1. Inert Gas Fire Extinguishants
CXS490 New Technology
Inert Gas Fire Extinguishants

2. Introduction relevant standard is NFP-A2001
At least four inert gases or gas mixtures commercialized
clean total flooding fire suppression agents
design concentrations of 35-50% by volume
reduces ambient oxygen concentration
14% to 10% by volume
agents mixed with air - extinguish by physical mechanisms
agents consist of nitrogen, argon & blends of these
One blend contains 8% carbon dioxide.

3. Inert Gases Not liquefied gases like Halocarbons
stored as high pressure gases
require high pressure storage cylinders
may have storage volume and weight impact.
use pressure reducing devices
at or near the discharge manifold
reduces the pipe thickness requirements
alleviates concerns regarding high pressure discharges.

4. Inert Gases Discharge times - one (typical) to two minutes
limit some applications - rapidly developing fires
(explosions)
Not subject to thermal decomposition
form no byproducts.
electrically non-conductive

5. Physiological Effects
Primary health concern
effect of reduced oxygen concentration on occupants
reduced oxygen extensively researched & studied
Many countries granted health & safety approval for
use of inert gases in occupied areas in the workplace
One product contains 8% carbon dioxide
intended to increase blood oxygenation &
cerebral blood flow in low oxygen atmospheres

6. Physiological Effects
Inert gas agent IG-541 (Inergen)
contains 8% carbon dioxide &
approved by the U.S. EPA SNAP rules
safe alternative to halon total flooding systems
At elevated concentrations
carbon dioxide not safe for human exposure &
lethal at fire extinguishing concentrations

7. Physiological Effects
Generic Name
Trade Name
Maximum Exposure Concentration 5 minutes
Maximum Exposure Concentration 3 minutes
Maximum Exposure Concentration Above 53% (Volume %)
IG-01
Argotec 43 52
(*4)
IG-55
Argonite
IG-100
NN-100
IG-541
Inergen

8. Notes 1: Nominal maximum discharge time is 60 seconds in all cases
2: Inert gas systems designed to concentrations below 43 percent (corresponding to an
oxygen concentration of 12 percent, sea level equivalent of oxygen) shall be
permitted, where means are provided to limit exposure to no longer than 5 minutes.
3: Inert gas systems designed to concentrations between 43 and 52 percent
(corresponding to between 12 and 10 percent oxygen, sea level equivalent of oxygen)
shall be permitted, where means are provided to limit exposure to no longer than 3
minutes.
4: Inert gas systems designed to concentrations between 52 and 62 (corresponding to
between 10 and 8 percent oxygen, sea level equivalent of oxygen) shall be permitted
given the following:
(a) The space is normally unoccupied.
(b) Where personnel could possibly be exposed, means are provided to limit the
exposure to less than 30 seconds.
(c) Inert gas systems designed to concentrations above 62 percent (corresponding
to 8 percent oxygen or below, sea level equivalent of oxygen) shall only be
used in unoccupied areas where personnel are not exposed to such oxygen depletion.

9. Environmental Factors
Inert gas agents are neither
ozone depleting substances nor
greenhouse gases
pose no risk to the environment

10. Environmental Factors
Generic
Trade
Ozone
Global
Name
Depletion
Warming
Potential
(100 year)
IG-01
Argotec
IG-55
Argonite
IG-100
NN-100
IG-541
Inergen

11. Specific Volume (m3/kg)
Physical Properties
Generic Name
IG-541
IG-55
IG-01
IG-100
Trade Name
Inergen
Argonite
Argotec
NN100
Agent Composition
Nitrogen
52%
50% -
100%
Argon
40%
Carbon Dioxide 8%
Properties
k1 (m3/kg)
0.6598
0.5612
0.7998
k2 (m3/kg)
Specific Volume (m3/kg)
0.697
0.708
0.602
0.858
Gas Density
20oC, 1 atm kg/m3
1.434
1.412
1.661
1.165

12. Extinguishing Design Concentration
Physical Properties
Generic Name
IG-541
IG-55
IG-01
IG-100
Trade Name
Inergen
Argonite
Argotec
NN100
Extinguishing Design Concentration
(% Vol.)
Minimum Class A fire (% Vol.)
36.7
41.1
39.9
39.0
Oxygen (% Vol.)
13.3
12.3
12.6
12.8
Class B Heptane (% Vol.)
31.7
36.5
39.3
33.6
Minimum Class B fire (% Vol.)
41.2
47.5
51.1
43.7
11.0
10.2
11.8
Inerting - Methane/Air (% Vol.)
47.3 *
61.4
41.7 -
8.1
12.2
* Not Reported

