Rebuilding the exterior of a chimney, Q about fire codes

[MrsCeedge]

We have a fireplace that has siding on the outside of it. Some of the siding needs to be replaced, so we are going to have it redone.
Problem is, I can't figure out what the circled part in the picture is called so that I can figure out if we need a fire proof sheathing under the Hardie we want to install.

Can anyone point me to the name of this part of the structure, or the building codes regarding this?

I've been scouring the interwebs for quite a while now, and I just can't seem to find what I'm looking for, which is how I eneded up here.
I'm sure it's a keyword problem.

Thanks for helping!

 

[bholler]

We have a fireplace that has siding on the outside of it. Some of the siding needs to be replaced, so we are going to have it redone.
Problem is, I can't figure out what the circled part in the picture is called so that I can figure out if we need a fire proof sheathing under the Hardie we want to install.

Can anyone point me to the name of this part of the structure, or the building codes regarding this?

I've been scouring the interwebs for quite a while now, and I just can't seem to find what I'm looking for, which is how I eneded up here.
I'm sure it's a keyword problem.

Thanks for helping!

View attachment 326415

Check the manual for your prefab fireplace

 

[MrsCeedge]

Check the manual for your prefab fireplace

We don't have it. It was here when we moved here.

 

[stoveliker]

I would think that a fireproof layer under hardiebacker is not that relevant; hardiebacker is noncombustible itself?
It was my understanding that one needs a certain distance between the flue and any combustible - whether there is any noncombustibles in between does not matter. So adding something beneath the hardie won't matter.

Maybe I'm wrong, though.

 

[Maint1]

I could be wrong, but I don't know the name of the circled part, but believe it is like that for looks?? Unless it is a masonry chimney. Really the construction of the chimney would only need to be as wide as code dictates for the flue liner. If I were to call the circled portion something I would go with "the base of the chimney".

 

[begreen]

Look in the door channel of the fireplace to see if there is an ID tag there. Post a picture showing the fireplace and maybe we can identify it.

 

[begreen]

I would think that a fireproof layer under hardiebacker is not that relevant; hardiebacker is noncombustible itself?
It was my understanding that one needs a certain distance between the flue and any combustible - whether there is any noncombustibles in between does not matter. So adding something beneath the hardie won't matter.

Maybe I'm wrong, though.

That's correct. If the prefab is correctly installed then the clearances have already been honored.