For a safe, agile and trouble-free steel pipe system there are a few ground rules that you need to consider: 

Avoid compressing or pulling out the hose axially.
Corrugated hoses installed in line with the longitudinal pipe should not be subjected to axial movements. 

Avoid twisting during installation. 
Steel hose mounts should not be used to compensate for misplaced bolt holes (fixed flanges). Loose flanges minimize twisting of the hose. Pipe couplings reduce torsion during the pipe coupling torque. The use of two wrenches prevents the hose from being twisted when the pipe connection is pulled. 

Prevent the hose from moving in several planes. When a hose moves in several planes, the entire hose assembly is pulled on. Always install the steel hose so that the snake's movement only occurs on a plane that is where the hose is bent. 

Avoid sharp angles. 
Use pipe bends or angle couplings to avoid sharp bends at the connections.   Do not exceed the minimum allowable bending radius (center line).