in cordless power tools.

BTU (British Thermal Unit) - A traditional unit of heat, defined by the amount of heat required to raise the temperature of one pound of water by one degree Fahrenheit. Heated gear, heat guns, and torches often have BTU ratings. 

Buckle - A connector for attaching a strap or webbing segment to either another strap or webbing segment or back to itself.

Bull Pole - A pole, generally a steel pipe, which is mounted laterally from the base of a derrick mast. It is used to swing the derrick manually.

Bull Ring - The main, large, ring where sling legs are attached. Also known as master link.

Bumper - An energy-absorbing device that reduces impact when two moving cranes or trolleys come into contact or when a moving crane or trolley reaches the end of its permitted travel. Also referred to as a buffer.

Buss Bar - Usually made of various thicknesses of copper that is drilled to accommodate ground system end connections (1/4” is a common thickness used). Also known as a ground bar.

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Cable Clip - A cable clip is a U-Bolt and saddle assembly used to hold a loop together on the dead end of guy cable or wire rope. “Never saddle a dead horse” is a way to remember proper installation of cable clips.

Cable Cutters - A cutting tool similar to bolt cutters, but with curved jaws that apply pressure around the diameter of cable during a cut, so that the cable is cut evenly.

Cable Grab - See Cable Safety Sleeve.

Cable Loss - The amount of RF signal lost while it travels on a cable.

Cable Safety Sleeve - A mechanical device which is part of a cable safe climb system to arrest the fall of a worker in the event they slip off of a ladder while ascending or descending. Available in a number of different designs, a cable safety sleeve, frequently called a cable grab, functions with a cam that positively clamps onto the cable when a rapid downward force is applied to the device. These devices also typically include a shock absorption feature to safely decelerate the worker. 

Cable Sleeve - See Cable Safety Sleeve.

Cable Slings - Wire rope slings.

Cable-Laid Wire Rope - A wire rope consisting of several independent wire ropes wrapped around a fiber or wire rope core.

Cadweld - A brand name of a process using exothermic welding shots in a mold to attach wires/rods/surfaces used in grounding.

Cal (Calorie) - A calorie is a unit of energy, typically used to define the amount of energy found in food. A small calorie is defined as the amount of energy required to raise the temperature of one gram of water by one degree Celsius at a pressure of one atmosphere, food is typically defined in kcals, which is 1000 small calories.

Candelabra - An antenna mounting platform, typically placed at the top of the tower, that is designed to hold multiple antennas.

Cantilever - The projection of a gin pole above a bridle or upper most support.

Capacity - The maximum amount that something can contain or manage. Safety equipment typically has capacities for the maximum amount of load or weight that a device or piece of gear can manage. Capacity can also refer to the maximum amount of equipment that can be stored in a bag, pouch, or bucket. 

Capstan Hoist - An axled rotating mechanical device, originally developed on sailing ships, which uses rope wrapped around a rotating drum to lift and lower loads. The wraps of rope create friction around the drum as it rotates, feeding the rope around the drum and lifting the load. Capstans are used in the telecom and utility industries to raise antennas,  tower components and transformers into position. 

Captive Pin - A pin which can be permanently installed into specially designed carabiners to create an isolated area to maintain the position of a slinglanyard, or other piece of hardware.

Carabiner - An oval or D-shaped ring, typically constructed from steel or aluminum, which has a spring-loaded gate used to connect components. Used in personal fall arrest and safety equipment configurations, a carabiner is widely used in telecomwind energy, climbing, rope access, construction, window cleaning, and more.

Carbide Steel - A highly abrasion resistant steel compound often used in cutting equipment like mag drill cutters and drill bits. A high temperature resistance also allows faster machining and fabrication.

Carrier (Ladder Safety) - The track of a ladder safety device consisting of a flexible cable or rigid rail.

Casing - A steel insert designed to support the walls of a foundation hole.

Catenary - A curve formed by a strand of wire rope when supported horizontally between two fixed points, e.g., the main spans on a suspension bridge or curtain antenna.

Cathead - An informal term for Capstan Hoist.

Cathode - A metallic structure such as an anchor that an anode attaches to, in order to prevent corrosion.

Cathodic Protection - Technology that utilizes electro-chemical principals to mitigate corrosion on underground buried structures. A means of controlling corrosion of metal through use of a sacrificial metallic anode.

CDL - Commercial Driver's License

CDMA - Code Division Multiple Access. One of three different technologies used to broadcast signals between towers and wireless telephones in a PCS or cellular telephone system. The other technologies are TDMA and GSM.

CE EN - A certification required within the European Union that personal protective products must obtain before they can legally be placed on the market.

Cell Site - A cellular site used for broadcasting cellular signals. Typically includes a tower, building, fencing, and miscellaneous site work. 

Center of Gravity - The exact point around which a load is balanced. An important concept to consider when performing overhead lifting and rigging.

Ceramic - An item made from clay and hardened by heat.

Certified Anchorage - An anchorage for fall arrestpositioning, restraint,or rescue systems that a qualified person certifies to be capable of supporting the potential fall forces that could be encountered during a fall or that meet the criteria for a certified anchorage.

CFR - Code of Federal Regulations

Chain Bracket - A mount for a capstan hoist that uses chains to secure itself to a structure. Typically mounted to the leg of a tower or a utility pole, chain brackets, also sometimes called chain mounts, are often the only way securely anchor the 3,000 lb capstan hoist made by Hubbell Power Systems.

Chain Jacket - A device used to apply tension to a guy wire using a lever-lock principle.

Chain Mount - See Chain Bracket.

Chain Positioning Assembly - A piece of hardware for use in work positioning consisting of a length of chain or webbing with snaphooks or carabiners on either end, with a floating rebar hook along the chain in the center. The ends attach to positioning D-Rings on a full body harness, and the center hook attaches to the tower or structure, allowing the use of both hands to work. 

Channelizer - A cone shaped device, typically made from plastic, to help divert and direct traffic in a construction zone. Thinner than a traditional traffic barrel, a channelizer is a great option when working in narrow construction zones. Channelizers vary in height, and can have different reflective properties in both material and location. 

Cheek Plate - The stationary plates that support the pin (axle) of a sheave or load.

Cheek Weights - Overhauling weights attached to the side plates of a lower load block.

Chemical - A substance that is formed when two or more other substances act upon one another or are used to produce a change in another substance.

Cherry Picker - A small crane that can be used for handling materials.

Chest D-Ring - Also known as the sternal attachment point, the chest D-ring is located on the chest strap of a full body harness. The chest D-ring is typically used when climbing a fixed cable safe climb system on a ladder, although it can also be used in fall arrest in certain industries with the proper equipment. 

Chest Strap - A piece of material, typically made from webbing, which connects the shoulder straps of a full body harness. Typically secured using mating buckles of quick connect connectors, the chest strap should be worn across the pectoral muscles. The chest strap on some harnesses can also include a chest D-ring.

Chicago Grip - A type of wire pulling grip.

Chocks - A block or wedge under a wheel, etc. to prevent motion. 

Choker (Sling Configuration) - A configuration of a rigging or fall protection sling where one end the sling passes around the load or anchorage point, and the other is fed through the first end and connected to the hook or fall protection system. This configuration is the weakest of the three, choker, basket, straight, due to the stress point at the connection. 

Choker Rope - A short wire rope sling that forms a slip noose around an object that is to be moved or lifted.

Chuck - A specialized design of clamp which is typically found in hand drills. A chuck uses jaws, sometimes called dogs, that are arranged symmetrically to tighten down on the drill bit.

Circuit - A conductor or system of conductors through which an electric current is intended to flow.

Circular Mil - A standard unit of measure used to indicate conductor size. One circular mil is equal to the area of a circle that has a diameter of .001 inches.

Clamp (Cable) - A cable fitting that transfers force by friction.

Class 1 (Hi-Vis) - A garment that provides the minimum amount of hi-vis material required to differentiate a worker visually from backgrounds around non complex work environments.

Class 2 (Hi-Vis) - A garment that provides longer detection and identification distances and increased conspicuity performance compared to class 1.

