Fitting a flange on a horizontal run

Fellas:

Hopefully some of ya'll can help me here; we're putting together some 600 lb flanges on some 20" and 24" runs of heavy-wall piping (1.219 wall) and the pipefitters and welders on the job have done that with a picker or a crane of some kind and a sling or cable choker ever since they've been fitting and welding. They rig the flange, swing it in, and then the operator holds it in place while the welder makes a root pass and a hot pass on it, and the welding procedure calls for that to be completed within ten minutes.

The problem is that Safety is saying that, according to OSHA, you can't do it that way, because you're working on a suspended load, and the welder can't be in there in the fall zone welding it up, so it has to be supported somehow and the rigging detached before the welder can begin work.

The fitters say that they can't use wooden cribbing because it's too bulky, and doesn't leave enough room for the welder to get in there and work, and they say that they've never done it any other way, but there are a couple of guys on the job who say that they've seen that fit made with flanges and 90-degree fittings by using a combination of three and four-legged pipe stands, and possibly an internal alignment tool, although some of them say that was just to provide another safety margin and to prevent the flange from getting away and falling once the rigging was removed.

One of the guys said that he saw some fitters using long (2 or 3-foot) stud bolts, and bolting them front and back into the flange, and then putting tall pipe jacks under the horizontal studs to support the face of the flange, and rigging a short pipe stand under the collar of the flange to support it underneath. Then some of the guys said that they'd run that internal alignment tool inside of the pipe and the flange to provide an extra safety so if one of the pipe stands blew out the flange couldn't fall straight down, but some of the others said that they didn't remember anything like that.

Anyhow, can someone explain to me how to make that fit safely without leaving the crane attached to it?

Thanks

Farfromhome