Question

A proposed piping and pumping system has 20-psig static pressure, and the piping discharges to atmosphere 160 ft above the pump. If the piping friction loss is 20 ft head, the minimum pressure rating (psi) of the piping system is most nearly:
(A) 50
(B) 100
(C) 150
(D) 250

Answer 1

Answer: (B) 100

Explanation:

Given that;

Pstatic = 20 psig , hz = 160ft, hf = 20ft

Now total head will be;

T.h = hz + hf

T.h= 160 + 20

T.h = 180ft

Minimum pressure = Psatic + egh

we know that specific weight of water is 62.4 (lb/ft3)

so

P.min = (20 bf/in² ) + (62.4 b/ft³ × 180 fr

P.min = (20 bf/in² ) + ( 62.4 × 180 × 1 ft²/144 in²)

P.min = 20 + 78

P.min = 98 lbf/in²

Therefore the minimum pressure rating (psi) of the piping system is most nearly B) 100