Viking Johnson MegaFit Long-Sleeve Pipe Coupling DN50-DN300

A long-sleeve wide-tolerance coupling with a very large setting gap

The Viking Johnson MegaFit Coupling is a ductile iron wide-tolerance coupling built around a long sleeve and long bolts. Its defining figure is the setting gap: 18 mm minimum and up to 60 mm on DN50, rising to 215 mm on DN250 and DN300. That makes it practical where pipe ends are far apart, where a damaged section has been cut out, or where an installer needs room to slide the coupling fully onto one pipe before swinging it back.

Ten sizes from DN50 to DN300 are listed, each with a published OD range, for example 107.2 to 133.2 mm on DN100. Materials, torque and gasket are given in the datasheet; the nitrile option is to DIN 3535-3 and the EPDM compound carries WRAS approval as printed.

MegaFit technical data

Size table from the datasheet (mm; A = end ring diameter, C = overall length, L x T = sleeve length x thickness).

Strengths and limits

• Setting gap on DN250 and DN300 is 18-215 mm, far above standard couplings, which suits repair closing pieces.
• The datasheet states that MegaFit does not resist end load from internal pressure, so adequate external restraint is required.
• Temperature rating to +90 C is higher than the restrained products, although hot service needs a bolt re-tightening schedule.
• Angularity of 8 degrees is larger than the 6 degrees of MaxiFit.

Selection and ordering

Choose by pipe OD and by the gap you need. Where the gap is short, a standard MaxiFit is lighter and cheaper; where it is long, MegaFit saves a cut-in spool. Select EPDM for water or nitrile for gas. The datasheet gives no single order code string, so the quotation should state size, gasket and bolt material, and a confirmation of the final configuration should be obtained from the manufacturer before ordering.

Installation notes

• Tighten M12 bolts at 55-65 Nm and M16 at 95-110 Nm, working evenly around each end ring.
• Check the OD range and gap before cutting out a pipe section.
• Fit thrust restraint; the coupling will not hold the pipe against pressure end load.
• Use the EPDM gasket for potable water, since the datasheet notes it as WRAS approved, and keep spare gaskets by mould number (6010 to 6018, plus 6030 for DN175).
• On hot lines above 60 C, add bolt re-tightening to the planned maintenance routine.

Applications in Oman and the GCC

Repairs of cast iron, ductile iron and steel mains, cut-in work on large water mains and temporary or permanent closing pieces on cooling water lines all benefit from the long gap. As with all rubber-gasketed joints, check chemical compatibility for treated or brackish water.

The weight range in the datasheet is 4.5 kg for DN50 to 39.4 kg for DN300, and the long bolts (235 mm on DN50 up to 420 mm on DN250 and DN300) are what allow the end rings to pull back far enough to clear the pipe ends. Keep the extra bolt length in mind when planning clearance in a narrow trench or chamber, since the bolts stand proud of the end rings during assembly.

When you enquire about the MegaFit, give both pipe outside diameters inside the DN50 to DN300 range, the gap between the pipe ends up to the 215 mm setting gap limit, and the medium, water at 16 bar or gas at 6 bar, so that the right body can be confirmed.

Selection and installation notes

Pipe couplings and clamps must be chosen from the actual pipe outside diameter, the pipe material, the working pressure and the joint movement expected, so measure the pipe before ordering and compare the reading with the size range on the data sheet. Clean the pipe surface and remove dirt, scale and sharp edges, mark the insertion depth, centre the coupling over the joint and tighten the bolts evenly in a cross pattern to the torque in the installation instructions. Check the joint again after the line has been pressurised, and do not use a coupling outside its stated pressure rating.

A long-sleeve coupling accepts a large gap between pipe ends, so check the gap before fitting and keep both pipes in line.

Information needed for a quotation

Send the full model code, the quantity, the delivery location in Oman or the GCC, the intended use and any accessories needed, so that the complete package can be quoted together.

Documents and supply information

The manufacturer data sheet is attached to this page and should be read together with the project specification and the site risk assessment before a purchase is confirmed. Ratings, standards and dimensions are quoted as printed on that sheet. Lead time, stock position and certificates available with the shipment are confirmed in the quotation, and we supply to Oman and the wider GCC region for industrial, utility and building services projects.

Related items and documents

See also MaxiFit and UltraGrip in our pipes and fittings category. The official datasheet is attached; Seven Star LLC can quote by DN.