Details of HIF Design	View HIF Definitions View Installation Instructions
Pipe Spool Connection The High Integrity Flange connection used to join plastic lined pipe spools to pipe spool consists of a passive and an active end, joined together through a steel Load Bearing Ring. The passive end is similar to the end of a standard pipe spool or fitting except that if the end is of lap-joint or raised-face construction, and the diameter of the metal flare on the pipe end or of the raised-face is slightly larger. The active end consists of a Belleville Washer(s) (Coned Disc Spring) and a Flat Washer (Force Distribution Ring) assembled behind the flare of the plastic liner. At installation, the Load Bearing Ring is inserted between the metal faces of the flanges or flared ends of the pipe. The joint is then bolted together in the usual manner, except that the nuts and bolts are secured with high torque values, thus establishing a highly preloaded assembly with metal to metal carry-through of the structural load. The Belleville Washer deflects during the boltup and, acting through the Flat Washer, applies a predetermined, optimum sealing load to the flared faces of the liners.
Fitting to Fitting Connections	View Fittings
All fittings in the High Integrity Flange system have passive ends. As with the passive ends of pipe spools, if the end of a fitting is of the lap-joint design, the diameter of the metal flare must be little larger than with standard piping. When a fitting is to be connected to a pipe spool, the adjacent face of the pipe should be of the active end design. The fitting and pipe are then joined together as described under Pipe Spool Connections. In the situation where a fitting is to be connected to another fitting, the adjacent passive ends of the fittings are joined together through an Adapter. The Adapter consists of a Load Bearing Ring, two Belleville Washers (Coned Disc Springs), two Flat Washers (Forced Distribution Rings) and a flared plastic liner of PTFE. When the joint is assembled, the adapter with the springs, washers and PTFE liner insert is placed between the fitting flanges. As with the active ends on the pipe spools, the Belleville Washers deflect and, acting through the Flat Washers, apply predetermined, optimum sealing loads to the flared liners of the fittings and adapters. Automatic Load Compensation Flanged connections in a High Integrity Flange system are all uniformly sealed. Stored energy in the Belleville Washers automatically compensates for any changes, such as deformation of plastic flares, that would affect sealing forces, and stored energy in the highly pre-loaded bolts copes with conditions affecting structural load. Miscellaneous HIF Components/Materials HIF Vent Connector: T61717, 316SS Porous Disc: Hastelloy "C"-276 Thick (Plain) Washer: T61571-XXX 016-064, Powder Metal F0008-R Thin Washer: T61580-XXX 016-032, 304SS 048-064, Carbon Steel Painted Belleville Washer: T61573-XXX SAE 64150 Austempered to RC 42-48