NOTE 1 Alternatively, it could be necessary to inform people about the meaning of the graphical symbol by including its meaning in manuals, instructions, or training.
NOTE 2 ISO 9186-2 specifies a method for testing the perceptual quality of graphical symbols by measuring the extent to which the elements of the graphical symbol can be correctly identified. ISO 9186-3 is under development; it is intended to specify a method of testing the association of graphical symbols with their referents and be applicable to those situations where the viewer tested might initially be unfamiliar with the referents.
BSI recommends this version of standard for organisations operating in or with the UK. The ISO edition is available here if required.