Hydraulic Nuts to replace A194 nuts

[studbolter]

Is anyone familiar with a product design called a hydraulic nut and what is your opinion on replacing the standard A194 nuts with this design. Does the hydraulic nut conform to any standards.

 

[unclesyd]

I don't know what the status is now but several years ago when we looked at them there was no standard. All are backed up by good engineering and analysis and could be used in lieu of A194 nuts upon approval by all jurisdictions. We had preaproval for our application.
We backed out of using the as we would have to have a special design as our temperature was 600°F and that pushed the cost way up. I understand now that off the shelf designs can handle higher temperatures. Engineering is required for each application and they do require skilled labor for installation and removal due to the pressures involved.

A local power company does use them and I've haven't heard of any problems.

One place we were considering using the hydraulic nuts we now use SuperNuts from Superbolt with good results.