Monday, October 9, 2017

5 Myths of Dust Explosion Propagation

Fike explosion testing
Dust explosion propagation testing at Fike labs.
Abstracted from
"Dust Explosion Propagation: Myths and Realities"
by Fike Corporation


The unfortunate propensity of dust explosions to destroy entire facilities and claim lives has been reported in numerous past incidents.

Powder handling processes are often comprised of interconnected enclosures and equipment. Flame and pressure resulting from a dust explosion can therefore propagate through piping, across galleries, and reach other pieces of equipment or enclosures, leading to extensive damage.

While the ability of dust explosions to propagate has been widely recognized, some misconceptions lead to the false sense of security that explosion isolation is not required.

This post will enumerate, illustrate and unravel 5 common myths about explosion propagation. Download the full Fike White Paper here, or read it in full at the bottom of this post.

Myth #1: A large amount of dust is needed for an explosion to propagate.

Dust explosions do not need large amounts of fuel to propagate.

A 1 mm layer can create a dust explosion hazard in a typical room. The explosion only needed a 1/100 inch layer of dust on the ground to fully propagate.

Myth #2: A dust explosion starting in a vented vessel cannot propagate through connected pipes.

It is a common belief that protecting an enclosure, by means of venting or suppression, will affect explosion propagation in such a manner that no explosion isolation is needed at all. 

Although venting protects a vessel from the high pressures generated by an explosion, it does not necessarily prevent the explosion from being propagated through piping into other vessels.

Myth #3: A dust explosion cannot propagate against process flow. 

An argument also often heard is that a dust explosion cannot propagate against pneumatic process flow. 

An explosion is capable of traveling both with and against process flow, even over long distances.

Myth #4: A dust explosion weakens as it propagates.

Literature includes numerous discussions about explosion behavior in interconnected vessels. 

Experimental evidence has shown that explosions not only propagate, but become increasingly more damaging.

Myth #5: Small diameter pipes do not support dust explosion propagation.

Dust explosion propagation in small pipes has always been a controversial topic. The primary argument being that flame propagation is challenged due to heat loss to the pipe walls.

While conditions for dust explosions to propagate in relatively small diameter pipes are not yet fully established, their ability to propagate has been clearly demonstrated by several researchers.

Contact Flow-Tech with any questions regarding explosion protection testing, isolation valves, vents and systems at http://www.flowtechonline.com or call 410-666-3200.