Building Code rules for adding a temporary thrust.

[Whos_Curly]

My stage is a proscenium stage with a small apron and orchestra pit. Before my time a pit cover was built and installed. I would like to add a thrust onto the stage that pushes 12 feet into the audience seating. It will curve back to the apron, basically the bow of a ship jutting into the audience.

To do this I will need to remove a few seats and create a walkway around the thrust wide enough to not impede egress. I have tried to research this extensively. I can not find any building code, fire code, or osha code that prevents me from doing it. But I could be one sided in my search so I only see what I want to. This is what I think I know: IBC code 105.2 exempts me from needed to get a city permit. IBC 410.4.1 may consider this to be a temporary platform. IBC 410.7.2 says I am not changing the "stage" enough to effect fire code so I don't need to install sprinklers.

I am hoping for some input on weather or not I can do this. What am I missing that keeps me from doing this. If you include the code that backs me up or proves me wrong so I can look up any ideas you have that would be awesome. Thanks for any help you may have.

 

[BillConnerFASTC]

Good questions and good research. Way above what I more commonly see. Sort of fundamental, but how long will this be up? I'm guessing not an unlimited run. As all things code, ultimately your local building official or authority having jurisdiction can permit what they want, so my comments are based on what I believe the codes intend and what code staff would say - always with a disclaimer of it not be official.
While it is not always enforced, as a guide, from the NFPA Life Safety Code: Scenery and stage properties not separated from the audience by proscenium opening protection shall be of noncombustible materials, limited-combustible materials, or fire–retardant-treated wood.
And the IBC says: 410.3.6 Scenery. Combustible materials used in sets and scenery shall meet the fire propagation performance criteria of Test Method 1 or Test Method 2, as appropriate, of NFPA 701, in accordance with Section 806 and the International Fire Code. Foam plastics and materials containing foam plastics shall comply with Section 2603 and the International Fire Code.
While FRT wood would be nice, I think painting with a paint with a flame spread rating is probably sufficient. Would be good to ask the official or authority.
After that, providing the necessary clearance for egress is definitely required. A clear width (can measure with seat up if self rising) not less than the width of the aisles that lead to and from this area - assuming two or more aisles its technically a cross aisle - is the most that is needed. There are circumstances where you could leave the seats right to the stage edge, but requires some measurements and calculations. Post a plan - entire auditorium - and I could review - or just leave the width noted and move on.
I could imagine other issues in unusual circumstances - like are you losing or doing something that would require supplemental aisle lights or exit signs, or are you losing required wheelchair spaces - but probably not.

 

[Whos_Curly]

Wow this is some great information thank you so much for your reply. I figured I had glossed over something that I needed to know. I could not find the NFPA code book to check either. I will look into the what qualifies as limited or noncombustible and that may affect how I build it and what materials I use. I always have trouble determining what they consider combustible in different circumstances.

 

[BillConnerFASTC]

Well, I think you'll be between FRT wood and paint. Avoid thin ply, fabrics, and those things that look like you could light with a match. Best would be discuss with building or fire department before you start.

Let's face the fact that people in theatre have built a lot into the house, and most without an issue. There may have been a few collapses but don't think you'll find a fire.

And thanks for returning. It's disappointing when "new members" as a question, receive sincere replies, and are never heard from after the initial question.

 

[Whos_Curly]

I started looking at this forum yesterday and saw some awesome information. I hope to make reading through some posts a regular routine I am sure I could learn a lot here and maybe share a little of what I know.

I think I know how to move forward, I think that I have a good plan, now to check with the local powers that be to make sure they agree. Thanks again for all the great info.

 

[BillConnerFASTC]

Forgot this in Life Safety Code - right on point:

12.4.6.2 Platform Construction.
12.4.6.2.1 Temporary platforms shall be permitted to be constructed
of any materials.
12.4.6.2.2 The space between the floor and the temporary
platform above shall not be used for any purpose other than
the electrical wiring to platform equipment.

