The "Q" Method

[@poppinsmoke8769]

I’m in firefighting school right now and missed a day due to a horrible migraine, this video saved me! Thank you so much for the clear explanation

[@ethanperry569]

Thank you so much! Much easier to understand than the IFSTA book!

[@jonathanbosco8458]

Thanks Matt appreciate all your efforts

[@reviewgallery570]

Why do we need to close the(discharge) isolation valve of a centrifugal pump during startup⁉️ #pumpsolutions #pump #discharge #startup #energy #oilandgas #hazard #saftey #gas #renewableenergy techproces.com/centrifugal-pump/

[@ldcortes8983]

Awesome explanation. Makes it so much easier to understand

[@Boxalarmtraining]

+Ldcortes89 Thank you!

[@TheTroopersCorner]

Thank you so much!!!! I couldn’t figure out how they were getting 5 & 15 in the equations out of the book.

[@ReelVA_Phil]

Is there a video for attack lines? Specifically 1.75" using the 12Q²

[@reviewgallery570]

Why do we need to close the(discharge) isolation valve of a centrifugal pump during startup⁉️ #pumpsolutions #pump #discharge #startup #energy #oilandgas #hazard #saftey #gas #renewableenergy techproces.com/centrifugal-pump/

[@kurthageman]

how do you get the 5 & 15 numbers? is there a formula for smaller lines, like 1, 1.25, 1.5, 1.75, 2, 2.5 also?

[@Boxalarmtraining]

The condensed Q method only works for 3", 4" and 5" hose. It is considered a fireground method for those hose lines. As far as dividing by 5 or 15, that is given in the formula and not something we derived. The fireground method for 1.75" and 2.5" is generally the hand method, which we have a separate video for in our pump operator training playlist. There is also a subtract 10 method for 2.5" hose.

[@ayneedels7749]

Kurt Hageman. Yes for the 1 3/4’’ Hose line is (Q/100 x 4)2. Q divide by 100 then multiply answer by 4. square. 150 Gpm /100 = 1.5 multiply by 4 = 6. 6x6=.36 FL 2’’ Q/10 - 10 Q divide by 10 then minus 10. Q 400 = 40 - 10 = 30 FL

[@mattandersen6738]

While I am a ways out timewise for this video, I am not certain the previous question was actually answered. By all appearances, the numbers "5" and "15" for 4- and 5-inch hose are constants, but the derivation of that constant is not known. Ay Needels shows a constant of 4 for 1.75" hose, but again, there is no explanation for where that number comes from and to add to Ay Needels comment, even that number is not explained. When the normal friction loss formula of FL=CQ2L is used, it is know that C is a mathematical coefficient and most DOs accept that as rote and move on. Is that where the numbers used for 4- and 5-inch hose are derived from? Thanks for the help.

[@mattandersen6738]

@@Boxalarmtraining While I am a ways out timewise for this video, I am not certain the previous question was actually answered. By all appearances, the numbers "5" and "15" for 4- and 5-inch hose are constants, but the derivation of that constant is not known. Ay Needels shows a constant of 4 for 1.75" hose, but again, there is no explanation for where that number comes from and to add to Ay Needels comment, even that number is not explained. When the normal friction loss formula of FL=CQ2L is used, it is know that C is a mathematical coefficient and most DOs accept that as rote and move on. Is that where the numbers used for 4- and 5-inch hose are derived from? Thanks for the help.