Long Radius Copper Bends

[oldbutnotdead]

Amusing myself calculating the headloss in the DHW and heating circuits (yes I should get out more but don't really want to right now)- should I class said long radius bends as elbows (500mm) or formed bends (300mm) or something in between.
It really doesn't matter but i'd like to be as accurate as possible
TIA
EDIT Title should be Long Radius Copper Elbows but it is well past gin oclock

 

[Registered Gas Man]

Formed.

 

[muggles]

Formed

 

[oldbutnotdead]

Cheers both, I'd hoped there was some benefit to using them apart from them looking better as well

 

[Gasguru]

But given modern copper pipe and benders often crease the inner bend radius you might loose any head loss advantage over elbows...
And given the huge head loss of most current heat exchangers the miniscule advantage of pulling bends is pretty futile...

 

[oldbutnotdead]

Very valid points- the CH I was curious about, DHW wanted to get relative numbers for the 2 bathrooms, once i've finished I'll do some bucket tests to see if real world bears any correlation to my sums. And yes my bargain Toolstation bender makes a right mess of 15mm, does OK on 22 though. All keeps me out of mischief (and the bottle) on a damp Sunday

 

[Gasguru]

You'll find very few cylinder manufacturers are willing to disclose (and don't waste your time asking their clueless technical teams) the headloss of the calorifier....on high recovery unvented cylinders it can be considerable.
Obviously the tank-in-tank designs eg, ACV cylinders the headloss is low.