Class 3 (Hi-Vis) - A garment that provides greater visibility in both complex backgrounds through a full range of body movements.

Class A (Fire Extinguisher) - A fire extinguisher designed for use on fires involving solid materials such as wood, paper, or textiles. Multipurpose extinguishers are often rated as A-B, or A-B-C.

Class A (SRL) - ANSI classification for SRL, SRD, & PFLs that covers arresting distance and force.

Class A Kits (First Aid) - ANSI classification denoting that the first aid kit is designed for common workplace injuries.

Class B (Fire Extinguisher) - A fire extinguisher designed for use on flammable liquids like grease, gasoline, and oil. Multipurpose extinguishers are often rated as, A-B, B-C, or A-B-C.

Class B (SRL) - ANSI classification for SRL, SRD, & PFLs that covers arresting distance and force.

Class B Kits (First Aid) - ANSI classification denoting that the first aid kit is intended to deal with injuries in complex or high-risk environments.

Class C (Fire Extinguisher) - A fire extinguisher designed for use on electrically energized fires, often fueled by motors, appliances, and electronic transformers. Multipurpose extinguishers are often rated as B-C, or A-B-C.

Class C (Hard Hat) - ANSI classification that denotes a hard hat is conductive and will not provide electrical protection.

Class D (Fire Extinguisher) - A fire extinguisher designed for use on flammable metals, such as titanium, magnesium, aluminum, and potassium. 

Class E (Hard Hat) - ANSI classification that denotes a hard hat can offer protection up to 20,000 volts.

Class E (Hi-Vis) - Supplemental apparel such as bibs, shorts, and gaiters, which are not compliant when worn alone, though, when combined with class 2 or class 3 apparel the combinations satisfies the class 2 or class 3 requirement.

Class G (Hard Hat) - ANSI classification that denotes a hard hat can offer protection up to 2,200 volts.

Class N (Respirator) - A letter class rating for respirators representing that the respirator is not oil resistant.

Class P (Respirator) - A letter class rating for respirators representing that the respirator is oil proof.

Class R (Respirator) - A letter class rating for respirators representing that the respirator is resistant to oil.

Clearance - The horizontal or vertical distance from any part of a crane to a point of the nearest obstruction.

Clevis - Clevis refers to the shank, shaft, or bolt in an attachment hardware that is certified for perpendicular strength. Often interchanged with the term shackle.

Climb Assist - A system which provides climbing assistance for workers ascending a permanent fixed ladder, often found inside wind turbines. These systems are in place to reduce fatigue, increase safety, and help eliminate the chances of a worker slipping during their ascent. 

Climb Higher - The Registered slogan from GME Supply Company, which is aimed to inspire people to not only physically climb higher vertically, but to continue to improve themselves individually. 

Climbers - An informal term for metal hooks, which strap to a lineman's feet used to climb wood utility poles. Used for ascending, descending, and maintaining the working position on poles when no other means of support are available.

Climbing Gaff - Metal hooks, which strap to a lineman's feet used to climb wood utility poles. Used for ascending, descending, and maintaining the working position on poles when no other means of support are available. 

Clove Hitch - A common knot used in rigging to attach a rope to round members. Mandatory for tower climbers to know how to tie. 

CO (Gas) - Commonly known as carbon monoxide - colorless, odorless, combustible, and lethal gas produced by incomplete combustion of fossil fuels (coal, natural gas, petroleum), biomass, and carbon containing products (such as wood).

Coaxial Cable - A type of transmission cable that has an inner conductor surrounded by a tubular insulating layer, surrounded by a conducting shield. Many also have an insulating outer sheath or jacket. On telecom and communications towers, coaxial cable is typically used as a transmission line to carry a signal to the top of the tower.

Coffin Hoist - See Chain Jacket.

Cold Galv (Cold Galvanizing Compound) - A zinc rich coating which bonds to iron, steel, or aluminum to provide protection against rust, rust creepage, and other oxidation, via al galvanic action. Cold Galvanizing Compound creates a similar finish to hot dipped galvanization, without requiring high temperatures or large zinc baths. Cold Galv is often used in the telecom and utility industry to seal steel which has been modified by cutting, grinding, or welding. 

Color Chart - A cardstock chart with windows through it to help compare the lightness, darkness, redness, and yellowness paint compliance for towers, corresponding with FAA rules.

Combustible - The ability of a substance to catch fire and burn easily.

Come Along - A hand operated winch, which uses a ratchet to pull objects. Typically using a drum wrapped with wire rope, two hooks, and a lever to turn the drum.

Competent Person - OSHA defines a competent person as someone who is capable of identifying existing and predictable hazards or working conditions, and has authorization to take prompt corrective measures to eliminate them. 

Competent Rigger - Knowledgeable and experienced with the procedures and equipment common to the communication structures industry and trained to identify hazards with authorization to take prompt corrective measures. Capable of supervising the lift and communicating the rigging plan effectively to the entire crew, including the crane operator for jobs in which a crane is used. This person is required on site at all times for rigging activity.

Compression Tool - A tool that is similar in appearance to cable cutters, but is designed to compress a connector onto a wire or cable.

Concave - A curve similar to the interior of a circle or hollow sphere. 

Concrete Anchor - A fall protection anchorage solution designed to be either permanent or temporary in a concrete structure. The anchor, which includes a D-Ring, is typically cast securely into the concrete to provide a 5,000 pound ANSI rated anchorage point. 

Conductive - The property of an item or substance to transmitt something. Typically heat or electricity.

Conductor - A material or device that conducts or transmits heat, electricity, or sound.

Confined Space - An area that has an opening large enough for a worker to access and enter to perform work. The area has a limited or restricted means of entry or exit, and is not designed for continuous human occupancy. Some examples of confined spaces include: storage or rail cars, manholes, tunnels, silos, grain elevators, bottom access enclosures like water towers. Confined spaces require specialty fall protection  and rescue equipment, as well as gas monitors and air circulation equipment.

Connector - A piece of hardware, typically a snaphookcarabiner, or shackle, which attaches a lanyard or tether to a full body harnessanchor, or load. Depending on the utility, the connector may be required to meeting specifications or standards, like ANSI.

Construction Classification I - An ANSI 10.48 Construction Classification. This class is described as any load less than 350 pounds gross load, requires a competent rigger, and does not require a written rigging plan.

Construction Classification II - An ANSI 10.48 Construction Classification. This class is described as any load less than 500 pounds gross load, requires a competent rigger, and requires a written rigging plan.

Construction Classification III - An ANSI 10.48 Construction Classification. This class is described as any load greater than 500 pounds gross load, requires a qualified person, and requires a written rigging plan.

Constuction Classification IV - An ANSI 10.48 Construction Classification. This class is described as any unique lift, member removal, or a lift that may have stability impacts. It requires a qualified engineer, and a written rigging plan.

Continuous Fall Protection - One or more fall protection systems that provide fall protection without interruption.

Controlled Descent - The act of using equipment and hardware to create friction on a rope in order to move downward. Often done with a descender.

Cordage Meter - A device which accurately measures length of rope, cord, or wire, using a toothed measuring wheel and stainless steel pressure shoe. A cordage meter is useful to precisely measure and cut a specific length of rope for use in rigging, rescue, or rope access style work.

Corrosion - The electromechancial process in which a refined metal returns to its native state such as steel to iron oxide. This process is magnified in certain conditions such as in low resistance electrolytes where a current can easily flow and/or when an anodic material is attached electrically to another metal.

Corrosion Resistant Steel - Chrome-nickel steel alloys designed for increased resistance to corrosion.

Corrugated - A term used to describe the grooves of a sheave or drum after it has been worn down to a point where it shows an impression of a wire rope.

Counter Torque - Torque applied in the opposite direction of pre-existing torque.

COWs - Cell-site On Wheels.

Crane - A large, tall machine used for moving heavy objects, typically by suspending them from a projecting arm or beam.

Creep - The unique movement of a wire rope with respect to a drum surface or sheave surface resulting from the asymmetrical load between one side of the sheave (drum) and the other. It is not dissimilar to the action of a caterpillar moving over a flat surface. 

