Seals in sewer fittings play a critical role in ensuring watertight connections between pipes and fittings, preventing leaks, infiltration, and exfiltration of wastewater. These seals are essential for maintaining the integrity and efficiency of sewer systems. Here are some common types of seals used in sewer fittings:

1. Rubber Gaskets: Rubber gaskets are one of the most common types of seals used in sewer fittings. They are typically made from materials such as EPDM (ethylene propylene diene monomer) rubber or neoprene rubber. These gaskets are placed between the mating surfaces of pipes and fittings and are compressed to create a tight seal. Rubber gaskets are flexible, resilient, and resistant to degradation from sewage and chemicals.

2. Compression Seals: Compression seals, also known as compression gaskets or O-ring seals, consist of a rubber or elastomeric ring that is compressed between the pipe and fitting surfaces. These seals provide a secure and leak-proof connection by creating a mechanical seal that prevents the passage of fluids. Compression seals are often used in conjunction with mechanical couplings or compression fittings.

3. Mechanical Joints: Some sewer fittings use mechanical joints, such as push-on joints or bolted flange joints, which incorporate integral sealing mechanisms. These joints typically feature a rubber or elastomeric gasket that forms a seal when the joint is assembled and tightened. Mechanical joints provide a reliable and durable seal that can withstand the harsh conditions present in sewer systems.

4. Threaded Seals: In sewer fittings with threaded connections, such as threaded plugs or adapters, seals are often achieved through the use of thread sealants or tapes. These sealants are applied to the threaded surfaces of the fittings to fill any gaps and prevent leakage. Thread sealants may be solvent-based or PTFE (polytetrafluoroethylene) tape, depending on the application and compatibility with the fluid being conveyed.

5. Compression Bands: Some sewer fittings, particularly those used in underground or buried applications, may incorporate compression bands or clamps to provide additional sealing force. These bands are tightened around the joint to compress the sealing gasket, ensuring a watertight connection. Compression bands are commonly used in conjunction with rubber gaskets or compression seals to enhance sealing performance.

Proper selection and installation of seals in sewer fittings are essential to ensure reliable and long-lasting performance. Factors such as material compatibility, operating conditions, and installation techniques should be considered to ensure effective sealing and prevent issues such as leaks, infiltration, and exfiltration in sewer systems. Regular inspection and maintenance of seals are also important to identify and address any signs of wear, deterioration, or damage that could compromise sealing effectiveness.