2-hour seperation to save a 155 year old tin ceiling

[Resident Artist]

We recently purchased a mixed use commercial building on a popular tourist strip, a three-story brownstone style build in 1855.

The main level retail will be our gallery/showroom, and we're converting the upper two floors into our private residence.

In the main floor galley it has the original 1855 tin ceiling. We need to make it a 2-hour fire separation. The tin in attached to 1/2" plaster and lath on 2x14 joists. The floor above is the original floorboards.

We had one person tell us we would need to remove the tin tiles and add dry-wall, and another suggested we could build up the floor above. The city says they'll approve whatever a certified expert says gives us a 2-hour fire separation.

The original plan is to add 23/32" OSB sub-floor, electric radiant heat floor system, 1/2" of quickcrete over that, and 3/4" hardwood flooring.

This is a logn way of asking if we can achieve a 2-hour rating by adding material to the top of the separation rather than the bottom?

 

[cda]

Welcome.

Give it a few days, for answers


Not my area, but I think you can add the two hour wall on top, may be a little problem to do

Who is helping you with code questions/ design??

Does the building have a fire sprinkler system??

If not are being asked to install one?

 

[cda]

How many square feet is each floor

Wonder if you could be a live work per IBC

 

[steveray]

Hire a designer or code consultant....doesn't seem right.would they accept sprinklers as an alternative?

 

[fatboy]

Agree with steveray, save yourself the time, money and sanity, and hire a RDP as the City has stated that is what they will accept.

"The city says they'll approve whatever a certified expert says gives us a 2-hour fire separation."

Trust us, you can play the "what if" game forever, but that does not get your project underway.

 

[Resident Artist]

More details:

The floors are 15' x 57', so just under 900 sq/ft. The top two floors are being opened to each other for an open loft floor plan for our personal residence, so as per the city inspector the 3rd floor doesn't enter into this.

We've 100% gutted the middle floor, so it's currently wide open, side to side and front to back.

What is an "RDP?" We did hire a local architect who put together a detailed multi-page score/rating report, and we fell just under the score we needed to not have to add a sprinkler system. Making the ceiling/floor between the main floor gallery and the residence 2-hour rated puts us above this score minimum.

Sprinkler is an option, but for both esthetics and budget we'd rather exhaust our options for the 2-hour separation first, especially so considering how many layers are already being added to the top.

 

[tmurray]

Your architect is the one who should be telling you how to get the rating.

I would not accept rating the ceiling from above. Building codes typically requires ratings of ceilings to be from below (the fire rated sheetrock would have to be below the joists).

 

[cda]

More details:

The floors are 15' x 57', so just under 900 sq/ft. The top two floors are being opened to each other for an open loft floor plan for our personal residence, so as per the city inspector the 3rd floor doesn't enter into this.

We've 100% gutted the middle floor, so it's currently wide open, side to side and front to back.

What is an "RDP?" We did hire a local architect who put together a detailed multi-page score/rating report, and we fell just under the score we needed to not have to add a sprinkler system. Making the ceiling/floor between the main floor gallery and the residence 2-hour rated puts us above this score minimum.

Sprinkler is an option, but for both esthetics and budget we'd rather exhaust our options for the 2-hour separation first, especially so considering how many layers are already being added to the top.

mid your Architect has a code book

More than likely a version of the international building code

Have them look at chapter 4 got Live/work section

See if that saves you some money

 

[Inspector Gift]

"RDP" = Registered Design Professional (i.e., Architect or Engineer)

 

[classicT]

Generally speaking, your issue will be that whatever you add to the top side of the existing floor/ceiling assembly to achieve the required 2-hr separation is going to be supported by that existing floor/ceiling assembly.

This means if the fire burns the existing floor out, whatever fire separation you added above, will just fall. Thus, you did not achieve the 2-hr separation.

Sorry to be the bearer of bad news, but the fire resistive almost always have to go on the underside of the floor (ceiling side).

Suggest that you start looking into how to salvage the existing tin roof, and then have it reinstalled.

 

[steveray]

Intumescent paint?

 

[classicT]

Intumescent paint?

Typically, intumescent paint protects an individual component and does not create a horizontal assembly.

As an example, you can coat a steal beam with intumescent paint to protect the beam. That beam could then support a horizontal assembly.

 

[redeyedfly]

Considering the small size of the spaces it seems you could design it as nonseparated occupancies. Ask your architect to review IBC 508.3.