Crew Chief - The head of a crew. A person that is authorized, designated, deemed competent and qualified by the employer.

Crimper - A crimper is a tool for adding indents or compressions on fittings or lugs for attachments to wires.

Critical Diameter (Wire Rope) - For any given wire rope, it is the diameter of the smallest bend that permits both wires and strands to adjust themselves by relative movement while retaining their normal cross-section position or size.

Crosby Clips (Crosbies) - Crosby is a brand of rigging equipment, but their cable clips are so universally used that many riggers just call them Crosbies. Crosby clips are used to connect two pieces of wire rope, or to form an eyelet at the end of a cable. The name refers to the manufacturer, The Crosby Group, Inc.

Cross-Rods - Also referred to as Diagonals, Hog Rods, or Wind Bars these are structural members on the tower that extend diagonally between two points on the tower face. On tall towers these are often removable for repair or replacement.

Crown Block  - The sheave assembly used to change the direction of the load line or jump line coming from the hoist and is attached at the uppermost location of the structure. Also referred to as Top Block or Load Block.

CSA - Canadian standards organization - similar to ANSI.

CTIA - Cellular Telecommunications Industry Association

Cubic Feet per Minute (CFM) - A standard measure of volumetric flow, measuring the amount of material passing through an area in a minute. Often used to quantify the performance of a blower, compressor, or fan. 

Current - The flow of an electrical charge, often carried by moving electrons in a wire, or via a magnetic field like those used in brushed motors or generators.

Cut Resistance - The ability for a material to prevent a sharp edge from penetrating the exterior of the material when pressed and drug across. Often used in gloves, shirts and pants, synthetic materials, like DyneemaKevlar, and to a lesser extent, Polyester and Nylon, provide cut resistance for workers handling sharp objects or using knives and blades.

Cycle (Electrical) - One complete transition from zero volts to maximum positive volts, down to zero volts, through to maximum negative volts, and back to zero.

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D-ring - A loop, typically made from steel or aluminum, which is affixed to an anchor point, or fall protection harness. The D-ring serves as a connection point to attach a lanyard, tether, or other fall protection equipment.

D/d Ratio - A ratio used to describe the diameter of the sheave of a pulley versus the size of the rope. The upper case D refers to the diameter of the sheave, while the lower case d represents the diameter of the rope. Depending on the type of rope being used, the D/d ratio varies from 6:1 to 10:1 according to ANSI A10.48.

Dampening Weights - Devices added to conductors to reduce conductor vibration or movement due to wind.

Damper - A device attached to the cable that modifies the structural response to dynamic loads.

Davit System - Commonly used to raise, lower, suspend, and rescue personnel working in confined space applications like manholes, tanks, or vaults, the system consists of an anchored base and arm which can be extended or swung over to work area. A davit arm or davit system uses a winchpulleys, or mechanical advantage system to raise and lower the worker.

dB (Decibel) - A unit used to measure the intensity of a sound. Hearing protection is rated by the level of decibel decrease it can provide to the wearer. 

DC (Direct Current) - The unidirectional flow of an electrical charge, such as the power supplied by a battery. Direct Current differs from alternating current because it does not travel as an oscillating wave, rather a straight constant line.

De-Rate - To take down the capacity rating due to friction, load, or bushing.

Dead Load - The weight of a structure and all the material permanently fastened to it.

Deadman Anchor - A type of underground anchor shaft foundation generally formed of concrete.

Deceleration Device  - Any mechanism, such as a rope grab, rip-stitch lanyard, specially woven lanyard, tearing or deforming lanyards, automatic SRL, etc. which serves to dissipate a substantial amount of energy during a fall event. 

Deceleration Distance - The additional vertical distance a falling worker travels, excluding lifeline elongation and free fall distance, before stopping, from the point at which the deceleration device begins to operate. Measured as the distance between the location of the full body harness attachment point at the moment of activation of the deceleration device during a fall, and the location of that attachment point after the employee comes to a full stop. 

Deceleration Stress - The additional stress that is imposed in a wire rope as a result of a decrease in the load velocity. The opposite of Acceleration Stress.

Decelerator - Any force which acts to slow or stop movement.

Deformation - The action or process of changing in shape or distorting, especially through the application of pressure.

Delineator - Similar to channelizers and cones, delineators help guide pedestrians and vehicles in a construction or work zone. Typically made from plastic and available in a variety of colors and reflectivity options, they can be permanently mounted or secured with weighted bases.

Derrick - A kind of crane with a movable pivoted arm for moving or lifting heavy weights. It is most commonly associated with ships.

Descender - A mechanical device which provides a means of controlled lowering on a synthetic rope for rescue and rope access work positioning. The rope is typically fed through or around a descender to create friction which can be controlled by the user to vary their descent speed and position. 

Dexterity - Having skill and precision in performing tasks, especially with the hands. Dexterity is an important factor to consider when selecting hand protection and gloves, especially if a worker will be performing tasks which require small tools or precise movements.

DGPS - Differential Global Position System.

Dielectric - Insulating material used between inner and outer conductors on transmission lines.

Diesel Fuel - A combustible petroleum distillate used as fuel in diesel engines.

Digital (Two-Way Radio) - Digital radios convert the audio signal into a series of 1's and 0's to transmit the communication. When these signals are received, they are reencoded into a standard audio format and projected from the radio speaker. In comparison, analog radios transmit the audio signal in the form of electrical signals resembling sound waves.

Digital Multimeter (DMM) - A tool to measure two or more electrical values, typically voltage in volts, current in amps, and resistance in ohms. Using two or more leads, which are insulated wires which serve as conductors, digital multimeters can accurately measure these electrical values. 

Direct Ventilation (Eyewear) - Ventilation in goggles where the vented section is front-facing and allows a direct, straight line passage from the outside to the inside of the eyewear. Direct ventilation goggles must still meet ANSI standards and prevent objects measuring 1.5mm in diameter or larger from entering the goggles. These goggles are not suitable for use where splash hazards are present.

Disciplinary Action  - Administrative action taken by the employer against the employee. May vary from verbal reprimand to dismissal.

Discreate Appurtenance - An appendage to a structure that is connected at one primary point on the structure. A small sign is an example of a discrete appurtenance.

Dish - A highly directional antenna, slang for a parabolic reflector.

Distance To Fault (DTF) - That distance between a test signal and the problem area on a transmission line. This test will determine the length of the cable system and the return loss of each component to identify the contributory affect of each component on the total antenna system.

Distortion - Distortion is the act of twisting or altering something out of its true, natural, or original state.

Doff - The act of removing an article of clothing. Taking off a full body harness is often called doffing the harness.

Dogleg - A permanent bend or kink in a wire rope caused by improper use or handling.

Domestic Shackle - A shackle that has been made in the United States. These shackles are often preferred to foreign made shackles due to better manufacturing and testing processes. 

Donn - The act of putting on an article of clothing. Putting on a full body harness is often called donning the harness. This process also includes properly adjusting the harness to a proper fit.

Dorsal D-Ring - Located on the top back of a harness that is the main connection point for nearly every fall protection harness.

DOT - Department of Transportation. A department of the government that is responsible for the national highways, railroad, and airline safety.

Double Braid - Rope constructed of a braided core surrounded by a braided sheath. Ideal for use as a load rope.

Drag Brake - A brake that provides reduction force without external control.

Drill Bit - A cutting tool used to remove material to create holes. Drill bits almost always have a circular cross section and come in many sizes and shapes. They can create many different types of holes in different kinds of material.

Drop Zone - The area below a tower or structure where work is being performed at-height where any object dropped will land. Generally figured to be one-half to one foot in diameter for each foot up.

Drum (Rope) - A cylindrical barrel, either of uniform or tapering diameter, on which rope is wound for operation or storage; its surface may be smooth or grooved.

Dry Chemical Fire Extinguisher - A fire extinguisher that is filled with Monoammonium phosphate, ABC Dry Chemical ABE Power, tri-class, or multi-purpose dry chemical used to extinguish class A, class B, and class C fires.

Duck Canvas - A heavy, plain woven cotton fabric that is more tightly woven than plain canvas. It is also referred to as cotton duck, duck, or duck cloth. This material is typically used in bags, buckets, and some forms of PPE.

