A note about fittings used in instrumentation

Fittings are extremely important accessory in a process plant. The array of fittings available is bewildering as they span across all the fields of human endeavor and  industry. No process industry which handles fluids can do without fittings, apart from industry they are found in transport (ships, aircraft, spacecraft, motor vehicles), HVAC (Heating Ventilation and Air conditioning), fuel and water supply systems. I have tried to collate some material available in Internet to understand the various types of fittings, the various thread types like NPT, BSP etc and links to resources to help order the required fittings for a job and also to understand and classify the fittings available in hand.

The document begins with introduction to various types of fittings and digresses briefly to understand the various 'thread' types and then describes how tube connections carrying process fluids and instrument Air are mated to the fitting. Each of these are labeled as sections. Section 1 is intro, 2 describes the thread technology, 3 describes way to identify a particular thread with aid of charts, 4 gives a special emphasis on BSP thread, a very confusing thread type (I hope the confusions should end once you go through the blog ;) ) 5, describes the tube connections like flared, flareless (bite type), o-ring face seal and 60 degree cone.

Section 6 has some misc resources on how much to tighten a fitting with a wrench after the initial 'hand-tight' and links to various guides by parker and swagelok. There is a link for on-line identification of a fitting type after giving the required inputs an some video resources for tube bending, sealing using teflon, selecting correct hoses and tubes etc.

I would have posted in the blog format, however, I had begun by creating the blog in MS word and though the text could be published to blog, the images and hyperlinks refused to resolve. Therefore, uploaded my created document to google drive and linked it here.

Click here to download the document and hope the information is useful
click here to download the pdf version of the same file.