Hazard symbol

File:Skull and crossbones.svg

The skull and crossbones, a or poison, and other sources of lethal danger.

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Types of hazard symbols

Name	Symbol	Unicode	Image
Toxic sign	☠	U+2620	Skull and crossbones
Caution sign	☡	U+2621	80px
Radiation sign	☢	U+2622	Radioactivity
Ionizing radiation sign	?	?	Radioactivity
Non-ionizing radiation sign	?	?	radiowave
Food irradiation symbol	?	?	Radura
Biohazard sign	☣	U+2623	Biohazard
Warning sign	⚠	U+26A0	Warning
High voltage sign	⚡	U+26A1	High voltage
Magnetic field symbol	?	?	80px
Chemical weapon symbol	?	?	Chemical warfare
Laser hazard sign	?	?	A typical laser warning symbol
Optical radiation	?	?	Warning for optical radiation, symbol D-W009 according to German standard DIN 4844-2

More hazard signs can be found on the list of DIN 4844-2 warning signs

Radioactive sign

Radioactivity

The early Radioactive trefoil. (1946)

The international radiation symbol (also known as trefoil) first appeared in 1946, at the University of California, Berkeley Radiation Laboratory. At the time, it was rendered as magenta, and was set on a blue background. (See right.) The modern version is black 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°.

Radioactivity

On February 15, 2007, the IAEA and the ISO announced this new ionizing radiation symbol to supplement the traditional trefoil symbol. The new symbol is aimed at alerting anyone, anywhere to the potential dangers of being close to a large source of ionizing radiation. Experts have felt that the trefoil symbol had little intuitive value and was less likely to be recognized by those not educated in its significance. According to the IAEA, in a survey conducted at an international school, many children mistook the trefoil for a non-threatening propeller. Hence, the Agency, along with the International Organization for Standardization has devised this symbol for sealed radiation sources. It depicts, on a red background, a black colored trefoil radiating waves, a skull and crossbones, and a person running away from the scene. The radiating trefoil suggests the presence of radiation and the red background and skull and crossbones warn of the danger. More important, the person running away from the scene suggests the action of avoiding the labeled material. The symbol had been tested in countries with different population of varying groups, ages, and educational backgrounds to ensure that it clearly conveys the message “Danger - Stay away”. The new symbol is to be displayed prominently on the device that actually houses the radiation sources so that if, even by mistake, someone attempts to disassemble the device it provides an explicit warning not to proceed any further.

Biohazard sign

Biohazard

Developed by the Dow Chemical company in 1966 for their containment products.

According to Charles Baldwin, 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.

It is used in the labeling of biological materials that carry a significant health risk, including viral samples and used hypodermic needles.

Drawing

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 circle, and arcs are erased at 90°, 210°, 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.

Toxic sign

Main article: Skull and crossbones

Skull and crossbones

The skull-and-crossbones symbol, consisting of a human skull and two bones crossed together under the skull, is today generally used as a warning of danger, 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 pirates. It is also used by Skull and Bones, a secret society at Yale University, as well as the international male collegiate fraternity Phi Kappa Sigma. It is also part of the WHMIS home symbols placed on containers to confirm that the substance inside is dangerous in a way.

In the United States, due to concerns that the skull and bones symbol's association with pirates encourages children to play with toxic materials, the Mr. Yuk symbol is also used to denote poison.

Warning sign

Main article: Exclamation mark

Warning

On warning signs, an exclamation mark is often used to draw attention to a warning of danger, hazards and the unexpected. It is normally supplied with a note, as it is a generic term.

Chemical hazard

File:NFPA 704 example.svg

NFPA 704 standard hazard sticker or placard. See NFPA 704 for details.

File:Tablica ADR.svg

European hazard sign, saying highly inflammable (33) - gasoline (1203)

A chemical hazard label is a pictogram applied to containers of dangerous chemical compounds to indicate the specific risk, and thus the required precautions. There are several systems of labels.

The U.S.-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. This label is used primarily in the USA.

In Europe, another standard is used, as fixed in the European Agreement concerning the International Carriage of Dangerous Goods by Road. Vehicles carrying dangerous goods have to be fitted with orange signs, where the lower number identifies the substance, while the upper number is a key for the threat it may pose.

European hazard symbols

→ Main Article: European hazard symbols

Non-standard warning signs

File:High voltage warning sign Beromuenster.JPG

High voltage sign on fence around Beromünster Reserve Broadcasting Tower

Sometimes warning signs of non-standard designs are in use.

See also

• Chemical safety signs
• International Standard ISO 3864: Graphical symbols — Safety colours and safety signs.
• NFPA 704 Fire Diamond
• Pictogram
• British Standard BS 5499: Graphical symbols and signs
• Canada's Workplace Hazardous Materials Information System
• Safety sign
• Warning sign

External links

• Hazchem Guide from The National Chemical Emergency Centre
• Safety symbols collection for hazard alerts A symbol library which offers various signs in the GIF and EPS formats. Licensed for free use only for writing technical documents.
• European Chemicals Bureau
• Directive 2001/59/EC
• Hazchem information
• free signage Library of signs in PDF format. Licensed to print and use in domestic and commercial premises.

ar:رمز الخطر