Can hard tubings use normal compression fittings

[Proprietary]

In a JayzTwoCents video, Jay mentioned that the only kind of fittings people really use for hard tubings are rigid compression fittings.

Why can’t one use normal compression fittings for rigid tubings?

[Quadriplegic]

What do you consider normal compression fittings? 

Compression fittings used with soft tubing are barb fittings with collar that locks soft tube on the barb.
Compression fittings used with hard tubing use suction and O rings to keep the tube in place. 

I wouldn't call either of them normal or abnormal.

[cluelessgenius]

have a closer look at what a soft tubing fitting looks like and what a hard tubing fitting looks like im sure youll figure out why using soft tubing fitting with hard tubing might be a bad idea

[Labeled]

don't think of them as "Normal" compression fittings.

You have compression fittings for soft tubing, these have a barb that you press the soft tubing over. You need to pay attention to both ID & OD Inner & Outer Diameter for soft tube fittings or you'll have a hell of a time getting them on.

 

Fittings for hard tubing you just press them in, usually you only need to worry about OD with these. Pressing a barb into your hard tubing if the ID is larger wont be a problem, but if it is smaller or similar you risk cracking your tube. Barbs seal because the tube gets stretched tight around it. You do not want this with hard tubing.

 

[SolarNova]

'Normal' softtube compression fittings consist of a barbed fitting and a compression collar. As such you cant use hard tubing as it will not go over the barb.