Dummy Load - A device that is used to simulate an electrical load. It is most commonly used for testing purposes.

Dynamic Range - The ratio of the largest signal level a circuit can handle to the smallest signal level it can handle (usually taken to be the noise level), normally expressed in dB.

Dynamic Rope - Dynamic usually refers to a dynamic type of rope, which is considered a somewhat elastic rope. The "stretch" caused by the elasticity is what makes the rope dynamic. Dynamic ropes are great for rock climbing, ice climbing, and mountaineering but are not used for industrial applications. They are the opposite of static ropes.

Dynamometer - A device that measures load, tension, and force. These devices are frequently used in guy wire tensioning or swap outs on a cell phone or communications tower. 

Dyneema - Dyneema is an Ultra High Molecular weight Polyethylene (UHMwPE) or High Modulus Polyethylene (HMPE) Fibre that has gained a reputation as being the lightest, strongest fiber in the world. It is 15 times stronger than steel, hydrophobic, and resistant to chemicals and UV rays.

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E (Extension Cord) - An extension cord jacket rating representing that the jacket is made of TPE (thermoplastic elastomer rubber).

Earth Screw Anchor - A ground anchor that screws into the ground to tie down cable or rope. Commonly used in guy wire applications.

Eddy Current Brake - A device for controlling load speed in the hoisting or lowering direction by placing a supplementary load on the motor. This loading results from the interaction of magnetic fields produced by an adjustable or variable direct current in the stator coils and induced currents in the rotor.

EDGE - Enhanced Data Rates for Global Evolution.

Edge Protection - Barriers used in construction, road, and event safety to prevent workers and pedestrians from falling over the edge of a surface.

Efficiency (Rope) - The ratio of a wire rope’s actual breaking strength and the aggregate strength of all individual wires tested separately; usually expressed as a percentage.

Egress - Right-of-way to line route, the action of going out or leaving a place. Egress is a term typically included in rescue or escape plans when working in confined spaces.

EIA - Electronic Industries Association.

Electric Arc - An electrical breakdown of a gas that produces an ongoing electrical discharge. Often used as a method of welding.

Electric Field Strength - The given strength or magnitude of the electric field expressed in units of volts per meter (V/m).

Electrical Length - The length of any electrical conductor, such as an antenna or transmission line, expressed in wavelengths, radians, or degrees.

Electrolytes -  A small electrical charge carried in certain minerals (sodium, potassium, calcium, etc) that interacts with cells, nerves, and tissues in the human body to provide the electrical current needed for many automatic processes. Electrolytes are lost when the body sweats and the most common way to replace these are with specially formulated drinks.

EME - Electromagnetic Energy

EMF - EMF or electromotive force is a measurement of the electric force that causes or tends to cause current to flow through a circuit (denoted and measured in volts).

EMI - Electromagnetic Interference

Endless Round Sling - An endless round sling (also referred to as a polyester sling or softsling) is a continuous loop of material, typically 100% polyester. It is most commonly used in lifting & rigging applications or, depending on company policy and preference, can be used in life safety.

Endothermic - A chemical change that absorbs a lot of heat. The opposite of exothermic.

Energized Lines - Electrical conductors that are carrying current (energized) due to an electrical connection to a source of potential different from earth ground. Usually describes a high potential.

Equipment Failure - The point at which the ultimate strength of a piece of equipment is exceeded, causing breakage or separation of component parts.

Ergonomic EquipmentEquipment that has been designed so that the user can perfom tasks easier and safer. Often used when talking about back supports and other personal protective equipment.

European Union (EU) - A political and economic coalition of 28 member states that are primarily located in Europe. Typically referred to as the EU.

Excavations - Any opening made in the ground, street, or sidewalk in connection with work being performed, such as holes, trenches, ditches, or tunnels. 

Exothermic - A chemical change that creates a lot of heat. Similar to the reaction that happens during welding. The opposite of endothermic.

Exposed - Exposed circuits or lines means in such a position that in case of failure of supports or insulation, contact with another circuit or line may occur. Exposed equipment means an object or device that can be inadvertently touched or approached nearer than a safe distance by any person. 

Exposure - Being in close proximity to an active antenna field. Exposure occurs whenever and wherever a person is subjected to electric, magnetic, or electromagnetic fields or to contact currents.

Exposure Level - The concentration of a hazardous substance that an organism is exposed to during a specific period. See permissible exposure limit.

Extension CordAn electric cord fitted with a plug at one end and an outlet at the other end. Most commonly used when equipment that needs electricity doesn't have a power cord long enough to reach the outlet in a wall or generator.

Eye and Eye Sling - An eye and eye sling is a "strap" composed of material (most commonly polyesternylon, or wire rope) that is commonly used in lifting & rigging applications or, depending on company policy and preference, can be used in life safety.

Eye Protection - A covering (commonly glasses, goggles, or shields) that prevents hazardous substances and materials from getting in the eyes.

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Factory Swage - The process of a manufacturer using hydraulics to create a connection between stainless steel wire rope and a fitting. Commonly used in reference to cable safe climb systems.

Fall Arrest - A form of fall protection in which a piece of equipment stops the descent of a person who is falling. Stage 4 in the Hierarchy of Fall Protection.

Fall Clearance - The height needed to safely arrest the fall of a person at-height. This includes a calculation of a safety factor, including the stretching of fall protection equipment like lanyards.

Fall Edge - The unprotected edge of a walking/working surface or an unprotected opening from which a person could fall to a lower surface or into a hazard.

Fall Hazard - Any location where a person is exposed to a potential free fall.

Fall Hazard Survey Report - A written document that contains information about existing or potential fall hazards and a method or methods for eliminating or controlling those hazards.

Fall Indicator - A special piece of material or equipment attached to a larger piece of equipment that is intended to visibly display, typically through deformation, or be revealed in the event the equipment experiences a fall. If a Fall Indicator is revealed, the equipment must be destroyed and removed from service. 

Fall Prevention - Equipment that has the purpose of completely preventing access to a fall hazard. An example of this would be guardrails. Stage 2 of the Hierarchy of Fall Protection.

Fall Protection - The use of controls, typically fall arrest systems, to protect people working at-height from falling or in the event of a fall to prevent the worker from serious injury.

Fall Protection Lanyard - Short sections (commonly 3 to 6-feet) of cable or webbing that attach to a worker's harness on one end and anchorage point on another. See Shock Absorbing LanyardPositioning Lanyard, Single Leg Lanyard, and Twin Leg Lanyard for more details.

Fall Protection Procedure - A written series of logical steps that describes in detail the specific practices, equipment, and methods to be used to protect authorized persons from falling when exposed to fall hazards.

Fall Rated - Ratings, typically developed by standards organizations like ANSI and CSA, that symbolize that the equipment has been approved to arrest a fall.

Fall Rated Carabiner - A carabiner that meets or exceeds the ANSI Z359.1 rating which establishes that a carabiner gate, side load, and minor axis should be rated to 3,600 lbs and major axis should be rated to 5,000 lbs. The gate rating should be stamped on the gate and the load rating should be stamped on the long axis.

Fall Restraint - A fall restraint system prevents a worker at-height from falling. This is done by using equipment, like a lanyard, to connect a worker to an anchor that prevents them from reaching an area where the risk of a fall exists. Stage 3 of the Hierarchy of Fall Protection.

Fan Plate - The steel portion of a guy anchor with holes to attach to guy wires.

Far Field - The portion of the electromagnetic energy field where the electric and magnetic components of the electromagnetic wave are in an orthogonal, or right angle relationship.

Far Field Region - The region of the field of an antenna where the angular field distribution is essentially independent of the distance from the antenna. In this region, also called the free space region, the field has a predominantly plane wave character, i.e., locally uniform distributions of electric and magnetic field strength in planes transverse to the direction of propagation.

Fatigue - As applied to wire rope, the term usually refers to the process of progressive fractures resulting from the bending of individual wires. These fractures may and usually do occur at bending stresses well below the ultimate strength of the material; it is not an abnormality although it may be accelerated due to conditions in the rope such as rust or lack of lubrication. Fatigue can also refer to physical tiredness of a worker due to dehydration, over exhaustion, heat or cold exposure, or other factors. 

