Hazard symbols or warning symbols are recognisable symbols designed to warn about hazardous or dangerous materials, locations, or objects, including electromagnetic fields, electric currents; harsh, toxic or unstable chemicals (acids, poisons, explosives); and radioactivity. The use of hazard symbols is often regulated by law and directed by standards organizations. Hazard symbols may appear with different colors, backgrounds, borders, and supplemental information in order to specify the type of hazard and the level of threat (for example, toxicity classes). Warning symbols are used in many places in place of or in addition to written warnings as they are quickly recognized (faster than reading a written warning) and more universally understood, as the same symbol can be recognized as having the same meaning to speakers of different languages.[ citation needed ]
Navigational hazards are generally marked on nautical charts, and are also often marked by moored buoys, and changes are published in notices to mariners.
Type of hazard | Unicode glyph | Unicode | Image |
---|---|---|---|
Generic caution | ⚠ | U+26A0 | |
Poison | ☠ | U+2620 | |
Ionizing radiation | ☢ | U+2622 | |
Ionizing radiation – high-level source | |||
Non-ionizing radiation | |||
Biological hazard | ☣ | U+2623 | |
Carcinogen | |||
High voltage | ⚡︎ | U+26A1 | |
Laser hazard | |||
Accident | ⛌ | U+26CC | |
Disabled car | ⛍ | U+26CD | |
Icy road | ⛐ | U+26D0 | |
More hazard symbols can be found on the list of GHS hazard pictograms and the list of ISO 7010 warning pictograms |
Tape with yellow and black diagonal stripes is commonly used as a generic hazard warning. This can be in the form of barricade tape, or as a self-adhesive tape for marking floor areas and the like. In some regions (for instance the UK) [1] yellow tape is buried a certain distance above buried electrical cables to warn future groundworkers of the hazard.
On roadside warning signs, an exclamation mark is often used to draw attention to a generic warning of danger, hazards, and the unexpected. In Europe and elsewhere in the world (except North America and Australia), this type of sign is used if there are no more-specific signs to denote a particular hazard. [2] [3] When used for traffic signs, it is accompanied by a supplementary sign describing the hazard, usually mounted under the exclamation mark.
This symbol has also been more widely adopted for generic use in many other contexts not associated with road traffic. It often appears on hazardous equipment, in instruction manuals to draw attention to a precaution, on tram and train blind spot warning stickers and on natural disaster (earthquake, tsunami, hurricane, volcanic eruption) preparedness posters and brochures, as an alternative when a more-specific warning symbol is not available.
☠ | |
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Hazard symbol | |
In Unicode | U+2620☠SKULL AND CROSSBONES |
The skull-and-crossbones symbol, consisting of a human skull and two bones crossed together behind the skull, is today generally used as a warning of danger of death, particularly in regard to poisonous substances.
The symbol, or some variation thereof, specifically with the bones (or swords) below the skull, was also featured on the Jolly Roger, the traditional flag of European and American seagoing pirates. It is also part of the Canadian WHMIS home symbols placed on containers to warn that the contents are poisonous.
In the United States, due to concerns that the skull-and-crossbones symbol's association with pirates might encourage children to play with toxic materials, the Mr. Yuk symbol is also used to denote poison.
This symbol has also been more widely adopted for generic use in many other contexts not associated with poisonous materials. It used for denoting number of dead victims caused by natural disasters (e.g. earthquakes and tsunamis) or armed conflicts on event infographics.
