Painting metal beam hangers with intumescent paint

[Ryan Schultz]

For a 2hr floor assembly, if you use a large timber beam that is rated for 2hrs, can that beam be hung by exposed metal hangers, if those hangers are painted with 2hr rated intumescent paint?

 

[RLGA]

Not with intumescent paint, but maybe with intumescent fireproofing. However, I don't think any of the manufacturers of intumescent fireproofing have data for metal rods. It may take an engineering judgment--if it's even possible.

In my opinion, a suspension rod probably does not have enough metal thickness so that it can be effectively covered by a thin coat of fireproofing to get a 2-hour rating. You may have to apply a really thick coat to adequately protect it.

 

[steveray]

Did you mean like a joist hanger beam hanger? I know Simpson has a 2hr through drywall hanger, not sure how that testing worked, but now you have me thinking....

 

[Ryan Schultz]

A hanger like this.

What about 1/2hr floor assembly? Would imagine intumescent paint provide enough rating?

Is there a source in the code, or otherwise where I can understand how to approach this situation?

Thanks, Ryan

 

[steveray]

No pic?....It needs to tested and listed as an assembly....Code sections will vary depending if it is rated for structure or passage of fire....

703.1 Scope. Materials prescribed herein for fire resistance
shall conform to the requirements of this chapter.
703.2 Fire-resistance ratings. The fire-resistance rating of
building elements, components or assemblies shall be determined
in accordance with the test procedures set forth in
ASTM E119 or UL 263 or in accordance with Section 703.3.
The fire-resistance rating of penetrations and fire-resistant
joint systems shall be determined in accordance Sections 714
and 715, respectively.

FIRE-RESISTANCE RATING. The period of time a building
element, component or assembly maintains the ability to
confine a fire, continues to perform a given structural function,
or both, as determined by the tests,

 

[Ryan Schultz]

The hyperlinks don't show up too well in this forum...

The following is the link to an example of a beam hanger...
https://www.google.com/search?q=sim...hUKEwift7q8iZ_oAhUMCM0KHbcqCBgQ_AUoAnoECAwQBA

 

[Ryan Schultz]

@RLGA, i wasn't quite sure what you meant by suspension rods.

 

[RLGA]

@RLGA, i wasn't quite sure what you meant by suspension rods.

I had suspension rods on my mind, because I'm going through this on another project (except it's all metal framing and not wood) where they where supporting a floor system from the roof structure using metal rods--I didn't even think of the typical joist hangers.

As for joist hangers, metal connectors are frequently used for Type IV construction, which provides a 1-hour assembly, so I don't think any added protection would be required under those conditions. However, for a 2-hour assembly, how do you plan to show that the wood, let alone the metal connectors, provides a 2-hour fire-resistive assembly?

 

[e hilton]

supporting a floor system from the roof structure using metal rods--

Hopefully with a better system than that KC hotel walkway.

 

[Ryan Schultz]

However, for a 2-hour assembly, how do you plan to show that the wood, let alone the metal connectors, provides a 2-hour fire-resistive assembly?

Using an approach like the following would allow one to demonstrate that the thickness of the wood would achieve a certain rating.
https://awc.org/pdf/codes-standards/publications/tr/AWC-TR10-1810.pdf

I think you can use a concealed hanger like the following in a fire rated assembly--as the wood that surrounds the metal hanger, in turn protects the hanger from fire.

---

Just curious if there's a way to use something like the following, in a 1/2hr, 1hr, or 2hr assembly if you paint it with am intumescent paint that is rated per the particular hour of the assembly.

 

[Phil]

Woodworks has a paper on fire rating of mass timber. Fire rating of connections begins on page 13.
https://www.woodworks.org/wp-conten...of-Mass-Timber-Members-WoodWorks-Apr-2019.pdf