BS ISO 3864-1:2011 pdf download
BS ISO 3864-1:2011 pdf download.Graphical symbols – Safety colours and safety signsPart 1: Design principles for safety signs and safety markings.
This annex relates to the perceptual quality of the graphical symbol elements of safety signs, not the comprehension or meaning of the safety sign. In addition to being comprehensible, a graphical symbol should have sufficient perceptual quality to enable the eventual user population in a practical situation to identify its elements correctly. If the symbol’s ultimate meaning is to be understood, it is essential that its elements be identifiable.
NOTE 1 ISO 9186-2 desaibes the concept of perceptual quality of grhleal symbol elements.
As the distance of observation from a safety sign increases, the subtended visual angles of graphical symbols decrease. The task of identifying the graphical symbol elements is more difficult as the distance of observation increases, which results in smaller percentages of the user population correctly identifying the graphical symbol elements. Hence at some short distance of observation, the design of the graphical symbol elements should be such that a very high percentage of the intended user population is able to oorrectty identify the graphical symbol elements: whereas at some longer distance of observation, a low percentage or none of the intended user population would be able to do so Because the distance for correct identification of the graphical symbol elements varies between individuals, the probability that a certain percentage of the intended user population can make the correct identification is statistical in nature, It is therefore important that a high percentage of the intended user population be able to correctty identity the graphical symbol elements and comprehend the meaning of the safety sign at a distance such that they are able to follow the safety message. A practical criterion is that at least 85 % of the intended user population would correctty identity the graphical symbol elements at the minimum safe observation distance for the safety sign
The evaluation of identifiability of graphical symbol elements is a complex task. Various factors and conditions influence the identifiability:
size of the graphical symbol elements and parts thereof within the safety sign geometrical shape:
whether the safety sign is an externally illuminated or internally illuminated safety sign and the materials used:
— luminance, luminance contrast or contrast between the graphical symbols and background of the safety sign geometrical shape;
illumination conditions:
observation angle.
— vsual acuity of the Intended user population — whether normal sighted (normal visual acuity), weanng correction lenses or having vision impairments:
— familiarity with the depicted object or shape.
NOTE 2 ISO 3864-4:2011, Annex D pruvIde5 guidance on contrast for extemaliy illuminated safety signs and luminance contrast for internally ibiminated safety signs.
For the height k of the sign take
— S for prohibition and mandatory action signs (see 6.2 and 6.3);
— I. for warning signs (see 6.4);
a for safe condition signs, fire equipment signs and supplementary signs (see 6 5, 6.6 and Clause 7).
The distance factor depends upon the perceptual characteristics of the graphical symbol elements and their size within the basic geometric shape of the safety sbgn. The relative size of the graphical symbol elements and the basic geometric shape of the safety sign are fixed in the safety signs registered in Iso 7010.
For a given intended user population and illumination condition, the value of ; can vary between safety signs For externally illuminated safety signs with about 100 lx measured on the surface of the safety sign and a user population with normal sight or corrected sight, use the test method specified in ISO 9166-2 to determine a value & associated with a cnterion percentage of at least 85 % correct identification of the graphical symbol elements. However. wtiere the percentage of a normal sighted population correctly identifying the graphical symbol elements is not known for the specific safety sign, use a general value of : of 60.
A.2.2 For externally illuminated safety signs. the distance factor is affected by the level of illumination at the sign. In general, for externally illuminated safety signs in a low illumination environment, such as illumination by emergency lighting. : should be multiplied by a factor of 0,5.
For externally illuminated ISO 7010-COOl and -E002 emergency exit signs, the recommended values of at different illumination levels are given in Table A. 1, The same values of z< can be applied to externally illuminated supplementary direction arrows.
