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Selection Guide | Threaded In-Line Flame Arrestors
Vent Stack Flame Arrestor Series 8800 & 9900 | Free Vent Flame Arrestor
Series 7 In-Line Flame Arrestor | Series 8 High Pressure Deflagration Flame Arrestor
Detonation Flame Arrestors | Pressure Vacuum Relief Valve with Flame Arrestor
Flame Arrestor Certifications | Vapor Flow Equations

Flame Arrestor Selection Guide

Choosing the proper flame arrestor is critical to the safety of equipment and personnel. Consult the table below to select the product which best fits your needs, taking into account vent/piping layout and gas group. For gas group classifications, see the table at the bottom of this page.

 

ENARDO Standard Flame Arrestor Selection Criteria

Including US Coast Guard and ATEX/US Coast Guard certified detonation arrestors

NEC Group "D" or IEC Group IIA Gases

Parameters End-of-Line
FVFA & SVFA
In-Line
(Standard)
S7 HP & IL
In-Line HP
Deflag. S8
Detonation Arrestor DFA
Length of pipe between the arrestor and the ignition source without bends (Mounted on end of pipe) 20 feet
(6 meters)
60 feet
(18 meters)
Unlimited
Length of pipe between the arrestor and the ignition source with one 90° bend (Mounted on end of pipe) 20 feet
(6 meters)
60 feet
(18 meters)
Unlimited
Length of pipe between the arrestor and the ignition source with multiple bends (Mounted on end of pipe) Not recommended with multiple bends Not recommended with multiple bends Unlimited
Flame stabilization at stoichiometric mixture and ambient temperature not to exceed 140°F (60°C) * 5 minutes
(minimum)
5 minutes
(minimum) 30 minutes (Factory Mutual Approved units)
15 minutes
(minimum)
2 hours
(concentric)
Operating Pressure Atmospheric 15.4 psia
(106 kPa)
19.7 psia
(134 kPa)
Conc. 3"-12" (22.7 psia) (75-300mm) 157 kPa
 
Conc. 2", 14"-20" (20.7 psia) (50, 350-500mm) 143 kPa

NEC Group "C" or IEC Group IIB3 Gases

Parameters End-of-Line
FVFA & SVFA
In-Line
(Standard)
S7 HP & IL
In-Line HP
Deflag. S8
Detonation Arrestor DFA
Length of pipe between the arrestor and the ignition source without bends (Mounted on end of pipe) 6 feet
(2 meters)
(open-ended pipe)
35 feet
(10.6 meters)
Unlimited
Length of pipe between the arrestor and the ignition source with one 90° bend (Mounted on end of pipe) 6 feet
(2 meters)
(open-ended pipe)
35 feet
(10.6 meters)
Unlimited
Length of pipe between the arrestor and the ignition source with multiple bends (Mounted on end of pipe) Not recommended with multiple bends Not recommended with multiple bends Unlimited
Flame stabilization at stoichiometric mixture and ambient temperature not to exceed 140°F (60°C) * 5 minutes
(minimum)
5 minutes
(minimum)
15 minutes
(minimum)
15 minutes
(minimum)
Operating Pressure Atmospheric 15.4 psia
(106 kPa)
16.7 psia
(115 kPa)
Conc. (2"-20") 20.7 psia (50-500mm) 143 kPa
 
Ecc. (3"-20") 18.7 psia (75-500mm) 129 kPa

NEC Group "B" or IEC Group IIC Gases (Except Acetylene)

Parameters End-of-Line
FVFA & SVFA
In-Line
(Standard)
S7 HP & IL
In-Line HP
Deflag. S8
Detonation Arrestor DFA
Length of pipe between the arrestor and the ignition source without bends (Mounted on end of pipe) 4 feet
(1.2 meters)
(open-ended pipe)
15 feet
(4.5 meters)
Unlimited
Length of pipe between the arrestor and the ignition source with one 90° bend (Mounted on end of pipe) Not recommended with a bend 15 feet
(4.5 meters)
Unlimited
Length of pipe between the arrestor and the ignition source with multiple bends (Mounted on end of pipe) Not recommended with multiple bends Not recommended with multiple bends Unlimited
Flame stabilization at stoichiometric mixture and ambient temperature not to exceed 140°F (60°C) * 2 minutes
(minimum)
2 minutes
(minimum)
15 minutes
(minimum)
15 minutes
(minimum)
Operating Pressure Atmospheric 15.4 psia
(106 kPa)
16.7 psia
(115 kPa)
Conc. 2"-6" (17.7 psia)
(50mm-150mm) 122 kPa

 

* Unlimited burning should not be allowed in any flame arrestor regardless of its burn time rating. We recommend the use of flame sensors, along with an appropriate means of extinguishing the fire, in any situation where a stabilized burn may occur.

