Lap Joint Flanges - Pumps, Valves, Piping and Fittings
Lap joint flanges are loose, rotating flanges used with lap-joint stub ends in marine piping systems. They simplify bolt-hole alignment and are useful where frequent dismantling, inspection, or corrosion-resistant wetted materials are required.
ProShipWorks provides end-to-end support to source and supply Lap Joint Flanges for marine vessels, ship operators, industrial facilities, maintenance teams and procurement departments.
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Product Information
| Product Name | Lap Joint Flanges |
|---|---|
| Product Category | Pumps, Valves, Piping and Fittings |
| Product Reference | 634 |
| Brands / Manufacturers | Galperti, Metalfar, ULMA Forged Solutions |
| Unit of Measure | Piece |
Key Features
| Key Feature |
|---|
| 1. Rotating flange ring permits easy bolt-hole alignment |
| 2. Used with a matching lap-joint stub end |
| 3. Stub end provides the pipe sealing and welding interface |
| 4. Suitable for stainless steel, duplex, nickel alloy, and lined piping systems |
| 5. Available in various nominal sizes, pressure classes, and facing types |
Applications of Lap Joint Flanges
| Application |
|---|
| 1. Marine seawater, ballast, cooling, and fire-main piping |
| 2. Pump, valve, strainer, and heat-exchanger connections |
| 3. Shipbuilding and repair piping requiring frequent dismantling |
Models & Manufacturers
| Model | Manufacturer |
|---|---|
| ASME B16.5 Class 150 Lap Joint Flange | Various qualified flange manufacturers |
| ASME B16.5 Class 300 Lap Joint Flange | Various qualified flange manufacturers |
| EN 1092-1 Type 02 Loose Flange | Various qualified flange manufacturers |
Technical Specifications
| Model | Specification | Value | Unit |
|---|---|---|---|
| ASME B16.5 Class 150 | Nominal size range | NPS 1/2 to 24 | NPS |
| ASME B16.5 Class 150 | Pressure class | 150 | Class |
| ASME B16.5 Class 300 | Pressure class | 300 | Class |
| EN 1092-1 Type 02 | Flange type | Loose plate flange for welding collar or lap-joint stub end | — |
| Typical marine construction | Common materials | Carbon steel, stainless steel, duplex stainless steel, nickel alloys | — |
| Typical marine construction | Facing | Flat face, raised face, or manufacturer-specific sealing arrangement | — |
Standards, Certifications & Class Approval
Review the available standards and approval information relevant to the product. Actual certification, material traceability, inspection and classification requirements depend on the product type, intended application and purchasing specification.
| Applicable Standards & Certification | Common standards include ASME B16.5, ASME B16.47 where applicable, EN 1092-1, ISO 7005, and MSS SP-44 where relevant. Material certificates are commonly supplied to EN 10204 Type 3.1 or equivalent project requirements. |
|---|---|
| Class Approval | Class approval is project- and material-dependent. Flanges may be accepted for classed vessels under DNV, ABS, Lloyd's Register, Bureau Veritas, or ClassNK requirements when supported by approved drawings, material certificates, dimensions, pressure ratings, and applicable piping-system documentation. |
Installation, Maintenance & Safety Information
| Installation Notes | Install with the correct matching lap-joint stub end, gasket, bolts, and nuts. Confirm flange standard, nominal size, pressure class, facing, material compatibility, and bolt-hole alignment. Tighten bolts progressively in a diametrically opposite sequence using the specified torque. |
|---|---|
| Maintenance Tips | Inspect for leakage, corrosion, distortion, gasket damage, and damaged bolt threads during maintenance. Replace removed gaskets and severely corroded or stretched bolts. Verify flange faces and stub ends remain clean and undamaged before reassembly. |
| Safety Notes | Depressurize, drain, isolate, and verify zero energy before loosening the connection. Use suitable lifting equipment for large flanges and follow approved bolting procedures. Confirm material suitability for temperature, pressure, seawater, chemicals, and fire-main service. |
Request a Quote for Lap Joint Flanges
Contact ProShipWorks for marine or industrial product sourcing, quotations and delivery.
- Vessel name and IMO number
- ETA / vessel schedule
- Berth or vessel location
- Required quantity
- Preferred delivery window
- Shipping agent contact details
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