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Pipe Fittings & Flanges
Lap Joint Flanges
Lap-joint flanges supplied with stub ends against confirmed project specification.
AvailabilityProject based
Representative product visual. Final configuration varies by project.
Overview
A lap-joint assembly pairs a loose backing flange with a stub end that is butt-welded to the pipe. The backing flange rotates freely for bolt-hole alignment and is not wetted by the process, so it can be a lower-cost grade than the stub end. FLOWTEC (UK) supplies lap-joint flanges and stub ends configured to order scope, with the final specification confirmed at quotation stage.
At a glance
Lap-joint flanges pair a loose backing flange with a butt-welded stub end, letting the backing flange rotate for bolt-hole alignment while staying unwetted by the process. Specification confirmed against your project requirements.
- Backing flange rotates freely and is not wetted — can be an economical grade
- Suited to frequently dismantled lines and alloy or stainless systems
- Referenced to the ASME B16.5 and B16.9 design bases for flange and stub end
- Materials and documentation confirmed at quotation stage
Typical applications
- Frequently dismantled systems
- Alloy pipework with economical backing flanges
- Process and utility pipework
Typical use & selection context
Suited to systems that are dismantled frequently for cleaning or inspection, and to alloy or stainless lines where using an economical backing flange over a matching-grade stub end reduces cost. Selection considers design pressure, stub-end standard, backing-flange grade and facing, each confirmed against the line specification.
Operating envelope
Indicative operating range
Values are confirmed against your project specification. Detailed figures are issued on request after engineering review, in model-specific documentation at quotation.
- Pressure class
- ASME Class 150 - 1500
- Size range
- ½″ - 24″ (DN 15 - 600)
Standards & facing context
Referenced against ASME B16.5 for the backing flange and ASME B16.9 for stub ends. Indicative envelope: ASME Class 150–1500, sizes ½″–24″. Raised-face or flat-face configurations per the mating arrangement. Standards references are a design basis only, not a statement of certification.
Standards referenced
References below indicate the standards a configuration can be worked to. They are not a statement of certification — scope is confirmed per project.
- ASME B16.5 — Dimensional reference (with stub ends)
Materials & documentation
Backing flange and stub end configured to order scope, in matching or mixed grades as specified. Material and test documentation is confirmed against the purchase-order requirement; dimensional data is available on request.
Documentation
Information to include in an enquiry
- Standard and class
- Nominal size
- Stub-end grade
- Backing-flange grade
- Facing
- Quantity
- Documentation required
- Application and operating conditions
Related
Configure lap joint flanges for your duty
Every enquiry is reviewed by our engineering team. Tell us your duty, fluid and standards and we will respond with a proposed configuration.