 

ENARDO ATEX Certified Flame Arrestor Selection Criteria

See above for information on ATEX/US Coast Guard detonation arrestor selection criteria.

IEC Group IIA Gases or NEC Group "D"

Parameters End-of-Line
FVFA
In-Line
(Standard)
S7 HP & IL
Detonation Arrestor DFA
Length of pipe between the arrestor and the ignition source. (Mounted on end of pipe) 2" (50 mm) - 6.5 ft (2 m)
3" (75 mm) - 7.5 ft (2.3 m)
4" (100 mm) - 10 ft (3 m)
6" (150 mm) - 13.1 ft (4 m)
8" (200 mm) - 13.3 ft (4 m)
10" (250 mm) - 16.6 ft (5 m)
12" (300 mm) - 19.7 ft (6 m)
2" - 12"
(50mm-300mm)
 
Unrestricted
(Designed for Unstable Detonations)
Flame stabilization at stoichiometric mixture and ambient temperature not to exceed 140°F (60°C) Short Time Burn Rating Short Time Burn Rating Short Time Burn Rating
Operating Pressure Atmospheric 15.95 psia
(110 kPa)
2"-6" 17.7 psia
(50 mm-150 mm 122 kPa)
8 - 12" 16.9 psia
(200 mm - 300 mm 116.5 kPa)

IEC Group IIB3 Gases or NEC Group "C"

Length of pipe between the arrestor and the ignition source. (Mounted on end of pipe) 2" (50 mm) - 8.3 ft (2.5 m)
3" (75 mm) - 12.5 ft (3.8 m)
4" (100 mm) - 16.6 ft (5 m)
6" (150 mm) - 25 ft (7.6 m)
8" (200 mm) - 33.3 ft (10.16 m)
10" (250 mm) - 39.3 ft (12 m)
12" (300 mm) - 39.4 ft (12 m)
2" - 12"
(50mm-300mm)
 
Unrestricted
(Designed for Unstable Detonations)
Flame stabilization at stoichiometric mixture and ambient temperature not to exceed 140°F (60°C) Short Time Burn Rating Short Time Burn Rating Short Time Burn Rating
Operating Pressure Atmospheric 15.95 psia
(110 kPa)
17.2 psia
(118.3 kPa)

 

Gas Group Chart

Group A   Group D (continued)
Acetlyene   Ethanol (ethyl alcohol)
    Ethyl acetate
Group B (IIC)   Ethyl acrylate
Butadiene   Ethylene dichloride
Ethylene oxide   Gasoline
Hydrogen
   Manufactured gases containing more
   than 30% Hydrogen (by volume)
  Heptanes
Propylene oxide   Hexanes
Propyl nitrate   Isoprene
    Methane (natural gas)
Group C (IIB3)   Methyl acrylate
Acetaldhyde   Methylamine
Cyclopropane   Methyl ethyl ketone
Diethyl ether   Methyl mercaptan
Dimethyl hydrazine   3-Methyl-1-butanol (isoamyl alcohhol)
Ethylene   Methyl isobutyl ketone
Hydrogen sulfide   2-Methyl-1-propanol (isobutyl alcohol)
* Methanol (methyl alcohol)   2-Methyl-2-propanol (tertiary butyl alcohol)
Methyl mercaptan   Naphtha (petroleum)
Unisymmetrical dimethyl hydrazine (UDMN)   N-Propyl acetate
    Octanes
Group D (IIA)   Pentanes
Acetone   1-Pentanol (amyl alcohol)
Acrylonitrile   Propane
Ammonia   1-Propanol (propyl alcohol)
Benzene   2-Propanol (isopropyl alcohol)
Butylene   Propylene
1-Butanol (butyl alcohol)   Styrene
2-Butanol (secondary butyl alcohol)   Toluene
Cyclohexane   Turpentine
N-Butyle acetate   Vinyl acetate
Isobutyl acetate   Vinyl chloride
Ethane   Xylenes

 

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