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Design Standard: EN545
Diameter range: DN40-DN2600
Pressure range: PN10-PN25
Medium: Water
Material: Ductile iron
Application fields: Water supply and drainage
Struggling with hard-to-reach valves or misaligned flanges in your water pipeline? A Dismantling Joint (also known as a breakout joint) is the ultimate solution for flexible installations and effortless maintenance. This comprehensive guide covers its working principles, key features, and step-by-step applications in water supply and drainage systems.
In rigid water pipeline systems, removing a valve or piece of equipment usually means cutting the pipe and fabricating new spools—an expensive and time-consuming process.
A Dismantling Joint (also referred to as a breakout joint or repair flange adapter) is a specialized pipe fitting designed to provide adjustable length and flange connection flexibility. It allows pipes, valves, pumps, and meters to be easily installed, removed, repaired, or replaced without cutting pipes or disturbing the existing pipeline alignment.
Manufactured to EN545 standards, these joints are typically made from high-strength ductile iron and are suitable for water supply and drainage systems ranging from DN40 to DN2600 and PN10 to PN25.
The genius of a dismantling joint lies in its telescoping design. It consists of several key components:
Outer Sleeve (Body): A cylindrical ductile iron housing with one fixed flange.
Inner Sliding Piece: A telescoping component that slides inside the outer sleeve.
Gland & Sealing Rings: Compressible elastomeric seals that prevent leakage while allowing axial movement.
Tie Rods & Adjusting Nuts: Heavy-duty threaded rods that connect the joint to the adjacent flange and control the extended length.
The Principle: By loosening the tie rod nuts, you can slide the inner piece to lengthen or shorten the joint (typically by 50-200mm). Once in position, tightening the nuts compresses the seals and locks the joint in place.
Why specify a dismantling joint for your next project? Here are its primary functions:
In water supply and drainage systems, the Dismantling Joint serves as an essential installation and maintenance device that provides flexibility in rigid flange-connected pipeline systems.
| Function | Description |
| Enabling Valve Removal Without Pipe Cutting | When a gate valve, butterfly valve, check valve, or other equipment needs replacement, the dismantling joint can be shortened to create clearance — allowing the valve to be lifted out without cutting the pipeline or moving adjacent pipes. |
| Compensating for Installation Tolerances | Pipelines and equipment are rarely positioned with perfect accuracy. The dismantling joint provides ±25–100mm of axial adjustment to accommodate real-world installation variations — eliminating the need for custom-cut pipe spools. |
| Providing Flange Connection Adaptability | Connects pipes with different flange drilling standards (e.g., EN1092 to ANSI, or PN10 to PN16) when special configurations are provided — simplifies procurement and reduces adapter requirements. |
| Allowing Pipe Expansion and Contraction | In long pipelines subject to temperature changes, dismantling joints with appropriate tie rod configuration can accommodate thermal expansion and contraction — reducing stress on flanges, valves, and pipe supports. |
| Simplifying Pump and Equipment Alignment | When installing pumps or other flanged equipment, the dismantling joint allows fine adjustment of the connection length — ensuring bolt holes align perfectly and flanges mate without stress. |
| Facilitating Emergency Repairs | In the event of a damaged valve or gasket, the dismantling joint can be quickly adjusted to remove and replace the component — minimizing system downtime and water service interruption. |
| Application | Specific Use |
| Valve Installation (upstream/downstream of valves) | Provides clearance for removing gate valves, butterfly valves, check valves, and control valves |
| Pump Station Connections | Allows pump removal for maintenance or replacement without cutting suction/discharge piping |
| Water Treatment Plant Pipework | Provides flexibility in rigid pipeline systems with multiple flanged components |
| Flow Meter Installations | Allows meter removal for calibration, cleaning, or replacement |
| Pressure Reducing Valve Stations | Facilitates PRV replacement without re-piping the station |
| Pipe-to-Flange Connections | Connects plain-ended pipe to flanged equipment when combined with appropriate adapters |
| Retrofit and Expansion Projects | Bridges gaps between existing pipeline flanges and new equipment |
| Bridge Crossing and Thrust Block Locations | Accommodates minor pipe movement while maintaining flange integrity |
WEIZIDOM’s Dismantling Joint is engineered specifically for water supply and drainage pipeline systems, providing installation flexibility and maintenance access.
| Feature | Advantage |
| EN545 Compliance | Manufactured to European standard for ductile iron pipes, fittings, and joints — ensures dimensional accuracy, material quality, and performance reliability for water supply applications. |
| Exceptional Diameter Range (DN40–DN2600) | Covers everything from small building service lines (DN40) to ultra-large water transmission mains (DN2600) — a single product family for projects of all sizes. |
| Pressure Range PN10–PN25 | Suitable for standard to medium-high pressure water systems — covers typical water supply and drainage pressure conditions (distribution mains to transmission lines). |
| Ductile Iron Construction | High-strength ductile iron body provides excellent mechanical properties, impact resistance, and durability — ideal for buried or above-ground water pipeline installations. |
| Adjustable Length Design | Provides significant axial adjustment range (typically 50–200mm depending on diameter) — allows easy installation, valve removal, and compensation for installation tolerances without special tools. |
| Integral Tension Rod System | Heavy-duty tie rods with adjusting nuts connect the dismantling joint to the adjacent flange — provides both length adjustment and mechanical retention, preventing separation under pressure. |
| Installation Guideline | Reason |
| Install between two fixed flanges (e.g., pipe flange and valve flange) | The dismantling joint provides adjustable connection between two points — requires flanges on both sides. |
| Ensure the joint is initially set to a mid-position in its adjustment range | Allows both lengthening and shortening capability during installation — provides maximum flexibility. |
| Tighten tie rod nuts evenly after final positioning | Even tightening ensures uniform gasket compression and prevents leakage. |
| Install with the longer sleeve on the side that will be adjusted more frequently | Provides better access to adjusting nuts for maintenance operations. |
| Do not exceed the specified maximum extension | Over-extension can pull the inner piece out of the sealing rings, causing leakage. |
| Do not compress beyond the minimum length | Over-compression can damage internal components and reduce seal life. |
| For buried installations, provide access for future adjustment | Valve boxes or access chambers allow future valve replacement without excavation. |
| For outdoor installations above ground, protect tie rods from corrosion | Stainless steel tie rods or regular coating maintenance is recommended. |
| When removing a valve, first loosen tie rod nuts and compress the dismantling joint | Creates the necessary clearance to lift out the valve. |
A Dismantling Joint is not just a pipe fitting; it is a vital maintenance tool that adds flexibility, safety, and cost-efficiency to any water pipeline system. By choosing a high-quality, EN545-compliant ductile iron joint, engineers and contractors can ensure seamless installations and rapid, hassle-free maintenance for decades.
Need a custom solution for your water project?
[Contact WEIZIDOM today] for expert technical advice and a no-obligation quote for Dismantling Joints, Flange Adaptors, and Flexible Joints.
