acetylene

A colorless flammable gas that is used in oxyfuel welding. Acetylene is the most commonly used gas for mixing with oxygen to fuel oxyfuel torches.

ACGIH

American Conference of Governmental Industrial Hygienists. A member-based organization that recommends and reviews threshold limit values for chemicals used in the workplace. The ACGIH advances worker protection.

air-supplied respirator

A breathing device that consists of a full face mask with a hose that connects to a freestanding compressed air cylinder. Air-supplied respirators are used in confined spaces to supply oxygen when exposure guidelines cannot be met.

alloying element

An element that is intentionally added to a metal in order to change its properties. Manganese is a common alloying element in steel.

alternating current

AC. Electric current that flows half the time in one direction and half the time in the opposite direction. Alternating current is more dangerous than direct current.

American National Standards Institute

ANSI. A private, non-profit organization that administers and coordinates voluntary standards and systems. ANSI helps set guidelines for personal protective equipment used in welding.

American Society of Testing and Materials

ASTM. An organization that writes and updates specifications for a broad range of materials. ASTM provides specifications for PPE standards for shoes and eyewear in welding.

American Welding Society

AWS. The non-profit organization that regulates the industrial standards for welding and promotes the welding industry in the United States. Welders should follow AWS recommendations.

ANSI Z49.1

A standards document published by the American National Standards Institute that covers welding PPE and other safety concerns. ANSI Z49.1 is titled "Safety in Welding, Cutting, and Allied Processes."

arc welding

A group of welding processes that joins different metal workpieces into one by heating them with a transfer of electricity from an electrode to the workpieces. Arc welding can occur with or without the use of filler metal.

atom

The smallest distinguishable unit of a material that maintains that material's characteristics. Atoms include protons, neutrons, and electrons.

attendants

Someone trained in permit space entry and surface rescue who remains outside a confined space to monitor the safety of workers in the confined space.

automatic external defibrillator

AED. A portable electronic device that can be used to treat cardiac arrhythmias by allowing the heart to reestablish an effective rhythm. An automatic external defibrillator is often used in CPR training.

base metal

The metal or alloy being welded. Welders must have access to information about the contents of the base metal so that they can take precautions and be aware of safety risks.

beryllium

A hard gray metal. Work involving beryllium should be done with local exhaust ventilation and air-supplied respirators.

cadmium

A soft, bluish-white metal found in zinc ores. Cadmium is commonly used in metal alloys and as a coating on base metals.

carbon monoxide

CO. A colorless, odorless, poisonous gas composed of carbon and oxygen. Carbon monoxide may be generated by some welding processes.

carcinogenic

Having the potential to cause cancer. Welding fumes are internationally classified as possible carcinogenic risks.

cardiopulmonary resuscitation

CPR. A technique designed to temporarily circulate oxygenated blood through the body of a person whose heart has stopped. Cardiopulmonary resuscitation can be used when a person has stopped breathing.

central nervous system

Comprised of the brain, spinal cord, and complex nerve tissues. The central nervous system controls many different bodily activities and may be affected by overexposure to some welding fumes.

chromium

A grayish metal that improves corrosion resistance. Chromium is sometimes added to electrodes.

circuits

A completely enclosed path, consisting of various devices, that contains an electrical current. In arc welding, the machine output circuit is also known as the welding circuit.

coatings

Any material that has been applied to the surface of the base metal. Coatings include primer, paint, zinc, and chrome.

combustible

Any substance that is capable of igniting and burning.

compressed gas

Any gas held under pressure in a gas cylinder.

conductor

A material that allows for the flow of electricity. Conductors include metals such as copper and aluminum.

confined space

An area not designed for continuous human occupancy with limited means of entry or exit that is large enough for an employee to enter and perform work. Welding in confined spaces may require an air-supplied respirator or air quality testing.

confined space entry program

A written set of policies and procedures for entering permit-required spaces. OSHA requires every employer whose employees enter permit-required spaces to develop a written plan.

