pump and pipe size

[rashas10]

I have a sprinkler system that will flow at a rate of 1.55 cu. ft/sec. What size pump and pipe would I need to maintain that flow with 60psi coming in from the street and a head of 82 ft.?

[PipeFlowCalcs]

You must tell me pipe diameter, pipe length, elevation difference between street pipe and sprinkler end.

[rashas10]

It's 82 feet from the pump in the basement to the water tank on the roof. I think 4inch pipe will be OK

[PipeFlowCalcs]

flow with 60psi coming in from the street

Height difference between point where you know pressure and sprinkler is needed.

Here is the report for your problem using Pressure drop and flow rate calculator

1. volume flow rate (q):
q : 1.55 ft3/s

2. weight flow rate (w):
w : 158007.61 kg/h

3. pipe length (L):
L : 82 ft

4. pipe diameter (D):
D : 4 in

5. pipe roughness (kr):
kr : 0.1 mm

6. density (ρ):
ρ : 1000 kg/m3

7. kinematic viscosity (ν):
ν : 1.006 mm2/s

8. dynamic viscosity (μ):
μ : 0.0010060001 Pas

9. K factor - minor lossed coefficient (K ):
K : 1

10. velocity (V):
V : 5.4137545 m/s

11. cross section area (A):
A : 8107.3193 mm2

12. friction coefficient (f):
f : 0.019540492

13. Reynolds number (Re):
Re : 546756.9

14. boundary layer (δ):
δ : 0.060756292 mm

15. pressure on the pipe start (p1):
p1 : 179.1536 ftWS

16. pressure on the pipe end (p2):
p2 : 150.69379 ftWS

17. pressure drop (p1-p2):
p1-p2 : 12.341893 psi

Velocity of more than 5 m/s is high for water pipeline, so I should use 6" pipe for your problem.
As pressure p2 is 150 ftWS it means that pressure on street that you have of 60 psi is enough to push water 150-34=114 ft above the street pipe elevation. So it is enough depending on the position of your roof.