Workplace Safety Glossary

Safety buying runs on shorthand. A glove spec says A4, a respirator box says P100, a hi-vis vest says Type R Class 2, and a purchase order says the extinguisher must meet NFPA 10. This glossary explains the 60 terms, standards and ratings that come up most often when you are specifying or buying personal protective equipment and safety supplies.

Every definition here is drawn from the source that actually governs the term - the OSHA regulation, the ANSI or ISEA standard, the NFPA standard, or NIOSH and EPA guidance - rather than from marketing copy. Where a term has a precise regulatory meaning, that meaning is used. Terms link to the matching product category where we carry it.

2 · A · B · C · D · E · F · H · L · N · O · P · R · S · T · U · W · Z

2

29 CFR 1910.132
OSHA's general PPE standard. It requires protective equipment wherever hazards make it necessary, a workplace hazard assessment with written certification naming the workplace, the certifier, and the date, employee training, and employer payment for most required PPE.

A

ABC Dry Chemical Extinguisher
A multipurpose extinguisher charged with monoammonium phosphate, rated for Class A, B, and C fires. The agent melts into a sticky residue that smothers fuel, but NFPA 10 says dry chemical is not for protecting delicate electronic equipment. Shop ABC Dry Chemical Extinguishers.
Anchorage (Anchor Point)
A secure point of attachment for lifelines, lanyards, or deceleration devices. For construction fall arrest, OSHA requires anchorages capable of supporting at least 5,000 pounds per attached employee, or designed with a safety factor of at least two under a qualified person's supervision.
ANSI/ISEA 105
The American National Standard for hand protection classification. It rates gloves on cut resistance (levels A1 through A9), abrasion resistance on a 0 to 6 scale, and puncture resistance on a 1 to 5 scale, so buyers can compare products on the same terms. Shop Cut-Resistant Gloves.
ANSI/ISEA 107
The American National Standard for high-visibility safety apparel. It sorts garments by type (O off-road, R roadway, P public safety) and by performance class, based on how much fluorescent background and retroreflective material the garment carries. Shop High-Visibility Vests & Apparel.
ANSI/ISEA 138 (Impact Rating)
The standard for impact-resistant gloves, which tests how well back-of-hand padding protects the knuckles and fingers. Levels run 1 to 3, with 3 the most protective: mean transmitted force under 4 kN, versus under 9 kN for Level 1. Shop Hand and Arm Protection.
ANSI/ISEA Z308.1
The American National Standard for workplace first aid kits. It sets minimum contents by class and sorts containers into Types I through IV, from fixed indoor mounting to portable use in mobile or outdoor settings requiring corrosion, moisture, and impact resistance.
ANSI/ISEA Z87.1
The American National Standard for occupational and educational personal eye and face protection devices. It sets criteria for selecting, testing, marking, and caring for protectors against impact, non-ionizing radiation, and liquid splash. The 2020 edition added an anti-fog lens assessment. Shop Eye and Face Protection.
Arc Rating
Under NFPA 70E, the value attributed to a material describing its performance when exposed to an electrical arc discharge, expressed in calories per square centimeter as either ATPV or EBT. Garment arc rating should meet or exceed the calculated incident energy. Shop Protective Clothing.
Assigned Protection Factor (APF)
The workplace level of respiratory protection a respirator or class of respirators is expected to provide when the employer runs a continuing, effective respiratory protection program. A half-mask air-purifying respirator has an APF of 10 in OSHA's Table 1. Shop Respiratory Protection and Detection.
Authorized Employee
A person who locks out or tags out machines or equipment in order to perform servicing or maintenance on it. This is distinct from an affected employee, whose job requires operating or using equipment that is under lockout or tagout. Shop Lockout / Tagout.
Automated External Defibrillator (AED)
A computerized defibrillator that automatically analyzes the heart rhythm of a person in cardiac arrest and delivers an electrical shock to restore a normal rhythm when one is needed. Semi-automated units prompt the rescuer to press a shock button.

