Ice in the Environment: Proceedings of the 16th IAHR International Symposium on Ice Dunedin, New Zealand, 2nd–6th December 2002 International Association of Hydraulic Engineering and Research

EMERGENCY EVACUATION OF INSTALLATIONS IN ARCTIC ICE CONDITIONS

F.G. Bercha1

ABSTRACT Safe and reliable methods for the evacuation of installations or ships in polar marine ice conditions have not been developed. Following a review of the difficulties with polar evacuation, this paper describes general conceptual engineering solutions for reliable safety craft for polar evacuation and survival. A reliability analysis for the new systems for various ice conditions compares their performance to that of conventional methods under polar conditions. The reliability analysis confirms the need for new developments to assure safe emergency evacuation and survival for installations and ships in polar conditions. Detailed conclusions and recommendations for further work are given. INTRODUCTION Although extensive investigations and studies have been carried out and regulated (IMO, 1997) on escape, evacuation, and rescue (EER) from installations in non-Arctic waters, no definitive guidelines and recommendations exist for EER of marine installations in ice covered waters. Only several conceptual level engineering and risk analytic studies by the authors (Bercha et al., 2001, 2000a, 2000b, 1994) and their colleagues (Cremers, 2001) appeared in the public literature on Arctic ship or installation EER. With the renewed interest in Arctic oil and gas developments, both in the North American Arctic seas and the Russian and Asian Arctic seas, there is a need to address the problem of safely evacuating and rescuing workers from installations that may become uninhabitable due to operational accidents such as ignited blowouts or major production fires and explosions. Indeed, the criticality of having reliable evacuation methods for a full range of accident scenarios has been tragically demonstrated by the extensive losses of life in offshore oil and gas installation disasters such as the Ocean Ranger, the Piper Alpha, and the Alexander Kielland. In this paper, following a brief discussion of Arctic EER problems, focus is directed toward the subject of evacuating personnel safely from installations in solid or broken ice. Clearly, conventional technologies, primarily lifeboats, are suited neither for solid nor broken ice. They have no means of moving away from the impaired installation if placed on solid ice; in broken ice, even if successfully launched, they are not structurally designed to deal with pressure induced by ice pack convergence. The paper

1 Bercha Group, 2926 Parkdale Boulevard NW, Calgary, Alberta, T2N 3S9, Canada

presents some of the conceptual developments on evacuation systems for installations in a range of ice conditions. These include both novel launch systems, capable of safely depositing the vessel on solid or broken ice, as well as ice-reinforced vessels, called IRTs (Ice Reinforced TEMPSC (Totally Enclosed Motor Propelled Safety Craft)), designed to both move on the ice surface and survive in a floating mode in pressured broken ice. Finally, risk and reliability simulation results for EER operations in Arctic offshore conditions are presented. The results clearly illustrate the requirement for new or non-conventional EER technologies for current and future developments in the Arctic offshore. Conclusions and recommendations for future work are given. POLAR EER PROBLEMS Clearly, the principal hazard to conventional EER procedures in Arctic or Antarctic regions is created by the presence and behaviour of marine ice. Whether the ice manifests itself as a solid ice sheet, dynamic ice floes, broken pressured ice, or ridging and hummocks, current SOLAS approved life saving devices are unlikely to perform adequately. The mechanical threat of ice is further exacerbated by extreme cold, bad visibility, and frequent storms. A summary of challenges to polar EER follows: Ice conditions variable – dynamics and ice fraction can change quickly. Ice pressure, ride-up, adfreeze, pile up. Ice movement direction unpredictable. No free fall or fast descent system due to ice. Visibility bad often – fog/Arctic winter. Very cold with possible adfreezing snow/ice. Damage to capsule greatly decreases survival. Arctic system should also work for open water.

Figures 1 and 2 illustrate broken ice and ice pile up from a solid ice sheet, two sets of ice conditions for which conventional lifeboats will certainly not function.

Figure 1: Broken Ice – Kulluk Figure 2: Ice Pile-Up – Confederation Bridge

TECHNOLOGICAL SYSTEMS FOR POLAR MARINE EER Basic Definitions for EER Before proceeding into a discussion on EER technological concepts, the components of EER should be defined as used in the balance of this paper. In an offshore installation such as a gravity based structure (GBS), a floating production and storage operation

(FPSO), or for conventional ice capable ships, the EER process is subdivided into the following three principal components: Escape - Movement of personnel from their location at the time of the alarm to

a Temporary Safe Refuge (TSR) or must point.

Evacuation - Movement from the TSR to a lifeboat or other safety craft, and its launch and movement to a safe distance from the installation.

Rescue - Survival and transfer of personnel to a safe haven.

