steel lintel door header in 1 hour rated wall

[ccollings]

I have some 45 minute rated doors in a 1 hour masonry wall that have steel lintels. does anyone know if i need to protect the steel?

 

[RLGA]

Maybe, but probably not depending on the span and whether it is connected to the structural frame. See Section 704.11 (2018 IBC).

 

[classicT]

I presume that the steel lintel is because the masonry wall was not originally constructed with the opening, so a steel C-channel was added to reinforce the masonry and provide a lintel?

If so, the C-channel should be demonstrated to match the 1-hr wall. If the lintel fails, the wall fails. The lintel reinforcement becomes part of the 1-hr wall assembly. I would suggest looking into an intumescent coating on the lintel steel.

 

[classicT]

Maybe, but probably not depending on the span and whether it is connected to the structural frame. See Section 704.11 (2018 IBC).

That only applies to the bottom flange though...

704.11 Bottom Flange Protection​

Fire protection is not required at the bottom flange of lintels, shelf angles and plates, spanning not more than 6 feet 4 inches (1931 mm) whether part of the primary structural frame or not, and from the bottom flange of lintels, shelf angles and plates not part of the structural frame, regardless of span.​

If the lintel is reinforced such as pictured below, I think it needs to be protected with the same rating as the wall. This is typical to what I have seen. C channel attached to the wall via anchor bolts similar to a ledger board.

 

[RLGA]

That only applies to the bottom flange though...

704.11 Bottom Flange Protection​

Fire protection is not required at the bottom flange of lintels, shelf angles and plates, spanning not more than 6 feet 4 inches (1931 mm) whether part of the primary structural frame or not, and from the bottom flange of lintels, shelf angles and plates not part of the structural frame, regardless of span.​

If the lintel is reinforced such as pictured below, I think it needs to be protected with the same rating as the wall. This is typical to what I have seen. C channel attached to the wall via anchor bolts similar to a ledger board.
View attachment 8726

To be honest, I have never seen a steel lintel installed that way in my 30+ years of practice (I am sure there are some out there but are probably rare--they are just not energy efficient). If a lintel was installed as your image illustrates, then I would agree that everything but the bottom flange would need to be protected (sometimes, the tops of beams in direct contact with the element they are supporting is not required to be protected per the tested assembly).

For loadbearing masonry walls, every structural engineer I have worked with used built-in masonry lintels utilizing CMU bond-beam blocks, grout, and reinforcing bars (loadbearing walls constructed entirely of brick are rarely used anymore). The only time I have seen steel lintels used for masonry is for masonry veneers and they are usually steel angles. The vertical portion of the steel angle lintel is protected by the masonry, but the bottom is exposed and susceptible to fire exposure; thus, the excepted condition per Section 704.11. Similarly, back-to-back steel angles or structural steel tee shapes can be used. Again, the vertical portions of the steel would be protected by the masonry leaving the bottom flanges exposed.

 

[mtlogcabin]

Intumescent paint might be a simple solution

 

[RLGA]

Intumescent paint might be a simple solution

Just to make sure everyone understands, there is a difference between intumescent paint and intumescent coatings.

The paint variety is only approved for reducing the flammability of a material (think ASTM E84/UL 723 or NFPA 286 performance).

The coating variety is tested per ASTM E119 or UL 263 to resist thermal exposure to steel elements that would reduce the steel element's loadbearing capacity.

These terms, I admit, are used interchangeably in the industry, but the coating variety involves a lot more than just spraying a substrate with a thin layer of material. Intumescent coatings can be a lot thicker than your standard paint coatings, and they typically require a separate paint or colored coating, as permitted by the coating manufacturer, if you want the finish to be colored.

Before accepting a manufacturer's claim that their intumescent "paint" will protect steel, ask to see the ASTM E119/UL 263 test data. I had one manufacturer make that claim and I asked for the test data--they never sent it to me (I did not specify them). Another intumescent "paint" manufacturer provided me with data for a "modified" ASTM E119 test. The "modified" meant that the beam was not loaded. Needless to say, I did not specify them, either.

 

[ccollings]

THANK YOU!

 

[TheCommish]

Ron, I wish all the designers, builders, installers were as diligent as you.

I just had a project tell me Thexxx had a 1 hour fire rating based on manufactures literature having a statement "COMPONENT OF 1-HOUR FIRE ASSEMBLY See DrJ Evaluation Report 1210-01 for use of xxxx in a 1-hour re-rated wall system in accordance with the Standard Methods of Fire Tests of Building Constructions and Materials using ASTM E-119 testing procedures."

I look up the test report, no one hour rating, called the manufactures engineer who said it does not have a 1 hour rate as a material it self, and then presented this to the contractor, he still want to argue the installer said it was allowed and no one else is requiring the assembly be built properly.

End of rant

 

[e hilton]

and no one else is requiring the assembly be built properly.

Did he also say “we always do it this way” ?

 

[TheCommish]

Did he also say “we always do it this way” ?

the usually comes in the sentence after I explain the correct way for the 3rd time