EP0466792A1

EP0466792A1 - Escape chute

Info

Publication number: EP0466792A1
Application number: EP19900906279
Authority: EP
Inventors: Michael John Telescape Gibbs (Uk) Limited
Original assignee: TELESCAPE Ltd
Current assignee: TELESCAPE Ltd
Priority date: 1989-04-08
Filing date: 1990-04-06
Publication date: 1992-01-22
Also published as: GB2232138B; WO1990011799A1; CA2051433A1; GB2232138A; GB8907962D0; AU642646B2; AU5423090A; GB9007878D0

Abstract

Assemblage destiné à servir d'unité d'évacuation en masse par laquelle des ouvriers peuvent s'échapper successivement, en cas d'urgence, d'un poste de travail à effectifs mutiples (par exemple, un appareil de forage en mer), et comprenant une série de tuyaux à extrémité ouvertes (2, 8); chacun desdits tuyau (2, 8) étant suffisamment large à l'intérieur pour pour permettre à un ouvrier des y glisser; des moyens d'enchaînement desdit tuyau (2, 8) définissant, lors de l'utilisation, un tunnel allongé à extrémités ouvertes dans lequel se glissent lesdits ouvriers et d'où ils sortent, par l'effet de la gravité; lesdits tuyaux (2, 8) étant formés, reliés et d'une taille telle que (a) ils s'emboîtent, ainsi définissant à intérieur un tunnel sensiblement continu, et (b) au moins certains desdits tuyau s'articulent permettant à la zone de sortie dudit tunnel de se cambrer vers l'horizontale. Dans la réalisation préférée décrite, les tuyaux (2, 8) s'insèrent les uns dans les autres, de multiples treuils (28) suspendus constituant les moyens de ladite extension; l'assemblage, y compris les treuils (28), est monté au plancher d'un poste de travail, la plupart ou la totalité du tunnel étant logée avec les treuils (28) ledit plancher sous ledit plancher; des moyens d'aide flottants, sous forme de radeau de sauvetage (32, 39) sont incorporés à la sortie du tunnel, adapté au déclenchement du restant de la zone de sortie du tunnel, après que le tunnel a été déclenché et se cambre vers la surface de l'eau.Assembly intended to serve as a mass evacuation unit through which workers can escape successively, in the event of an emergency, from a multi-staff workstation (for example, an offshore drilling rig), and comprising a series of open-ended pipes (2, 8); each of said pipes (2, 8) being wide enough inside to allow a worker to slide therein; means for chaining said pipe (2, 8) defining, during use, an elongated tunnel with open ends into which said workers slide and from where they exit, by the effect of gravity; said pipes (2, 8) being formed, connected and of a size such that (a) they fit together, thus defining inside a substantially continuous tunnel, and (b) at least some of said pipes are articulated allowing the exit area of said tunnel to arch towards the horizontal. In the preferred embodiment described, the pipes (2, 8) are inserted into each other, multiple suspended winches (28) constituting the means of said extension; the assembly, including the winches (28), is mounted on the floor of a work station, most or all of the tunnel being housed with the winches (28) said floor under said floor; floating aid means, in the form of a liferaft (32, 39) are incorporated at the exit of the tunnel, suitable for triggering the remainder of the exit area from the tunnel, after the tunnel has been started and arches towards the surface of the water.

Description

ESCAPE CHUTE

Background to the Invention

The invention relates to escape chutes .

The invention is particularly applicable to situations where there is a need for mass evacuation in an emergency from a multiple-occupancy work station such as an offshore oil- drilling rig . Recent well-publicised disasters in this field have highlighted the need , currently unfulfilled , to solve this problem . The conventional life rafts do not solve it and their drawbacks have again been graphically illustrated by the television and press coverage of (for example ) the

" Piper Alpha" rig explosion and its aftermath .

Summary of the Invention

In its broadest aspect the invention provides an escape chute assembly , intended for use as a mass evacuation unit through which a succession of workers can escape in an emergency from a multiple-occupancy work station (for example an offshore oil-drilling rig ) and comprising a linked succession of open- ended pipes ; each of which pipes is large enough internally for a worker to slide through ; and all of w hich pipes are so linked as to define , in use , an elongate open-ended tunnel down which the escapees slide , and from which the escapees exit , under the force of gravity ; the pipes being so shaped , sized and linked that in use ( a ) they fit one within another to define a tunnel which has a substantially continuous interior , and ( b ) at least some of them articulate to allow the exit region of the tunnel to arch towards the horizontal .

