Showing posts with label explosion protection system. Show all posts
Showing posts with label explosion protection system. Show all posts

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.

Friday, August 18, 2017

Explosion and Fire at Chemical Plant Case Study

Fire and explosion testing to mitigate risk.
Fire and explosion testing to mitigate risk. (Fike)
Industrial accidents, whether minor or catastrophic, can serve as sources of learning when analyzed and studied. Operators, owners, and technicians involved with industrial chemical operations have a degree of moral, ethical, and legal responsibility to conduct work in a reasonably and predictably safe manner without endangering personnel, property, or the environment.

Part of a diligent safety culture should include reviewing industrial accidents at other facilities. There is much to learn from these unfortunate events, even when they happen in an industry that may seem somewhat removed from our own.

The U.S. Chemical Safety Board, or CSB, is an independent federal agency that investigates industrial chemical accidents. Below, find one of their video reenactments and analysis of an explosion that occurred at a Louisiana chemical processing plant in 2013. A portion of the reenactment shows how a few seemingly innocuous oversights can combine with other unrecognized conditions that result in a major conflagration.

For more information on industrial plant safety products that mitigate fire and explosion risk,  contact Flow-Tech at 410-666-3200 in Maryland, or 804-752-3450 in Virginia

Thursday, December 1, 2016

Toxic Gas and Vapor Detectors - What Can Be Measured

hazardous toxic gas detector explosion proof
Explosion Proof Toxic Gas Detector
Courtesy Dräger
Industrial sites that employ or produce hazardous or toxic gases have a high level of responsibility for protecting workers and the environment from exposure or harm. A significant component of efforts to mitigate the risk posed by toxic gas or vapor is to install instruments capable of detecting the target gases at levels sufficient to provide an alert before, or when, levels reach unacceptable concentrations.

Dräger manufactures gas detectors utilizing electrochemical sensing technology, providing continuous detection of target gases and vapors under a wide range of environmental conditions. The sensors are factory calibrated and ready to use when shipped. The sensor connection is intrinsically safe, so a flame arrestor is not needed. Intelligent self-testing provides predictive maintenance assistance.

There is more to learn about the toxic gas and oxygen sensors from Dräger. The document included below provides a guide to the over 100 toxic gases and vapors detectable by the unit. Share your toxic gas, vapor, and oxygen detection challenges with a product application specialist. The combination of your process knowledge with their product application expertise will produce effective solutions.


Thursday, February 18, 2016

The Concept of Explosion Protection Venting

Explosion venting products
Explosion venting products
(courtesy of Fike)
When a spark or other ignition source ignites particulate in a vessel a fireball develops as material burns in grows at an exponential pace. The pressure front expands as the fireball grows reaching the explosion vent. The explosion vent opens at a specified pressure, limiting the stress on the vessel on allowing it to maintain structural integrity, while also releasing the pressure and allowing the fireball to vent into a safe area outside the facility.

Alternatively, when the process can not be vented safely outside, the explosion vent opens and directs the fireball into a flameless venting device. the flames are extinguished as they pass through the flame arresting screens allowing pressure release, but preventing dangerous flames from entering the work area protecting personnel and preventing secondary explosions. It is also necessary to isolate the deflagration, preventing the transmission the flame into interconnected vessels.

During a deflagration, the pressure wave from the explosion reaches the detector connected to the explosion protection control panel, which processes 4,000 data points per second. The system alarms at a preset pressure level and sends an activation signal to the isolation devices.

The system opens a rupture disk on isolation container that uses 500 psi of nitrogen to drive suppressant into the ductwork, providing a chemical isolation barrier that prevents the propagation of the explosion. the system maintains a history of the event for future reference.

Simultaneously, the gas cartridge actuator drives the piston on the isolation valve, closing the slide gate, and provides mechanical isolation which prevents the propagation of the explosion through the duct work too interconnected vessels.

Sunday, January 31, 2016

Explosion Detection and Suppression Systems

explosion detection system
Explosion detection system (by Fike)
A typical explosion detection sequence begins when a spark or other ignition source ignites particulate in a vessel. The resulting deflagration grows at an exponential pace as the material burns. The pressure front preceding the deflagration expands, reaching the pressure detector connected to the explosion protection control panel, which processes 4,000 data points per second. The system alarms at a preset pressure level, and activates the gas cartridge actuators on the suppression and isolation devices. The system maintains a history event for future reference.

The gas cartridge actuator drives the piston on the isolation valve, closing the slide gate and provides mechanical isolation which prevents the propagation of the explosion through the duct work to interconnected vessels. The actuator opens a rupture disk on the suppressor bottle, that uses nitrogen pressurized to 900 PSI to drive suppressant into the vessel, filling the entire cavity and extinguishing the advancing deflagration.

It is also necessary to isolate the deflagration, preventing the transmission of the flame into interconnected vessels. The system simultaneously opens a rupture disk on an isolation container that uses 500 PSI of nitrogen to drive suppressant into the ductwork, providing a chemical isolation barrier that prevents the propagation of the explosion. Fike’s explosion protection system effectively saves lives and property from explosion damage.