Biohazard symbol Hazard symbol

biohazard symbol used since 1966

the biohazard symbol used in labeling of biological materials carry significant health risk (biohazards), including viral samples , used hypodermic needles (see sharps waste).

history

the biohazard symbol developed dow chemical company in 1966 containment products.

according charles baldwin, environmental-health engineer contributed development: wanted memorable meaningless, educate people means. in article in science in 1967, symbol presented new standard biological hazards ( biohazards ). article explained on 40 symbols drawn dow artists, , of symbols investigated had meet number of criteria: (i) striking in form in order draw immediate attention; (ii) unique , unambiguous, in order not confused symbols used other purposes; (iii) recognizable , recalled; (iv) stenciled; (v) symmetrical, in order appear identical angles of approach; , (vi) acceptable groups of varying ethnic backgrounds. chosen scored best on nationwide testing memorability.

geometry

all parts of biohazard sign can drawn compass , straightedge. basic outline of symbol plain trefoil, 3 circles overlapping each other equally in triple venn diagram overlapping parts erased. diameter of overlapping part equal half radius of 3 circles. 3 inner circles drawn in  ⁄3 radius of original circles tangent outside 3 overlapping circles. tiny circle in center has diameter  ⁄2 of radius of 3 inner circles, , arcs erased @ 90°, 210°, , 330°. arcs of inner circles , tiny circle connected line. finally, ring under drawn distance perimeter of equilateral triangle forms between centers of 3 intersecting circles. outer circle of ring under drawn , enclosed arcs center of inner circles shorter radius inner circles.