BANG! Boiler Explosion | Rasmussen Mechanical Services
While boiler explosions are rare today, they happened much more frequently a few hundred years ago. Thankfully in 1880 the American Society of Mechanical Engineers (ASME) was founded in response to the numerous deadly boiler explosions. ASME went on to published the Boiler and Pressure Vessel Code (BPVC) in 1915. This became the basis for what we call “ASME Section I” today. The ASME boiler code has been adopted by countries around the world. It is the go-to code for design, construction, operation, and inspection of boilers.
What Causes Boiler Explosions?
When a boiler explodes it can send shock waves, extreme heat and multidirectional debris flying with tremendous force. So what causes a boiler to explode? There are three types of boiler explosions. One involves failure of the pressure vessel, the second is caused by super-heated liquid and the third is caused by improper fuel combustion.
Pressure Vessel Failure
This is most often caused by weakening of the boiler through rusting. It also can be caused by low water conditions, excessive scale, broken safety values, water hammer and more. The issue arises when the pressure envelope of the boiler is compromised. This pressure change can allow water in a steam boiler operating at 100 PSIG to expand 1600 times its original volume. As you can imagine this puts off tremendous force and is why explosions can be so dangerous.
Super-Heated Liquid
This is a form of vapor explosion that is caused by a combustion valve closing and extra energy being added to the system. The result can create a super heated liquid. This liquid is heated above it’s boiling point and begins to vaporize rapidly. As this rapid vaporization occurs, the system is thrown out of equilibrium.
“Often, part of the vessel breaks away because the liquid is vaporizing to gas so rapidly. The rarefaction wave moves within the vessel and the resulting compression wave violently forces the liquid particles out through the vessel breach. This sequence of events spells split-second disaster” — National Board of Boiler and Pressure Vessel Inspectors.
Fuel Combustion Explosion
This most often happens when the burner flame is out. Ignition failure, loose valves, and faulty gas lines can all allow for the buildup of combustion gas in a high temperature vessel. This can cause not only a boiler explosion, but gasses can also leak throughout the facility. While the initial explosion is dangerous, this can also result in the rupturing of the pressure vessel. This can in turn create a second explosion that can be equally powerful.
Alternatively, failure to purge combustible gasses from the firebox before ignition can result in a similar situation.
Preventing A Boiler Explosion
Fighting boiler explosions involves a number of different methods, but can drastically reduce the risk. First, ensure all employees who operate the boiler are trained. Boiler issues are often attributed to mistakes made by operators who do not have proper training.
Second, it is important to have a regular maintenance schedule in place. Many boiler explosions get traced back to years of neglected maintenance. Third, have regular safety training and protocols in place in case of emergency. This can reduce the likelihood of an explosion and prevent injuries should one occur.
Recent Examples
Processing Plant Explosion
https://www.youtube.com/watch?v=Kf9kj0mbL88&feature=emb_logo
Citrus Plant Boiler Explosion
https://www.youtube.com/watch?v=D8Byb39rOOs&feature=emb_logo
Have Questions?
Be sure to follow the manufacturers recommendations for maintenance to ensure your boiler system runs as efficiently as possible . If you need help with your boiler, reach out for a free estimate , call us at 1–800–237–3141 or chat with an agent . Our team is here to help!
Originally published at https://www.rasmech.com on November 17, 2020.
