When you sip your milkshake and it is too thick, often the straw collapses. The straw failed because the internal pressure was lowered by you sucking on the end. Sucking means that you have lowered the pressure inside your mouth below the pressure of the air around you. Most people can lower the pressure inside their mouth by at least 20 inches of Mercury on a manometer or gauge. This is the equivalent of about 9.8 PSI drop, so on the inside of the straw the absolute pressure is around 4.9 psi. while on the outside of the straw is atmospheric pressure or about 14.7 psi absolute. The only thing preventing the straw from collapsing is the strength of the straw wall. So the same thing will happen when you try to used soft sleeve to draft. The soft sleeve is not ridgid, like hard sleeve. You can't suck milk shake up a flat straw, and you can't suck water up a flat fire hose. I see that your station houses two engines, a utility, and an ambulance. You probably need to have a sit down session with one or more of your pump operators, who should be able to help you understand drafting.
So where did the coyote get all his money to keep the ACME in business for all those years?
Not sure, I missed that episode of "Where are they now?, the life and times of Wyle E."
I heard he ended up roaming Charlie Sheens back yard though,.... strung out
Posed question - is it possible to draft using soft-suction/LDH without the implementation of a Turbo-Draft? If so...do tell. Thanks
Sam
Captain
Cy-Fair Vol. Fire Dept. Station #4
Sure we do it all the time! What, I thought that the Norm?
Stay Safe
Bull
“Guys if you get hurt, we’ll help you. If you get sick we’ll treat you. If you want to bitch and moan, then all I can tell you is to flick the sand out of your slit, suck it up or get the hell out!”
- Capt. Marc Cox CFD
Nothing in life is so exhilarating as to be shot at without result.
-WINSTON CHURCHILL
“Guys if you get hurt, we’ll help you. If you get sick we’ll treat you. If you want to bitch and moan, then all I can tell you is to flick the sand out of your slit, suck it up or get the hell out!”
- Capt. Marc Cox CFD
Nothing in life is so exhilarating as to be shot at without result.
-WINSTON CHURCHILL
There was an evolution LACFD did or used to do with 3.5" hose from an elevated static water source. Length could not be over 5 (250') sections and the water source had to be higher (elevation) then the engine. The Engineer would fill the line up to the source ensuring all air was expelled. He would then disconnect the line from the discharge and transfer it to the intake. Supposedly it would support 2 lines. 1 1.75" and 1 1.5" or two 1.5". Not really a draft as you are not going negative on the Compound gauge but still an interesting drill.
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