Can I simply add fire ratings ?

[blugosi]

While protecting columns, can we simply add fire ratings achieved by different rating methods?
I mean, if we have a column with 1 hour of fire rating based on vermiculite or intumescent paint and we enclose it in gypsum boards calculated for say 1 hour, do we get a two hours fire rating on the column?

 

[Yankee Chronicler]

New construction, or existing building?

What code?

 

[TheCommish]

If the components ar listed and built in accordance with it tested assembly

 

[Yankee Chronicler]

The prescriptive values in IBC (2021) Table 721.1(1) do not seem to allow adding/combining systems At least, the footnotes do not say that adding is allowed.

The situation is different under the IEBC -- that's why I asked what code you are under.

 

[blugosi]

New construction, or existing building?

What code?

New construction.

The Code is NFPA 5000. For other upcoming projects the same question is raised for IBC 2021/ NFPA 101 as the adopted Codes.

 

[Penguin87]

While protecting columns, can we simply add fire ratings achieved by different rating methods?
I mean, if we have a column with 1 hour of fire rating based on vermiculite or intumescent paint and we enclose it in gypsum boards calculated for say 1 hour, do we get a two hours fire rating on the column?

Generally no. You can only "build your own assembly" up to a 1 hour rating; anything higher requires a tested, listed UL assembly. Which could include a multitude of different products and approaches.

I suspect if you want a 2 hour you need to go for the two layers of Type X. Gyp is cheap, no reason to make your life harder with the building official.