FCC - The Federal Communications Commission. The organization that is responsible for enforcing the laws written for the regulation of radio communications.

Feasibility Structural Analysis - A preliminary review to determine the overall stability and the adequacy of the main structural members of an existing structure to accommodate a proposed change in condition.

Federal Aviation Administration (FAA) - The Federal Aviation Administration of the United States is a national authority with powers to regulate all aspects of civil aviation. Most commonly their involvement in at-height industries has to do with requirements and regulations for tall structures like telecom towers. Their power also expands to shorter structures that are in close vicinity to airports.

Ferrule - A metallic button, usually cylindrical in shape, normally fastened to a wire rope by swaging but sometimes by spelter socketing.

Fiber Optic - A medium resembling cable that consists of thin flexible fibers with a glass core which transfers light signals (data) with very little loss of strength. Most commonly used for internet and mobile infrastructure applications.

Fiber Testing - Evaluating the performance of fiber optic components including cable coverings, connection points, and cleaning equipment.

Fiberglass - A reinforced plastic material composed of glass fibers embedded in a resin matrix.

Field (Physics) - In physics, a space within which magnetic or electrical lines of force are active. A mathematical specification of a physical quantity of electric charge density.

Figure Eight - A belay or controlled descent device, usually constructed from metal, typically aluminum, in the shape of an 8 with one large end and one small end. This piece of hardware uses a large surface area in contact with a climbing rope to provide sufficient friction along with proper technique to control the descent or lowering of a worker. 

Fire ExtinguisherA portable device that discharges a jet of water, foam, gas, or other material to extinguish a fire. Fire extinguishers have different classifications and ratings based on the size of the extinguisher and the types of fires that can be put out.

Fire Extinguisher Ratings - Fire extinguisher ratings (also referred to as UL ratings) are a numerical rating that shows the extinguishing power of the fire extinguisher for various types of fire.

Fire Watch - The sole activity of observing and responding to fire hazards associated with hot work. No other duties may be assigned to a worker when performing Fire Watch. This personnel must continue their fire watch duties a minimum of 30 minutes after hot work is complete.

First Aid Kit - A bag or case that contains medical supplies. ANSI has classifications for first aid kits that denote what kits are acceptable to be used in specific situations.

Fisk - A brand name controlled descent device similar to a figure eight

Fit Test (Respirator) - A respirator fit test is a test that ensures a respirator properly fits the face of the person wearing it. The test is done by securing the respirator to the face and placing a hood over the head. Then a second person sprays a bitter or sweet solution into the hood. If you can test the solution the respirator must be re-adjusted and the fit test performed again.

Fixed Body Belt - A belt used by utility lineman that does not allow any movement of the hip D-rings along the belt. A body belt also has accessory loops and connection points for tools. Semi-Floating and Full Floating Body Belts are also available.

Flag (Lifting & Rigging) - A marker placed on a rope making it easier to locate the load position.

Flagger - A person or people on a construction site who control traffic. The people along roads and highways who help traffic keep flowing through construction zones, despite shutdown lanes. They often work in teams, with each person controlling the flow of traffic in a certain direction. 

Flame Retardant - A chemical that has been added to an otherwise flammable material to make them flame resistant.

Flares - Indicates flares, torches, fuses, red lanterns, reflectors, or any other equipment that is adaptable for the purpose intended.

FM - Frequency modulated, meaning that the frequency of the carrier frequency is varying in the same manner as the audio signal you are transmitting.

Fog Off (Eyewear) - Fog Off is a brand name anti-fog technology that can be applied to lenses that prevents fog from distorting the wear's view.

Foreman - Any person, regardless of classification, who is directly in charge of a specific job. 

Forged - The method of making or shaping a metal object, like rope clips, cable grips, and pulleys, by heating it in a fire or furnace and beating or hammering it.

FPS - FPS (Foot Per Second) expresses the distance in feet traveled or displaced by an object divided by the time in seconds. Commonly used in fall protection when referring to the rate at which an object or person falls and triggers their fall arrest system.

FR (Flame Resistant) - The characteristic of a material not igniting and burning in air. Commonly confused with Flame Retardant.

Fraying - Description of the exposed and broken threads on damaged woven material such as webbing, rope, and cloth. 

Free Climbing - Climbing on a tower or structure without any positive fall protection in place.

Free Fall - The act of falling before a personal fall arrest system begins to apply force to arrest the fall.

Free Fall Calculation - A calculation used to determine the total vertical distance traveled in the event of a fall. This number is achieved by adding the free fall distancedeceleration distance, height of dorsal D-ring, the harness stretch and dorsal D-ring shift, and a safety factor.

Free Fall Distance - The vertical distance a person falls from the moment the fall occurs until the moment their fall arrest system activates.

Frequency - Regarding radio transmissions, the number of times a radio wave passes through one cycle. The "frequency Spectrum" is divided into sections, alloted by Federal license to various users. Different frequencies have different behaviors. 

Full Body Harness - See Body Harness.

Full Floating Body Belt - A belt used by lineman that allows full travel of the hip D-rings along the belt. A body belt also has accessory loops and connection points for tools. Semi-Floating and Fixed Body Belts are also available. 

Full Grain Leather - Full grain leather is leather dressed with the grain outward and comes from the top layer of hide. Can be used in the construction of lineman tool belts.

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Gaff Guard - A protective sheath, typically made from leather or a synthetic material, which covers a utility lineman's climbing gaffs.

Gain - A ratio, expressed in decibels, of the action of an antenna, or amplifier, increasing the strength of a signal.

Galloping (Guy Wire) - A term used to describe the whipping action of excessively loose guy wires, usually wires with tension set at less than 8% of working strength.

Galvanized Steel - Steel that had a zinc coating applied to prevent rust. Hot-Dip galvanizing is the most common method for this process.

Gas Monitor - Also referred to as a gas detector, a gas monitor is a device that detects the presences of gasses in an area.

Gasoline - A refined petroleum that is used as a fuel for internal combustion engines.

Gate - The section of a carabinersnaphookrebar hook, or other connector that opens in order to attach the connector to another object.

Gate Mechanism - The way that the gate of a carabiner, snaphookrebar hook, or other connector functions.

Gate Strength - The amount of force the gate of a carabiner, snaphookrebar hook, or other connector can handle before it fails. This strength rating, usually presented in lbs, kN, or m, should be stamped on the gate to stay in compliance with ANSI Z359.1.

Gauntlet Cuff - An extended cuff on gloves that provides additional wrist and forearm protection. Gauntlet cuffs are often 4.5 inches longer than a standard glove and are typically found on leather work gloves, welders gloves, or gloves for chemical protection. 

Gear Experts® - The exclusive status of GME Supply team members. This term denotes that each and every GME Supply team member has extensive industry know-how and will provide unmatched customer service, prompt delivery, and continued innovation for all of our customers. The industry knowledge of Gear Experts® ensures that our team has the ability to get you exactly what you need, when and where you need it.

Generator - A gas or diesel powered device which provides power when no electricity is available on a jobsite. Also used for emergency backup power to keep equipment functioning during a power outage. Typically on site at telecommunications towers to maintain network service. 

GFCI (Ground Fault Circuit Interrupter) - A fast acting circuit breaker designed to shut off electric power in the event of a ground-fault within as little a 1/40 of a second. Most commonly used on construction sites in conjunction with corded power tools.

Gin Pole - A lattice device used to erect towers, typically 200 feet or taller. This device is attached to a tower, and slid to a taller height than the tower during erection, providing additional head room. Cables and rigging are attached to the gin pole, which is then used to hoist tower sections and other accessories into place. 

GLONASS - Global Navigation Satellite System is a Russian space-based satellite navigation system operating the radionavigation satellite service. It provide an alternative to GPS and is the second navigational system in operation with global coverage and comparable precision to that of GPS.

GogglesA form of PPE that are close-fitting eyeglasses with side shields that protect the wearer's eyes from chemicals, dust, water, and more.

