Subsea saturation diving, at depths down to 1,000 feet (300 meters) below the surface, tests equipment and men to the limit. To protect divers from the cold in the diving bell, manufacturer Unique System turned to Trelleborg Offshore for a syntactic foam insulation.
“The engineered Trelleborg syntactic foam insulation, and the company’s 3D modelling design capabilities, provide us with high accuracy thermal and buoyancy properties,” said Shane Julias, design engineer, Unique System. “This enables us to predict the thermal insulation thickness required, and the uplift of the bell for accurate system buoyancy control.
“The performance of previous insulation systems used was more difficult to predict. It was also susceptible to damage and water ingress, which could affect the thermal and buoyancy properties. In contrast, the Trelleborg polyurethane-based foam has a high impact resistance and is totally impervious to water ingress under pressure.”
The Unique System diving bell is designed as a submersible decompression chamber for a three-man saturation diving team. It transports them from a ship’s live-in hyperbaric chamber down to working depths with typical sea temperatures of between 45˚F and 65˚F (9˚C and 20˚C). Typical subsea tasks include pipeline repair, maintenance and inspection, cable maintenance, platform installation and removal.
“Trelleborg used its Trident Insulation system, which is based on BASF’s ZeroHg glass syntactic polyurethane foam technology, in a one pour, one lift foam application. The application technique ensured no insulation interface joints for complete integrity,” explains James Vultaggio, product group manager, Trelleborg Offshore. “This eliminates water ingress into the foam which could affect the thermal properties.”