Change in Risk Category?

[SteelPE]

I have a project that I am looking at for a client. The project consists of a renovation of an existing masonry building and turning it into a building that houses an ambulance company. The project was pitched as “we are just adding some openings in the exterior masonry walls:

On the surface that looks great until you start digging into the code (The code to be used for the building is IBC 2012 and ASCE7-10). Upon further review we are basically taking a structure that is Risk Category II and turning it into a Risk Category IV structure. Now, would an upgrade of the entire building be required or just the areas that I am modifying (poking holes into the wall)?

Now chapter 34 of the IBC deals with change of occupancy but it was noted in ASCE7-10 that they changed the Occupancy Category to Risk Category to avoid confusion…. so, I’m not quite sure how to handle this.

 

[msquared48]

"The project consists of a renovation of an existing masonry building and turning it into a building that houses an ambulance company."

This does constitute a change of use as you noted, and affects not only the structure, but fire requirements too due to the vehicles inside the building. You will also have hazardous chemicals such as oxygen to contain. This is not going to be a slam, bam, thank you mam, project. There will be a of of additional factors to consider.

As to whether the whole building would have to be retrofitted, that will probably have to be negotiated with the local jurisdiction.

Mike McCann, PE, SE (WA)

 

[RefEngr]

Doesn't the International Existing Building Code apply?

 

[msquared48]

Only if it is recognized and adopted by the local jurisdiction.

Mike McCann, PE, SE (WA)

 

[SteelPE]

msquared

Since the original structure was used for industrial purposes I believe the hazardous concerns/fire requirements remain relatively the same.... which is why the architect isn't picking up on this issue.

Ref,

I thought the IEBC was optional not mandatory. Chapter 34 allows you to use the IEBC but you can also use the contents of chapter 34. Essentially, from what I can tell, they contain similar language with regards to structural concerns with the IEBC going a little more in depth.

 

[CBSE]

SteelPE:

I have basically an exact same project...except I'm turning a Masonry Grocery Store into a State Police Station. I'm attacking it from the standpoint of:

1) Occupancy risk category is going from II to IV. Walls, Foundations, Connections, new openings must be checked and verified...or at least that is my interpretation of the code. I haven't verified what is required yet from the building department. I'm waiting on a call back. But I believe they will govern what needs to be upgraded.

The load increase is a big deal for these masonry buildings. My client wants to know if it is worth the work to upgrade, or just tear the building down and build a new structure...tear down would be much easier for me!!!! I will watch your post here and let you know how the building department wants me to proceed with mine.

 

[SteelPE]

CBSE,

Your situation may be a little different from mine.

Since my last post I have spoken to the architect about my concerns and they have spoken to the owner. It has been decided that we will design the structure as if it was a Risk Category II and if the BO decides otherwise they will give the owner a proposal for additional services associated with the upgrade. This is based upon the conversations the architect had with the owner.... I think they said that they don't receive emergency calls (I'm not sure if this would exactly qualify but at least they are aware of my concerns).

You might want to check out ASCE7-10 figure C1-1 on page 382 which I have found fascinating from the stand point of...... why would they introduce this chart and implement more confusion.

I also find it interesting that they change table 1-1 of ASCE7-05 to the point that they don't even describe the types of facilities are classified in Risk Category IV..... just more confusion.

 

[sandman21]

Chapter 34 of the IBC deals with an occupancy, as in volume one of IBC occupancy. If the change in occupancy requires a change in risk category an upgrade of the building is required.

 

[SteelPE]

sandman,

But if the building was always designed as a garage then the occupancy would not change and you would not trigger that particular section of the code hence the question. It would be a change in the tenant that would require the change in Risk Category.

 

[CBSE]

SteelPE:

You are taking a building designed under Risk Category II conditions and changing the occupancy to a risk category IV...I don't agree with your argument of a garage is a garage. You now have an emergency facility which is substantially different than a typical garage.

Is the tenant not changing, they are just adding services? I would think the added ambulance service would trigger a full building upgrade.

 

[XR250]

I always let the Architect figure out these details

 

[SteelPE]

CBSE,

My comment was directed to sandman when he referenced a change in occupancy.

If the building was previously used as a garage and they are now going to use the building for an ambulance company then from an architectural standpoint the occupancy is not changing. Chapter 34 lists a change in occupancy which is an architectural criteria not a structural criteria. This section of the code would be triggered if the building was switching from a I occupancy to say a R occupancy.

 

[CBSE]

Your risk category would change though correct? Because it would technically be considered an essential facility if it houses an ambulance service?

 

[SteelPE]

Well, according to the architect no it will not change. They arrived at this by reviewing the code (which I gave them) and talking to the owner. The BO may feel otherwise but we will cross that bridge we get to it.

Do I agree with it....... I'm not sure as they have certainly introduced some confusion when the rewrote the table and introduced figure C1-1.

 

[TLHS]

I really like figure C1-1. It makes things a lot clearer for industrial structures and unusual buildings. It clarifies the intent of the risk categories. It also gives you a basis if you're doing a formal hazard analysis. You shouldn't be using it every day, which is why it's part of the commentary and not a core code figure. It's context for the engineer and for the people making policy decisions on what types of facilities should fall in which risk category.

Pulling the list of specific structure types out of the ASCE document and placing that judgement onto the local code or officials, as mentioned in the commentary makes sense too. They still have a bunch of examples in the commentary text. For instance, a small ambulance dispatch facility might be a critical facility in a small town that only has one small dispatch, but might be inconsequential in a large city. The contents of Risk Category IV is really a disaster management policy decision on the local level.

 

[steellion]

If it's a structure that houses emergency services, it's a Risk Category IV structure, period. In the event of a natural disaster such as an earthquake, it's all hands-on deck to help protect people. Not being able to use an ambulance service because the garage was damaged is not acceptable. Of course the owner doesn't want to pay to modify the structure; it's up to you to tell them it is required by code. Your stamp is the one on the line.

If there's a building expansion joint, my understanding is only the portion of the building required for emergency services would be required to be designed as Risk IV.

 

[sandman21]

What is the current occupancy? S-1 or S-2? Is it ambulatory care? Is the ambulance company conducting business on the property? Are the drivers and medics staying in the building? I don't know how you are not going to a B occupancy.

 

[JAE]

Occupancy (architectural-wise) has not much to do with structural risk category. They are different things.

I agree with steellion's post just before this one. If you now will house emergency vehicles the Risk Category goes to IV and you need to fully investigate the structure.

The use of "garage" way back when may or may not mean much with regards to RC IV requirements.

Also - SteelPE - your statement that the project team will proceed and then if later the BO requires the upgrade sounds a bit worrisome to me in that you may then have to tear out new stuff to upgrade should the BO require it.



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[SteelPE]

JAE

The building needs to go through permitting before construction begins. I don't think it will get to a point that everything is constructed and then we need to tear down what we did and start over again.

I needed to put together a proposal for the client. What the difference if I put together a proposal based upon the clients needs and then if the needs change I change the proposal vs doing the renovation on an hourly basis for the owner. The owner and the architect are aware of what the concerns are.

 

[JAE]

Makes sense....but I still think it needs to be redesigned or checked at IV.




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