r/Firefighting 13d ago

Videos Firefighting drones make their debut in China

602 Upvotes

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155

u/blackmamba329 13d ago

I wonder what the friction loss is on that

86

u/ironmatic1 13d ago

Nothing compared to elevation

26

u/Fif112 13d ago

Forgive me if I’m wrong, but since they’re using hose and not pumping up a standpipe, isn’t the pressure loss per hydraulic length more than the pressure loss due to elevation?

Assuming they’re using a smaller diameter hose, considering the drone has to lift the hose plus the water in it.

Sorry, I’m new to pumping and any explanation would be appreciated!

36

u/Sad-Pay5915 13d ago

You need to overcome both those issues. I’d be curious how many gpm they’re getting out of that setup.

21

u/MuscularShlong 13d ago

It doesnt look like much lol.

3

u/Fif112 13d ago

Sorry yeah that is what I meant!

Just figured that more pressure loss would be because of friction than because of elevation

3

u/Unstablemedic49 FF/Medic 13d ago

Not enough to overtake the BTUs from the fire. It looks like the water is just turning to steam.

2

u/fetal_genocide 11d ago

Looks like they're spraying foam.

3

u/[deleted] 12d ago

You know the captains who always want a 2 1/2” line will lose their minds when they see this! lol

7

u/Jessejets 13d ago

When calculating operating pressures, you must account for friction loss, elevation loss, and—if applicable—the nozzle operating pressure. Friction loss will vary depending on the diameter of the hose being used. As a general guideline, elevation loss is approximately 5 psi per floor when dealing with vertical applications.

Based on current observations, most drones are not discharging plain water but rather a water/solution mixture (foam). The use of foam significantly reduces the overall load on the drone by making the hose lighter and easier to manage. This reduction in weight may also decrease the pressure required to effectively operate these devices.

1

u/Cpt_Soban Volunteer Firefighter Australia 12d ago

"Yes"

1

u/Bubbly-Bowler8978 11d ago

Yeah how much weight are those drones carrying? The hose and the water got to weigh a ton