☢ | |
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Radioactive sign | |
In Unicode | U+2622☢RADIOACTIVE SIGN |
The international radiation symbol is a trefoil around a small central circle representing radiation from an atom. It first appeared in 1946 at the University of California, Berkeley Radiation Laboratory. [4] At the time, it was rendered as magenta, and was set on a blue background. The shade of magenta used (Martin Senour Roman Violet No. 2225) was chosen because it was expensive and less likely to be used on other signs. [5] However, a blue background for other signs started to be used extensively. Blue was typically used on information signs and the color tended to fade with weathering. This resulted in the background being changed on the radiation hazard sign. [6] The original version used in the United States is magenta against a yellow background, and it is drawn with a central circle of radius R, an internal radius of 1.5R and an external radius of 5R for the blades, which are separated from each other by 60°. The trefoil is black in the international version, which is also used in the United States. [7]
The symbol was adopted as a standard in the US by ANSI in 1969. [6] [8] It was first documented as an international symbol in 1963 in International Organization for Standardization (ISO) recommendation R.361. [9] In 1974, after approval by national standards bodies, the symbol became an international standard as ISO 361Basic ionizing radiation symbol. [10] The standard specifies the shape, proportions, application and restrictions on the use of the symbol. It may be used to signify the actual or potential presence of ionizing radiation. It is not used for non-ionizing electromagnetic waves or sound waves. The standard does not specify the radiation levels at which it is to be used. [10]
The sign is commonly referred to as a radioactivity warning sign, but it is actually a warning sign of ionizing radiation. Ionizing radiation is a much broader category than radioactivity alone, as many non-radioactive sources also emit potentially dangerous levels of ionizing radiation. This includes x-ray apparatus, radiotherapy linear accelerators, and particle accelerators. Non-ionizing radiation can also reach potentially dangerous levels, but this warning sign is different from the trefoil ionizing radiation warning symbol. [11] The sign is not to be confused with the fallout shelter identification sign introduced by the Office of Civil Defense in 1961. This was originally intended to be the same of the radiation hazard symbol but was changed to a slightly different symbol because shelters are a place of safety, not of hazard. [6] [12]
On February 15, 2007, two groups—the International Atomic Energy Agency (IAEA) and the International Organization for Standardization (ISO)—jointly announced the adoption of a new ionizing radiation warning symbol to supplement the traditional trefoil symbol. The new symbol, to be used on sealed radiation sources, is aimed at alerting anyone, anywhere to the danger of being close to a strong source of ionizing radiation. [13] It depicts, on a red background, a black trefoil with waves of radiation streaming from it, along with a black skull and crossbones, and a running figure with an arrow pointing away from the scene. The radiating trefoil suggests the presence of radiation, while the red background and the skull and crossbones warn of danger. The figure running away from the scene is meant to suggest taking action to avoid the labeled material. The new symbol is not intended to be generally visible, but rather to appear on internal components of devices that house radiation sources so that if anybody attempts to disassemble such devices they will see an explicit warning not to proceed any further. [14] [15]
☣ | |
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Hazard symbol | |
In Unicode | U+2623☣ BIOHAZARD SIGN |
The biohazard symbol is used in the labeling of biological materials that carry a significant health risk, including viral and bacteriological samples, including infected dressings and used hypodermic needles (see sharps waste). [16]
The biohazard symbol was developed by the Dow Chemical Company in 1966 for their containment products. [17]
According to Charles Baldwin, [17] an environmental-health engineer who contributed to its development: "We wanted something that was memorable but meaningless, so we could educate people as to what it means." In an article in Science in 1967, the symbol was presented as the new standard for all biological hazards ("biohazards"). The article explained that over 40 symbols were drawn up by Dow artists, and all of the symbols investigated had to meet a number of criteria: "(i) striking in form in order to draw immediate attention; (ii) unique and unambiguous, in order not to be confused with symbols used for other purposes; (iii) quickly recognizable and easily recalled; (iv) easily stenciled; (v) symmetrical, in order to appear identical from all angles of approach; and (vi) acceptable to groups of varying ethnic backgrounds." The chosen scored the best on nationwide testing for memorability. [16]
All parts of the biohazard sign can be drawn with a compass and straightedge. The basic outline of the symbol is a plain trefoil, which is three circles overlapping each other equally like in a triple Venn diagram with the overlapping parts erased. The diameter of the overlapping part is equal to half the radius of the three circles. Then three inner circles are drawn in with 2⁄3 radius of the original circles so that it is tangent to the outside three overlapping circles. A tiny circle in center has a diameter 1⁄2 of the radius of the three inner circles, and arcs are erased at 90°, 210°, and 330°. The arcs of the inner circles and the tiny circle are connected by a line. Finally, the ring under is drawn from the distance to the perimeter of the equilateral triangle that forms between the centers of the three intersecting circles. An outer circle of the ring under is drawn and finally enclosed with the arcs from the center of the inner circles with a shorter radius from the inner circles. [7]
A chemical hazard symbol is a pictogram applied to containers of dangerous chemical compounds to indicate the specific hazard, and thus the required precautions. There are several systems of labels, depending on the purpose, such as on the container for end-use, or on a vehicle during transportation.
