Jhon:
You posted:
"In a piece of pipe without a valve, the bore thrusts impinge upon components such as elbows and since the thrust is equal and opposite, the forces balance AS LONG AS THERE IS STRUCTURAL CONTINUITY (continuous pipe wall)"

1)Does this mean that it is not reqiured to use a thrust block at the elbow(high flow rate) ?
2)Is pressure thrust in a continous pipe is covered by(PD/4t)
3) if there is change in momentum (like a Wye with different flows in and out)does the same criteria applies?