Why have holes in handrail?

[zen2000]

Dear All;
I found all the handrail in my plant have the holes especially at the elbow 90 degree.
Can anyone explain me why it has hole in the handrail?

Thank you in advance.

 

[IFRs]

Possibly to relieve pressure and allow for drainage during galvanizing?

 

[civeng]

Hi everyone,

If your guardrail is galvanized, the holes are there to prevent a build up of the presure inside the tube when the gaurdrail is dipped in the galvanizing stage. If the holes were not there, the guardrail would blow up like a plugged canon.
However, many of the machines used in cutting (shearwise) the tubes for guardrails have a sort of protuberance in the cutting blade which automatically makes that hole, thus saving the trouble of making those holes with a torch, which does not make a very clean job.
Have a good one everyone.