Evacuation chute

It was initially tested on the 16/11 S (now Draupner S) riser platform on the Statpipe gas transport system operated by Statoil. The background was an official requirement for alternative means of evacuating all Norwegian installations.

On Statfjord, personnel were to be evacuated if necessary by helicopter, flotel and lifeboats – in that order. If none of these options were unavailable, a climbing rope was the final solution. Using one of these while wearing a bulky survival suit was risky.

With the Statfjord B flotel due to be removed, operator Mobil was required to come up with another evacuation method and the Selantic net chute proved to be the answer. Several options were studied and tested, including a gondola cableway from platform to standby ship which proved unworkable.

However, inventor Svein Nortvedt at Selantic in western Norway had come up with a completely new concept – a chute of netting made from modern Kevlar fibre which was fireproof, soft and flexible. This offered a new and secure escape route of last resort in the event of an accident. Statoil saw the system’s potential and provided financial support for its development.

The first version lacked barriers, but was a kind of evacuation slide – a taut chute. It was tested from the high City Bridge in Stavanger, where a large man and a small slim woman acted as the guinea pigs. While the man got stuck and had to work to get down, the woman slid straight down and into the sea. They were never in any danger, but improvements were needed. The answer was a long tube of rope netting, tensioned at intervals by galvanised steel rings well covered in rope. Inside the chute, a section of net was fastened at an angle between each pair of rings to act as a kind of slide for users as they descended. A spring at the base of each angled net kept it tensioned against the ring.

People stood at the top of the chute, jumped in, slid down the angled net, twisted their bodies past the spring and dropped onto the next slide just like a slalom skier. When the chute was not in use, it could be folded up in a container which extended past the topside edge. The offshore version terminated in a rubber dinghy which automatically inflated when it hit the water. The big advantage of the evacuation chute was that everyone could use it, regardless of size, training or instructions.

Sources
Statoil Magazine no 4, 1984. “En strømpe for sikkerhet”.
Norsk Oljerevy 1988.
Oral report from Oddbjørg V Greiner, former platform manager on Statfjord.
Interview with Geir Pettersen, former platform manager.