By Ray McCormack
The four-camera view of a hose stream comparison test has caused much debate. The video shows a home with two rooms on fire on the second floor with a common hallway and straight run staircase leading to it. The rooms are both on fire and each one is attacked with a different style hose stream. The room on the right with a straight stream the one on the left with a fog stream.
The rooms are hit hard from the yard with varying degrees of effectiveness as seen on the hidden camera interior view. To me, the exterior view contrasts widely with what is seen inside and could cause exterior firefighters to believe more has been accomplished than in actuality. Both streams knock down fire, however firefighters outside looking on would be lead to believe that no additional fire exists or its location remained the same–but that is not what is seen from the interior view. The hallway has sustained fire in it, again. Something is definitely lost in the translation of transition.
The problem with this particular test is that the set up could have been defined better. The two rooms share a common hallway and appear to have doorways that are opposite each other; the rooms are similar in size and shape, and had identical fire loads and placements, but they should have been attacked separately, one by one.
The fire on the right side should have been lit and attacked completely independently of the one on the left. The reason is because we see flames from the opposite free burning room moving and combining with the room that is being hit, making it difficult to distinguish the amount of fire sharing and fire support or cooling that may have taken place on the adjoining room.
The length of stream application by the straight stream into the right side room is less than half that of the left side fog stream room, so the actual comparison pound for pound or gallon for gallon is off. Each stream was equal 150 GPM and start distances they travel on the outside of the building appear to have been the same.
In my opinion, if the fires were hit for the same duration and independent of each other the test would have eliminated any chance of fire sharing or support between the rooms and have been a better and more accurate assessment of stream application and fire movement. Hallway temps could also have been effected by fire redevelopment in the right side room.
Keep the tests coming, NIST. Thanks to Dan Madrzykowski for factual details provided.
Keep Fire in Your Life
RAY McCORMACK is a 30-year veteran and a lieutenant with FDNY. He is the publisher and editor of Urban Firefighter Magazine. He delivered the keynote address at FDIC in 2009 and he is on the Editorial Board of Fire Engineering Magazine. For more on Urban Firefighter, visit http://emberly.fireengineering.com/urbanfirefighter.html.
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