13. Flooding Factor Calculation (X)
X - volume of inert gas ONLY added at 14.7 psia, 70oF
(1.013 bar, 21oC) per volume hazard space (ft3/ft3 or m3/m3)
VS - specific volume at 70oF (21oC) at 14.7 psia (1.013 bar)
(ft3/lb or m3/kg)
sV - specific volume at lowest temperature at 1 atmosphere
t - minimum anticipated temperature (oF or oC)
c - inert gas design concentration (%)

14. Specific Volume Inert gas k1 k2 Unit type SI English IG-01 (Argotec
0.5612
IG-55 (Argonite)
9.8809
IG-100 (Nitrogen)
0.7997
11.973
0.0261
IG-541 (Inergen)
0.659
0.0024
9.858
0.0214

15. Flooding Factors (X)
The calculation result in a series of flooding factors required to achieve various inert gas concentrations.

16. Flooding Factors (X) 36
36.1
36.2
36.3
36.4
36.5
36.6
36.7
36.8
36.9 37
37.1
37.2
37.3
37.4
37.5
37.6
37.7
37.8
37.9 38
38.1
38.2
38.3
38.4
38.5
38.6
38.7
38.8
38.9 39
39.1
39.2
39.3
39.4
39.5
39.6
39.7
39.8
39.9 40
40.1
40.2
40.3
40.4
40.5
40.6
40.7
40.8
40.9 41
41.1
41.2
41.3
41.4
41.5
41.6
41.7
41.8
41.9 42
42.1
42.2
42.3
42.4
42.5
42.6
42.7
42.8
42.9 43
43.1
43.2
43.3
43.4
43.5
43.6
43.7
43.8
43.9 44
44.1
44.2
44.3
44.4
44.5
44.6
44.7
44.8
44.9 45
45.1
45.2
45.3
45.4
45.5
45.6
45.7
45.8
45.9 46
46.1
46.2
46.3
46.4
46.5
46.6
46.7
46.8
46.9 47
47.1
47.2
47.3
47.4
47.5
47.6
47.7
47.8
47.9 48
48.1
48.2
48.3
48.4
48.5
48.6
48.7
48.8
48.9 49
49.1
49.2
49.3
49.4
49.5
49.6
49.7
49.8
49.9 50
50.1
50.2
50.3
50.4
50.5
50.6
50.7
50.8
50.9 51
51.1
51.2
51.3
51.4
51.5
51.6
51.7
51.8
51.9 52
52.1
52.2
52.3
52.4
52.5
52.6
52.7
52.8
52.9

17. Sample Calculation - Inert Gas
Room houses electronic equipment
Ambient temperature is 70° F
Room Dimensions are:
Length: 40 feet
Width: 20 feet
Height: 10 feet
Room Volume = L x W x H
= 40 x 20 x 10
= 8000 cubic feet

18. Amount of Agent A = V x X where A is amount of agent (m3 or ft3)
V is volume of space (m3 or ft3)
X is flooding factor of space from calculation or chart
(m3/m3 or ft3/ft3)

19. Sample Calculation - Inert Gas
Using IG-541 Inergen
Class A design concentration is: 39.9%
Maximum Human Exposure Concentration for 5 minutes is: 42.8%
Maximum Human Exposure Concentration for 3 minutes is: 52.3%
Available cylinder sizes for Inergen are:
205 ft3, 266 ft3, 355 ft3 and 439 ft3
Flooding factor for 39.9% concentration is:
Amount /Volume of Inergen required to create a 39.9%
concentration in an 8000 ft3 enclosure is:
A = V x X = 8000 x = 4074 ft3 of Inergen

20. Sample Calculation - Inert Gas
Cylinder Selection
Round up to ft3 cylinders
AACTUAL = NumberCYLINDERS x CylinderSIZE
= 10 x 439 = 4390 ft3

21. Sample Calculation - Inert Gas
Check to determine the actual concentration that will be achieved, by looking at “Flooding Factors for Inert 70° F for selected concentrations.
relates to a concentration of ≥ 42.2% but ≥ 42.3%.
This is < maximum allowable concentration of 42.8%
for 5 minute human exposure & > Class A design concentration 39.9%
The quantity of Inergen is acceptable.