Fire Extinguishment
A Historical Perspective
Broken Links
Thanks to Lieutenant Matt Leech of Tualatin Valley Fire and Rescue for letting me know that there are a number of broken links in my earlier blog posts. A fix is in the works and hopefully all links will be functional by next Monday.
Historical Perspective
While researching the Iowa Fire Flow Formula, I came across some interesting information (trivia?) related to the use of water fog for firefighting. In The Safe and Effective Use of Fog Nozzles: Research and Practice, John Bertrand and John Wiseman observed that fog nozzles have been in existence for more than 100 years.
. Early versions of this type of nozzle were imported to the United States from Europe.
In 1924, Glenn Griswold, a firefighter from Colorado Springs moved to California and joined the newly formed Los Angeles County Fire Protection District. He quickly rose to the rank of Captain and was assigned to Station 17 in Santa Fe Springs. Captain Griswold applied his prior education as a hydraulic engineer to the practice of firefighting and experimented with development of a nozzle to break water into small droplets. Eventually he patented the design under the name Fog Nozzle
.
Subsequent innovations in the design of combination nozzles resulted in nozzles that could maintain the same flow rate regardless of pattern, adjustable flow nozzles could be set to provide different flow rates while maintaining consistent flow for all patterns, and finally automatic nozzles that maintained a relatively constant nozzle pressure through a specific flow range.
However, there was a reference to the January 1877 issue of Scientific American in Nelson’s Qualitative Fire Behavior that intrigued me. He stated that this article extolled the virture of little drops of water and the latent heat of steam
and that it
attempted to point out in a scientific manner that spray or fog nozzles could greatly increase the efficiency of the fire service.
I located a copy of the magazine in the archives of the Portland State University library. The article that Nelson referenced, was actually a letter to the editor written by Charles Oyston of Little Falls, NY.
Scientific American, January 1877
To the Editor of the Scientific American
In our issue of December 30, you recommend discharging water through perforated pipes in the form of spray for extinguishing fire. If water in the form of spray be a good extinguisher, as it undoubtedly is, as numbers of proofs exist in our factories and picker rooms, why do not our fire departments use it in that form in all cases where they can? Leaving firemen to answer that question, I will proceed to adduce a few facts in support of the theory that a spray is the true method of applying water wherever the burning object can be reached by it.
Water operates, in extinguishing fire, by absorbing the heat and reducing the temperature of the burning substance so low that fire cannot exist; and as the amount of heat that water will absorb depends on the amount of surface of water in contact with the fire, the more surface we can cover with a given amount of water the better. As flame is the principle propagator of fire, to arrest it is the first thing to do; and as it is more than three thousand times lighter than water, and in most cases a mere shell or curtain, a fraction of an inch thick, the extreme absurdity of trying to subdue it with solid streams of water will be apparent. If a man in the character of a sportsman were to fire an inch ball into a flock of humming birds, with the intention of killing as many as possible, he would be regarded as a fool; but if he were to melt the inch ball up, and cast it into shot one thirtieth of an inch in diameter, he would have twenty-seven thousand such shot, and their aggregate surface would be thirty times greater than the inch ball. If he were to load his gun with this shot and fire into the flock, at proper distance, the slaughter of the little beauties would be terrible; and if a fireman would divide up his stream into spray, so that he could cover thirty times more flame, he might expect a corresponding result. The globules of water would be so small that a large portion of them would be heated through and converted into steam; and as steam contains five more heat (latent) than boiling water, we gain a great advantage in this. Steam is also an excellent extinguisher, and this is an additional advantage. As a large portion of this water is converted into steam when applied in the form of a pray, a small amount serves, and the damage by water is very small.
If the first two engines that reached the burning Brooklyn theater could throw five hundred gallons of water each minute, and divide every cubic inch of water into sixty thousand drops, in two minutes the smoke and heat would have been sufficiently subdued to have enabled outsiders to enter and rescue the unfortunate inmates. I am well aware that this statement may seem extremely absurd to firemen who have never experimented in this line; but before they condemn it, let them take out a couple of engines and try the experiment. The barbarous system now in use that so frequently desolates portions of our cities, fills our houses with mourning and our cemeteries with new-made graves, must give way to the dictates of Science. Humanity demands it, and I call on the scientists and chemists throughout the land to aid in introducing this needed reform.
Little Falls, N.Y. Charles Oyston
Scientific American Vol. XXXVI No. 4, Page 52
January 27, 1817
The Rest of the Story
Oyston does not mention that he holds a patent for a device called Improvement in Nozzles which used a series of movable hooks inside a relatively standard solid stream nozzle to create a broken stream pattern of broken droplets. In the Fire Stream Management Handbook, David Fornell astutely observes that attempting to introduce change in the 19th century was apparently as difficult as it is today.
While it is obvious that Oyston is not a firefighter or fire protection engineer with a sound understanding of the tactical applications of straight streams and water fog in firefighting operations, he did have a reasonable grasp of the basic physics involved in the use of cooling for fire control and extinguishment.
His call for scientists and chemists to weigh in on the issue resonated strongly with me as firefighters stand across a chasm from scientists, engineers, and researchers. Much progress has been made in this regard in other nations such as Sweden and in the US by the work of the National Institute for Standards and Technology (NIST) and others. However, this integration of science with the practical experience of firefighting needs to continue and be expanded.
Ed Hartin, MS, EFO, MIFireE, CFO
Tags: Add new tag, Fire Control, fire streams
January 22nd, 2009 at 13:15
Benji, Seven is correct when you consider the difference between heating water from 20 to 100o C. The quote from Oyston was taken directly from his letter (not quoted as fact, but simply his statement).
Ed