Home page > Anglais > Articles vrac > Schema Offshore

Caisson seals

Our caisson seals, also called dynamic upper caisson seals, are used to seal the top of caissons to maintain an internal operating pressure/burst pressure and prevent any ingress from the environment. Once activated, our caisson seals allow a pre-determined vertical movement of the pipes (risers, inspection tubes, umbilicals, etc) running inside the caisson to compensate for any expansion or contraction effects due to temperature while holding pressures of up to 10 Bar. Our topside caisson seal design is suitable for 25 years.


Our caisson seals are designed using either rubber, polyurethane or a combination of the two materials. They can accommodate a wide range of size and working temperatures. All caisson seals are typically full-scale tested (water and nitrogen tests) to a customer defined pressure requirement. Individual sealing elements (picture 1) are added around each pipe to avoid contamination from debris, etc

  • Integral caisson seal :

Our integral caisson seal design is securely fastened to the top flange of the caisson using a top plate. Below the top plates are sealing elements designed to accommodate the client specific caisson design/layout. The number and position of risers, tubes, umbilicals, etc, will be taken into account to ensure consistent sealing around all the pipes. For integral caisson seal, Exsto can supply either a solid design or a split design (for retrofitting offshore).

  • Individual caisson seal :

Our individual caisson seals are installed on top of the client caisson top plate. Each riser, tube, umbilical…will be sealed using an individual sealing system. Like the integral caisson seal, our individual caisson seals allow for riser movement while activated. Our individual caisson seals are usually supplied with rubber gaiters to prevent any environmental, or other cause of contamination.

Design parameters

The following parameters (typical) are needed to design the Caisson seal :

Caisson, Riser, pipe, umbilical… diameters including coating thicknesses and tolerances • Caisson flange dimension, PCD, etc • Required sealing pressure • Required riser, pipe, umbilical…displacement • System operating temperature • Design life
Site Map | Disclaimer

ZI 55 av. de la Déportation
BP 280 - 26100 Romans Cedex
Tél. 33 (0)4 75 72 72 72 - Fax 33 (0)4 75 72 26 11
E-mail: info@exsto.com