The cause of the fire at the Happy Moose? Pyrolysis

The Streetsboro Fire Department has wrapped up its investigation of the odd kitchen fire at Happy Moose, a Streetsboro restaurant, and found decomposition to blame.

The fire, which started before the restaurant opened on the morning of Jan. 21, was contained inside the walls and was invisible to kitchen staff. In the follow-up investigation, construction crews tore away a wall in the restaurant’s kitchen to reveal the cause of the fire as pyrolysis, Fire Prevention and Investigations officer Captain Kevin Grimm said in a statement.

Not exactly spontaneous combustion, pyrolysis occurs when wood is dried out and decomposed over time by heat — in this case coming from the restaurant’s grill — and low oxygen levels. The process lowers the combustion point of the wood so that it can easily catch fire, even without direct contact with a flame. 

The fire ignited behind the wall and traveled upward in the direction of the building’s HVAC system, which both fed oxygen to the fire and activated the alarm system, Grimm said. 

Several area fire departments were alerted and crews controlled the blaze in under 30 minutes using thermal imaging technology to detect the hidden flames. Damage to the building is estimated to exceed $250,000.