Pipe Supports to be Directly Rested on Grating

[ASHOKK1969]

Dear Forum Members,

My query is related to Oil & Gas / Chemicals Projects.
In general, piping assemblies laid out on an elevated structural platform are supported on main steel beams exposed through a cutout in the grating or chequered plate.

Can we rest the supports directly on grating upto certain load and size limit of pipe to avoid multiple cutouts in the grating?
We have ensured the load taking beam underneath all such locations.

Just to elaborate a sketch has been attached.

Best Regards,
Ashok Kumar

 

[pennpiper]

Just a suggestion, I think you should talk to the people in the maintenance department to see if they have any thoughts or objections. Some times they have to remove the grating to access other areas/objects under the grating and the support would make that very hard.

Sometimes its possible to do all the right things and still get bad results

 

[BigInch]

Wouldn't be the first time I've seen it done. Normally including a small base plate seal welded to the pipe support column above as you have shown, although always tack welded to the grating, or seal welded to ck plate below. Pipe should move on the supports, if movement is necessary. Supports shouldn't move. If that were offshore, corrosion would soon start eating up the interface between base plate and ck plate, if that was not seal welded too.

 

[LittleInch]

Can you do it - Yes, in practice you see it all the time. Is it a good idea - No. Not only can't you lift up the plate for access, the actual strength of the grating is suspect for point loading. To remove the grating sometimes they then cut out the grating around it leaving a small square of grating which then has a high chance of collapsing as it has lost a lot of strength.

The other point is that once people see you doing it they think that you can do it anywhere and you end up supporting loads on grating where it is not well supported.

Don't do it (IMHO).

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[BigInch]

Of course it should only apply to very small diameter pipe.

 

[bimr]

Supports like this would be considered in a case by case consideration.

For this to work, the grating would have to be permanently attached to the steel support beams. Most of the time the grating is not attached in this manner.

 

[ASHOKK1969]

Hi,

Thanks for your inputs and replies.

At present we are limiting the criteria of not providing a cutout essentially up to 13 kN (3 kips) vertical load.

Rgds,
Ashok Kumar

 

[BigInch]

That's certainly too much load for grating alone. It would need a support directly under a load that large.

 

[ASHOKK1969]

Yes you are right. Steel member has been provided below grating.

 

[LittleInch]

You or the contractor is just being lazy. There is no excuse for this.

Save a few cents now and pay dollars later.

I wouldn't let someone do it on my project.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.