505.3.1 Equipment platform area limitation question

[khumbert45]

We are doing preliminary layout work for a new process tower at an existing manufacturing facility. This is an unlimited area building, fully sprinklered. There are two other process towers at other locations of the building with multiple equipment platforms serving the stackups in those towers. They want to put in another process tower which would have 4 walls around the space with multiple levels of equipment access. The multiple levels of equipment platforms would exceed the 2/3 area limitation of this enclosed space. I can not find any exceptions in the code allowing for this. However, in the other two towers at this facility, there are platforms exceeding the 2/3 area limitation in those spaces as well, so I know this has been done before.

My question... is there an exception somewhere in the code that I am not seeing that would allow the platforms to exceed the 2/3 area limitation or is this something that I would need to request a variance from the jurisdiction? If so, has anyone had any luck with a variance?

 

[cda]

Welcome

Which building code and edition?


"However, in the other two towers at this facility" and I know you were going to say, just because they are there, does not make them legal.

 

[khumbert45]

2017 Ohio Building Code (based on 2015 IBC).

Yes, you are correct. Just because they are there does not make them legal. Just trying to determine if anyone has any ideas for how this could be permitted. If we go to a multi-story tower, we are no longer an unlimited area building, which won't work. If I add a fire wall to make it a new building, I need to be 60' away from the unlimited area building, which also won't work. At this point, I'm thinking the base level needs to be enlarged to provide us with enough floor area so that the platforms are no more than 2/3, cut back on the platforms to the point we are under 2/3 or go for a variance.

 

[cda]

Not into chapter five, but does this help:::

Check against the OHIO book,,,, Plus wait a day or two and you will get some great answers.




503.1.1 Special industrial occupancies

Buildings and structures designed to house special industrial processes that require large areas and unusual building heights to accommodate craneways or special machinery and equipment, including, among others, rolling mills; structural metal fabrication shops and foundries; or the production and distribution of electric, gas or steam power, shall be exempt from the building height, number of stories and building area limitations specified in Sections 504 and 506.

 

[khumbert45]

The 503.1.1 does give us an exception for height and area. However, it doesn't list an exemption from 505 where mezzanines and platforms are listed, of course...

I have checked against Ohio code and it is identical between Ohio and IBC for section 505.

Thanks for the response. I look forward to other thoughts on the topic! This is something we come up against on many projects and it's always a struggle. The clients have a need for a bunch of platforms to service the equipment, but can't afford the large footprint below that would require to get you there using the 2/3 area calculation. I am Interested to hear how other people have dealt with this issue.

 

[RLGA]

Are you including the area of the equipment, too, or just the actual area of the platforms to determine the platform area?

 

[khumbert45]

I am only including the area of the equipment if it is suspended above the platform level on legs. Most of the equipment is silos that span multiple levels so at those platform levels I would remove the silos from the area.

 

[Enri Code]

I am only including the area of the equipment if it is suspended above the platform level on legs. Most of the equipment is silos that span multiple levels so at those platform levels I would remove the silos from the area.

A lot of this really depends on what is being processed or handled and what the operations are. Based on your description, I am speculating - and you can correct me - that the towers are primarily storage silos and what they do is probably batching which then gets conveyed onto the main building for processing.

These types of material handling towers really fall into U occupancy or even agricultural (if you are handling bulk ingredients) that get treated as a big piece of equipment in its entirety. Think the difference between considering the tower structure as a garage and the equipment inside as a car versus thinking of the tower and the equipment as all parts of one car. One is an actual building beside your main building and the other is just a piece of equipment parked beside your main building.

This would explain why maybe the existing towers were permitted to be configured as they were.

You'll find that most jurisdictions that have several manufacturing plants within them and have a greater familiarity with these types of equipment stack ups will understand this. You can explore that option.

The operations is the other part that may throw a wrench into things. If the towers are actually doing further processing and are set up to where operators will actually be in them at certain levels and they are not just accessed for the occasional maintenance... that's a different animal altogether.

There is also a more controversial interpretation of aggregation of equipment platforms based on what elevation the platforms are at that I have encountered in other jurisdictions but I'll save that for another day as it probably deserves a different post to get it covered.

From a practical standpoint, you may also just want to review the stack up itself and see if you can value engineer the platforms enough to keep it all under the 2/3rds limit. I find from experience with these projects that we tend to go crazy with the platforms in the conceptual stage mainly because final equipment set up is still a moving target. We do often get to a very efficient layout to where the platforms are usually well within the area limitation once we get the equipment information firmed up at the tail end.

 

[ADAguy]

interesting topic, good analysis