Difference in flange and union?

Question

Difference in flange and union?

Answer 1

Unions are pipe/tube fittings that are used to connect two pieces of pipes. Its not actually referred as fittings, it is actually referred to as 'unions'. they have female thread and pipe and tube with male threads are threaded and sealed as required. This allows for the tube or pipe to be longer than its manufactured lengths.

Flanges on the other hand are generally used to connect pipes to equipment (Pumps, heat exchangers, vessels, valves).

I hope this helps. to see difference between them, you should look up picture on google image search