4.2.1 Visual signal devices should be located
to provide complete coverage of the protected space.
4.2.1.1 The area of coverage of a bulkhead-mounted
visual signal device is a rectangle with the device mounted halfway
along one edge of the rectangle as shown in Figure 1. The maximum
horizontal dimension (X) of the area of coverage for varying effective
intensities is found in Table 2.
4.2.1.2 The area of coverage of a ceiling-mounted
visual signal device is a square with the device located in the centre
of the square as shown in Figure 1. The maximum horizontal dimension
(X) of the area of coverage for varying effective intensities and
lens heights is found in Table 3.
4.2.1.3 When the visual signal device is not mounted
per 4.2.1.1 or 4.2.1.2, the maximum horizontal dimension (X) should
be determined by doubling the distance from the device to the farthest
edge of the area of coverage. The pertinent edge for a bulkhead-mounted
device is the side edge, not the edge opposite the device.
Figure 1 Area of Coverage
Table 2 Maximum dimension versus
effective intensity
| Maximum horizontal
dimension (m)
|
Minimum effective
intensity (cd)
|
| 6
|
15
|
| 8.5
|
30
|
| 9
|
33
|
| 10
|
41
|
| 11
|
50
|
| 12
|
59
|
| 13
|
69
|
| 14
|
80
|
| 15
|
92
|
| 16
|
104
|
| 17
|
118
|
| 18
|
132
|
| 19
|
147
|
| 20
|
162
|
| 21
|
179
|
| 22
|
197
|
Table 3 Effective intensity of ceiling-mounted devices by maximum dimension and
height of lens
footnote
4.2.2 Bulkhead-mounted visual signal devices should
be mounted on the bulkhead such that the entire lens is not less than
2,030 mm and not greater than 2,440 mm above the deck surface. For
spaces with multiple levels, the mounting height should be determined
above the nearest deck surface.
4.2.2.1 If the bulkhead-mounted visual signal
devices cannot be mounted at least 2,030 mm above the deck due to
low ceiling height, the devices should be mounted within 150 mm of
the ceiling. The maximum horizontal dimension (X) should be reduced
by twice the difference between the actual mounting height and 2,030
mm.
4.2.3 Ceiling-mounted visual signal devices may
be mounted on or suspended from the ceiling. If ceiling heights exceed
10 m, ceiling-mounted visual signal devices should be suspended at
or below 10 m.
4.2.4 For corridors less than 6 m in width, the
following specification may be used instead of 4.2.1.
4.2.4.1 The minimum effective intensity of the
visual signal device should be 15 cd.
4.2.4.2 Visual signal devices should be located
not more than 4 m from the end of the corridor with a separation not
greater than 30.5 m between devices.
4.2.4.3 If there is an interruption of the concentrated
viewing path, such as a fire door, an elevation change, or any other
obstruction, the area should be treated as a separate corridor.