Its intended for head tables in ballrooms, boxing rings, and the like, but seems to fit your application.

 

[Whos_Curly]

Friend, you are a Wealth of knowledge! I think that this applies perfectly and it makes my life easier so in turn makes me very happy. Thank you so much for your efforts and help.

 

[Jay Ashworth]

This thread brought to you by the letters A, H, and J.

(Authority Having Jurisdiction, regulatory language for the people who will shut you down if you screw up, and whom you should hence talk to before swinging a hammer.)

 

[Whos_Curly]

Just wanted to drop in and say thanks for all the help. I had to battle a little to make it happen but it turned out great. Love having the band on stage.

 

[BillConnerFASTC]

Looks like good in that build. Congrats!

 

[Kristi]

This is pretty cool.
The theater I just was hired at had built a false stage OVER the seats last year. So, 4'ish off the ground. Unfortunately it wasnt the AHJ shutting them down it was our own school district refusing to take on the liability since it wasn't built by an engineer. Had to take it down. So now we have a pile of construction I beams in the corner... standing up, probably bent...waste of money. I wonder what they'll say if we wanted to put a whole band up on a platform?! We in no way can afford to hire an engineer to build our shows. What high school can?! However, this information from Bill is fantastic! This site is amazing!

 

[BillConnerFASTC]

This is pretty cool.
The theater I just was hired at had built a false stage OVER the seats last year. So, 4'ish off the ground. Unfortunately it wasn't the AHJ shutting them down it was our own school district refusing to take on the liability since it wasn't built by an engineer. Had to take it down. So now we have a pile of construction I beams in the corner... standing up, probably bent...waste of money. I wonder what they'll say if we wanted to put a whole band up on a platform?! We in no way can afford to hire an engineer to build our shows. What high school can?! However, this information from Bill is fantastic! This site is amazing!

I don't believe they mean actually built by an engineer, but that the design is reviewed by and perhaps the final work is reviewed by an engineer or architect, what the codes refer to as registered design professionals. You could probably find an architect or structural engineer that would review your plans and write a letter saying it was OK for a few hundred dollars at most. Maybe a return visit to see if you done it as planned or better would be another $100 or so. You should ask the school district if you had an engineer or architect just review the finished work before first use, if that would satisfy their concerns and liability. Alternatively, perhaps submit plans to the building department and have them inspect it. Probably a small fee. Obviously, finding a parent or interested community member who was an engineer or architect and would "donate" this service would be ideal.

Those three home built pit fillers that collapsed in one year and made national news kind of changed the landscape (bad pun), especially as far as forestage platforms of any sort. We've become such a litigious and ofetn angry seeking revenge society that I expect this trend will continue.

 

[Kristi]

Yes you are probably correct, I'll have to get a better story from the district side. A couple hundred sounds better than thousands, still a hard pill to swallow on small budgets. I'm thinking that fee might be something the District Health and Safety department might go dutch with us on...to keep the kiddos safe! Thanks for the alternative view!
I was actually thinking about mentioning those catastrophes but i didn't know enough about them to speak. However it's same as the spiderman accidents that put more public eyes on our rigging standards. It's all a good thing, anybody that sees it differently is going to hurt someone.

 

[Whos_Curly]

This is a high school, I had to jump a lot of hoops to make this happen. I had a structural engineer come in and inspect the build design and build and she did a full write up with her stamp to approve it. I also had a registered contractor come in and verify construction. I still got blow back from the district. I did not pay anything to get these people to help, reach out to your school and community find people who are willing to volunteer to help. Make sure you do everything you need to to cover your self. And most important make sure it is SAFE before doing anything. I do this job for my students I want to give them every opportunity I can and I don't let politics get in the way of that. Do it right do it safe and do it. It was awesome for them to work on a thrust stage a whole new experience.

 

[BillConnerFASTC]

Very good work and extra credit for getting it done at no cost. I'm sure if you wrote that up and attached a few pictures, you'f find a publisher. I can think of one or two right off that would be interested in it. Contact me off line if you are interested and need help.