Preferably the pipes telescope and the assembly incorporates or is used in conjunction with, a means (other than the pipe- linking njeans ) for telescoping them.

Advantageously the assembly may incorporate , or be designed to be used in conjunction with, means to vary the degree by which and/or the direction in which the exit region of the tunnel arches in use.

Where the assembly is incorporated into, or intended for use on, a multi-deck work station (for example an offshore oil-drilling rig ) then the in-use combination of work station and escape chute assembly preferably incorporates "between decks" interfitting-pipe tunnels each comprising a linked suc¬ cession of open-ended pipes and each intended for use as an emergency worker-escape unit to allow workers to reach the main escape chute assembly from the upper decks of the work station.

In the case just outlined , one (or more than one , if a plurality are provided ) of such between-decks tunnels may incorporate pipe sections which articulate to allow the exit region of the tunnel to be directed appropriately onto or adjacent a specified region of the work station.

Any escape chute assembly which embodies the invention and which is intended for use on a water-surrounded work station (again, by way of example , an offshore oil-drilling rig ) may incorporate buoyancy aiding means at or adjacent the exit region of the tunnel . An assembly in the case just outlined may also incorporate trailing lines and /or individual floats which the escapees can grasp and cling to until they are rescued from the water .

Brief Description of the Drawings

The invention will now be described, by way of example only , with reference to the accompanying drawings , in which:

Figure 1 shows an escape chute assembly according to the invention, the chute being shown in an extended , "in use" condition;

Figure 2 is a more detailed view of part of the chute shown in figure 1 ;

Figure 3 shows a modified form of chute assembly , the chute being shown in a retracted condition;

Figure 4 is a side view of a rig (for example an offshore oil-drilling rig ) structure on which two escape chutes , each according to the invention, are mounted;

Figure 5 shows part of an escape chute assembly which incorp¬ orates "between decks" interfitting-pipe tunnels , each intended for use as an emergency worker-escape unit to allow workers to reach the main escape chute assembly from the upper decks of the work station;

Figure 6 shows an alternative mounting arrangement for an escape chute;

Figure 7 shows two escape chutes mounted on a supp- ort running between the two rig structures , the support com_¬ prising a gantry and being mounted at each opposite end on the rig structures by known mounting means ; Figures 8-10 show a buoyancy aid which may be used in conjun¬ ction with the escape chute; and

Figure 11 shows a life-raft buoyancy^* aid .

Description of the Preferred Embodiment

The chute assembly shown in figure 1 is mounted on an access support platform 1 which is situated beneath the accommodation modules of a multiple occupancy work station for example , an offshore oil-drilling rig or . gas rig . The decking floor of the accommodation modules includes a trap door , which provides access from the accommodation modules to the platform

1.

The platform 1 includes a circular aperture, in which an open ended pipe 2 is mounted. The means mounting the pipe in the aperture are provided by an inwardly directed flange (known per se ) formed around the periphery of the aperture, and a ring ( known) • - which is supported on the flange, and is so sized and shaped as to be rotatably mounted within the aperture. The ring includes two diametrically opposed lugs 3 , in each of which a hole 4 is formed . Two diametrically opposed bosses 5 project radially outward from a flange 6 formed in the top of the pipe 2 , each boss 5 fitting within one hole 4.

The arrangement is such that the pipe 2 is mounted within the aperture of the platform 1 via a "gimbal-type" mounting which allows the pipe 2 to pivot within the aperture in any direction with a limited degree of articulation.

Referring to figure 2 , which shows a portion of the pipe

2 beneath the flange 6 , the pipe 2 includes a central flange

7 , and is tapered from top to bottom . The shape of the pipe 2 is such that the pipe 2 is a telescoping fit within the first of a succession of open ended pipes 8. A flange 9 is formed in the top end region of each pipe 8 , and each pipe 8 tapers from top to bottom in such a way as to enable adjac¬ ent pipes 8 to telescope together .

