I have been given the task of running vent piping in a section of a large high school in TX. It is new construction. The space is wide open with nothing to support the sections of pipe save for the truss supporting the roof. The distance between the floor and the ceiling is about 32'. I am accustomed to using a riser clamp at every floor and supporting piping to a wall. What they've got me doing now is a bit new to me. Since this piping is in such a wide open space with so little to support it, this is what we came up with: we run two lengths of Unistrut across the truss supports. We attach the Unistrut with beam clamps when the top of the truss is the only option. We attach the Unistrut on the top of the bottom of the truss and secure with a small section of Unistrut with rod and nuts when we have that option. We then use 1/2" rod and riser clamps to support the piping. One riser clamp is secured to the Unistrut close the roof and to the top 10' section of pipe. Rod is run 10' down to allow us to secure the second section with a riser clamp as well. We then support the pipe coming up through the floor by drilling into concrete and inserting anchors, attaching 1' of 1/2" rod and riser clamp 1' above the floor and to the piping. I did not notice a problem when we used 3" riser clamps to both secure the 3" C.I piping and suspend it from 1/2" rod using nuts and washers. I am wondering if this will work with 2" piping as well when using 2" riser clamps. My feeling is that the 2" riser clamp may not be able to close into the 2" piping enough if it also has the 1/2" rod going through it as well. The foreman instructed me to use 1/2" rod for securing the riser clamps and pipe for both 2" and 3" piping. What are your thoughts on all of this?

is there a welder available ??
is there any flat bar available??
sounds like you will need to get creative..

I thought about a welder being useful. Appreciate your input and will hit someone up about that tomorrow.