Lap Joint Flange
Lap Joint flanges are also known in the industry as Backup flanges, Loose Ring flanges, Loose Hubbed flanges, and Van Stone flanges.
While distinct from structural Rolled Angle Rings, Lap Joint flanges are specifically engineered for pressure piping systems. They are the ideal choice for applications that require frequent dismantling for inspection or cleaning, as the design allows for rapid disassembly without cutting the pipe.
There are two standards to which Texas Flange offers a variety of stub ends to accompany our flanges. The MSS standard is the regular length stub end and the most commonly used in the flange industry. The ASA-type stub end is of a longer length and is less common than the MSS type, though it may be more suitable for your application. MSS Type A stub ends are the industry norm and are utilized with standard flat-face lap joint flanges.
While the hubs of Lap Joint flanges are typically longer than those of Slip On flanges, especially in larger sizes, they can be modified to meet your specific requirements.
When hub height is not critical, or if a 'True Lap Joint' is unavailable, we offer a solution known as 'Lap Joint to SO LTH' (Slip On Length Thru Hub). This consists of a Slip On flange machined with a lap joint face and ID radius. If strict adherence to ASME B16.5 length is required, please specify 'True Lap Joint' to ensure the parts are not manufactured from Slip On stock.
A key benefit of the Lap Joint design is that the flange itself does not contact the process media. This allows for significant cost savings by pairing a less expensive flange material with the required grade of stub end.
Lap Joint Flanges and Rolled Angle Rings
A Lap Joint flange serves as a backing ring in a two-part assembly, designed to slide over a Stub End which is butt-welded to the pipe. This allows the flange to rotate freely, simplifying bolt alignment during installation.
Unlike Rolled Angle Rings, which are typically used for tank stiffness or ducting, Lap Joint flanges are designed to B16.5 specifications to ensure pressure retention in critical piping operations.
Lap Joint Flanges
1) Lap joint flanges are a two-piece design with a backing flange and a rolled angle ring.
2) It is available in butt-weld and slip-on configurations.
3) Different materials are used for the backing flange and the rolled angle ring.
4) The backing flange allows for easier alignment because it is free to rotate.
Rolled Angle Rings
1) Rolled angle rings is a two-piece design with a rolled angle ring and a backing flange
2) It is available in butt-weld configuration.
3) Just like Lap joint flanges, different materials are used for the rolled angle ring and the backing flange
4) The backing flange is not free-to-rotate in roll angle rings compared to lap joint flanges.
Which Type of Fitting is Right for you?
Choosing the right flanges for your industrial application is crucial. It entirely depends on the requirement of the intended application.
Lap joint flanges are suitable for piping systems, allowing easy disassembly, while rolled angle rings are suitable for structural applications to create curved or rounded shapes within various structures; then a lap joint flange is an ideal choice.
Are you looking for something more rigid and challenging to disassemble? A rolled-angle ring is the best choice for you.
Products
Texas Flange stocks a wide variety of flanges in all sizes and specifications.
ANSI Flanges
ASME Flanges
AWWA Flanges
Pipe Flanges
Industrial Flanges
Oil & Gas Industry Flanges
Custom Flanges
Petrochemical Flanges
Texas Waterworks Flanges
Ring Joint Flanges
Large Industry Standard Flanges
Metric System Flanges
Plumbing And Mechanical Industries Flanges
Industrial Pumps, Valves And Vessels
Manufacturing Industries Flanges
Heating Systems Industries Flanges
Flange Food And Beverage Industries Flanges
Frequently Asked Questions (FAQs)
The difference between a lap joint flange and a slip-on flange lies in their design and functionality. A lap joint flange consists of two parts: a stub end, which is welded to the pipe, and a loose backing flange that can rotate freely around it.
In contrast, a slip-on flange is a single-piece component that slides over the pipe and is welded in place, providing a simpler and more cost-effective connection. Slip-on flanges are commonly used in low-pressure applications where frequent dismantling is not required.
The difference between a swivel flange and a lap joint flange is that a swivel flange consists of two separate components: a rotating ring flange and a welded hub or collar that is attached to the pipe.
A lap joint flange also has two parts, but it uses a stub end rather than a welded hub, and its backing flange is loose rather than fully rotating like a swivel flange.
Lap joint flanges are not recommended for high-pressure applications because the design does not provide the same strength or seal integrity as other flanges, such as welded or slip-on flanges, in high-pressure environments.
In applications where there is severe vibration or significant movement (such as in machinery or dynamic systems), lap joint flanges may not provide the necessary seal integrity or stability, as the loose flange may shift or loosen under intense vibration.
Weld the stub end (a part of the lap joint flange) securely onto the pipe using the appropriate welding method. Slip the loose flange over the stub end. The loose flange can rotate, allowing you to align it with the bolt holes on the other side of the pipe or flange.
Position the flange so that it fits over the stub end with the bolt holes properly aligned with the corresponding holes on the other flange.
Insert the bolts through the aligned holes of both flanges and tighten them evenly using the specified torque, ensuring a secure connection.