consumables

An input that is part of the welding process but that is released, changed, or otherwise altered during welding. Consumables include electrodes, gases, coatings, torch tips, and other items.

current

The rate and amount of electrical flow. Arc welding requires a continuous flow of electricity to maintain the arc.

cylinder cart

Also called a hand truck. A cart on wheels used for moving small, heavy objects.

direct current

DC. A current formed when electrons flow in one continuous direction. Direct current is not as dangerous as alternating current (AC).

direct current electrode negative

DCEN. Current that travels in only one direction, with straight polarity. In direct current electrode negative, or straight polarity, the electrode is the negative pole of the welding arc and the workpiece is the positive pole.

direct current electrode positive

DCEP. Current that travels in only one direction, with reverse polarity. In direct current electrode positive, or reverse polarity, the electrode is the positive pole of the welding arc and the workpiece is the negative pole.

earplugs

Hearing protection made of silicone or rubber designed to fit in the ear. Earplugs can be single-use, or they can be pre-formed for long-term use.

electric burns

An injury caused by the flow of electric current through tissue or bone. Electric burns can cause severe tissue damage.

electric shock

The flow of electricity through the body. Severe electric shock can be fatal.

electrically charged

A way of describing a wire or device that has current flowing through it. Welders must observe all necessary safety precautions near electrically charged devices.

electrically live

Carrying an electric charge. Electrically live components in a welding power source include the interior lead and conductor.

electricity

A form of energy created by the movement of electrons. Arc welding utilizes electricity.

electrocution

To be fatally or seriously injured by electricity.

electrode

A device that conducts electricity. In welding, the electrode also can act as the filler metal.

electrode circuit

The output circuit of a welding power source, also called the secondary circuit. Electrode circuits are enclosed paths that contain the 60-100 volt electrical power used for welding.

electrode holder

The insulated handle into which a stick electrode is inserted, also referred to as a "stinger. " The electrode holder must be dry and in good condition.

electrons

A negatively charged particle that orbits the center of an atom. Electrons play an integral role in conducting current.

exposure limits

Legal guidelines set by OSHA, as well as recommended guidelines established by independent agencies such as the American Conference of Governmental Industrial Hygenists (ACGIH). Exposure limits include permissible exposure limits and threshold limit values.

face shields

A rigid, transparent plastic guard that covers the welder's entire face to protect against dust or splashes. Because face shields do not protect against impacts, they are often worn with goggles or safety glasses with side shields.

filter lens

Welding PPE that protects vision against radiant energy given off by the arc. Different shade numbers indicate the intensity of light radiation allowed to pass through a filter lens.

flammable

Any material that can easily ignite and start a fire.

flash point

The lowest temperature at which a liquid produces enough vapor to form an ignitable mixture. Liquids with low flash points pose the greatest danger.

fluorine

A highly reactive chemical element. Gas welding fluxes containing fluorine compounds may give off fumes when heated that may cause eye, nose, and throat irritation.

flux

A non-metallic material that is intended to protect the weld puddle and solid metal from atmospheric contamination. Flux is often a part of an electrode.

fume plume

A cloud-like area above the arc containing welding gases, metallic fumes, and particulates. Welders must keep their heads out of the fume plume and use adequate ventilation.

Globally Harmonized System

GHS. An international standard for communicating chemical hazards through signs, labeling, and safety data sheets. The Globally Harmonized System is intended to standardize hazard communication information worldwide.

grounded

Safely connected to a neutral body, like the earth, which can absorb a stray electrical charge. Electric tools must be grounded to prevent electric shock.

grounding

A means of providing a safe path for electricity should it stray from its intended path. Grounding substantially reduces the risk of electrical shock.

Group 1

The list of agents classified by the International Agency for Research on Cancer (IARC) as carcinogenic to humans. Group 1 includes welding fumes.

hand truck

A cart on wheels used for moving small, heavy objects. Cylinder carts are also called hand trucks.

hazard assessment

A written, formal appraisal of the safety risks that exist within a workplace. Hazard assessment is included in a confined space entry program.