GPS - GPS, or the global positioning system, is a group of approximately 30 satellites that are positioned in earth's orbit to allow people on the ground with equipment to pinpoint their geographic location.

Grain Leather - Leather dressed with the grain side outward. Commonly used to describe the construction of gloves. For more information see full-grain leather and top-grain leather.

Grease (Mechanical) - Grease is a type of shear-thinning or pseudo-plastic fluid, which means the viscosity of the fluid is reduced under shear.

Green (Safety Can) - Color that denotes that the safety can has been designed to hold oil.

Griphoist - A grip hoist differs from a traditional hoist because there is typically not a rotating drum. A grip hoist functions by locking a set of jaws on the wire, then pulling the rope back, handing the wire off to a second set of jaws, and pulling the rope back again, similar to how someone might pull a rope hand over hand. 

Grommet - A small piece of material (usually metal or plastic) placed in a hole in a material to protect or insulate a rope or cable passed through it or to prevent the material from being torn.

Gross Load - Gross load is the total load to be lifted. This includes the weight of the lifted object (lift load), headache ball, the load line, vertical tag line load, and any other attachments.

Grounding - A safety measure used to help prevent people from accidentally coming in contact with electricity. Can be done in the form of above ground wiring, or by rerouting electricity back into the earth.

GSM - Global System for Mobile Communications. One of three different technologies used to broadcast signals between towers and wireless telephones in a PCS or Cellular telephone system. The other technologies are TDMA and CDMA.

GuardrailA rail used to prevent people from falling off of a structure. Guardrails are considered part of fall prevention.

Guy Anchor - A steel shaft with concrete anchorage below grade that is used to support guy cables.

Guy Grip - See Wire Pulling Grip.

Guy Wire - Guy wire (also referred to as guy line, guy rope, guy cable, or guy) is a tensioned cable designed to add stability to a free standing structure. Commonly used in the windtelecom, and utility industries.

Guy Wrap - A wrapped wire device used to attach the end of a guy wire to an attachment on a pole or an anchor.

Guyed Tower - A lattice tower with guy wires or wires to support the structure vertically. Typically used where heavy loads are required and land is plentiful. 

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H2S (Gas) - Hydrogen sulfide is a colorless, flammable gas. It is extremely hazardous and has a "rotten egg" smell. It occurs naturally in crude petroleum and natural gas.

Hairpin - A device used to hold and provide adjustment on a guy wire at the anchor point. Typically found on large-scale towers.

Half Hitch - A common knot used in rigging. Mandatory for tower climbers to know how to tie.

Half Power (Beamwidth) - In a plane containing the direction of the maximum lobe of an antenna pattern, half-power is the angle between two directions in which the radiated power is one-half the maximum value of the lobe.

Halogen - Elements occupying group 17 of the periodic table. Commonly used in lamps and radiant heat sources that contain a filament surrounded by the vapor of iodine or another halogen.

Hangers - Typically stainless steel or plastic devices used to fasten coaxial cable to a tower or other structure. Standards exist to keep fastening distances consistent, typically every 3-4 feet. 

Hard Hat - A hat that is made of a rigid or strong material used in industrial applications to protect workers from head injuries caused by falling or dropped objects. Also referred to as safety helmet or helmet.

HASP - A slotted hinged metal plate that forms part of a fastening for a door or lid and is fitted over a metal loop and secured by a pin or padlock. Commonly used in lockout tagout systems.

Haul System - A haul system is a combination of ropescarabiners, and pulleys that offers a mechanical advantage to make lifting and hauling easier in rescue and evacuation situations, when tensioning lines, or other rigging situations. Haul systems often come pre packaged with all of the equipment needed to utilize the system.

Hazard - A danger or risk. In the at-height industry it most commonly refers to equipment and/or situations that can cause injury or death.

Hazard Assessment - The act of detecting either real or potential hazards through the use of a recognized procedure. 

Hazard Elimination - The act of completely removing a hazard via construction or maintenance. For example, fixing a hole in the outer wall of a building. Once it has been fixed no one can fall out of the hole. Stage 1 in the Hierarchy of Fall Protection.

Headache Ball - Item used as a counter weight at the end of a cable or rope to bring the weight of the cable down a tower. A slang term for the heavyweight used to draw a rigging line back to the ground. May or may not have a hook or block assembly included.

Headache! - A term often used by tower hands to warn ground men of falling objects.

Heat Treating (Hardware) - A metalworking process used to change physical and/or chemical properties of a material. Heat treating is most commonly associated with metals.

Heel Block - A block or pulley which is secured to the base of a tower. A load rope is fed from a capstan or hoist, through the heel block and directed to the top of the tower through another pulley.

Helmet - A hat shaped object made of a rigid material that is designed to protect a person's head in the event of a fall or dropped object. Also referred to as safety helmet or hard hat.

HEPA - A high efficient particulate air (also known as a high-efficiency particulate absorber, high-efficiency particulate arresting, or high-efficiency particulate arrestance) is a type of air filter that removes 99.97% of particles that have a size greater than or equal to 0.3 microns from the air that passes through it. This filter can be used with reusable respirators and shop vacs to stay compliant with the OSHA Silica Dust Standard.

Hertz - The standard unit of frequency. It is equal to one cycle per second.

Hi-Vis (High Visibility) - Denotes outer clothing made of a fluorescent or reflective material intended to ensure that the person wearing the clothing can be easily seen by other people. It is considered a part of PPE in most industries and has ANSI classifications.

Hierarchy of Fall Protection - A method of categorizing fall protection into 5 stages going from "No Risk" (stage 1) to "High Risk" (stage 5). The stages of the hierarchy of fall protection are: 1. Hazard Elimination, 2. Fall Prevention, 3. Fall Restraint, 4. Fall Arrest, and 5. Safety Monitor.

Hip D-Ring - A D-ring attached to the side (hip) of a full body harness. The hip D-ring is suitable for use in work positioning (when used as a pair) and restraint applications.

Hog Rods - See Cross-Rods.

Hoist - A hoist is a device used for lifting or lowering a load by using a drum or wheel with a rope or chain wrapped around it. They are typically manually operated and can be driven electrically or pneumatically. Most commonly they feature chains but can have fiber or wire rope as well. Often used in lifting & rigging applications.

Holding Brake - A brake that automatically sets and prevents motion when power is off.

Horizontal Lifeline - A temporary fall protection safety system that is used to prevent workers on a horizontal structure from falling in situations where there is no access to suitable anchorage points.

Horizontal System - See horizontal lifeline.

Hot Dipped Galvanization - The process of applying a zinc coating to steel or iron by submerging the metal in a bath of molten zinc.

HP - The abbreviation for Horsepower, a unit of measurement of power. There is not a single standard or type of horsepower, but two common definitions are: mechanical horsepower, which is about 745.7 watts, and metric horsepower, which is approximately 735.5 watts.

HVAC - An abbreviation for Heating, Ventilation, and Air Conditioning. The technology of indoor and vehicular environmental comfort.

Hydraulic Winch - An winch that operates by a liquid moving in a confined space under pressure.

Hydrophobic - The tendency of a material to repel or fail to absorb water. Commonly used when describing PPE and other types equipment.

Hz (Hertz) - The standard unit of measurement used in measuring frequency. 1 Hz = 1 second. Commonly associated with the computing power of electronics.

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Ice Bridge - A structure placed above cables and transmission lines to protect the cable from falling ice. Installation elevations may vary as necessary. 

Ice Traction - The ability of an object to grip ice. Ice traction devices can be added to work boots to increase worker stability and productivity while working on slick surfaces.

IEEE - Institute of Electricians and Electrical Engineers

Import Shackle - A shackle that has been made in a country outside of the United States. These shackles are often cheaper than domestic shackles but have lesser manufacturing and testing processes. Many companies do not allow import shackles to be used on job sites.

Independent Wire Rope Core (IWRC) - A wire rope used as the axial member of a larger wire rope.

Indirect Ventilation (Eyewear) - Ventilation in goggles where the vented section does not allow for direct, straightline passage from the outside to the inside of the eyewear. Best suited for acid and chemical handling.