B

Barricade Tape
A non-adhesive strip of polyethylene or vinyl positioned to block access and alert people to a temporary or unexpected hazard or condition. OSHA's construction sign rule incorporates ANSI Z535.5, which covers safety tags and barricade tapes for temporary hazards.
Bloodborne Pathogens
Microorganisms present in human blood that can cause disease, including HIV, hepatitis B, and hepatitis C. OSHA's standard requires employers to treat all blood and certain body fluids as infectious, write an exposure control plan, and provide protective equipment.
Breakthrough Time
For chemical-resistant gloves, the elapsed time between a chemical first contacting the outside of the glove and its detection on the inside, measured under ASTM F739. A result shown as greater than 480 minutes means no permeation was detected during the test. Shop Chemical-Resistant Gloves.

C

Class A First Aid Kit
The baseline workplace kit under ANSI/ISEA Z308.1, stocked to handle the most common workplace injuries with items such as adhesive bandages, antiseptic, burn dressing, eye covering, gauze pads, scissors, and a triangular bandage. Class B kits add larger quantities plus a splint and tourniquet.
Clean Agent Extinguisher
An extinguisher using a non-conductive gaseous agent such as Halotron that interrupts the combustion chain reaction and leaves no residue. Rated for Class B and C fires, with larger units also rated Class A, it is chosen for electronics and sensitive equipment. Shop Clean Agent Extinguishers.
CO2 Extinguisher
A carbon dioxide extinguisher rated for Class B and C fires. It displaces oxygen and cools the fuel, leaves no residue, and is non-conductive. Discharge range is only about three to eight feet and cylinders need hydrostatic testing every five years. Shop CO2 Extinguishers.
Competent Person
One who is capable of identifying existing and predictable hazards in the surroundings or working conditions that are unsanitary, hazardous, or dangerous to employees, and who has authorization to take prompt corrective measures to eliminate them.
Cut Level (A1-A9)
The ANSI/ISEA 105 cut-resistance scale, tested on a TDM-100 machine under ASTM F2992 with a fresh blade over 20 mm of travel. A1 withstands at least 200 grams of cutting load, A4 at least 1,500 grams, and A9 at least 6,000 grams. Shop Cut-Resistant Gloves.

D

dBA (A-Weighted Decibel)
A sound level measured through a filter that mimics human hearing sensitivity, emphasizing mid frequencies and de-emphasizing very low and very high ones. NIOSH uses A-weighted levels to predict hearing risk, and its recommended exposure limit is 85 dBA over eight hours. Shop Hearing Protection.
Donning and Doffing
Putting on and taking off personal protective equipment. OSHA's PPE training requirement in 1910.132(f) specifically covers how to properly don, doff, adjust, and wear PPE, along with its limitations and its care, maintenance, useful life, and disposal.

E

Emergency Eyewash Station
Equipment meeting ANSI/ISEA Z358.1 that delivers a fifteen-minute flush of the eyes with flushing fluid after a corrosive exposure. The unit must be reachable within ten seconds of the hazard and deliver fluid at a safe, tepid temperature.
Energy Isolating Device
A mechanical device that physically prevents the transmission or release of energy, such as a manually operated circuit breaker, a disconnect switch, or a line valve. Push buttons, selector switches, and other control circuit devices do not qualify. Shop Lockout / Tagout.
Engineering Controls
Controls that reduce or prevent hazards from reaching workers by changing the equipment or workplace itself, such as machine guarding, protective barriers, and ventilation. They sit above administrative controls and PPE in the hierarchy of controls.

F

Face Shield
A secondary protector covering the face against flying particles, molten metal, chemical splash, and injurious light radiation. OSHA requires eye or face protection where those hazards exist; face shields are worn over safety glasses or goggles rather than instead of them. Shop Face Shields.
Fire Classes (A, B, C, D, K)
The five fire categories used to match an extinguisher to a hazard: Class A for ordinary combustibles like wood and paper, Class B for flammable liquids and gases, Class C for energized electrical equipment, Class D for combustible metals, and Class K for cooking oils and fats. Shop Fire Extinguishers.
Fit Test
The use of a protocol to qualitatively or quantitatively evaluate the fit of a respirator on an individual. A qualitative test is pass/fail based on the wearer's response to a test agent; a quantitative test numerically measures leakage into the facepiece. Shop Respiratory Protection and Detection.
Flame-Resistant (FR) Clothing
Clothing built to self-extinguish rather than continue burning. NFPA 2112 certifies garments for short-duration flash fire using the ASTM F1930 manikin test, a three-second exposure at 2 cal/cm2, which the garment passes with under 50 percent predicted body burn. Shop Protective Clothing.
Full-Body Harness
Straps secured about the employee so that fall arrest forces are distributed over at least the thighs, pelvis, waist, chest, and shoulders, with a means of attaching to the other components of a personal fall arrest system such as a lanyard or lifeline.

