What is static flushing for chilled water pipe? Anyone can explain?

I am familiar with static flushing of engines and pumps so I will assume same. Static means without a pump running, just street pressure. You can forward or backward flush. A dynamic flush is with the engine running, developing internal pressure from the pump. We did this on fire pumps. The static pressure washes out debris that you don't want running through impellers and seals. Others may have a different answer.

General meaning ; flushing CH W loop with pump OFF.