Definition Page




Attendant – an individual stationed outside one or more permit-required confined spaces who monitors the authorized entrant and performs all attendant duties assigned in the employer’s permit-required confined space program.

Authorized Entrant – an individual authorized by the employer to enter a permit-required confined space.

Benching -- excavating the sides of an excavation to form one or a series of horizontal levels or steps, usually with vertical or near-vertical surfaces between levels

Blanking/Blinding – the absolute closure of a pipe, line or duct by the fastening of a solid plate that completely covers the bore and that is capable of withstanding the maximum pressure of the pipe, line or duct with no leakage beyond the plate.

Boom – An inclined spar, strut, or other long member supporting the hoisting tackle

Buddy System – a system of organizing employees into work groups in such a manner that each employee of the work group is designated to be observed by at least one other employee in the work group.

Clean-up Operation – an operation where hazardous substances are removed, contained, incinerated, neutralized, stabilized, cleared-up, or in any other manner processed or handled with the ultimate goal of making the site safer for people or the environment.

Confined Space – a space that: 1> is large enough and so configured that an employee can bodily enter and perform assigned work; 2> has limited or restricted means for entry or exit; and 3> is not designed for continuous employee occupancy.

Confined Space Entry – the action by which a person passes through an opening into a permit-required confined space and subsequent work within the space. Entry is considered to have occurred as soon as any part of the entrants body breaks the plane of an opening to a confined space.

Crane – Consists of a rotating structure for lifting and lowering horizontally on rubber tires or crawler treads

Decontamination – the removal of hazardous substances from employees and equipment to the extent necessary to preclude the occurrence of foreseeable adverse health affects.

Double Block and Bleed – the closure of a pipe, line or duct by closing and locking or tagging two in-line valves and by opening and locking or tagging a drain or vent valve in the line between the two closed valves.

Emergency – an event or occurrence that could endanger site personnel, the public or the environment.

Emergency Response – a response effort by employees from outside the immediate release area or by other designated responders to an occurrence which results, or is likely to result, in an uncontrolled release of a hazardous substance. Control of releases by employees in the immediate vicinity of the release where the release is absorbed, neutralized or otherwise controlled at the time of release and releases where there is no potential for safety or health hazards are not considered emergency response.

Engulfment – the surrounding and effective capture of a person by a liquid or finely divided (capable of flowing) solid substance that can be aspirated to cause death by filling or plugging the respiratory system or that can exert enough force on the body to cause death by strangulation, constriction or crushing.

Excavation – a man-made cut, cavity, trench, or depression formed by earth removal.

Floor hole - An opening in the floor, platform or pavement that measures less than 12 inches, but more than 1 inch; and through which materials – but not people - may fall.

Floor opening - An opening in the floor, platform or pavement that measures 12 inches or more, and through which persons may fall.

Hazardous Atmosphere – an atmosphere that may expose employees to the risk of death, incapacitation, impairment of ability to self-rescue, injury, or acute illness due to: 1> an atmosphere containing greater than 10% of the lower flammable limit (LFL) of a flammable vapor, gas or mist; 2> airborne combustible dust at or above the LFL; 3> an oxygen deficient atmosphere; 4> an oxygen enriched atmosphere; 5> concentrations of a hazardous substance above permissible exposure limits (PELs) or, where PELs do not exist, above published exposure limits; or, 6> any other atmosphere that is immediately dangerous to life and health.

Hazardous Substance – any substance that: 1> defined under section 101(14) of CERCLA; 2> any biological agent or other disease-causing agent capable of either directly or indirectly causing serious health effects or death; 3> any substance listed by the Department of Transportation (DOT) as hazardous materials under 49 CFR part 172.101 and appendices; and 4> any hazardous waste.

Hazardous Waste – a waste or combination of wastes as defined under RECRA in 40 CFR Part 261.3 or defined as a hazardous waste in 49 CFR (DOT) Part 171.8.

Health Hazard – a chemical, mixture of chemicals or pathogen for which there is statistically significant evidence based on at least one acceptable study that acute or chronic health effects may occur in exposed employees.

Hoist - Used to lift and lower load.

Hot Work Permit – the written authorization to perform operations capable of providing a source of ignition.

Immediately Dangerous to Life and Health (IDLH) – a condition that poses an immediate or delayed threat to life or that would cause irreversible adverse health effects or that would interfere with an individual’s ability to self-rescue from a hazardous atmosphere.

Inerting – using noncombustible gas (excluding air – i.e. carbon dioxide, nitrogen) to displace the atmosphere within a confined space. Note: the resultant atmosphere is IDLH due to oxygen deficiency.

Isolation – the separation of a work area from all sources of energy or atmospheric hazards originating outside of the protected work area. Lock out/tag out, blanking/bleeding, mechanical disconnections and breaking of pipe, line or duct connections (misaligning the ends or removing sections) are used to create isolation of a work space.

Jib – Extension attached to the boom point to provide added boom length for lifting specified loads.

Load – The weight of the object being lifted including: Load block and hook, Wire rope, Rigging, Boom attachments, Ancillary attachment

Lower Flammable Limit (LFL) – the minimum concentration of a vapor in air (or other oxidant) below which propagation of flame does not occur on contact with an ignition source.

Lower Explosive Limit (LEL) - – the minimum concentration of a vapor in air (or other oxidant) within a contained area below which propagation of flame does not occur on contact with an ignition source.

Non-permit Confined Space – a confined space that does not contain or have the potential to contain any atmospheric hazard capable of causing death or serious physical harm.

Outrigger – Support members attached to the crane’s carrier frame which are used to level the crane

Oxygen Deficiency – an atmosphere containing less than 19.5% oxygen by volume.

Oxygen Enriched – an atmosphere containing more than 23.5% oxygen by volume.

Permissible Exposure Limit (PEL) – the exposure, inhalation or dermal permissible exposure limit specified in OSHA regulations contained at 29 CFR Part 1910, subparts G and Z.

Permit-required Confined Space – a confined space that: 1> contains or has the potential to contain a hazardous atmosphere; 2> poses a threat of engulfment; 3> is internally configured so that an entrant could be trapped or asphyxiated by inwardly converging walls or by a floor that slopes downward and tapers to a smaller cross-section; or 4> contains any other recognized serious safety or health hazard.

Published Exposure Limits – the Recommended Exposure Limits (RELs) published by the National Institute of Occupational Safety and Health (NIOSH) or, if no REL is specified, the Threshold Limit Values (TLVs) published by the American Conference of Governmental Industrial Hygienists (ACGIH).

Shield - a structure able to withstand a cave-in and protect employees

Shoring - a structure that supports the sides of an excavation and protects against cave-ins

Sloping - a technique that employs a specific angle of incline on the sides of the excavation. The angle varies based on assessment of impacting site factors.

Standard railing - Consists of a top rail, mid rail and posts. The height from the upper surface of the top rail to the floor level is 42 inches. Mid rail height is one-half as high as the top rail (21 inches).

Standard toeboard - Blocks an opening along the base/floor of stairs or other walking or working surfaces where materials or body parts might otherwise inadvertently fall through. It should be 4 inches high, with not more than Ό inch clearance above the floor.

Trench – a narrow excavation. The depth is greater than the width, but not wider than 15 feet.

Wall opening - An opening in a wall or partition that is at least 30 inches high and 18 inches wide, and through which persons may fall.