The United Nations has designed GHS hazard pictograms and GHS hazard statements to internationally harmonize chemical hazard warnings. Several European countries have started to implement these new global standards, but older warning symbols are still used in many parts of the world.
European standards are set by:
The Workplace Hazardous Materials Information System, or WHMIS, is Canada's national workplace hazard communication standard.
The US-based National Fire Protection Association (NFPA) has a standard NFPA 704 using a diamond with four colored sections each with a number indicating severity 0–4 (0 for no hazard, 4 indicates a severe hazard). The red section denotes flammability. The blue section denotes health risks. Yellow represents reactivity (tendency to explode). The white section denotes special hazard information. One example of a special hazard would be the capital letter W crossed out (pictured left), indicating it is water reactant.
A large number of warning symbols with non-standard designs are in use around the world.
Some warning symbols have been redesigned to be more comprehensible to children, such as the Mr. Ouch (depicting an electricity danger as a snarling, spiky creature) and Mr. Yuk (a green frowny face sticking its tongue out, to represent poison) designs in the United States.
A biological hazard, or biohazard, is a biological substance that poses a threat to the health of living organisms, primarily humans. This could include a sample of a microorganism, virus or toxin that can adversely affect human health. A biohazard could also be a substance harmful to other living beings.
A pictogram is a graphical symbol that conveys meaning through its visual resemblance to a physical object. Pictograms are used in systems of writing and visual communication. A pictography is a writing system which uses pictograms. Some pictograms, such as hazard pictograms, may be elements of formal languages.
Ionizing radiation (US) (or ionising radiation [UK]), including nuclear radiation, consists of subatomic particles or electromagnetic waves that have sufficient energy to ionize atoms or molecules by detaching electrons from them. Some particles can travel up to 99% of the speed of light, and the electromagnetic waves are on the high-energy portion of the electromagnetic spectrum.
A skull and crossbones is a symbol consisting of a human skull and two long bones crossed together under or behind the skull. The design originated in the Late Middle Ages as a symbol of death and especially as a memento mori on tombstones.
Radioactive contamination, also called radiological pollution, is the deposition of, or presence of radioactive substances on surfaces or within solids, liquids, or gases, where their presence is unintended or undesirable.
"NFPA 704: Standard System for the Identification of the Hazards of Materials for Emergency Response" is a standard maintained by the U.S.-based National Fire Protection Association. First "tentatively adopted as a guide" in 1960, and revised several times since then, it defines the "Safety Square" or "Fire Diamond" which is used to quickly and easily identify the risks posed by hazardous materials. This helps determine what, if any, special equipment should be used, procedures followed, or precautions taken during the initial stages of an emergency response. It is an internationally accepted safety standard, and is crucial while transporting chemicals.
Chemical hazards are typical of hazardous chemicals and hazardous materials in general. Exposure to certain chemicals can cause acute or long-term adverse health effects. Chemical hazards are usually classified separately from biological hazards (biohazards). Main classifications of chemical hazards include asphyxiants, corrosives, irritants, sensitizers, carcinogens, mutagens, teratogens, reactants, and flammables. In the workplace, exposure to chemical hazards is a type of occupational hazard. The use of protective personal equipment (PPE) may substantially reduce the risk of damage from contact with hazardous materials.
ADR, formally the Agreement of 30 September 1957 concerning the International Carriage of Dangerous Goods by Road is a 1957 United Nations treaty that governs transnational transport of hazardous materials. "ADR" is derived from the French name for the treaty: Accord relatif au transport international des marchandises Dangereuses par Route). Until 31 December 2020, the treaty was fully named European Agreement concerning the International Carriage of Dangerous Goods by Road. However, as the word "European" might have given the impression that the treaty was only open for accession to European states, an amendment was decided in the end of 2019.