I've never heard of scoring for sprinklers. They're either required for the occupancy or you're adding them to reduce other fire protective requirements.

 

[jeffc]

I would hire a Fire Protection Engineer. More than likely, this will be a performance design that substitutes an alternative, but equivalent, means of protection. For example, install combination, or mix of, a sidewall fire sprinkler system below, smoke detection above and below the ceiling, enhanced exiting above...

 

[cda]

Live work help any??? Chapter 4

 

[mtlogcabin]

The tin in attached to 1/2" plaster and lath on 2x14 joists. The floor above is the original floorboards.

Ask your architect to look at this section. If you sprinkle the entire building then you reduce the fire separation rating from 2 hours to 1 hour. The exception below may let you use the existing construction to meet that one hour requirement if your architect will verify that is what is there.


2018 International Existing Building Code (IEBC)
1011.5.3 Fire barriers.
Where a change of occupancy classification is made to a higher-hazard category as shown in Table 1011.5, fire barriers in separated mixed use buildings shall comply with the fire-resistance requirements of the International Building Code.

Exception: Where the fire barriers are required to have a 1-hour fire-resistance rating, existing wood lath and plaster in good condition or existing 1/2-inch-thick (12.7 mm) gypsum wallboard shall be permitted.

2018 IBC
711.2.3 Supporting construction.
The supporting construction shall be protected to afford the required fire-resistance rating of the horizontal assembly supported.

Exception: In buildings of Type IIB, IIIB or VB construction, the construction supporting the horizontal assembly is not required to be fire-resistance rated at the following:

1. Horizontal assemblies at the separations of incidental uses as specified by Table 509 provided that the required fire-resistance rating does not exceed 1 hour.

2. Horizontal assemblies at the separations of dwelling units and sleeping units as required by Section 420.3.

3. Horizontal assemblies at smoke barriers constructed in accordance with Section 709.

 

[Resident Artist]

They're either required for the occupancy or you're adding them to reduce other fire protective requirements.

I think this is closer to what I meant to say. I only remember that it was a longer questionnaire/list of specifics/conditions that included "sprinklers?" (that was a 'no' on the list) and we had to be above a set cumulative number for occupancy. A "Sprinklers; Yes" would put us above this number, as well as a few other changes on the list (most couldn't be changed), and a 2-hour separation was one of them (currently rated a 1-hour separation).

 

[fatboy]

When Resident Artist spoke of the "scoring", my thoughts went to the International Existing Building Code, there is a path for performance of existing buildings.

 

[Resident Artist]

When Resident Artist spoke of the "scoring", my thoughts went to the International Existing Building Code, there is a path for performance of existing buildings.

View attachment 7530

So I had to look it up, it was called: "Performance Compliance Evaluation IEBC Section 1401.5" checking for "Fire Safety", "Means of Egress," and "General Safety," and at the end of the survey it says, "A negative score fails."

 

[Resident Artist]

#16: Mixed Occupancy Value is what hurts the score. Adding a 2-hour separation adds 10 points.

 

[fatboy]

So I had to look it up, it was called: "Performance Compliance Evaluation IEBC Section 1401.5" checking for "Fire Safety", "Means of Egress," and "General Safety," and at the end of the survey it says, "A negative score fails."

What code cycle is/are he/they using? In the 2018, Chapter 14 is Moved/Relocated Buildings.

 

[cda]

Anyone want to say if live work helps???

IBC

419.2 Occupancies

Live/work units shall be classified as a Group R-2 occupancy. Separation requirements found in Sections 420 and 508 shall not apply within the live/work unit where the live/work unit is in compliance with Section 419. Nonresidential uses that would otherwise be classified as either a Group H or S occupancy shall not be permitted in a live/work unit.
Exception: Storage shall be permitted in the live/work unit provided the aggregate area of storage in the nonresidential portion of the live/work unit shall be limited to 10 percent of the space dedicated to nonresidential activities.

 

[Resident Artist]

What code cycle is/are he/they using? In the 2018, Chapter 14 is Moved/Relocated Buildings.

It doesn't say. I only see, "Performance Compliance Evaluation IEBC Section 1401.5" on the top of this.

 

[jar546]

I had this situation and the RDP found a product that was spray on which required a special inspection for thickness. With RDP and special inspections, they were able to protect the metal ceiling from being removed. Chapter 7 had to be utilized for the balance of the horizontal separation requirements.