Thread: Bottom of Bar Joist

Hello All,

Does anyone have any reference (such as IBC, IFC, ASTM, etc.) that you can or cannot use the bottom of steel bar joists to support sprinkler pipes, HVAC equipment, ducts, hanger wires for a suspended ceiling, etc.

Thanks.

Sincerely,

Corey Friedman

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Corey,

While this is not "official" it explains why not and how seldom it is allowed: RE: Hanging on bottom of Steel bar joists

Here is another discussion regarding trying to support the steel joist from the bottom chord - just the opposite of what you are asking, but still a no-no: Structural engineering other technical topics - Steel Joists-Is mid-span bearing permitted?

From what I've been told, learned, and read in the past is that, no ... no loads on the bottom chords.

You would want to contact the Steel Joist Institute, Steel Joist Institute - Home , for clarification and a definitive answer.
Contact the Steel Joist Institute (SJI)

Originally Posted by Jerry Peck

Corey,

While this is not "official" it explains why not and how seldom it is allowed: RE: Hanging on bottom of Steel bar joists

Here is another discussion regarding trying to support the steel joist from the bottom chord - just the opposite of what you are asking, but still a no-no: Structural engineering other technical topics - Steel Joists-Is mid-span bearing permitted?

From what I've been told, learned, and read in the past is that, no ... no loads on the bottom chords.

You would want to contact the Steel Joist Institute, Steel Joist Institute - Home , for clarification and a definitive answer.
Contact the Steel Joist Institute (SJI)

Hi Jerry,

Thanks for the reply.

I've contacted SJI and will keep you posted. Thanks for the fast response.

Sincerely,

Corey

Also consult ICC (International Code Council) for any bulletins or "white papers" they've put out to-date on this. If not found in code, these interim discussions and directions can be very helpful. ICC member.

One could say that it is the standard in the industry to hang any system that will impose more than 150# on the bar joist to be hung from the top chords of the bar joist.
It has been in every commercial specifications for as long as I can remember.
Any point loads or concentrated loads have to be approved by the Structural Engineer of record for the design.

Most bottom chord attachments are limited to miscellaneous items such as copper piping, vents, pvc piping, etc.

When I was a super, I had the same situation come up.

I don't know if this is new or old construction, but I simply put it to rest by pulling out the project 'Spec book' and there is was clear as day.

Every section of the spec book clearly stated how all materials are to be supported and it pointed to the fact the bottom chord shall not be used.