The Globally Harmonized System of Classification and Labelling of Chemicals (GHS) is an internationally agreed-upon standard managed by the United Nations that was set up to replace the assortment of hazardous material classification and labelling schemes previously used around the world. Core elements of the GHS include standardized hazard testing criteria, universal warning pictograms, and safety data sheets which provide users of dangerous goods relevant information with consistent organization. The system acts as a complement to the UN numbered system of regulated hazardous material transport. Implementation is managed through the UN Secretariat. Although adoption has taken time, as of 2017, the system has been enacted to significant extents in most major countries of the world. This includes the European Union, which has implemented the United Nations' GHS into EU law as the CLP Regulation, and United States Occupational Safety and Health Administration standards.
Hazard statements form part of the Globally Harmonized System of Classification and Labelling of Chemicals (GHS). They are intended to form a set of standardized phrases about the hazards of chemical substances and mixtures that can be translated into different languages. As such, they serve the same purpose as the well-known R-phrases, which they are intended to replace.
Hazard pictograms form part of the international Globally Harmonized System of Classification and Labelling of Chemicals (GHS). Two sets of pictograms are included within the GHS: one for the labelling of containers and for workplace hazard warnings, and a second for use during the transport of dangerous goods. Either one or the other is chosen, depending on the target audience, but the two are not used together for the same hazard. The two sets of pictograms use the same symbols for the same hazards, although certain symbols are not required for transport pictograms. Transport pictograms come in wider variety of colors and may contain additional information such as a subcategory number.
European hazard symbols for chemicals are pictograms defined by the European Union for labelling chemical packaging and containers. They are standardised currently by the CLP/GHS classification.
ISO 21482 is a technical standard that specifies the design and usage of a "supplemental radiation warning symbol", a warning symbol intended to warn of the dangers of radiation hazards posed by sealed sources and encourage the viewer to get away from the source. The symbol's design was the result of a joint project between the International Atomic Energy Agency (IAEA) and International Organization for Standardization (ISO) in the early 2000s.
Barricade tape is brightly colored tape that is used to warn or catch the attention of passersby of an area or situation containing a possible hazard. It acts as a minor impediment to prevent accidental entrance to that area or situation and as a result enhances general safety. Barricade tape is also known as construction tape or barrier tape, or in reference to the safety hazard involved as caution tape, warning tape, danger tape or hazard tape. When used by police, the tape is named police tape.
In the process industry, chemical industry, manufacturing industry, and other commercial and industrial contexts, pipe marking is used to identify the contents, properties and flow direction of fluids in piping. It is typically carried out by marking piping through labels and color codes. Pipe marking helps personnel and fire response teams identify the correct pipes for operational, maintenance or emergency response purposes.
ISO 7010 is an International Organization for Standardization technical standard for graphical hazard symbols on hazard and safety signs, including those indicating emergency exits. It uses colours and principles set out in ISO 3864 for these symbols, and is intended to provide "safety information that relies as little as possible on the use of words to achieve understanding."
Safety signs are a type of sign designed to warn of hazards, indicate mandatory actions or required use of Personal protective equipment, prohibit actions or objects, identify the location of firefighting or safety equipment, or marking of exit routes.
Workplace safety standards are sets of standards developed with the goal of reducing risk from occupational hazards.
ANSI Z35.1 the Specifications for Accident Prevention Signs, was an American standard that dictated the layout, colors and wording of safety signs in the United States. The standard is the first American standard that made specific demands for the design, construction, and placement of safety signage in industrial environments. The first edition was published in January 1941, and the fourth and final edition in November 1972. Changes in societal needs of signage, and further research into signage would result in the establishment of a new committee, the ANSI Z535 Committee on Safety Signs and Colors, combining the separate committees of Z35.1 - Specifications for Accident Prevention Signs, Z35.2 - Specifications for Accident Prevention Tags, and Z53 - Marking Physical Hazards Safety Color Code, resulting in a new combined standard, ANSI Z535.
The three-bladed radiation warning symbol, as we currently know it, was "doodled" out at the University of California Radiation Laboratory in Berkeley sometime in 1946 by a small group of people.