2 - Definitions
2.1Effective 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).
2.2Field of view is the line of sight over any 135° sector from any location.
2.3Flash rate is the number of flashes per unit of time reported in Hertz (Hz).
2.4Illumination is the amount of light incident on a surface measured in lumens per square metre.
2.5Photosensitive 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.
2.6Polar diagram is a graph employing polar coordinates to show the variation in effective intensity as a function of direction from the visual signal device.
2.7Public 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.
2.8Pulse duration is the time interval between initial and final points of 10 per cent of maximum intensity of the flash.
2.9Synchronized is appearing to occur at the same time as seen by a human observer.
2.10Visual signal is the element of the general emergency alarm conveyed by regular repeated flashes of light.