Automist Smartscan Hydra
®
DIOM Manual - version 3.01.0
Plumis Ltd Copyright © 2020. All Rights Reserved.
Page 35 of 116
S MA RT SC AN
®
Hydraulic Calculations
Automist is a pre-engineered system with a maximum total hose length of 60m. All fire tests were
performed with the worst-
case scenario; 60m total hose lengths with 20m of 1⁄4” and 40m of 5/16”. This
causes the longest possible delay and pressure loss for the water output.
Maximum high pressure hose length when:
a)
Both 5/16” and 1/4” hoses are used
Max. 1/4" hose length (m)
Max. 5/16" hose length (m)
Total hose length (m)
20
40
60
b)
Only 5/16” hose is used
Max. 1/4" hose length (m)
Max. 5/16" hose length (m)
Total hose length (m)
0
50
50
Below are the hydraulic calculations for the most unfavourable sprayhead configurations:
1/4" hose
length (m)
5/16" hose
length (m)
Total hose
length (m)
Pressure
loss (bar)
Time
delay (s)
Flow Rate
(l/min)
Pressure
at pump
(bar)
Pressure
at nozzle
(bar)
20
40
60
11.29
21
6.02
105.67
94.38
0
50
50
7.8
20
6.07
103.68
95.85
Discharge performance and duration
Electronic activation ensures only one watermist nozzle activates with not less than the pressure and flow
given by the pass criteria determined by the BS 8458 fire test in Annex C. The system is designed to run at
5.6 lpm, 80-110 bar pressure. The minimum and default runtime is 30 minutes.
IMPORTANT!
30 mins or longer (60 mins for cat 4 sprinkler equivalent) is available on request. An unlimited
runtime is possible when Automist is connected to the main water supply and not limited by a tank.
Increasing the design density
It is always possible to increase the robustness of the sprayhead placement from obstructions by adding
additional heads. In rooms where there is an increased likelihood of obstruction adding additional heads,
over and above the minimum requirement, is an easy way to reduce the risk. A Person-Centred Fire Risk
Assessment (PCFRA) can be used to identify any attributes of individuals with greater propensity to obstruct
the head or tamper with the system.
Installing two Automist systems in parallel
It is possible to increase the resilience of the system and double the watermist output by installing two
systems in parallel. This can be achieved by protecting the same space with two heads from different
pumps. Care must be taken to consider the water supply requirement (see page 36) for this configuration
as both systems may run at the same time depending on the fire (at least 16 lpm required).