Hazard Communication Standard

HCS. An established OSHA policy that sets guidelines for communicating information about hazardous materials and is aligned with the Globally Harmonized System (GHS). The Hazard Communication Standard emphasizes that employers provide training and manufacturers use labeling and SDSs.

hazard statement

A statement that describes the hazard, its degree, the class, and category. The hazard statement is required by the OSHA HCS.

hexavalent chromium

A grayish metal that contains the elements chromium and oxygen. Hexavalent chromium may be produced when welding with certain consumables, such as stainless steel.

IARC

International Agency for Research on Cancer. An agency dedicated to the promotion of international collaboration in cancer research. The International Agency for Research on Cancer is part of the World Health Organization (WHO).

insulation

Material that prohibits the flow of electricity. Insulation is necessary to prevent electrical shock.

insulators

A material that is highly resistant to the flow of electricity. Rubber and plastic are insulators.

International Agency for Research on Cancer

IARC. An agency dedicated to the promotion of international collaboration in cancer research. The International Agency for Research on Cancer is part of the World Health Organization (WHO).

manganese

A hard, brittle, gray-white metal often added to electrodes and steel. Manganese removes oxides and increases strength and hardness in the weld.

mechanical ventilation

An automatic system of extracting fumes from the arc. Mechanical ventilation either exhausts or filters vapors.

mercury

A heavy metallic element. Confined space or indoor welding operations involving mercury-bearing materials must be done using local exhaust ventilation or respirators.

natural gas

A flammable gas that occurs underground. Natural gas is used as a cutting gas in welding.

natural ventilation

The process of supplying and removing air through a space without using a mechanical system. Natural ventilation uses outdoor air flow.

nonconductive

Unable to transfer electrical energy. Nonconductive materials can provide insulation in welding environments.

Occupational Safety and Health Administration

OSHA. A government agency that sets the standards for working conditions in the United States and ensures that employees work in safe and healthy environments.

ocular melanoma

A type of cancer that develops in the melanin within the eye. Treatment of ocular melanoma can result in vision loss.

OSHA

Occupational Safety and Health Administration. A government agency that sets the standards for working conditions in the United States and ensures that employees work in safe and healthy environments.

oxidation

A material's chemical reaction with oxygen. Oxidation takes place in the welding arc as a result of the base metal and electrode composition reacting with oxygen in the atmosphere.

P.A.S.S. Technique

A common procedure for operating a fire extinguisher. P.A.S.S. is an acronym for PULL, AIM, SQUEEZE, and SWEEP.

particulate matter

Microscopic, solid contaminants including metal, dirt, sand, and dust.

permissible exposure limits

PEL. Legal limits set by OSHA to protect employees from hazardous substance exposure. Permissible Exposure Limits are based on a time-weighted average for an eight-hour shift.

personal protective equipment

PPE. Articles of clothing or safeguarding devices that employees use to prevent injury in the workplace or on worksites. Welding PPE includes safety glasses, insulated gloves, face shields, and earplugs.

pictogram

An illustration of a hazard, intended to be understood even if the viewer cannot read or speak English. There are nine different pictograms required for use on labels by the Globally Harmonized System (GHS).

polarity

Having a positive or negative charge. During arc welding, the electrode and the workpiece form a pair of poles: one negative and one positive.

power source

A device that supplies current and voltage suitable for welding. Home and factory power sources are connected to residential or industrial electrical power, while portable units create their own electrical output utilizing a gasoline or diesel engine and a rotating electrical device.

PPE

Personal Protective Equipment. Articles of clothing or safeguarding devices that employees use to prevent injury in the workplace or on worksites. PPE for welding includes safety glasses, insulated gloves, face shields, and earplugs.

precautionary statements

A statement that offers ways to minimize the effects of exposure and may suggest particular PPE to use. A precautionary statement is required by the OSHA HCS.

primary voltage shock

An electrical shock that occurs due to touching an electrically live component at the same time as a grounded conductor. Primary voltage shock ranges from 120-575 volts and can be fatal.

product identification

Includes the name or number of a hazardous chemical and information that can be cross-referenced with the written hazard communication program, SDS, and labels. Product identification is required by the OSHA HCS.

proprietary

A product whose rights are owned by the company that designed it. Proprietary products can be used only with the permission of the owner.

propylene

Also known as propane. A flammable gas that can be used in oxyfuel welding instead of acetylene.

radiant energy

Energy from a magnetic field that is produced by the motion of electric charges such as an electric current. Radiant energy is also called electromagnetic energy.

regulator

The device used to control the amount of gas that flows from a cylinder during a weld. Turning off the regulator on a cylinder helps to ensure that the hose is not pressurized.

