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Figure 1

. Typical Model DFA-7236 

Detonation Flame Arrestor

Model DFA 7236  

Detonation Flame Arrestor

WARNING

!

Failure to follow these instructions or to 

properly install and maintain this equipment 

could result in an explosion, fire and/or 

chemical contamination causing property 

damage and personal injury or death.
Enardo detonation flame arrestor 

must be installed, operated and 

maintained in accordance with federal, 

state and local codes, rules and 

regulations and Emerson Process 

Management Regulator Technologies Tulsa, 

LLC (Emerson) instructions. 
Failure to correct trouble could result in a 

hazardous condition. Call a qualified service 

person to service the unit. Installation, 

operation and maintenance procedures 

performed by unqualified person may 

result in improper adjustment and unsafe 

operation. Either condition may result in 

equipment damage or personal injury. Only 

a qualified person shall install or service the 

detonation flame arrestor.

Introduction

Scope of the Manual

This Instruction Manual provides instructions for 

installation, startup and maintenance information for the 

Model DFA-7236 detonation flame arrestor.

Product Description

The DFA Series detonation flame arrestor represents the 

best value in flame arrestor protection. The detonation flame 

arrestor provides protection against flame propagation in piping 

systems that are manifolded or have long run-up distances. 

These are typically used for extended pipe length or multiple 

pipe bend configurations to stop high pressures and flame 

velocities with detonations and overdriven detonations. It 

also stops confined and unconfined, low and high-pressure 

deflagration. The design is unique in the ability to provide large 

flame channels which requires less frequent maintenance and 

greater ease in cleaning when service is required, translating 

to less down time. DFA Series detonation flame arrestors are 

bi-directional and proven to stop an ignited flammable vapor 

mixture approaching from either direction that can be travelling 

at subsonic or supersonic velocities. The element assembly 

offers maximum flow to pressure drop characteristics enhancing 

the value of the flame arrestor in any system.
The DFA Series is designed with flanged connections. The 

arrestor provides the option of the removal of the flame cell 

element assembly for cleaning and replacement with the 

arrestor removed from the ping.

Table of Contents

Introduction ............................................................................1
Principle of Operation ............................................................2
Specifications ........................................................................2
Factors Affecting Flame Arrestor Performance ......................2
Installation .............................................................................4
Piping Expansions and Reductions Adjacent to 

Detonation Flame Arrestor.....................................................4
Maintenance ..........................................................................6
Element Assembly, Disassembly and 

Reassembly Instructions .......................................................6

Instruction Manual

D104263X012
March 2018

Model DFA 7236

North America 

Only

Summary of Contents for Enardo DFA 7236

Page 1: ... arrestor provides protection against flame propagation in piping systems that are manifolded or have long run up distances These are typically used for extended pipe length or multiple pipe bend configurations to stop high pressures and flame velocities with detonations and overdriven detonations It also stops confined and unconfined low and high pressure deflagration The design is unique in the ...

Page 2: ...e Arrestor Performance Gas Group WARNING Methanol is classified as a Group D IIA vapor However our lab tests indicate that methanol exhibits characteristics unlike other Group D IIA vapors under certain conditions We therefore recommend that an arrestor rated for Group C IIB3 vapors be specified for methanol service The type of gas in the system determines its gas grouping and therefore predetermi...

Page 3: ...ssure is the pressure of the system at or near static flow conditions High pressure deflagration and detonations can occur more easily at higher system operating pressures than at pressures near atmospheric Elevated pressures condense the ignitable gas giving the flame more matter and energy to release thereby boosting the flame heat intensity Unstable over driven detonations exist during a deflag...

Page 4: ...w located on the unit points in the direction travelling with the vapor flow Models that have drain plugs are designed for horizontal installation and should be installed with the drain ports aligned at the bottom of the unit Models that have pressure taps are designed to allow pressure gauges to be installed on both sides of the flame cell assembly to determine blockage The pressure taps should b...

Page 5: ...Figure 4 Lifting Diagram CENTER OF GRAVITY CENTER OF GRAVITY 5 Model DFA 7236 North America Only ...

Page 6: ...ssembly Following Flame Propagation Event 1 Inspect the outboard flame cells for damage immediately following a deflagration detonation and or stabilized burn 2 Carefully remove the element assembly from the arrestor with the entire flame arrestor out of the line 3 Inspect the flame cells and the screens visually for any signs of corrosion or other damage and inspect the flame cells with a calibra...

Page 7: ...le the nuts to the studs such that the amount of thread extending outboard beyond the nut is approximately equal on both ends 4 Tighten the nuts to the torque values shown in Table 1 following the designated sequence repeating the sequence as shown Flange pattern tightening sequences are shown in Figure 5 Bolt Lubrication Lubrication affects required torque of clean fasteners in good condition mor...

Page 8: ...sented for informational purposes only and while every effort has been made to ensure their accuracy they are not to be construed as warranties or guarantees express or implied regarding the products or services described herein or their use or applicability We reserve the right to modify or improve the designs or specifications of such products at any time without notice Emerson Process Managemen...

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