Pipe Grid Layout for space with very low ceiling

Discussion in 'Lighting and Electrics' started by click, Jun 8, 2016.

  1. click

    click Member

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    I'm designing a pipe grid layout for a basement space below an existing theatre. The coffered concrete ceiling is between 7'-6" to 9'-0" clear to the floor. The grid will be installed professionally by a theatrical rigging company.

    There's no question that I am asking for a 1.5" ID Schedule 40 grid, and the presumption is that all lighting fixtures will yoke up or overhang as much as they can. There will be vertical space between the ceiling coffers to allow this in most areas (the grid will be just below the coffered beams). I will probably ask for installation using speedrail (or its equivalent) so the entire grid can be at one consistent elevation (instead of the US-DS pipes sitting above or below above the SL-SR pipes).

    My inclination is to specify a standard 4'-0" x 4'-0" grid module, but I am entertaining possibly tighter pipe centers, say 3'-0", which might (or might not) make things more flexible and I wonder what people think about that. I'm also curious if readers have anecdotal comments about whether there should be a pipe on the space's centerline, or if the grid should split center so a yoked fixture can actually have its lens on center.

    Finally I have an idea about stopping the grid short of the walls of the space to allow overhung fixtures at the end of the grid to light a backdrop (for example) mounted to a wall. I wonder if people have opinions about doing so.

    Many thanks for the ideas....
     
  2. Skervald

    Skervald Active Member

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    I'm shooting from the hip here but I'd make a detailed drawing of your ceiling including the coffers and then one at a time overlay a 4x4' and then a 3x3' grid. Depending on the size of your coffers, you might find that one or the other option will align more pipe in the open spaces allowing you to yoke up more fixtures. You might also find an alternate spacing works better. Of course, the best way to know what you should do is to install it and then live with it for a few years. At that point you'll be an expert. I can't tell you how many times I've wanted to go back and kick my past self for not doing something a certain way.
     
  3. BillConnerFASTC

    BillConnerFASTC Well-Known Member

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  4. rwhealey

    rwhealey Well-Known Member

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    You may have discussed this project with an engineer already, but your existing conditions would be worth a look by a structural engineer if you haven't. if your slab above is post-tensioned you may have limitations on the locations the contractor can put hangers due to the tensioning cables, which would affect your grid spacing. It is possible to drill into a post-tensioned slab, just a bit more complicated than a cast-in-place slab with normal rebar.
     
  5. Footer

    Footer Senior Team Senior Team Premium Member

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    Why not build boxes that actually sit inside the coffer opening tight to the ceiling instead of below it? You won't have neat pipes but might be a bit more flexible. Overhanging by default is a real pain and a big time suck. You also have to tightly anchor those pipes to prevent pipe spin.
     
  6. BillConnerFASTC

    BillConnerFASTC Well-Known Member

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