Escape on Polar Installations The process of escape on installations under polar winter conditions, is not significantly different from that on installations in temperate frontier regions. The escape process, by definition, is restricted to activities on the installation. Polar escape inside the installation remains essentially unchanged from that in non-polar locations. Escape along outdoor walkways, stairways, and ladders may be hampered by accumulating snow, adfreezing ice, and low visibility and strong winds, but require no new tech-nologies, rather only the usual cold weather provisions such as non-slip surfaces, heat traced walkways or ladders, or wind and snow barriers. Evacuation from Polar Installations The conventional evacuation process needs to be significantly altered to ensure safe evacuation of ships or installations in ice. For lifeboats, alterations are needed both in the launch method and in the craft configuration. Modifications to the craft are described in the next section within the context of survival and rescue. Other methods of evacuation such as chutes, gondolas, inflatable carpets, also need significant modifications to adapt to polar conditions, but the discussion here will be restricted to lifeboats, the most common form of evacuation craft. The launch must safely transfer the loaded lifeboat from the installation to the ice surface or into the ice lead. Location and stowage of the lifecraft needs to be considered within the context of the polar environment. An indoor, heated location is preferable to ensure that all mechanisms are not impaired by ice or snow buildup. The orientation and location with respect to prevailing wind and ice motion must also be considered. Often, the prevailing lee and windward location, each with 100 % capacity is favoured. Next, a launch mechanism which can accommodate both the installation geometry and all expected ice conditions is needed. Figure 3 shows different conceptual designs intended to effect safe and reliable evacuation utilizing a TEMPSC or lifeboat. As can be seen, the concepts have been designed around a typical GBS with a sloped ice wall, requiring the launch mechanism to deposit the craft well beyond the toe of the ice wall or pile-up at the ice or water surface. All of the concepts employ an indoor-stowed lifeboat, with different launching mechanisms. The relative simplicity, and containment of the telescoping boom davit launch mechanism shown in Figure 3(b) have made that concept the optimal candidate for more detailed engineering, which is ongoing at this time. Rescue After Evacuation from Polar Installations The rescue component of EER, as defined above, consists of the survival of the evacuees and their safe transfer to a safe haven. First, consider the craft in pressured broken ice. The Norwegian explorer, Fridtjof Nansen, with the help of his British Naval Architect, Colin Archer, solved this problem in 1890 with the hull design of his vessel, the Fram. The efficacy of the design was borne out by the fact that the Fram survived

pressured Arctic ice in the winters of 1893–95, as well as several subsequent expedi-tions in later years. Nansen’s principle was that “the ship should be pushed upwards by the expanding ice as it froze (or pressured) by giving the hull very rounded lines… flaring out over the ice in the main ice contact belt” (ODIN, 2002). An adaptation of the basic lifeboat using the Fram principle is shown in Figure 4. Thus, having a slope-sided lifeboat hull would greatly assist in its survival in pressured broken ice. For the on-ice case, the main problem is to maintain upright stability of the vessel, and to permit it to propel itself on the ice surface away from the installation, which could be on fire or about to explode. The simplest adaptation is the provision of sled runners together with a winching mechanism, powered by either the lifeboat engine or a battery operated winch, so that the boat could winch itself to a pylon or anchor which would be deployed by appropriately qualified crew. Such a concept is illustrated in Figure 5. In this case, the primary objective is the clearing away from the potential hazardous installation to a stable location, where the occupants can await a rescue craft. Clearly, there is no limit to the possible on-ice locomotion designs, ranging from the amphibious ARKTOS, to the confirmed on- and off-ice reliable but high-energy consumptive air cushioned vehicle lifeboats.

Figure 3: (a) Portal (b) Telescoping Boom (c) Articulating Ramp (d) Modified Boom

(a) (b)

(c) (d)

Figure 4: Fram Principle IRT

Figure 5: Anchor and Winch Sled

POLAR EER RELIABILITY ASSESSMENT The EER risk and performance tool (RPT) developed by the authors partially for Transport Canada, and extensively described elsewhere (Bercha et al., 2001, 2000a, 1999), was used to assess EER success for installations under various ice conditions with conventional and polar EER systems. Then\ integrated EER process must be considered within the combined effects of installation or vessel type, complement, passengers, range of open water and environmental conditions, available rescue modes, and their integrated synergistic effects. Because no substantial database exists for polar installation or vessel emergencies, the likely effectiveness of EER under Arctic conditions can currently only be assessed utilizing modeling techniques, such as RPT. The RPT model lends itself well to the assessment of both the performance and associated risks for any EER process, and particularly for processes without history such as Arctic EER. Table 1 summarizes the ice zone parameters for which comparative integrated EER reliability assessments were made, based on areas selected for the Arctic Euro-Asian region, where considerable interest and activity in oil and gas exploration and production is currently ongoing. The analysis was conducted on an annual average basis with a 40-man GBS ice resistant installation utilizing either conventional twin-davit launched lifeboats or IRTs with the launching mechanism shown in Figure 3(b) above.

