1 CXS490 New Technology Inert Gas Fire Extinguishants.

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CXS490 New TechnologyInert Gas Fire Extinguishants

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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.

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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.

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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

• 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

Physiological Effects

• Inert gas agent IG-541 (Inergen)• contains 8% carbon dioxide &• approved by the U.S. EPA SNAP rules• safe alternative to halon 1301 - total flooding systems• At elevated concentrations• carbon dioxide not safe for human exposure & • lethal at fire extinguishing concentrations

Physiological Effects

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 43 52 (*4)

IG-100 NN-100 43 52 (*4)IG-541 Inergen 43 52 (*4)

Notes1: Nominal maximum discharge time is 60 seconds in all cases2: 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.

• Inert gas agents are neither• ozone depleting substances nor• greenhouse gases• pose no risk to the environment

Environmental Factors

Environmental Factors

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Generic Trade Ozone GlobalName Name Depletion Warming

Potential Potential(100 year)

IG-01 Argotec 0 0IG-55 Argonite 0 0

IG-100 NN-100 0 0IG-541 Inergen 0 0

Physical PropertiesGeneric Name IG-541 IG-55 IG-01 IG-100

Trade Name Inergen Argonite Argotec NN100

Agent Composition

Nitrogen 52% 50% - 100%

Argon 40% 50% 100% -

Carbon Dioxide 8% - - -

Properties

k1 (m3/kg) 0.65799 0.6598 0.5612 0.7998

k2 (m3/kg) 0.00239 0.00242 0.00205 0.00293

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

Physical PropertiesGeneric Name IG-541 IG-55 IG-01 IG-100

Trade Name InergenArgonit

eArgote

cNN100

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

Oxygen (% Vol.) 12.3 11.0 10.2 11.8

Inerting - Methane/Air (% Vol.) 47.3 * 61.4 41.7

Oxygen (% Vol.) 11.0 - 8.1 12.2* Not Reported

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 (ft3/lb or m3/kg)t - minimum anticipated temperature (oF or oC)c - inert gas design concentration (%)

Specific VolumeInert gas k1 k2 k1 k2

Unit type SI SI English English

IG-01 (Argotec 0.5612 0.00205 8.40299 0.018281

IG-55 (Argonite) 0.65979 0.001207 9.8809 0.021496

IG-100 (Nitrogen) 0.7997 0.00293 11.973 0.0261

IG-541 (Inergen) 0.659 0.0024 9.858 0.0214

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The calculation result in a series of flooding factors required to achieve various inert gas concentrations.

Flooding Factors (X)

Flooding Factors (X)36 36.1 36.2 36.3 36.4 36.5 36.6 36.7 36.8 36.9

0.446368 0.447932 0.449498 0.451067 0.452638 0.45421 0.45579 0.457367 0.458949 0.46053237 37.1 37.2 37.3 37.4 37.5 37.6 37.7 37.8 37.9

0.462119 0.463708 0.465299 0.46689 0.46849 0.470088 0.471690 0.473294 0.474901 0.47651038 38.1 38.2 38.3 38.4 38.5 38.6 38.7 38.8 38.9

0.478122 0.479736 0.481354 0.482973 0.484596 0.486221 0.487848 0.48948 0.491111 0.49274739 39.1 39.2 39.3 39.4 39.5 39.6 39.7 39.8 39.9

0.494385 0.496026 0.497670 0.499316 0.500966 0.502617 0.504272 0.505929 0.50759 0.50925240 40.1 40.2 40.3 40.4 40.5 40.6 40.7 40.8 40.9

0.510918 0.512586 0.51426 0.515931 0.517608 0.51929 0.520970 0.522655 0.524343 0.52603441 41.1 41.2 41.3 41.4 41.5 41.6 41.7 41.8 41.9

0.527728 0.529424 0.531124 0.532826 0.534532 0.536240 0.537951 0.539665 0.541382 0.54310242 42.1 42.2 42.3 42.4 42.5 42.6 42.7 42.8 42.9

0.544825 0.546551 0.548280 0.55001 0.551747 0.553485 0.555226 0.556970 0.558717 0.56046743 43.1 43.2 43.3 43.4 43.5 43.6 43.7 43.8 43.9

0.562220 0.563976 0.565736 0.567498 0.569264 0.571032 0.572804 0.57458 0.576357 0.5781444 44.1 44.2 44.3 44.4 44.5 44.6 44.7 44.8 44.9

0.57992 0.581711 0.583501 0.585295 0.587093 0.588893 0.590697 0.59250 0.594314 0.59612845 45.1 45.2 45.3 45.4 45.5 45.6 45.7 45.8 45.9

0.597945 0.599765 0.601588 0.603415 0.60525 0.607079 0.608916 0.610756 0.612600 0.61444746 46.1 46.2 46.3 46.4 46.5 46.6 46.7 46.8 46.9

0.616297 0.618151 0.620008 0.621869 0.623733 0.625601 0.627472 0.629347 0.631226 0.63310747 47.1 47.2 47.3 47.4 47.5 47.6 47.7 47.8 47.9

0.634993 0.636882 0.63877 0.640670 0.642570 0.644473 0.646380 0.648291 0.65020 0.65212348 48.1 48.2 48.3 48.4 48.5 48.6 48.7 48.8 48.9

0.654044 0.655970 0.657899 0.65983 0.661768 0.663708 0.66565 0.667600 0.669551 0.67150749 49.1 49.2 49.3 49.4 49.5 49.6 49.7 49.8 49.9

0.673466 0.675429 0.677396 0.679367 0.681341 0.683320 0.685302 0.687289 0.68928 0.69127450 50.1 50.2 50.3 50.4 50.5 50.6 50.7 50.8 50.9

0.693272 0.695274 0.69728 0.699291 0.701306 0.703324 0.705347 0.707374 0.709404 0.71143951 51.1 51.2 51.3 51.4 51.5 51.6 51.7 51.8 51.9

0.713478 0.715522 0.717569 0.719621 0.721677 0.723737 0.725801 0.727870 0.729943 0.73202052 52.1 52.2 52.3 52.4 52.5 52.6 52.7 52.8 52.9

0.734101 0.736187 0.73828 0.740372 0.742471 0.744575 0.746682 0.74879 0.750912 0.753033

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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

Sample Calculation - Inert Gas

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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)

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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: 0.509252

Amount /Volume of Inergen required to create a 39.9%

concentration in an 8000 ft3 enclosure is:

A = V x X = 8000 x 0.509252 = 4074 ft3 of Inergen

Sample Calculation - Inert Gas

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Cylinder Selection

Sample Calculation - Inert Gas

Round up to 10 439 ft3 cylinders

AACTUAL = NumberCYLINDERS x CylinderSIZE

= 10 x 439 = 4390 ft3

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Check to determine the actual concentration that will be achieved, by looking at “Flooding Factors for Inert Gases @ 70° F for selected concentrations.

0.54875 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.

Sample Calculation - Inert Gas