The pipe 2 and the pipes 8 are large enough internally for a worker to slide through . Thus, with the chute assembly extended in the way shown in figure 1 , the pipe 2 and the pipes 8 define an elongate tunnel down which , in use , escapees slide . The tube 2 and each of the tubes 8 is formed as a fibreglass moulding comprising alternating layers of fibreglass and a suitable fire resistant laminating resin, for example a resin confirming to BS 476 Part 7 1971. Such a resin is currently sold in the UK under the trading style NORPOL 84- 73 by Jotun Polymer . Each flange 9 is formed by moulding the fibreglass of its respective pipe 8 around a steel band, one of which is shown as a detail on figure 1. The flanges 6 and 7 are formed in a similar way.

The steel bands provide extra structural rigidity for the pipes , and also provide mounting points for a number of attach- ments which project from the steel bands , but are not en¬ cased in the fibreglass of the pipes .

Two such attachments for the pipes 8 are a pair of double eyelets 10 which provide mounting points for two chains 11 or 12 which link together adjacent pipes 8. In figure 1 , the chains 11 and 12 are shown as a series of individual lengths, each length linking an adjacent pair of pipes . Alternatively , the chains 11 and 12 could be formed as two continuous lengths of chain, each linking all of the pipes 8. The chain 11 links the first of the pipes 8 to the pipe 2 in a similar way .

The flange 7 , and each flange 9 , also includes a second pair of attachments 13 which are diametrically opposed , and each of which defines a conduit . A cable 14 is wound around a winch 15 mounted on the platform 1 , and passes over a pulley 16 and through the conduits defined by the attachments 13 on one side of the chute assembly, the attachments 13 acting as cable runners . One end of the cable 14 is secured to a lug 17 formed on a exit pipe 18 which fits telescopically over the lowest of the succession of pipes 8. A second length of cable runs along the opposite side of the assembly in the same way.

The pipes 2 , 8 and 18 are so shaped as to permit a certain degree of relative articulation between two adjacent pipes, the combined effects of which articulation is to enable the exit region - -of the tunnel , the region adjacent the tube 18 , to be curved towards the horizontal . Two buoyancy floats 19 are mounted on the underside of the exit tube 18, and where the chute is to be used on, for example , an offshore drilling rig, serve to support the exit tube 18 on the water surface. The floats 19 thus serve to maintain the curved shape of the tunnel , and help the exit tube 18 to follow the move¬ ment of the water surface in heavy seas ; as does the articu¬ lation. The top of the exit tube 18 stops short of the bottom so as to define a lower lip 20 on the tube 18. This arrangement makes it easier for an evacuee to pull himself out of the end of the exit tube 18 by gripping its side walls , whilst the lip 20 provides some support for escapees already in the water .

The chute assembly can be retracted by operating the winch 15 to reel in the cables 14, pulling the exit pipe 18 towards the pipe 2 , and thus causing adjacent pipes to telescope tog¬ ether . The winch 15 may be manually operated using a system of handles and gears as known . Alternatively , the winch

15 may be an electrically , hydraulically or pneumatically operated winch . The winch 15 includes a locking mechanism (. known ) for maintaining the chute assembly in a retracted condition (figure 3 ) . The winch 15 also includes a release mechanism ( known ) which is operable to launch the chute from a retracted into an extended condition. Operation of the release mechanism causes the winch 15 to free— wheel as the pipes 8 and 18 drop under the influence of gravity, unwinding the cables 14 in the process .

A protective cowl 21 is mounted above the aperture in the platform 1. The cowl 21 serves to protect the mounting means for the pipe 2 against the elements , and may facilitate location of the aperture in the platform 1 in any emergency.

The chute assembly shown in figure 3 differs from that shown in figure 1 in that there are no buoyancy floats on the exit pipe 18. In this case, the means arching the exit region of the tunnel towards the horizontal are provided by a cable 22 which is attached to the pipe 18 via linking cables 23. The cable 22 is wound around a tension drum 24 which with the chute assembly in an extended condition, appropriately tensions the cable 22 causing it to pull the exit pipe 18 in to the position corresponding to the required shape of the exit region of the tunnel . The tension drum 24 may be movably mounted on the platform 1 in such a way that the degree by which and/or the direction in which the exit region of the tunnel arch is in use may be varied by appropriately moving the tension drum on the platform 1 .

