Oops! the Furnace and the Boiler Exploded

Why?

Presentation by:

Eng. Roberto Fernández Blanco

SISTEMAS DACS SA

rfblanco@dacs.com.ar

ABSTRACT

 (For the Case Histories with Lesson Learned session)

On February 7, 2010, there was a catastrophic and fatal explosion at Kleen Energy Power Utility Station, Middletown, Connecticut, which resulted in 6 people being killed, some 50 injured workers of different degrees of severity and economic losses that amounted to several million dollars.

This accident gave rise to a TIA (Tentative Interim Amendment) of NFPA 54 (August 2010), but in August 2009, the author had already recommended the revision of NFPA 69 regarding the emptying and filling of tanks for storage of flammables gases.

It is worth pointing out that pipes and Fireboxes are essentially tanks” with flammable gases or vapors flowing through and, therefore, the same operating precautions necessary to prevent the formation of an explosive mixture that causes explosions are valid in this case.

Every year, there are explosions of different severity in furnaces and boilers all over the world. The industrial universe already has a vast record of misfortunes and damages to individuals, as well as great losses in property and production falls.

This presentation is focused on the particular hazard of the flammable mixture that, through the burner (or burners), is present in the Firebox of Furnaces and Boilers in order to generate the calories required by Industrial Processes, to heat up the product that is part of the Process (in the case of Furnaces) and to generate the necessary amount of steam required for the different stages of the Process (in the case of Boilers).

Furnaces and Boilers share this common denominator which is the flammable mixture used to generate calories that, under certain circumstances, can give rise to the accumulation of an Explosive Mixture at the Firebox which, in case of reaching an ignition source, will trigger a catastrophic explosion with serious consequences.

As in every combustion process, the causes of this type of incident are well known and foreseeable and there is easily available, excellent and plentiful related technical information as well as, additionally, vast experience.

Even so, explosions still occur with painful and terrible consequences.

What is conspiring against Process Safety?

Natural and usual enemies of safety are lack of knowledge, lack of education and lack of calling for expert advice, lassitude, negligence, complacency and, sometimes, an imprudent conceit of sufficiency (“I know it all).

Is there someone responsible?

Yes, but it is not a person (or some persons) in particular, but rather a condition of collective lack of culture (“collective lack of culture” defined as the thoughtless behavior and conditioned reflex reactions that characterize the group), the “main responsible” being the management policy of the company evidenced by a lax commitment regarding the safety level of its processes, the prevention and protection of their personnel’s safety and the careless behavior in relation to the importance of protecting the integrity of their production assets.

All this gives rise to an explosive cocktail that I will try to pass on to you through “specific representative images" of the essential aspects of this knowledge with the aim of inducing conditioned reflex reactions with respect to the dangers and risks you are exposed to and by providing a synthetic review (rather a flash, given the time available) of the stoichiometric reactions of flammables, the proportions in volumes that allows mixtures easily to ignite, the Flammability Triangle (essential tool, almost unknown and sometimes forgotten in Risks assessments), Minimum Ignition Energies (“MIE”) required to cause the ignition of a “Flammable Vapor Cloud” and its resulting explosion, the fundamental Rules and Procedures regarding Care and Maintenance to protect the Integrity of components, the appropriate design of Combustion Regulation Loops (BPCS – Basic Process Control System) to prevent it from becoming the cause of incidents’ initiating event and the essential components of the Protection System (BMSIS - Burner Management Safety Instrumented System, according to the name registered by the author).

I will also add a fast revision (A Case History with Lessons Learned) of the most recent and above mentioned severe explosion that took place at Kleen Energy Power Utility Station, Middletown, Connecticut, on February 7, 2010.

And there will be no doubts that, given the available knowledge on this issue and having the opportunity to get the “necessary support from experienced specialists,” if there is an explosion of flammables it will be most probably due to the lack of safety culture and management commitment with safety.

The Protection of Individuals (and Production Assets) is the responsibility of everyone, without exception, to have processes operating safely with appropriate  procedures and protections. It includes: Government’s officials (Authority Having Jurisdiction) who -representing the people- approve the installations and release the permission for the Plant to stay operating (which should also enforce their frequent auditing), the corporate safety policy (Process Safety Management) -as well as that of labor unions - and every member of the company regardless of their level of responsibility (Design, Engineering, Installation, Operation, Maintenance, Health and Safety and Training Depts) and regardless of their hierarchical positions (from Managers to the entire workforce).

It is necessary to always remember that our own lives and the lives of our coworkers are in danger.

It is a problem of Education (thoughtful replies), Training (conditioned reflex replies) and responsible behavior (Process Safety Culture).

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Keywords: Flammable Triangle, Flammable Zone (Lower Flammable Level “LFL”, Upper Flammable Level “UFL”), Minimum Ignition Energy “MIE”, Basic Process Control System “BPCS” as Incident’s Initiating Event, Process Safety Culture (Education, Training, Awareness, Commitment and Alertly).

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Eng. Roberto Fernández Blanco

AIChE Member # 90143640

SISTEMAS DACS SA

rfblanco@dacs.com.ar

rfblanco@fibertel.com.ar

Movil (54-9) 11-6605.5786

Buenos Aires

Argentina