In recent months I've come across some different web postings and discussions that address the issue of the difference in handline nozzle shutoff styles and their impact on smooth bore stream performance. The essential conclusion being conveyed as the information passes down the grapevine is that one brand of nozzles had an inferior ball valve design to other brands, and therefore leads the end users to potentially draw the conclusion to avoid using that brand in favor of others when using smooth bore nozzle tips. One specific article that is published which discusses this topic provides good photographic representation of the differences of ball valves, but doesn't clearly explain in writing the responsibility of the end user to specify the proper style shutoff when using smooth bore nozzles. Like much of what we pass along in our trade, I wondered if there was more to the story than I had been able to find in these articles, so I did some research.
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| The playpipe nozzle has a split/cutaway ball valve. The middle nozzle has a standard full ball valve. The stacked tip set is not referred to in this article. |
Before I believed the hype, I decided to do the experiment myself with one of the guys at the firehouse. The results were exactly as the articles had reported, a substantial visual difference in stream quality between a full ball valve shutoff and one with a split/cutaway valve. It was certainly clear to see, and even without the use of calibrated flow test equipment and there was no doubt that an issue existed. Originally I has assumed that a difference in brands and styles of smooth bore tips was the culprit, so we tried using a 1 1/4" leader tip (the base tip in a triple stack set) in comparison to a 1 1/4" plain tip. I assumed the shorter orifice length on the leader tip was responsible for the stream degradation, until I saw the articles online. The test showed that the results were almost identical, regardless of the tip. Once I had seen these results I began to wonder; why would the manufacturer sell a nozzle shutoff that provided such a terrible quality stream? That's what motivated me to look further.
The only manufacturer of record that I know who produces the split ball valve (or cutaway as it is officially referred to) is Elkhart Brass. Elkhart was very quick to return my request for info, submitted via their online form. I had a 20 minute or so conversation with a product development specialist who listened to my questions and concerns. I was surprised to hear they weren't as acutely aware of the misapplication of their products as I expected them to be. It turns out that Elkhart offers 3 styles of ball valves, each for different purposes, but only one is specifically intended to be used with smooth bore nozzles, and that is the full ball style valve. The split/cutaway series is intended for use with automatic and fog style nozzles, where the stream is formed at the tip by the baffle and shaper. It provides a smoother operating and adjustable seat valve that performs better under higher pressures (typically found in fog nozzle applications). The inherent waterway imperfections with the valve opened are virtually irrelevant for these types of nozzles, but cause havoc with smooth bore tips. After the conversation concluded, I received a through explanation of the differences in designs and principles of each ball valve style from Elkhart via email. I was quite satisfied with the time they spent addressing the concern. They discussed making some changes to their literature and field delivery training courses to clarify the proper application as well.
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| The "dual cutaway" ball valve-closed |
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| Note that when opened there are two "pockets" at the bottom of the waterway that trap and agitate the water |
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| Note on a different brand of shutoff the waterway shows a smoother path due to the full ball valve |
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| Elkhart does recommend the full round valve for smooth bores, but doesn't specifically warn against use of the cutaway in this application. Courtesy Elkhart Brass |
If you are familiar with basic hydraulics, you know that smooth bore streams require a waterway that is smooth and a nozzle tip that is tapered to a nice uniform diameter bore to create the best possible stream. Any obstruction within the nozzle waterway will create pockets where water will crash around (turbulence) and in the short distance to the nozzle outlet, there is no way to correct this, resulting in a broken stream. You will also note that bending the hose near the coupling of a smooth bore nozzle will yield similar results, regardless of the style valve used. The stream is very susceptible to degradation if the ingredients aren't all there (proper nozzle tip match to the hose diameter, proper valve and no kinks near the nozzle). The economical solution if you use these valves is to attach mini stream shapers, which will drastically improve performance.
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| The test shows the results - the ball valve in the bottom photos was a "double cutaway" type |
In conclusion, the proper application of equipment is truly a balance of your needs and a good salesman who can understand what you seek to accomplish as well as having a mastery of the product line. In our trade, there are vendors that do not provide a mastery level of the products they market. This forces the "buyer beware" mentality. Its easy to discredit a manufacturer for ending up with a product that is inferior or not appropriate for the intended application, however unless you've done your due diligence, it isn't fair to place the burden on them up front. This article, and its attached research are intended to clear up the misconception that the Elkhart brand nozzle as a whole is not as well suited for use with smooth bore nozzles, as other brands. As a fireman, who doesn't sell equipment, I attempt to be diligent in being objective. This was a case where I see two important final points to underscore. One is to do your homework when buying equipment, and the second is to check your current equipment to see it if it properly matched up. Interestingly enough, between three firehouses where we have Elkhart Nozzles, every single one is a cutaway style valve, with smooth bore tips. With their purchase being before my time, I can only suspect that they were purchased without full knowledge of this phenomeon. It is also pertinent to note that each nozzle had optional fog tips to go along with the smooth bores, with sopme being automatic 100 PSI tips. I suspect the nozzles were brought as break-apart fogs with spare smooth bore tips. Check your nozzles, and do your research. The manufacturers are often very willing to educate and listen, don't hesitate to ask them. Special thanks to Elkhart Brass who demonstrated exceptional customer service.
Check out Elkharts website for more info, and refer to the 375 series shutoffs for proper application with smooth bore tips.
http://www.elkhartbrass.com/files/aa/downloads/catalog/catalog-f2-01.pdf
Stay safe, train hard, and always be a student.
