-Something many firefighters forget/overlook or just plan do not understand is that the stand pipe is designed and engineered by fire protection experts to be used with and pumped/suppled for a 2 1/2" hose and a play pipe.
-Stand pipe systems are most often not designed for nor will they properly facilitate the PDP associated with an 1 3/4" and/or a fog nozzle. Coupled with stand pipe systems equipped with pressure reducers, the excessive pressures needed to properly operate an 1 3/4 and/or fog nozzles will many times damage the stand pipe system itself.
-Obviously the system engineer had something in mind when the fire protection system was designed and the responders need to understand this in order to utilize the system properly and safely.
-Lastly, hydraulics aside, those that still advocate employing an 1 3/4" with a fog nozzle have not taken into account the flex time in this operation.
-Flex time being the amount of time that is measured beginning when the company arrives on scene and stopping when the company has accomplished a definitive task; i.e. water flowing or a rescue is under way.
-The average flex time in a high rise operation is on the order of 8-10 minutes for an engine to get water flowing on the fire from the time of arrival. With that amount of time ticking off just to get water flowing... you'll want the extra punch that the 2 1/2" will deliver because many people just seem to overlook that the fire is getting bigger until you do something about it. Just arriving doesn't stop the forward progress or growth of the fire.

Hi,

 

These videos proove absolutly nothing. Or, in fact they don't proove what you think they proove!

The difference you see between the fog nozzle and the solide bore, don't came from the fact you have a solide bore in one side and a fog nozzle on the other.

It came from the fact that the fog is an automatic one, which is the worst kind of nozzle you can find. But, it's not becausen it's a TFT. If you try with a POK automatic, you'll have the same result.

What' happening? Inside the automatic, there is a system trying to change the "out" pressure of the nozzle. If you lower the "in" pressure, this system try to increase the "out" pressure, by closing the flow rate system inside the nozzle.

So these nozzle can be used only if you are sure of the "in" pressure.

 

If you use a non-automatic nozzle (eg a TFT Quadrafod or and Akron or a POK and so...) you don't have this effect.

This bad effect is NOT linked the the fact it's a solide bore or a fog but due to the way the flow rate is set. We've tried by comparing TFT Quadrafog (selectable galonnage nozzle) vs a TFT Ultimatic and the Ultimatic sucks a lot. The worst think you can get, is when you connect an automatic nozzle and a selectable galonnage (or a fixed gallonage) nozzle, together, using a single hose line and a divisor: while having the automatic opened, wait a little, they open the "manual nozzle": you will see immediatly the automatic loosing it's flow rate.

 

For structural firefighting, NEVER use automatic nozzle.

 

After that, if you want, we can speak of slide bore vs fog nozzle.But this can't be with such a video.

 

Best regards

Piertre-Louis

 

I agree that automatic nozzles are problematic. In fact, I personnaly wish they were outlawed for the fact they are deceptive. It is difficult for the nozzleman to actually know the GPM of line because of the spring compensating for the pressure. Though to know the actual gpm is impossible with any nozzle selection, the nozzleman can tell if the stream is generally adequate with a smoothbore or constant gallonage fog. Unfortunately, too many departments have been lured by elequent salesmanship and slick presentations.

 

The main piont attempting to be communicated is to NEVER use an 1 3/4" or 2 1/2" with a fog nozzle from a standpipe when an active fire is brewing. A smoothbore will give a decent stream with as low as 45 psi. Even the best fog nozzles cannot achieve that. Also, the importance of using a 2 1/2" line, in case a very low pressure situation is encountered. If the 45 psi situation is encountered, the 2 1/2" with a smoothbore is more likely to achieve a positive result. As Michael brought up in a previous post, by NFPA the standpipes are specifically designed for the larger line with a smoothbore.

 

Remeber this is the HIGH RISE GROUP; meaning the tactics and tools discussed is that a HIGH-RISE fire is the basis for the discussions.

Damn my lying eyes!