H

Hearing Conservation Program
The program OSHA requires under 1910.95(c) when employee noise exposures equal or exceed an 8-hour time-weighted average of 85 decibels, or a 50 percent dose. The permissible exposure limit itself is 90 dBA over eight hours. Shop Hearing Protection.
Hierarchy of Controls
NIOSH's ranking of hazard control methods by effectiveness: elimination, substitution, engineering controls, administrative controls, and personal protective equipment. The top three work independently of worker behavior, which is why PPE alone should not be relied on when better options exist.
High-Visibility Safety Apparel
Garments that make a worker conspicuous using fluorescent background fabric plus retroreflective material. Under 23 CFR Part 634, workers on foot in a Federal-aid highway right-of-way who are exposed to traffic or construction equipment must wear at least ANSI/ISEA 107 Class 2 apparel. Shop High-Visibility Vests & Apparel.

L

Lockout
The placement of a lockout device on an energy isolating device, under an established procedure, ensuring that the energy isolating device and the equipment it controls cannot be operated until the lockout device is removed. Shop Lockout / Tagout.

N

N95 Respirator
A NIOSH-approved particulate respirator whose filter removes at least 95 percent of airborne particles. The N means the filter is not resistant to oil, so N-series filters should not be used where oil aerosols are present. Shop Respiratory Protection and Detection.
NFPA 10
The National Fire Protection Association standard for portable fire extinguishers. It covers selection, purchase, installation, listing, inspection, and maintenance of extinguishers and Class D extinguishing agents, and calls for extinguishers to be inspected at least once every month. Shop Fire Extinguishers.
Noise Reduction Rating (NRR)
The EPA-required single-number rating in decibels on every hearing protector label. It reflects laboratory attenuation across one-third octave test frequencies, accounting for variation in noise spectra and fit. Real-world protection is usually lower than the printed number. Shop Hearing Protection.
NRR Derating
The adjustment applied because laboratory NRR overstates field performance. OSHA's method in 1910.95 Appendix B subtracts 7 dB from the NRR before subtracting the remainder from an A-weighted time-weighted average exposure to estimate protected exposure. Shop Hearing Protection.

O

Oil-Only Sorbent
White, hydrophobic sorbent that picks up petroleum-based liquids while repelling water, which makes it usable on wet ground or open water. Universal (gray) sorbent handles most liquids, and hazmat (yellow) sorbent is built for aggressive and corrosive chemicals. Shop Sorbents and Powders.
OSHA 1910.147
The control of hazardous energy standard, commonly called lockout/tagout. It requires documented energy control procedures so machines cannot be started up or release stored energy while employees perform servicing or maintenance. Shop Lockout / Tagout.

P

P100 Filter
A NIOSH filter class that removes at least 99.97 percent of airborne particles, the highest particulate efficiency in the NIOSH scheme. The P designation means the filter is strongly resistant to oil, so it can be used where oil aerosols are present. Shop Respiratory Protection and Detection.
Permissible Exposure Limit (PEL)
The legal limit on employee exposure to an air contaminant under 29 CFR 1910.1000. Most PELs are 8-hour time-weighted averages; some are ceiling values marked C in Table Z-1 that must not be exceeded at any time.
Personal Fall Arrest System
A system used to arrest an employee in a fall from a working level, consisting of an anchorage, connectors, and a body harness, and possibly a lanyard, deceleration device, or lifeline. Arresting force on a harness is limited to 1,800 pounds.
Powered Air-Purifying Respirator (PAPR)
An air-purifying respirator that uses a blower to force ambient air through air-purifying elements to the inlet covering. Because it supplies filtered air under positive pressure, it does not rely on the wearer's lungs to pull air through the filter. Shop Respiratory Protection and Detection.

