User's Manual

Design
September 2013 3-4 P/N 81-CO2MAN-001
When the position of an opening is such that a fire in the protected area could spread through
it to adjacent combustibles or work areas, the opening shall be provided with an automatic
closure or local application nozzles. Where such measures are not practical, protection shall be
extended to include the adjacent work area or process.
3-5.1.2 VENTILATION
The total flooding agent quantity calculations are designed for a reasonably tight enclosure
with static conditions prevailing at the time of system discharge. Static conditions prevail when
all forced air ventilating systems servicing the protected area are stopped at the time of agent
discharge. Forced air ventilation systems must be shut down or closed (or both) prior to, or
simultaneously with, the start of the carbon dioxide discharge. Additional carbon dioxide must
be provided if forced ventilation cannot be dampered or shut down.
3-5.1.3 INTERLOCKS
It is essential that all potential re-ignition sources in the protected area be eliminated prior to,
or concurrently with, the start of the carbon dioxide discharge. This requires that a control
system be designed to shut down all processing equipment, to shut off electrical power to all
equipment in the area, and to perform any other interlocks necessary to ensure the
effectiveness of the system.
If interlocks cannot be provided, additional carbon dioxide may be required to compensate for
openings, forced ventilation, or other factors that are detrimental to system performance.
3-5.1.4 INTERCONNECTED VOLUMES
Where two or more interconnected volumes allow "free flow" of carbon dioxide between the
protected spaces, the carbon dioxide quantity for each volume shall be calculated individually.
If one volume requires greater than normal concentration, the higher concentration shall be
used in all interconnected volumes.
3-5.2 Calculations for Surface Fires
Surface fires involve burning of flammable liquids and of ordinary, non-smoldering
combustibles.
3-5.2.1 EXTINGUISHING CONCENTRATIONS
The minimum carbon dioxide design concentration for total flooding systems is 34%. However,
the required concentration may be increased when flammable liquids and gases are involved.
A list of design concentrations for several known fuels can be found in Table 3-1.
Table 3-1. Minimum Carbon Dioxide Concentrations for Extinguishment
Material
Minimum Design
CO
2
Concentration (%)
Acetylene 66
Acetone 34
Aviation Gas Grades 115/145 36
Benzol, Benzene 37
Butadiene 41
Butane 34