Forensic Engineering Analysis of a Propane Fueled Residential Gas Explosion

Article Author(s): David S. Komm, P.E., P.Eng., CFEI (NAFE 737S)

Volume: 28
Volume #: 1
Month: June
Year: 2011

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Abstract:

The use of liquid petroleum or commercial propane gas (hereafter referred to as propane) for residential
heating and cooking is common in the rural United States where providing the infrastructure for
natural gas distribution would be too costly. A typical installation may include a 500 gallon pressurized
vessel containing a mixture of liquid and vapor propane with the vapor fed to an individual residence
through an underground line. Safety features, such as odorization of the propane, multi-regulator installations, prudent selection of gas line components, and system leak checks are utilized to prevent and/or recognize fugitive gas leaks.

In 2005 an event occurred in Michigan which involved a flammable gas leak, corrosion, gas migration
through soil, a buildup of the flammable gas, and subsequent ignition resulting in an explosion
which destroyed a two story home. This forensic investigation eventually revealed that the root cause of
the incident lay in actions taken during the original construction. Some 16 years after the installation of
the subject gas system circumstances came together to create an explosion.

Keywords
Forensic Engineering, propane, explosion, ferrule fitting, explosive limit, fugitive gas, mercaptan,
ball valve, compression fitting, finite element analysis, metallography, corrosion, odorant scrubbing