R

Retroreflective Material
Tape or trim that returns light back toward its source, so a garment lights up in vehicle headlights. It does nothing without a light source, which is why ANSI/ISEA 107 also requires fluorescent background fabric for daytime conspicuity. Shop High-Visibility Vests & Apparel.

S

Safety Data Sheet (SDS)
The 16-section document a chemical manufacturer or importer must supply for each hazardous chemical, covering identification, hazards, first aid, firefighting, handling, exposure controls, and more. Employers must keep current sheets readily accessible to employees during every work shift.
Safety Goggles (D3 Rating)
Eyewear with a face seal that fits close to the face. Under Z87.1, D3 marks a chemical-splash goggle with indirect ventilation, D4 a dust goggle, and D5 a fine-dust goggle. Spectacles without a face seal cannot carry a D3 splash rating. Shop Safety Goggles.
Secondary Containment
The second line of defense if primary containment fails, holding oil temporarily until cleanup. Under EPA's SPCC rule, sized containment for bulk storage must hold the largest single container plus sufficient freeboard to contain precipitation. Shop Spill Containment.
Self-Contained Breathing Apparatus (SCBA)
An atmosphere-supplying respirator for which the breathing air source is designed to be carried by the user. Unlike an air-purifying respirator, it supplies clean air rather than filtering the surrounding atmosphere, so it can be used in oxygen-deficient conditions. Shop Respiratory Protection and Detection.
Self-Retracting Lifeline (SRL)
A deceleration device with a drum-wound line that pays out and retracts under slight tension during normal movement and automatically locks the drum to arrest a fall. ANSI/ASSP Z359.14-2021 sorts these into Class 1 for overhead anchorage and Class 2 for lower anchorage.
Shock-Absorbing Lanyard
A lanyard incorporating a deceleration device, such as a rip-stitch or tearing element, that dissipates energy during fall arrest. OSHA limits the resulting free fall to six feet and the deceleration distance to 3.5 feet.
Signal Word
The word at the top of a safety sign that ranks severity under ANSI Z535.2. DANGER means a hazardous situation that will result in death or serious injury and is reserved for extreme cases, WARNING means it could, CAUTION means minor or moderate injury, and NOTICE is non-hazard information.
Sorbent Sock
A flexible tube of sorbent material used to ring a spill, dam a leak, or block a drain before absorbent pads are used to soak up the liquid. Like pads, socks come in oil-only, universal, and hazmat versions. Shop Pads, Rolls, and Booms.
Spill Kit
A staged set of sorbents, personal protective equipment, and disposal bags kept where a release could occur. Kits are matched to the hazard, such as universal, fuel, or hazmat, and are intended for incidental spills rather than emergency releases. Shop Spill Kits and Stations.

T

Tagout
The placement of a tagout device on an energy isolating device, under an established procedure, to indicate that the energy isolating device and the equipment it controls may not be operated until the tagout device is removed. Shop Lockout / Tagout.
Time-Weighted Average (TWA)
An exposure averaged over a work period, normally eight hours. For air contaminants it is computed as the sum of each concentration multiplied by its duration, divided by eight. For noise it is the steady level producing the same dose as the actual varying levels.
Traffic Cone
A predominantly orange channelizing device. MUTCD requires cones to be at least 18 inches tall, and at least 28 inches on freeways, high-speed highways, or at night, where they must also carry a six-inch white retroreflective band plus a four-inch band below it.

U

UL Rating (2A:10B:C)
The tested capacity marked on an extinguisher. The A number is a water equivalent, where 1A equals about 1.25 gallons; the B number is the approximate square feet of flammable liquid fire a trained user can extinguish. Class C carries no number because it certifies non-conductivity. Shop Fire Extinguishers.

W

Wet Floor Sign
A portable, usually yellow A-frame warning placed before a slippery area to prevent slips and falls. OSHA does not name the sign itself, but 1910.22 requires floors to be kept clean and dry and hazards to be marked.

Z

Z87+ (High-Impact Rating)
The Z87.1 marking for high-impact protection, earned by passing a high-velocity test using a quarter-inch steel ball at 150 feet per second. Both the frame and the lens must carry the Z87+ mark; basic-impact Z87 products pass only a drop-ball test. Shop Safety Glasses.

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