Indoor/Outdoor (Eyewear) - A classification of eye protection that can be used both indoor and outdoor (I/O) without any risk of color distortion, and a minimal loss of light transmission. 

Inspection Log - A collection of forms used when inspecting gear or usability. It also helps keep track of past inspections and provides insight into past uses of products. These forms are perfect for use with any fall protection gear that requires regular inspection.

Insulator - A material that prevents the flow of an electric current. Most commonly insulators are made of porcelain, glass, fiberglass, or polysil.

INTELSAT - International Telecommunications Satellite Organization

Internal Shock Absorption - A construction method for shock absorbing lanyards where the shock absorption technology is built into the lanyard itself instead of being added by means of a shock pack.

International System of Units - Abbreviated SI from the French Système international, it is the modern form of the metric system, the most widely used system of measurement. It is built on seven base units: ampere, kelvin, second, meter, kilogram, candela, and mole. 

Intrinsically Safe - A design technique used when developing electrical equipment that will be used in hazardous areas. The design process involves limiting the available energy in the item to a level that is too low to cause an ignition.

Ionizing - A type of energy, in the upper end of the electromagnetic spectrum, that has the ability to strip electrons from atoms and molecules. This process can produce molecular changes that can lead to permanent damage in biological or human tissue.

ISEA - International Safety Equipment Association. The leading association for personal protective equipment and technologies that enable people to work in hazardous environments, and an ANSI accredited standards developing organization. 

ISO - International Organization for Standardization. An independent, non-governmental international organization with membership of 160 national standards bodies, which develops and publishes International Standards.

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J (Extension Cord) - An extension cord jacket rating representing that the cord has a standard 300 volt insulation.

Jacket Rating (Extension Cord) - A letter based rating system (S, P, J, V, T, E, O, W) that represents what the construction of the extension cord can handle.

Jersey - A knit fabric used predominantly for clothing and apparel. Originally made of wool, it is now made from many other synthetic fibers and cotton. Jersey gloves are a common type of economical hand protection which are very stretchy and light-weight. 

Jib - A fixed length extension used on either cable or hydraulic cranes attached to the main boom to provide extra height. The load capacity decreases rapidly the longer the jib is.

Johnny Ball - A Johnny Ball is a guy cable insulator. It is typically made of ceramic material and designed so that if it should break, the guys are looped together and will catch together. Used on AM tower guys and electrical transmission line pole guys.

Joule - A unit of energy which is equal to the energy transferred to an object when a force of one newton acts on that object in the direction of its motion through the distance of one meter. 

Jump Line - A line that is required to raise and lower a gin pole into its desired location on the structure for lifting heavy loads. The line is attached to a separate drum on a hydraulic winch that runs through a heel block at the base of a tower, then up through a block on the tower or pole track.

Jump the Pole - A term used to describe the procedure of raising a gin pole to a higher elevation.

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KernmantleA rope construction consisting of twisted parallel fibers (the kern) surrounded by a tightly braided sheath (the mantle) The core fibers of kernmantle rope provide the majority of the ropes strength, where the sheath provides great abrasion resistance due to its tightly braided construction. Kernmantle ropes are available in either static or dynamic constructions. 

Kerosene - A lighter fuel that is made by distilling petroleum.

Kevlar - A heat-resistant and strong synthetic fiber, related to other aramids such as Nomex and Technora. Developed by DuPont, it can be spun into ropes or sheets, and has a very high tensile strength to-weight ratio. 

Kilonewton (kN) - Equal to 1,000 newtons, a kN is typically a measurement used in safety equipment to quantify overall strength. An important measurement for fall protection, ANSI requires life safety hardware to have a specific minimum breaking strength typically calculated in kN.

Kink - A unique deformation of a wire rope caused by a loop of a rope being pulled down tight. It represents irreparable damage and an indeterminate loss of strength in the rope.

Knitwrist - A design of hand protection, typically made of wool, acrylic, or other knit fabrics. Knitwrist style gloves are typically an economy glove, purchased in bulk. 

Knot - A method of fastening that is done by tying a rope, piece of string, or something similar. Knots sevearly reduce the strength of a rope. To prevent the strength reduction other methods can be used like a termination plate.

Knot Passing Pulley - A large pulley designed with a wide sheave to allow knots in rope to pass through. These pulleys, often called Kootenay pulleys typically are made from aluminum and feature large swiveling side plates with additional attachment points for other rigging. 

Knowledge Base - Our home for all things informative. Visit it here to learn about fall protection components, rescue techniques, safe climbing practices, and more. 

KW - The abbreviation for kilowatt, which is equal to 1,000 watts. Typically used to express the output of motors, tools, and machines, it's also a common unit used to express the electromagnetic power output of broadcast radio and television transmitters. 

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L&A - The acronym for "Transmission Line and Antenna", typically referring to a specific crew type which constructs, maintains, and decommissions equipment on telecom towers and rooftop cell sites, including antennascoaxial cables, fiber, microwaves, dishes, etc.

Ladder Cage - A structure built around a ladder which protects a climber inside the cage.

Lang Lay Rope - Wire rope in which the wires in the strands and the strands in the rope are laid in the same direction.

Lanyard - A generic term for a rope or webbing positioning lanyard, shock absorbing lanyard, or tool tether.

Lanyard Park - A feature of full body harnesses which provides a location to store or "park" a shock absorbing lanyard while it is not in use. Lanyard parks are designed to break away, releasing the attached lanyard at a specific force to prevent a snagged lanyard from tugging or pulling on a worker, potentially causing an accident or fall.

LASER - Light Amplification by Stimulated Emission of Radiation

Lattice Tower - A tower that utilizes diagonal and horizontal bracing in its structural design. 

LCD - Liquid Crystal Display, often included on measuring tools, antenna alignment tools, and more

Leading Edge - The edge of a floor, roof, or formwork for a floor or other walking/working surface which is considered an "unprotected side or edge" during periods when it is not actively and continuously under construction. 

LED - Light Emitting Diode - Used in digital screens

Lever - A bar resting on a pivot that can be used to help move a heavy or firmly fixed load on one end when pressure is applied to the opposite end.

Life Safety - A general term used to differentiate between active fall protection and the use of other equipment for work positioning. Life Safety equipment is all considered part of 100% tie-off and often must meet different standards and specifications than work positioning equipment. 

Lifeline - A piece of a fall protection system, typically made with a synthetic rope or steel wire, which a worker uses to secure themselves to while working at-height. A lifeline can be either vertical or horizontal. A worker ties-off to the lifeline using a connector like a lanyard or SRL, or with a fall arresting device like a cable or rope grab.

Lifeline Tensioner - A device, such as a turnbuckle, used to tighten a horizontal lifeline or as a weight to tension a vertical lifeline.

Line Sweeps - Line Sweeps is the term used to describe the procedure for electronically testing coaxial cable and antenna systems.

Lineman - A person who sets up or repair electric wire communication or power lines. Often referred to as a linesman, this person primarily works in the utility industry.

Linear Appurtenance - An appendage or addition to a structure that is connected at several points vertically to the structure. A run of cable is an example of linear appurtenance.

Litmus - A dye that comes from certain lichens that changes colors when it comes in contact with certain chemicals like acids or alkalis.

Load Binders - A device to tighten chains or cables.

Load Capacity - The maximum amount of force that a load can place on equipment for extended periods of time under normal specifications. Fall protection and lifting & rigging equipment will always have the load capacity documented.

Load Cell - A measuring device used to test guy wire tensions on guyed towers.

Load Rated Bucket - A bucket, typically constructed from canvas or a synthetic fabric, used for material handling, which has been tested to support a given weight. Often used in overhead lifting, load rated buckets provide a more known degree of safety versus other methods, like a plastic 5-gallon bucket. 

Load Rating - A weight, typically in pounds or pound-feet, which a piece of equipment has been safely tested to, and should not be exceeded. Load ratings are stamped on lifting and rigging equipment in the form of Working Load Limits.

