2.1
Effective intensity is a measure
of the brightness of a flashing light equivalent to the brightness
of a steady-burning light as seen by a human observer. It is determined
using specialized photometric equipment and reported in candela (cd).
2.2
Field of view is the line of
sight over any 135° sector from any location.
2.3
Flash rate is the number of flashes
per unit of time reported in Hertz (Hz).
2.4
Illumination is the amount of
light incident on a surface measured in lumens per square metre.
2.5
Photosensitive epilepsy is a
chronic neurological disorder characterized by recurrent seizures
triggered by visual stimuli that form patterns in time or space, such
as flashing lights, bold, regular patterns, or regular moving patterns.
2.6
Polar diagram is a graph employing
polar coordinates to show the variation in effective intensity as
a function of direction from the visual signal device.
2.7
Public accommodation spaces are
those accommodation spaces for public use by passengers, such as public
spaces, dining rooms, lounges, showrooms, public restrooms, corridors,
lobbies, stairways, cinemas, gymnasiums, atriums, shops, and other
similar spaces. It excludes cabins and associated balconies.
2.8
Pulse duration is the time interval
between initial and final points of 10 per cent of maximum intensity
of the flash.
2.9
Synchronized is appearing to
occur at the same time as seen by a human observer.
2.10
Visual signal is the element
of the general emergency alarm conveyed by regular repeated flashes
of light.