The chute assemblies shown in figure 4 also use cables to maintain the required arch shapes of the exit region of their respective tunnels . In these case , however , the cable is direct- ly anchored to a fixed structure, and a waterproof sleeve 8A surrounds the pipes constituting the exit region, corrugating as necessary w hen the tunnel is winched up . It should also be noted that the upper pipes of each of these chute assemblies are longer than the pipes positioned near¬ er the exit pipe . Consequently, the portion of the chute defin¬ ed by the upper pipes is relatively inflexible , enabling the chute to be held clear of the rig structure , whilst the portion of the chute defined by the lower pipes is relatively flexible allowing the desired degree of curvature of the exit region of the tunnel to be obtained .

Another way of supporting the tunnel in the required shape is to pivotally connect a rigid boom to one of the pipes near the exit region of the tunnel , and to part of the rig structure .

Referring to figure 5 , where the chute assembly is to be used on a work station having a plurality of levels , a number of curved pipes 25 may be provided, each pipe 25 having an entrance 26 and an exit end 27. Each pipe 25 defines a

"between decks" interfitting pipe tunnel through which an escapee may access a level from the deck on the level above. Thus , by travelling through the tubes 25 in succession, escapees can access the platform 1 , and hence the chute, from the higher levels . Alternatively, the "between decks" interfitting pipe tunnels may be defined by a linked succession of open ended pipes similar to the pipes 8, wholly or partially tele¬ scoping , and variable in curvature and/or direction, like the main chute . The "between decks" interfitting pipe tunnels may also be used to evacuate workers from one part of a work station, for example a hellideck, to a safer part of the work station.

Figure 6 shows part of a chute assembly which is adapted to be installed in situations where available space is severely limited . In this case , the winch for the cables 14 has been replaced by two underslung winches 28 , which occupy less above deck space than the winch 15 , and are in fact wholly below -deck . The inner surfaces of the pipes 2 , 8 , and 18 are smooth , reducing the chances of descending escapees sustaining friction burns on contact with those inner surfaces . However , the inner surfaces may include rubber strips so positioned as to enable a descending escapee to control his rate of descent . The prob¬ lems of friction burns may be further reduced by directing a cascade of water down the inner surfaces.

Figure 7 illustrates chute assemblies mounted between two offshore work stations . In each case , the exit pipe 18 is equipped with a set of trailing floats 30 and an inflatable raft 31, both of which inflate automatically on contact with the water . The chute-carrying gantry is referenced 3QA

The chute assemblies may also be equipped with flares which fire when the assemblies are launched into their extended conditions , and which facilitate location of the exit pipes

18 by rescue services .

The chute assemblies may be required to be used in many instances where all the power supplies on the work stations have failed . The pipes may therefore include a set of photo- luminescent strips on their outer surfaces which also aid in the location of the exit pipe by rescue services .

The buoyancy aids shown in figures 8 , 9 and 10 may be provided in a magazine of suitable kind (not shown) .. mounted beside the entrance to the chute assembly . These buoyancy aids may be used by escapees who have not had time to strap on a normal life jacket . As well as providing support in the water , the buoyancy aids may be used as mats by the escapees to control their rate of descent down the tunnel of the chute assembly.

The aids incorporate the straps enabling them to be tied tog¬ ether (figure 9 ) , and lifting points which allow them to be used as a lifting harness for lifting an escapee from the water into, for example, a rescue helicopter .

Figures 11 A, 11B and 11C show an arrangement in which a life-raft 32 is fixed to the exit pipe 18 of the escape chute . The raft 32 comprises two preformed . glassf ibre reinforced shells 32A and 32B hinging about a common axis 33. The shells are mirror images about this axis and they come together , as shown, to embrace the end of the exit pipe 18 and to lock releaseably to the pipe by means which are known in ^• themselves .

Initially, as Figure 11A shows, the raft is locked firmly to the end of pipe 18 and descends with it when the chute as a whole is released . The raft 32 then floats on the water until the first of the escaping workers comes down the chute, through pipe 18 , and is automatically deposited inside the raft 32. He then releases the locking mechanism which allows shell 32A to spring open away from shell 32B about hinge 33 (Figure 11B ) whilst still retaining shell 32B on pipe 18.

When shell 32A has fully opened about hinge 33 ( Figure 11C ) there is defined an elongate life-raft which is configured as a hull with a keel and which is essentially open-topped .

Up to a dozen men, for example , can be accommodated in this raft and an inflatable canopy 34 subsequently raised .

