PE-X LINED FITTINGS

Construction of flanged fittings

Completed fittings are one piece construction. Flanges are fixed. The preparation and assembly of welded branch connections a re in accordance with BS 2633 or ASME B31.3.

Attachment of flanges and collars

Attachment of flanges and collars are done by both back fillet and bore welds.
Transition from the bore to the flanged face must incorporate a radius to prevent undue stressing of the liner.

Fabrication dimensional tolerances

Tolerances for flanges and fittings is in accordance with the relevant standards.
Fabricated pipework are in accordance with the following tolerances:

• Squareness of flanges – Square to the axis of the pipe or fitting to within 0.05 mm per 25 mm measured across the face.
• Flange faces – Faces should not be uneven or concave. Convexity from the bore to the periphery must not exceed 0.4 mm per 25 mm width of face.
• Flange drilling – PCD +/- 1.5 mm. c/c of bolt holes +/- 0.8mm. Eccentricity between PCD and RFD up to 2-½” +/- 0.8 mm, 3” and greater +/- 1.5 mm.
• Bolt holes – Bolt holes are off center and equally spaced about the center line to an accuracy of 1.5 mm.
• Linear and angular dimensions – Linear dimensions +/- 1.5 mm; angular dimensions +/- 0.25 degrees

Internal finish of housings

The interior surfaces and flange faces are clean and free of sharp corners, burrs, rust, scale, weld spatter or other protusions that could adversely affect the lining.

Lining

The method of lining and the fit of the lining ensures that the lining is capable of withstanding the temperature, pressure and vacuum ratings of the system.
All interference fit linings in straight pipes are normalized prior to flaring.
Completed linings show no evidence of pinholes, porosity, cracks or bad workmanship. Sealing surfaces are free of surface defects that could impair sealing effectiveness.
Scratches, dents, nicks or tool marks on the sealing face are not deeper than 0.15 mm.
Any of these defect types less than 0.15mm but extendingacross the face cause the product to be rejected.
Blind flanges have linings firmly attached linings.

Production testing

For each batch, at least one representative sample of each nominal size of fittings is selected; tests are carried out to determine mechanical properties and SG.
Where samples do not comply with the requirements stated in this specification, each tube in the batch must have samples cut from each end and the samples are subjected to the same tests.
Any sample not meeting the specified requirements leads to rejection of the whole tube.
The outside diameter and wall thickness are measured.
Tubes not complying with the standard are rejected. with at least 50mm of adjacent material.
When specified, each liner tube is subjected to a flattening test. Each length of tube is passed through a pre-set gap between two powered rollers. The gap is set at 50% of the outside diameter of the tube. The tube is rotated about the longitudinal axis through 90° and then passed back through the roller gap.
The tube is examined for cracks. A crack, if found, is cut out along with at least 50 mm of adjacent material.

Hydrostatic pressure test

Hydrostatic pressure test is carried out at 16 bar water in air. Any evidence of leakage are cause for rejection.

Electrostatic test

Electrostatic testing is carried out at a minimum voltage of 20,000V. The full surface of every lining is tested. Any pinholes are cause for rejection.

Final Examination

Each item is examined visually. Following satisfactory completion, the outside edge of the flange is stamped with a letter “I” to indicate compliance.

External finish

The outside surface of all pipe and fittings are finished as follows.
Shot blast SA 2-½ and coated with one coat zinc phosphate, zinc epoxy or zinc silicate primer. After painting, blocked bolt holes and vents are cleared.
Marking and identification: The following information is marked permanently on each fitting by casting into the body or by hard stamping the flange edge in letters at least 6 mm high:

• Manufacturer’s marking
• Lining material

Packaging

All flanges are fitted with protective covers. These covers are removed just prior to installation.
Fittings are fitted with medium density fiberboard blanks or alternatively snap-on proprietary plastic blanks could be used.

Performance

All lined fittings meet the temperature, pressure, and vacuum ratings stated in the Lined Fittings manual.

Service limitations

For positive and negative pressure limitations versus temperature, see table next page. Service temperature limits, subject to compatibility with the fluid being handled are:
PE-X: -50° to +115°C
When lined fittings are exposed to very low temperatures (below -50°C) consideration must be given as to the suitability of the material used for the housings. See section below for further information.

Notes:

• Lined pipes and fittings made with PE-X inner coating can be manufactured in diameters from 2” and up to 24”.
• Lined pipes and fittings made with Teflon inner coating can be manufactured in diameters from 1” and up to 24”.
• For lined pipes or fittings in lower/higher diameters please consult with Golan.

The pressure ratings for ANSI 150# and PN16 dimensioned fittings are based on ratings in ANSI B 16.5.
The pressure ratings for ANSI 300# dimensioned fittings are based on the rating in ANSI B 16.5 300#, down rated to compensate for the decrease in mechanical properties at elevated temperatures of the lining materials.

System design and supports

Pipe systems must be adequately supported to avoid excessive deflection of flanged joints, and supports should be installed close to flanges. The requirement for adequate support is critical in areas of high levels of concentration of valves and fittings.

Butterfly valves are usually designed for straight metallic or thermoplastic systems, with the diameter of the vane being defined as a function of the inner diameter of the pipe system under consideration.

The inner diameter of lined steel pipe is considerably smaller than the actual steel pipe. Inner diameters of thermoplastic pipes tend to be considerably smaller due to their heavy wall thickness. Consequently, some interference =between the inner liner of a lined pipe and the valve vane might be experienced.

The designer should consider this possibility early in the selection process for pipe systems and valves, and if required, incorporate adequate conical spacers between the flanges of plastic fittings and the valve.

Installation and maintenance instructions for lined fittings

• Lined products must not be welded, brazed or torch cut to prevent damaging the lining.
• Handle the material with due care and attention, avoiding all mechanical shocks.
• All flanges are covered to protect them from damage during shipment, storage and handling onsite. If covers are removed for inspection purposes prior to installation, replace them immediately after inspection of each item is completed.
• When joining a Pexgol pipe and lined fittings together, the use of gaskets between the sealing faces is usually not necessary.
• Under normal conditions, remove covers only immediately prior to installation. As gaskets are often not required, utmost attention is required to avoid scratching or otherwise damaging the lining on flange faces.
• In case of leakage, inspect the sealing faces of each component for grooves or chips. Grooves or nicks not deeper than approximately 15% of the flare thickness can be removed with a fine-grade abrasive paper.