Max. Wall Opening Width in Anchored Brick Before a Loose Lintel is Required? Horz. Angle Leg Width?

[abusementpark]

Have y'all come up with any good rules of thumb for the wall maximum opening width in anchored brick veneer before a loose lintel is required? They are commonly provided for door widths as narrow as 32 inches. However, it can be questionable for things like small mechanical louvers (say 16" wide) or scuppers (24" wide).

Also - what is the maximum width that you use for a horizontal leg on a loose lintel? I have been telling architects 4" maximum and that is causing some coordination issues with newer energy codes. If they want a horizontal leg wider than 4 inches, we switch to a WT lintel.

 

[Struct123ure]

If its a tiny mechanical louver opening why would you show it on structural? Leave it to the architect.
If the architect is asking you then similar to concrete beams we assume concrete has no tensile capacity, so an unreinforced masonry lintel wouldn't be able to span anything. In reality that's not the case and I believe you would be able to calculate the beam span assuming some tensile capacity of the mortar and or clay bricks whatever governs.
As a rule of thumb I would think of it as no more then 2 bricks wide, this way both bricks have something to bear on and bear against each other. 2 bricks is approximately 16" subtract 1.5" of bearing surface on both sides; I would say the maximum opening is 13".
I don't see what the issue is with using s steel angle with a 6" leg or 8" leg? You can get standard angles with 10" legs.

 

[jayrod12]

I provide them for all openings. Maybe ones that are less than 8" I can get behind the veneer spanning over it, but otherwise there's nothing holding it up besides mortar in tension. Not ideal.

 

[abusementpark]

If its a tiny mechanical louver opening why would you show it on structural? Leave it to the architect.

We don't show the openings, but architects always expect us to provide a loose lintel schedule for anchored brick veneer.

I don't see what the issue is with using s steel angle with a 6" leg or 8" leg? You can get standard angles with 10" legs.

The whole loose lintel concept is pretty shaky from a engineering perspective. I get uncomfortable as the vertical leg of the angle moves further away from the brick veneer.

 

[abusementpark]

I provide them for all openings. Maybe ones that are less than 8" I can get behind the veneer spanning over it, but otherwise there's nothing holding it up besides mortar in tension. Not ideal.

I think most masons would tell you openings 24 inches or less don't need loose lintels, if they aren't immediately adjacent to control joints. I've seen where the arch action of brick can be significant factor.

 

[GeorgeTheCivilEngineer]

All openings greater than a brick length unless whatever is filling the openings can support the weight of the bricks. Brick arching greatly relieves the load but doesn't mean bricks can't drop.

In the UK thin cold-formed galvanized steel lintels are readily available so contractors would have no problem fitting one as the brickwork is built.