When the raft is full , the means which still lock shell 32B to the end of pipe 18 can be released and the raft is then free to function as a lift-raft independently of the escape chute .

The raft may be a simple drifting hull or it may incorporate means of self-propullsion. Finally Figures 11D and HE show another form of the inven¬ tion in which a buoyancy aid is attached to the exit pipe 18 of the escape chute . This time the buoyancy aid comprises a preformed glassfibre reinforced plastics pod 35 which , like the life-raft 32 of Figures 11A to 11C , consists of several sections hinged to one another .

A main one of these sections is referenced 36 and embraces the lower half of the pipe 18. It may be formed integrally with the pipe or it may be releaseably secured to it by known means .

Secondary sections 37 and 38 are each hinged to the sides of the main section 36 of the pod 35. When the pod hits the water after the escape chute has been released, the secondary sections 37 and 38 automatically open, hinging about the res- pectively opposite sides of the main pod section 36 as shown in Figure HE to release a flexible self-inflating bag pontoon 39.

The pontoon 39 is so configured as to act as an inflated raft for workers escaping via the chute and exiting the pipe 18 i-^nto the raft . The inflated raft 39 can then stay where it is , or alternatively , be released by releasing the main pod section 36 from the pipe 18 via known quick-release means to allow the raft 39 to float away from the escape chute . In that latter instance the pod sections 36 , 37 and 38 may remain attached to the raft or they may be readily releaseable from it if not needed as an inherent part of the stability of the raft itself .

Claims

CLAIMS:

1. An escape chute assembly, intended for use as a mass evacuation unit through which a succession of workers can escape in an emergency from a multiple-occupancy work station (for example an offshore oil-drilling rig ) and comprising a linked succession of open-ended pipes; each of which pipes is large enough internally for a worker to slide through; means linking the pipes so as to define, in use , an elongate open-ended tunnel down which the escapees slide, and from which the escapees exit, under the force of gravity; the pipes being so shaped , sized and linked that in use (a) they fit one within another to define a tunnel which has a substantially continuous interior, and (b ) at least some of them articulate to allow the exit region of the tunnel to arch towards the horizontal .

2. An assembly according to Claim 1 , in which the pipes are so sized and shaped that at least some of them - preferably those adjacent the exit region - can telescope; the pipe-linking means link the pipes in such a way as to facilitate such tele¬ scoping; and the assembly incorporates means - other than the pipe-linking means - to effect the telescoping .

3. An assembly according to Claim 2 and including means adapted to mount the assembly as a unit on the deck of a work station with the majority or the entirety of the tunnel accommo¬ dated below the deck .

4. An assembly according to Claim 3 and in which the pipe-telescoping means comprises a winch and the winch is mounted wholly or substantially beneath the mounting means which mount the assembly on the deck of the work station.

5. An assembly according to any of Claims 1 to 4 and characterised by the feature that the assembly incorporates , or is designed to be used in conjunction with , means to vary the degree by which - and preferably the direction in which - the exit region of the runnel arches in use .

6. An assembly incorporated into , or intended for use on, a multi-deck work station - for example an offshore oil drilling rig - and characterised by the feature that the in- use combination of work station and escape chute assembly incor¬ porates "between-decks " tunnels ; each such tunnel is so shaped , sized and positioned as to constitute an emergency worker-escape unit allowing workers to reach the main interfitting-pipe escape chute assembly from the upper decks of the work station; each such tunnel has an exit region which arches towards the horizontal and preferably terminates on or adjacent a deck surface; and one or more such tunnels preferably incorporates an arti¬ culated interfitting-pipe region, as the main escape chute does , to enable it to arch .

7. An assembly according to Claim 6 and in which there are means to vary the degree by which and/or the direction in which the exit region of any one or more of the between- decks tunnels arches in use .

8. An assembly according to any of the preceding Claims and which is intended for use on a water-surrounded work station, characterised by the incorporation of buoyancy aiding means at or adjacent the exit region of the tunnel .

9. An assembly according to Claim 8 and in which the buoyancy aiding means is adapted to be released from the remainder of the exit region of the tunnel , once the tunnel has been released to arch towards the water surface ; and to function thereafter as a life-raft .

10. One or more assemblies according to any of the preceding Claims in combination with a gantry ; means mounting the or each assembl y on the gantry when the combination is in use ; and means mounting the gantry, in use, on a work station.