Automist Smartscan
®
Handbook v1.2.3
Plumis Ltd Copyright © 2017. All Rights Reserved.
Page 13 of 64
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®
6.
Mark as “indirect coverage” all shadowed points that are less than 0.3m from a directly covered
point. This rule allows for the way that the spray becomes turbulent around obstructions and for
the fact that activation of a heat detector requires a larger fire.
7.
The Effective Shadow Area is the remaining shadowed zone of the room after “not required for
coverage” and “indirect coverage” areas have been removed.
8.
Adjust until the effective shadow area is below the maximum square metreage for the project type
(see below).
9.
The diagram (later submitted to Plumis) should show the Effective Coverage Area and state its area
in square metres for each compartment to be protected.
Figure 3: 6m radius semi-
circular pattern showing shadow areas (hatched yellow) and openings “not required for
coverage”
(hatched blue). Combined Effective Shadow Area is well below 2m2 which is within specification for a
three storey house with open plan ground floor and fire separation between ground and first floors.
“Preferred Positions” and Avoidance of Potential Obstru
ctions
A Preferred Position is a location for a spray head where it is highly unlikely that a bookcase or other high
furniture item will meaningfully block the spray pattern, because there is no reasonable location that such a
blocking object can be placed. This does not relate to a householder deciding to disable the suppression
system; full obstruction of the spray head or the creation of
de facto
room partitions with bookcases are
akin to wilfully removing fire doors or removing smoke detectors and are beyond the scope of this
recommendation.
Where a spray head can be mounted in one of these Preferred Positions, unobstructed both to its left and
right, its spray pattern can be assumed to be a semicircle of radius 6m as mentioned above (truncated by
any known obstacles, these creating a geometric shadow).
1 documents the Preferred Positions, and
they are further explained on pages 17 to 20.
Shadow area
Indirect Coverage,
0.3m margin beyond
geometric coverage
Not Required
for Coverage
