Concrete wall fire resistance

[bobby83]

Hello all,
I have a case where the formwork system has tie rods that are removed with the formwork (see image). Cones at both ends of the tie rod are filled with mortar, but it leaves a cylindrical void inside the wall. Does that affect the fire rating of the wall?

 

[bobby83]

If so, is there any documentation on this?

 

[MIStructE_IRE]

Normally the entire void is filled with grout (at least in my part of the world. If you don’t do this then i imagine that yes, there is a fire issue - in theory..

Will a fire actually spread through such a small hole? Probably not.. Will anyone stand over that assumption..? Probably not.

Would make an interesting thesis for someone!

 

[WARose]

Here is something that should point you in the right direction (first the IBC, then the UL if you can't satisfy the IBC):

https://ncma.org/resource/firestopping-for-concrete-masonry-walls/

 

[KootK]

I have a case where the formwork system has tie rods that are removed with the formwork (see image). Cones at both ends of the tie rod are filled with mortar, but it leaves a cylindrical void inside the wall. Does that affect the fire rating of the wall?

I would say that it does not compromise the fire rating given that:

1) flames can't get through.

2) Smoke can't get through.

3) You've surely still got the required cover to your rebar to keep it non-melty.

 

[Spanky7]

With the appropriate type and depth of patching mortar applied to both sides of the wall the fire rating should be maintained.

See this thread on Hilti Ask: Link

 

[Ron]

No. It does not affect the fire rating. Check any of Gustaferro's publications.

 

[bobby83]

Thank you all, have a great week-end!