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Chemical Couplings

(100-1000mm diameter)

Provide a watertight connection where a chemically inert flexible coupling is required

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 Flexseal Chemical Couplings provide a flexible and watertight connection on underground drainage systems that require a high chemical resistance to a wide range of chemicals.

Manufactured to meet specific site requirements, Flexseal Chemical Couplings are able to withstand the widest possible range of chemicals, due to the shear band and clamping bands encasing a high performance elastomeric sleeve with a chemically resistant one-piece Fluoropolymer (FEP) liner and expanded PTFE seals.

Flexseal Chemical Couplings are available with either Grade 1.4301 (304) or Grade 1.4401 (316) stainless steel clamp and shear bands.

Please contact our sales office for further details.

Chemical Resistance

The FEP liner and PTFE seals are chemically inert and solvent resistant to most chemicals with the exception of molten alkali metals, fluorine at elevated temperatures and other complex halogenated compounds, for example, chlorine trifluoride, at elevated temperatures and pressures.

In situations of extreme temperatures, 80% sodium hydroxide, metal hydrides, aluminium chloride, ammonia and certain amonios (R-NH2) may attack the film in a manner similar to molten alkali metals.

Although special testing may be required when such extreme reducing or oxidizing conditions are evident, the FEP liner and PTFE seals exhibit a very broad range of chemical and thermal serviceability. Final selection should be based on functional evaluations or experience under actual end use conditions.

Further information is available from the Flexseal Technical Department, or take a look at our chemical coupling video above to see how they should be installed.


  • Meet specific site and contractor requirements
  • Watertight connection on chemical drainage systems
  • Highly chemical resistant


  • Used on chemically resistant drainage systems
  • Joint flexibility enables pipeline to accommodate settlement during construction, and subsequent differential ground settlement
  • Suitable for above ground and underground drainage applications

Chemical Coupling Installation

For information about couplings for plumbing applications, please click here.