Way guidance systems for smoky conditions
a:† Conventional code complying system:† Spaced point sources of light
b:† Continuous low location system at skirting board:† Photoluminescent shown: location apply for electric back-lit systems also
c:† Continuous low location photoluminescent system at floor center line
d:† Continuous tactile system:† Safety rail with directional notches - may include photoluminescent or powered marking
Visibility in heavy smoke
Region marked with the asterisk apply to guidance systems designed for light to heavy smoke.† Note the convergence of both curves (incandescent white† -† photoluminescent black) towards zero visibility at 100% obscuration, indicating the insignific≠an≠ce of luminance† -† especially for class I smoke conditions (OD > 1.5) where visibility is less than 2 m.
Smoke density and visibility in the tests
Figures of smoke obscuration in %/m represent the smoke conditions at which the visual element of the guidance systems just about become invisible at max viewing distance.
Implications of High,† Middle or Low Location Marking
In Smoky Conditions