olemus
IEC 80000:
tase, millest alates muutub ohutu stiimul ohtlikuks:
paljudel juhtudel taseme ületamisel, aga
näiteks külma puhul vastupidi
=
level at which a stimulus changes from being safe to not being safe
Note. In many cases a stimulus is safe below a safety threshold (a maximum safe level) and unsafe above (for example a hot object), but there are cases where the stimulus is safe above a safety threshold (a minimum safe level) and unsafe below (for example a cold object).