IPVMU Certified | 10/29/14 02:37pm
There are a few ways to do this. Electricians have the same problems hanging conduit, so in many cases, your local electrical distributor will have clips or brackets that will work great, like this conduit pipe clamp that costs a few bucks each:
Also, the Spinning Camera Mount is designed for this exact application.
'Truss/Joist Brackets' are sometimes available as options for standard camera mounts that are generally u-bolts or carriage bolts that mechanically fasten to steel without need to cut or thread through them. However, these are generally for webbed joists, not solid steel girders.
From experience: make sure any metal-to-metal mechanical fastener is tightly installed, and use a thread locker during install to keep nuts from vibrating loose over time.
Especially at an airport, where wind/engine vibration is pretty constant, any nuts can back off in mere weeks. Make it tight, keep it tight, and ensure your camera doesn't crash down into someone's multi-million dollar airplane.
I always used Caddy beam clamps and conduit hangers. They've got a lot of varieties for various beam types. They're simply clamped to the steel and you hang conduit, J-hooks, cameras, etc. from there. You may need to adapt whatever it is you're mounting to whatever thread type the clamp has (usually 3/8 or 1/4-20), but that's just a matter of getting the right screws.
IPVMU Certified | 10/29/14 06:15pm
Caddy is a manufacturer of fasteners designed for fastening conduit, boxes etc. to steel I-beams. There are others that do the same. Where you are running conduit at 90 degreres to the I-Beams, you may want to consider strut as the support mechanism.
There are other optiions based on your layout of the Hanger. Check the cost of each and always check with the AHJ - authority having jurisdiction for acceptable options