Hose/Fitting fastening torque

[frans]

Some of my guys rarely finish a piping job with no leaks. Watching them they seem to over-fasten if anything. I read that fastening torque is important and came accross some sketchy info on a method of measuring the number of flats and also some tables specifying fastening torque.

What is the best approach to prevent over/under torque?

Is there a suitable torque wrench system for open ended spanners?

Where can I find a comprehensive torque guide?

Your assistance will be greatly appreciated because I am tired of fill-up buying oil!

 

[danhelgerson]

There is a new certification program from the Fluid Power Society specifically for conductors and connectors. The major manufacturers of hoses and fittings got together and asked the Fluid Power Society to establish a training and certification program to address some of the very questions you raise. It was noted that, on any given day of the year, somewhere on the planet there was an attorney in court defending a manufacturer because of a hose or fitting failure. In 90% of the cases, the problem was caused by an improper application of product. The certification program is designed to be sure those who are installing equipment are properly trained for their own safety and for the safety of the users of that equipment.

I know this does not answer your specific question but proper training would address the issue once and for all.


Dan Helgerson CFPS, AFPI, AJPP

http://www.cfpsos.com

 

[aviat]

Torque values vary with types of fittings you are using. It depends on weather the fitting is steel or aluminium, flared or flareless, lubricated or not etc. It would be best to get information from the manufacture or dealer.

As for wrenches, you can get flared crow’s feet from major tool suppliers like Mac. They would be ok for the smaller sizes but get pricey in larger sizes. Some people make their own by buying old wrenches at the flea market etc. then cutting them off and welding on a nut.

When you are using an adapter with your torque wrench you have to do a little math to compensate for the extra length. The formula is at the site below as well as a picture on bottom of the previous page of same site.

http://www.tpub.com/air/3-8.htm