Load Resistor (Fiber Tool) - A device, often called a dummy load, used to simulate an electrical load, used for testing purposes. Usually a simple resistor, load resistors are available in a variety of impedances, the dummy load provides a standing wave ratio of 1:1, providing a reliable environment to adjust transmitters. 

Load Rope - Also known as pulling rope, load rope is used in lifting and rigging work. Typically a double braid rope, a good load rope should remain round under tension, and have low rotational force when loaded. Load rope is usually used on a capstan hoist.

Load Table - A table used to determine the lifting capacities of a gin pole under specified parameters.

Loadline - See Load Rope.

Locking Gate - Referring to a proper gate on a carabiner or snaphook used for life safety, a locking gate should automatically close and lock shut. For safety, they require 2 or 3 separate motions before they can be opened. 

Lockout / Tagout (LOTO) - Specific practices and procedures to safeguard employees from unexpected energization or startup of machinery or equipment, or the release of hazardous energy during service or maintenance activities. Lockout devices hold a device in a safe or "off" position and require a key or other unlocking mechanism to turn back "on". Tagout devices are prominent warning devices that are attached to notify others that work is being done. Tagout devices are easier to remove or ignore, and provide less protection than lockout devices.

Lubricant - A substance, such as oil or grease, used for minimizing friction, especially in an engine or component.

Lumbar - The lower spine or an area of the back in its proximity. This area is susceptible to injury, especially while lifting heavy objects, which is why back supports or back belts are often used if repetitive lifting is required in a workplace. 

Lumen - A measurement of the total quantity of visible light emitted by a source. The higher the lumen rating, the brighter the light source is. Flashlights, headlamps, and work lights are typically given a lumen rating to help determine their overall brightness. 

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Mag DrillShort for Magnetic Drill, this is a specialized portable power tool used for drilling holes in steel and similar metals. These drills use an electromagnet at the base to adhere itself to the cutting surface. This magnet is strong enough to hold the drill in any position, vertical, horizontal, even overhead or upside down. Mag drills use bits called annular cutters to bore the holes in the steel.

Magnetic Field Strength -  The magnitude of the magnetic field vector, expressed in units of amperes per meter (A/m).

Man-Lift Basket - A basket of safe design attached to a boom or cable used for lifting workers.

Manhole - A sub-surface confined space which personnel may enter; used for the purpose of installing, operating, and maintaining equipment and/or cable.

Marline Spik - A marline spike is a tapered steel pin used as a tool for splicing wire rope.

Master Link - The main, large, ring where sling legs are attached. Also known as bull ring.

Matte - A color, paint, or finish that is dull and flat, without a shine. Matte surfaces produce less reflection than glossy surfaces. Many PPE items, like safety glasses and safety helmets, are often offered in a matte finish. While they may not necessarily serve a major function, matte items are a personal preference to some workers. 

Mechanical Advantage - A measure of the force amplification achieved by using a tool, mechanical device, or haul system. The device preserves the input power and simply trades off forces against movement to obtain an amplification in output force. Some examples of mechanical advantage would be a lever, gears, or block and tackle, also known as a haul system.

Mechanical Load Break - A friction device, usually using multiple discs or shoes, for controlling load speed in the lowering direction only. The brake prevents the load from overhauling the motor.

MHz - Megahertz. One million Hertz.

Microwave Dish - A specific type of antenna, which is used in point-to-point radio, television, and data communications. Also commonly used by wireless carriers for backhaul. Microwave dish antennas must be precisely aligned, typically using antenna alignment devices. 

Milled - A machining process of using rotary cutters to remove material from a workpiece by feeding the cutter into and along the workpiece in specific directions. Many mechanical pieces of hardware have milled pieces or may be entire milled. These items include pulleysrigging platescarabiners, and more.

Minimum Breaking Strength (MBS) - Minimum Breaking Strength is the lowest amount of force required to break an object.

Monopole - Cylindrical pole with platforms attached to support antennas. Typically used where aesthetics is an issue and land is scarce.

MSDS - Material Safety Data Sheet. It contains all safety-related information on a chemical product used in industry. It provides handling procedures, first aid, cautions, and more. OSHA requires that these be in easy access for each chemical or chemical product used on a job site.

Multipath Interference - A phenomenon in the physics of waves where a wave from a source travels to a detector via two or more paths. An example of this would be using an antenna alignment tool. A signal from a GPS satellite could hit a sensor directly and also bounce off of a nearby antenna, causing a miscalculation by the antenna alignment tool.

MUTCD (Manual on Uniform Traffic Control Devices) - Manual on Uniform Traffic Control Devices (TCDs). The MUTCD contains the national standards governing all traffic control devices, by setting minimum standards and providing guidance, ensuring uniformity of traffic control devices across the United States.

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NATE - The National Association of Tower Erectors

Nebulizer - A device which produces a fine spray of liquid, often used in medical treatments, it's also used for fit testing respirators.

Neoprene - A material in the family of synthetic rubbers. It has good chemical stability and maintains flexibility over a wide temperature range. It's used frequently in PPE and ergonomic equipment, such as balaclavas, wrist braces, knee pads, back supports, gloves, and more. 

Newton - The International System of Units derived unit of force. Named after Isaac Newton, it is the force needed to accelerate one kilogram of mass at the rate of one meter per second squared in the direction of the applied force. 

NFPA - National Fire Protection Association. A global nonprofit organization, established in 1896, devoted to eliminating death, injury, property, and economic loss due to fire, electrical, and related hazards. The NFPA delivers information and knowledge through more than 300 consensus codes and standards. It has over 50,000 individual members around the world. 

NFPA 70E (Standard) - A standard which covers electrical safety requirements for employees. It addresses workplace electrical safety requirements, focusing on the safeguards that allow workers to be safe and productive. 

NIOSH - National Institute for Occupational Safety and Health, it is responsible for conducting research and making recommendations for the prevention of work-related injury and illness. It is part of the Centers for Diseas Control and Prevention within the U.S. Department of Health and Human Services.

Nitrile - An organic rubber compound which is frequently found in latex-free gloves, as well as many exterior coating. It is typically resistant to oils and acids, and has superior strength. Nitrile gloves are more puncture-resistant than natural rubber gloves, and less like to cause allergic reactions

Nomex - A flame-resistant meta-aramid material developed by DuPont in the 1960s. It has excellent thermalchemical, and radiation resistance, and is often used in flame retardant and thermally protective clothing and PPE.

Non-Ionizing - A type of energy, in the lower range of the electromagnetic spectrum, that does not have the ability to strip ions from molecules.

Non-Operational Loading - A factor that should be considered during a rigging plan. A non-operational load differs from an operational load. It is a laod applied to a structure by outside forces such as wind and weather. It takes into consideration the rigging system, material, equipment, or other loading attached to the structure when lifts are not being performed. Loads such as snow, ice, rain, and earthquake are not considered due to the low probability of occurrence during construction unless specific to the region you're working in. 

Non-Standard Structure - Locations for mounting wireless communications other than communication towers, i.e., rooftops, tanks, billboards, etc.

Non-Thermal Effect - See athermal effect.

Non-Vented Helmet - A safety helmet or hard hat which does not have vent holes in the shell. Non-Vented Helmets are required for use around electrical lines or when welding. 

Nose Cup - A component of a respirator, the nose cup fits around a user's chin and up over the nose. On reusable respirators, the filtering cartridges attach to the nose cup. 

NRR - An acronym for Noise Reduction Rating, this is a unit of measurement to determine the effectiveness of hearing protection to decrease sound exposure. The higher the NRR number, the greater the potential for noise reduction. 

Nylon - A tough, lightweight, elastic synthetic polymer material which can be made in strands, sheets, or molded objects. Many ropes, bags, webbing, and other safety equipment is made in at least part with Nylon. 

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O (Extension Cord) - An extension cord jacket rating representing that the cord is oil resistant. Non oil resistant cords will break down and lose insulation performance when exposed to oil.

O2 (Gas) - The chemical symbol for Oxygen found in the ozone, which constitutes 20.8% of the Earth's atmosphere. For confined space work, gas monitors are often used to ensure there is a safe level of O2 present in the work environment. 

Ohm - A unit of measure for electrical resistance between two points of a conductor. 

Oil -