Question on garden hose length vs flow/psi

[MrOneEyedBoh]

So I was wondering something here... I don't know if this is in my head or if this is something else. I noticed that when going from a 50' to a 75' hose the water spraying out of the nozzle isn't that strong . it seemed stronger with the 50' hose. Possible?

[novaman]

So I was wondering something here... I don't know if this is in my head or if this is something else. I noticed that when going from a 50' to a 75' hose the water spraying out of the nozzle isn't that strong . it seemed stronger with the 50' hose. Possible?Only if there different circumference.

novaman

[2black1s]

Absolutely! With a constant and equal inlet pressure the flow rate from the hose end will decrease as hose length increases.

Here's an example of the flow rate though various lengths of 5/8" hose at 50 psi inlet pressure...

50 ft. = 25 gpm (gallons per minute)
75 ft. = 18.8 gpm
100 ft. = 12.5 gpm

Reference - Garden Hose Flow and Time Calculator (http://irrigation.wsu.edu/Content/Calculators/Residential/Garden-Hose-Flow.php)

[MrOneEyedBoh]

Thanks. Thats what I was thinking. I'm also thinking what if I get a 1/2 hose versus the standard 5/8 hose, wouldn't that give me a little more perceived pressure? I mean we're washing cars here not soaking crops etc. No?

[2black1s]

You can achieve that same "perceived" pressure by changing nozzles.

What you are actually seeing as "perceived" pressure is the combination of the velocity and volume of the water leaving the hose/nozzle, but the actual pressure is always zero once the water leaves the hose/nozzle. The velocity and the resulting force of the water will increase as you restrict the outlet opening, thus the "perceived" pressure increase.

I wouldn't change to a 1/2" hose. A 5/8" hose will always flow more than a 1/2" hose at equal pressures. I'd simply play with various nozzles.

[oldmodman]

Last time I needed to replace a crappy, cheapo garden hose, I bit the bullet and spent the money.

I got two 50 foot all rubber 3/4 inch garden hoses at Home Depot. They were on sale for 40% off. Probably due them having about 30 on the shelf and it being the start of winter.
Yes, they are heavy and not the easiest thing to drag around. But they sure can move water.

I had a take off pipe put in the water main coming from the street before the pressure regulator so it gets full mains pressure. With these hoses and a long brass nozzle I can spray the top of a 60 year old pine tree in my front yard.

[Riff]

What 2black said.

A longer hose will give you less flow. A smaller diameter hose will give you less flow. Both resulting in the lower "perceived" pressure you were talking about.

The nozzle is your best bet for getting the pattern and velocity you want.

[BillE]

Absolutely! With a constant and equal inlet pressure the flow rate from the hose end will decrease as hose length increases.

Here's an example of the flow rate though various lengths of 5/8" hose at 50 psi inlet pressure...

50 ft. = 25 gpm (gallons per minute)
75 ft. = 18.8 gpm
100 ft. = 12.5 gpm

Reference - Garden Hose Flow and Time Calculator (http://irrigation.wsu.edu/Content/Calculators/Residential/Garden-Hose-Flow.php)

GREAT find on that equation!

Bill

[MrOneEyedBoh]

Thanks guys. I use a fireman nozzle. Is there another you recommend.