Results of the integrated EER analysis are illustrated in Figure 6. As can be seen, for an open water base case, the success rate, which combines availability and reliability, for both systems is in excess of 90 %. For the IRT equipped installation, the success rate remains close to 90 % in each of the zones, with some decrease in that, to approximately 85 % for the most severe Siberian zone, Zone 2. The conventionally equipped installation, however, shows EER success rate below 80 % for all zones, dropping to 60 % for the most extreme ice zone (Zone 2). Clearly, such low averaged success rates would not add encouragement to employment on such an installation. With the ice IRT equipped installations, however, EER rates would be very close to those of operations in temperate conditions.

Table 1: Ice Zone Parameters for Comparative Integrated EER

NRS Zone

Number of days temperature is

–30 °C and below

Number of days temperature is

–40 °C and below

Number of days temperature is

–50 °C and below Zone 1: Atlantic 5–75 0–5 0 Zone 2: Siberian 100 5–25 0 Zone 3: Pacific 25–75 5 0

Figure 6: Integrated Arctic EER Results

The integrated assessment of a specific Arctic EER system can also be carried out utilizing the Monte Carlo approach through the RPT, in order to adequately address the many uncertainties in input variables and parameters associated with operations without history. Specifically, the event tree shown in Figure 7 can be utilized with inputs added for the escape and evacuation phases to provide a combined integrated EER success probability. The integrated success rate considering the weighted averages of the ice conditions then appears in the far right-hand column. The expected success rate for the Zone 2 IRT is 0.86, as given in Figures 6 and 7. A Monte Carlo evaluation of this success rate, using probability distributions for the key input variables is shown in Figure 8.

Figure 7: EER Event Tree CONCLUSIONS AND RECOMMENDATIONS The paper has attempted to illustrate both conceptually and analytically that there is a need to adapt evacuation and rescue processes and technologies for operations in polar winter conditions. Due to limitations of space, the analytical demonstration was restricted to results from a methodology described in earlier publications (Bercha et al., 2000a, 1999). The following specific conclusions regarding EER under polar conditions can be derived from this paper: The escape component of the EER process is relatively similar to that for frontier

installations in temperate regions.

The evacuation and rescue process, however, requires major modification or new technologies to provide adequate reliability under polar winter conditions.

Figure 8: Arctic EER Success Histogram

There is a lack of operationally developed evacuation and rescue technologies and associated performance data for Arctic conditions.

The success of rescues under polar conditions depends on the highly variable ice and weather conditions, as well as a rescue mode availability.

The following recommendations for further work are derived from this paper and its conclusions: Development of optimal evacuation and rescue systems suitable for both open water

and ice-covered conditions.

Further development of the Fram principle IRT, both new built and existing technology modification, to serve optimally in both ice and open water.

Use of Monte Carlo models such as those described in the paper for preliminary assessment of the Arctic EER system, and definition of key parameters to test out.

Conduct of model-scale ice tank and full-scale Arctic field tests on the developing technologies for emergency evacuation from polar installations under winter marine conditions.

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Bercha, F.G., Churcher, A.C. and Cerovšek, M. Escape, evacuation and rescue modeling for frontier offshore installations. In Proceedings of the 2000 Offshore Technology Conference, OTC, Houston, Texas, USA, 1–4 May (2000a).

Bercha, F.G., Churcher, A.C. and Cerovšek, M. Risk assessment of marine evacuation systems for arctic conditions. In Proceedings of 6th International Conference on Ships and Marine Structures in Cold Regions (ICETECH 2000). Society of Naval Architects and Marine Engineers – Arctic Section, St. Petersburg, Russia 12–14 September (2000b).

Bercha, F.G., Cerovšek, M., Churcher, A.C., and Williams, D.S. Escape, evacuation and rescue modeling for the arctic offshore. In Proceedings of the 5th International Conference on Development of the Russian Arctic Offshore, RAO, St. Petersburg, Russia, September (1999).

Bercha, F.G. Evolution of Arctic marine structural forms. In Proceedings of the 26th Annual Offshore Technology Conference, OTC, Houston, Texas, USA, 2–5 May (1994) 415–425.

Bercha Engineering Limited. Escape, Evacuation and Rescue Research Project. Final Report to Transportation Development Centre, Transport Canada, June (2001).

Cremers, J., Morris, S., Stepanov, I. and Bercha F. Emergency evacuation from ships and structures and survivability in ice-covered waters: current status and development. In Proceedings of the 16th International Conference on Port and Ocean Engineering under Arctic Conditions, POAC-01, Ottawa, Canada, August 12–17 (2001).

International Maritime Organization. SOLAS. Consolidated Edition (1997) 287–356. ODIN Utenriksdepartementet. The Polar Vessel Fram. http://odin.dep.no (2002).