By Steve Green
In the summer of 2015, the Fire Instructors Association of North Texas commissioned a study to evaluate the differences between low-pressure fog nozzles.
The purpose was to compare and contrast 50-, 75-, and 100-pound-per-square-inch (psi) fog nozzles at various gallon-per-minute (gpm) flows. The results of this study are summarized in this article. The merits and differences of smooth bore nozzles are not in debate and were not used during these tests. As always, your fireground results and observations may be different. Also, your practical experiences will differ depending on building construction, weather, and fire load. Base all your tactical decisions on near and expectant fire conditions.
The Scope and Mission
Numerous discussions determined that there is not a “set standard” for nozzle selection in the Metroplex (the region that comprises Dallas, Fort Worth, and Arlington, Texas). That can be said of most of the country, but in the South, there is a large usage of fog nozzles. That is not to say that we use fog nozzles only but that there is a proclivity to attach them to our most frequently used lines. In the Metroplex, it is common to see a dual crosslay with 1¾-inch hose varying in lengths from 150 to 250 feet with some type of fog nozzle. What has been of interest is the move toward lower pressure nozzles over the past five years. Numerous departments have made a decision to go to a 50- or 75-psi nozzle using roughly the same diameter line.
Along with this, there seems to be some debate among firefighters as to which setup is the most effective. So, this study put some cold facts on the table for firefighters to discuss. For the purpose of the study, we stayed consistent with our 1¾-inch attack line and used 200 feet. We thought this was a good compromise and the average for the departments in our region.
The group evaluated the nozzles based on the following:
- Reach and penetration.
- Hose kinks and deployment issues.
- Nozzle reaction and ease of use.
- Overall performance in suppression activities.
Again, this article does not cover the merits of smooth bore for reach and penetration, and we did not use them as a comparative factor.
As a setup for what follows, let us do a quick review. Our goal in the fire service has always remained the same: put the fire out. How you do it and what works best for you and your jurisdiction will always differ from others. How you best accomplish this usually depends on how well your people are trained, staffing, equipment, and the hard lessons learned by those who came before you. Whether you use smooth bore, fog, compressed-air-foam systems, positive pressure attack, etc., it all comes down to one simple truth: Do what works, and repeat it every time.
If you attempt to recreate what we have done here, be realistic. Do not base your results on four- to five-person staffing if your department does not use that. If you have two- to three-person engines, factor that into your evaluations. Otherwise, you are going to have some very unrealistic expectations for your crews on scene.
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1 This portable monitor stand allowed evaluators to move nozzles around into different environmental conditions
Read more
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Posted: Nov 2, 2016
By Steve Green
In the summer of 2015, the Fire Instructors Association of North Texas commissioned a study to evaluate the differences between low-pressure fog nozzles.
The purpose was to compare and contrast 50-, 75-, and 100-pound-per-square-inch (psi) fog nozzles at various gallon-per-minute (gpm) flows. The results of this study are summarized in this article. The merits and differences of smooth bore nozzles are not in debate and were not used during these tests. As always, your fireground results and observations may be different. Also, your practical experiences will differ depending on building construction, weather, and fire load. Base all your tactical decisions on near and expectant fire conditions.
The Scope and Mission
Numerous discussions determined that there is not a “set standard” for nozzle selection in the Metroplex (the region that comprises Dallas, Fort Worth, and Arlington, Texas). That can be said of most of the country, but in the South, there is a large usage of fog nozzles. That is not to say that we use fog nozzles only but that there is a proclivity to attach them to our most frequently used lines. In the Metroplex, it is common to see a dual crosslay with 1¾-inch hose varying in lengths from 150 to 250 feet with some type of fog nozzle. What has been of interest is the move toward lower pressure nozzles over the past five years. Numerous departments have made a decision to go to a 50- or 75-psi nozzle using roughly the same diameter line.
Along with this, there seems to be some debate among firefighters as to which setup is the most effective. So, this study put some cold facts on the table for firefighters to discuss. For the purpose of the study, we stayed consistent with our 1¾-inch attack line and used 200 feet. We thought this was a good compromise and the average for the departments in our region.
The group evaluated the nozzles based on the following:
- Reach and penetration.
- Hose kinks and deployment issues.
- Nozzle reaction and ease of use.
- Overall performance in suppression activities.
Again, this article does not cover the merits of smooth bore for reach and penetration, and we did not use them as a comparative factor.
As a setup for what follows, let us do a quick review. Our goal in the fire service has always remained the same: put the fire out. How you do it and what works best for you and your jurisdiction will always differ from others. How you best accomplish this usually depends on how well your people are trained, staffing, equipment, and the hard lessons learned by those who came before you. Whether you use smooth bore, fog, compressed-air-foam systems, positive pressure attack, etc., it all comes down to one simple truth: Do what works, and repeat it every time.
If you attempt to recreate what we have done here, be realistic. Do not base your results on four- to five-person staffing if your department does not use that. If you have two- to three-person engines, factor that into your evaluations. Otherwise, you are going to have some very unrealistic expectations for your crews on scene.
|
1 This portable monitor stand allowed evaluators to move nozzles around into different environmental conditions
Read more
- 272
- Article rating: No rating
| |