Marzolf flanges accommodate most variations of VanStone and lap joint style connections.  Marzolf’s unique two-piece interleaving design allows rings to be installed after the stub ends or angle rings have been fused, welded, or glued; to simplify installation.  Using Marzolf two-piece flanges to replace cracked, broken, or corroded VanStone rings is instrumental to getting your facility back on line quickly, safely, and cost effectively.  Our flanges save you money by, expediting repairs to reduce labor costs, and by minimizing down time to maximize productivity.  Our line of stand alone rings are used in place of standard one piece rings on all types of piping including carbon steel, ductile iron, stainless steel, polyethylene, fiberglass, and even PVC and CPVC. Our line of backing rings fit behind molded fiberglass flanges and molded PVC and CPVC flanges. These backing rings facilitate higher bolt torques than customarily allowed on molded fiberglass and plastic rings.  They also eliminate the cracking which commonly occurs on those types of molded flanges. If you need a split flange or two-piece backing ring for a particular line in your system, you can rely on us to provide it. If we don’t have the exact item you require, we will custom manufacture it for you. Our rings are made of standard materials and non-standard alloys.  Marzolf flanges and backing rings are made to most standard specifications, or configurations, including any national or international standard dimensions.  Custom rings can be engineered and produced quickly.  Please take the time to browse our catalog for a full range of your most commonly required items. A Combination of Engineered Form and Function Marzolf flanges are designed, engineered, and manufactured to improve your operations by increasing your productivity and profitability, safely and efficiently.

  • Efficiency – By eliminating the need cut and re-weld pipe ends when replacing backing rings, Marzolf flanges have proven to reduce replacement time by as much as 66%.  Every minute spent on a redundant or lengthy repair operation is a minute where your production is stalled and your profits diminishing. Marzolf’s flanges are designed to significantly reduce replacement downtime, bringing your line back up in no time and putting money directly back into your budget.
  • Ease – No matter how complex your system is, Marzolf flanges introduce an element of refreshing simplicity. You’ll find installation and replacement with Marzolf flanges to be quick and effective.
  • Effectiveness – Marzolf flanges utilize an interleaving two-piece design where the two half rings share common bolt holes and interlock around a pipe with rigidity and strength.  This proven design has been used in the fluid process industries worldwide, since we invented it in 1955.


MARZOLF® Two-Piece Lap Joint Flanges are made of carbon steel, 304L and 316L stainless steel, PVC/CPVC, and special alloys including Titanium, Hastelloy®, and several duplex and super duplex materials. Our most common coatings include electro-zinc plating, e-coat epoxy, Teflon®, and corrosion resistant paint. MARZOLF® FLANGES are designed to fit steel and stainless tube and pipe stub ends and angle rings, polyethylene pipe stub ends and flange adapters, ductile iron pipe, fiberglass pipe, and PVC/CPVC/PVDF piping.

To Fit Pipe

The following tables will include specifications for rings to fit iron pipe sized fittings and tube sized angle face rings.  The tables include Class 150 drilling and Class 300 drilling, sized for Class 75 service, Class 150 service, and Class 300 service.  You’ll find specifications for rings to fit stub ends, angle rings, and ductile iron pipe.  There are separate tables for both carbon steel and stainless steel.

Specifications For: Class 75
Specifications For: Class 150
Specifications For: Class 300
Specifications For: Ductile Iron Pipe Size

To Fit Polyethylene Pipe

The links to the tables below will help you locate rings to fit Polyethylene Pipe and HDPE Flange Adapters, in both carbon steel and stainless steel.

Specifications For: Class 150

To Fit Tube

The following tables include specifications for rings to fit OD Tube Stub Ends and OD Tube Angle Rings in both Class 75 and Class 150.  We stock all these in both carbon steel and stainless steel.

Specifications For: Class 75
Specifications For: Class 150

To Fit Fiberglass

Here you will find two solutions to strengthen and eliminate cracking molded FRP flanges. Lightweight backing rings designed to back-up and strengthen fiberglass reinforced pipe flanges.  These rings fit behind molded fiberglass reinforced pipe flanges, effectively dispersing bolt stresses, to facilitate greater allowable bolt torques, and eliminate cracked FRP flanges. Spacer Plates in this section are engineered to fit between fiberglass flanges and raised face flanges to preclude bending of the fiberglass flanges.  Spacer Plates are available in a variety of materials; including coated carbon steel, polypropylene, and stainless steel.

Specifications For: Backing Rings
Specifications For: Spacer Plates


Here you will find two solutions to strengthen and eliminate cracking Van Stone style PVC or CPVC flanges. Marzolf® Two-Piece Backing Rings can be made to fit PVC/CPVC/PVDF Van Stone style flanges.  This line of lightweight backing rings is engineered specifically to back-up and strengthen plastic pipe flanges.  These rings allow for greater bolt torques without cracking PVC/CPVC Van Stone style flanges.  The two-piece design allow the backing rings to be installed before or after the hubs have been assembled.  These backing rings come in epoxy coated carbon steel, or stainless steel. Marzolf® Two-Piece Replacement Rings should be used if you have already cracked your plastic flanges.  This line of rings allow you to simply remove and replace the cracked PVC or CPVC rings with a Marzolf® Two-Piece replacement ring.  These rings can be made of PVC, CPVC, coated carbon steel, or stainless steel.  They are designed to fit all major manufacturers of plastic piping.  Please contact us for dimensional information.

Specifications For: Replacement Rings