Jointing Systems for GRE/GRP Pipes

Key Features

• Adhesive (Butt & Wrap) Joints: Fiberglass tape and epoxy adhesive create a monolithic, leak-proof joint. These butt-and-wrap joints cure to full strength, becoming “as strong as the pipe itself”. They are ideal for high-pressure or permanent installations, and they eliminate metal parts at the joint.
• Flanged Joints (Full-Face & Lap Joint): GRP flange adaptors (often a stub end plus backing flange) allow pipes to connect to valves, equipment or other piping. Full-face flanges have one-piece construction covering the entire pipe face, while lap joints (van-stone) use a rotatable backing flange on a GRP stub end. Both types use rubber or PTFE gaskets for sealing.
• Mechanical Couplings: Stainless-steel or GRP sleeve couplings with compression or O-ring seals can quickly join plain pipe ends. Key-lock or other mechanical joints (like the Bondstrand Quick-Lock system) use interlocking taper designs for easy assembly.
• Sealants and Gaskets: Epoxy adhesives and elastomeric gaskets are selected for chemical compatibility and long-term sealing under load. All joint materials match the pipe’s service temperature and chemical requirements.
• Structural Reinforcement: For high-stress joints (high pressure or axial loads), we can add extra composite layers (“straps”) around adhesive joints to maintain strength under pressure and shock.

Benefits

• Leak-Proof Strength: Butt-and-wrap joints form a continuous fiberglass laminate around the joint, ensuring the pipe’s pressure rating is not compromised.
• Corrosion Immunity: GRP flanges and sleeves avoid galvanic corrosion. Even when stainless or carbon steel inserts are used, they can be isolated with non-conductive bushings if needed.
• Installation Flexibility: Mechanical and lap-flange joints allow for some misalignment and thermal movement, easing assembly in the field.
• Rapid Assembly: Key-lock couplings and clamp-style couplings require minimal surface preparation and no curing time, enabling quick startup.
• Maintenance Friendly: Lap flanges can be disassembled for inspection without cutting pipes. Quick-lock and clamp couplings can be reused if equipment changes.

Applications

• Corrosion-Resistant Piping Systems: Any FRP piping system conveying chemicals, seawater, acids, or fuels will benefit from welded-like adhesive joints and corrosion-proof flanges.
• High-Purity and ESD Lines: Adhesive joints provide smooth bore for sanitary or ESD-sensitive services, while conductive couplings are available for grounded systems.
• Utility and Service Connections: GRP flanged adaptors allow GRE/GRP pipes to mate with pumps, valves or steel pipelines using ANSI standard bolt patterns.
• Repair and Retrofit: Clamp couplings offer a fast solution for leak repairs or when inserting a GRP pipe liner inside existing host pipe.

Technical Specifications (Joint Types)

• Butt-and-Wrap (Adhesive): Pipes butt together and fillets of fiberglass cloth are wrapped around the joint with epoxy adhesive. Equivalent strength to pipe; requires curing.
• Tapered Adhesive: One bell end and one tapered spigot; adhesive-coated; pipe stops ensure alignment. Precise fit; high-pressure rating.
• Single/Double Bell (O-ring): Integral socket (bell) on one end; spigot end has O-ring groove. Double-coupling uses two bells with gaskets. Flexible axial movement; quick assembly.
• Key-Lock / Quick-Lock: Matching taper sockets on bell and spigot that lock when driven together. No adhesive needed; good for quick joins.
• Full-Face Flange (FRP): One-piece FRP flange bonded to pipe end; broad gasket surface. Excellent seal at low pressures; fully non-metallic.
• Lap Joint Flange (GRP + Metal): GRP stub end with loose backing flange (often carbon steel). Backing flange reusable; cost-effective for high-volume.
• Sleeve / Clamp Coupling: External band (FRP or metal) with bolts, plus internal rubber gasket. Can join different materials; allows pipe flexibility.

Unique Selling Points (USPs)

• Industry-Proven Methods: Our bonding techniques and flanges follow standards (ASTM/ISO/AWWA) and have decades of successful service.
• Integrated Design: Each joint system is engineered for the pipe type; for example, GRP flanges with carbon fiber rims to match GRE pipe expansion, or epoxy-filled flanges for maximum corrosion resistance.
• Full Support: We provide jointing consumables (adhesives, primers, fillers) and offer onsite jointing training.
• Flexible Options: From permanent glued joints to detachable couplings, we tailor joint solutions for the customer’s installation and maintenance strategy.