Fire Behavior Unit VI Essay

.pdf

School

Columbia Southern University *

*We aren’t endorsed by this school

Course

2303

Subject

Mechanical Engineering

Date

Dec 6, 2023

Type

pdf

Pages

Uploaded by MajorRoseTiger30

1 Unit VI Essay Stephen A Maccini Columbia Southern University FIR 2303-19A-SP23L-S2: Fire Behavior and Combustion Professor Timothy Whitham March 5, 2023

2 Unit VI Essay At 0905 hours, a mayday was transmitted for a missing member from engine 5. Shortly after, he was found unresponsive in a bedroom the crew was just in before retracting to a safer space. The dark smoke was completely concealing everything. The soot particles in the air seemed to soak up every ounce of the light. They began to drag out the unresponsive firefighter. They eventually passed a crew from engine 12 as they exited the building. Engine 12 continued towards the fire with an 1-3/4” hose line, noting the conditions were changing radically and the tenability was taking a toll on them. Engine 12’s crew became disorientated from the dense black smoke and heat. Factors that Influenced the Smoke According to Dodson, D (2006) there are 4 factors that influence smoke. • Container – can change the meaning of volume, velocity, and density • Thermal Balance – if the fire is not in balance, velocity is messed up • Firefighting Efforts – all four attributes should change: Volume increases; velocity surges then slow down; density immediately decreases; color goes white • Weather – hot/humid gives a narrow, defined column; hot/dry gives a cone shape column; cold/humid causes the smoke to crash and hangout near; cold/dry causes the smoke to crash but disperse easily. The weather in Columbia Southern that morning was warm and windy after a summertime rain storm. The humidity level is high. This strongly influences smoke conditions and behavior. Especially the wind playing a huge factor.

3 Products of Combustion The extreme fire behavior at the Garden Apartment fire involves aerosols (soot particles and liquid droplets) and gases. Dodson explains that in a simpler time, smoke was viewed as the particulates (solids) that are suspended in a thermal column. fire gases and aerosols were listed as separate products of the combustion process. In today’s world, that oversimplification is dangerous. When smoke is seen leaving a building, the smoke needs to be interpreted as an aggregate of solids, aerosols, and fire gases that are toxic, flammable, and volatile. The solids that are suspended in the thermal plume include carbon (soot), ash, dust, and airborne fibers. Concerning aerosols typically include a whole host of hydrocarbons (oils/tar). Fire gases are numerous with carbon monoxide, hydrogen cyanide, acrolein, hydrogen sulfide, and benzene leading the list. The bottom line: Hot smoke is extremely flammable and will ultimately dictate fire behavior. Dangers of Soot and Aerosol Droplets According to Gann there are two different types of smoke aerosols. First is Carbonaceous (Carbon) solid particles (soot), which generate the incandescent orange-yellow glow within a flame and are seen as black smoke emanating from the flame. The second type is liquid droplets (aerosol mist), which form as some gas molecules cool and condense. They are seen as light-colored smoke. The aerosol droplets from the condensation of gasses made it difficult for interior operations at the Garden Apartment fire because of the under-ventilated burning as well as the properties of burning synthetics. As burning took place, the smoke layer continued dropping. The members from engine 2 also spilled a container of cooking oil which contributed to the thick soot that was being experienced by firefighters in the building. Because of the now thickened smoke and extremely high temperatures, it severely impacted the ability to see. The effect that the smoke obscuration had on fire attack and rescue efforts was catastrophic. Firefighters

Your preview ends here

Eager to read complete document? Join bartleby learn and gain access to the full version