Safety Data Sheets

SDS. Mandatory chemical hazard information that must accompany almost every hazardous product or chemical in the workplace. An SDS includes specific sections with details such as the hazards, precautions, and first aid procedures associated with the chemical.

safety glasses

Protective eyeglasses with metal or plastic frames and impact-resistant lenses that may or may not offer vision correction. Safety glasses worn for welding applications must also have protective side shields.

safety-toed

Protective footwear with a reinforced toe area. Safety-toed boots prevent foot injury from falling objects.

SDS

Safety Data Sheet. Mandatory chemical hazard information that must accompany almost hazardous product or chemical in the workplace. An SDS includes specific sections with details such as the hazards, precautions, and first aid procedures associated with the chemical.

SDSs

Safety Data Sheet. Mandatory chemical hazard information that must accompany almost hazardous product or chemical in the workplace. An SDS includes specific sections with details such as the hazards, precautions, and first aid procedures associated with the chemical.

secondary voltage shock

An electrical shock that occurs as a result of touching the electrode and another conductor at the same time. Secondary voltage shock ranges from 60-100 volts.

signal word

A word that indicates the level of severity of a hazard. Signal words are required by the OSHA HCS and GHS specifies they be "Warning" and "Danger."

stainless steel

A very hard, corrosion-resistant steel. Stainless steel can be welded using many methods.

supplier identification

Information that includes the name, address, and telephone number of a chemical manufacturer, importer, or other party responsible for a hazardous chemical. Supplier identification is required on HCS labels.

synthetic fire-resistant materials

A manufactured synthetic textile that is flame retardant. Fire resistant synthetic material is lightweight and cooler to wear.

thermal cutting

A cutting process that uses heat to remove metal from a workpiece. Thermal cutting processes include oxyfuel and laser beams.

ultraviolet radiation

UV radiation. The energy emitted by light sources with wavelengths slightly smaller than violet light. Ultraviolet radiation, which cannot be seen with the human eye, can lead to serious skin and eye issues with prolonged exposure.

valve caps

A device used to protect the valve from being broken off in case they fall over. Valve caps should be in place when cylinders are not in use.

ventilation

A means of moving air to remove contaminants and provide clean air. Ventilation reduces the hazards posed by welding fumes and gases.

voltage

A measure of electrical pressure or potential. Voltage is measured in volts (V).

voltage reduction device

VRD. A device that can be fitted to a power source to reduce the voltage. Voltage reduction devices reduce the open circuit voltage.

volts

The basic unit of measurement for electrical "pressure" or potential. A high voltage of electricity can cause serious injury.

welder

A term used to refer to the person who welds. Some source materials use the term "welder" to refer to the power source, or welding machine.

welding

A joining process that permanently bonds together two separate components with heat, pressure, or a combination of those elements.

welding helmets

A heat-resistant head covering that protects against burns and eye damage. Welding helmets prevent burns from spatter and sparks and contain a darkened lens to protect the eyes from the welding arc.

work clamp

The component that connects the work cable to the workpiece. The work clamp and the electrode are typically the only components that come in direct contact with the workpiece during welding.

zinc

A bluish white metal that is corrosive resistant and has a relatively low melting point.

lead

A soft, heavy metallic element. Lead produces fumes that can cause health problems after prolonged exposure.

lead

Secondary circuit insulated cables inside the welder. The electrode cable connects the power source output to the electrode, and the work lead connects the workpiece to the welding machine work connection.