Second Phase Evaluation of a Protocol for Testing a Fire Resistant Oil Spill Containment Boom

Most response plans for in situ burning of oil at sea call for the use of a fire-resistant boom to contain the oil during a burn. Presently, there is no standard method for the user of fire-resistant boom to evaluate the anticipated performance of different booms. The American Standard for Testing Materials (ASTM) F-20 Committee has developed a draft standard, `Standard Guide for in situ Burning of Oil Spills on Water: Fire-Resistant Containment Boom'; however, the draft provides only general guidelines and does not specify the details of the test procedure. Utilizing the guidelines in the draft standard, a second series of experiments was conducted to evaluate a protocol for testing the ability of fire-resistant booms to withstand both fire and waves.     

Test and Evaluation of Six Fire Resistant Booms at Ohmsett

Six oil spill booms produced by five manufacturers for use as fire resistant booms, were tested at the Minerals Management Service's Ohmsett Facility, NWS-Earle, Leonardo, New Jersey. The tests were conducted between July 16, 1996 and October 4, 1996. Prior to being exposed to any fire, the booms were tested for: first loss tow speed, loss rate, critical tow speed, and wave conformance. No fires were used during these tests. Four of the booms performed within speed and rate loss ranges that have been measured for commercial non-fire resistant booms. One boom was found to be superior in wave conformance and critical tow speed. However, this boom was at the lower edge of the range for first loss tow speed. A prototype boom, with a unique paddle wheel operating principal was the sixth boom included in the study. This boom was found to need further development.     

Dynamic modelling of oil boom failure using computational fluid dynamics

The common response to an oil spill on water is to contain the oil with booms and recover it with skimming devices. In some situations, however, the booms cannot hold the oil and the oil will escape underneath the boom due to hydrodynamic forces. Computational fluid dynamics (CFD) is a powerful modelling tool combining fluid dynamics and computer technology. We have utilized a commercial CFD program, Fluent, to simulate the oil-water flow around a boom. The studies accurately model channel experiments conducted in recent years. The studies show that the flow patterns around booms are modified by the presence of oil and, therefore, suggest that towing and wave-conformity tests of booms will not be meaningful unless they are undertaken with the presence of oil.     

Test and Evaluation of Four Fire Resistant Booms at OHMSETT

During the period of 22 August–12 October 1998, seven commercial fire booms were involved in burn testing at the US Coast Guard Fire and Safety Test Detachment Facility in Mobile, Alabama in accordance with the proposed protocol, American Society for Testing and Materials-F20. Four of the seven booms survived the test sequence and were shipped from Mobile, Alabama to the Minerals Management Service’s OHMSETT facility for additional tests including first loss, gross loss, tow speed, oil loss rate, and critical tow speed. The four booms showed the same trend in response to various wave conditions; the long sinusoidal waves improved containment performance and the short choppy waves degraded performance. One of the four booms achieved slightly higher first and gross oil loss rate tests. One boom demonstrated superior stability at high tow speeds. The results of this test report are consistent with the evaluation of fire booms that had been previously tested at OHMSETT, but also show a slight increase in performance. The tests indicate that the existing fire booms can contain oil in currents up to 1 knot and in various wave conditions after being exposed to multiple burns. This information will be used by the Coast Guard to develop policies and procedures for the in situ burning (ISB) of oil during a spill.     

Quantitative analysis of shore-line protection by boom arrangements

The objective of this paper is to quantitatively analyze the arrangement of booms to improve their effectiveness in protecting natural resources. The boom arrangements tested were parallel booms placed at angles of 60°, 90°, and 120° to the shore-line. It was found that the angle between the shoreline and the parallel booms was effective in the range of 45° and 75° for all velocities. The arrangement that was found to be particularly effective was principally a set of three parallel booms placed at an angle of 60° to the shore-line with cylinders placed along the center-line.The open channel experiment was carried out for four different flow velocities, ranging from 0.2 to 0.7 knot. For each speed the position of the parallel booms and the size of the cylinders were changed. Cylinder sizes varied from 4.5 to 7.5 cm. A volume analysis was performed to determine the volume of oil contained. The variation of the length scales for the position of the parallel booms and the size of the cylinders were used to determine the optimum position for the parallel booms and the optimum cylinder diameter for each velocity. A relationship of effectiveness vs U₂/gR was found which displayed a maximum. This relationship was tested experimentally with random parameters, and verified. With a particular velocity U, the graph may be used to find the optimum radius R for the cylinders to be used. The maximum in the relationship can be explained as follows: for cylinders with smaller diameters the effectiveness increases with increase in diameter because of the increased contribution of the centrifugal forces. A maximum is reached because of the physical relationship between the cylinder diameter and the channel width.     

The technology windows-of-opportunity for marine oil spill response as related to oil weathering and operations

This paper identifies and estimates time periods as ‘windows-of-opportunity’ where specific response methods, technologies, equipment, or products are more effective in clean-up operations for several oils. These windows have been estimated utilizing oil weathering and technology performance data as tools to optimize effectiveness in marine oil spill response decision-making. The windows will also provide data for action or no-action alternatives. Crude oils and oil products differ greatly in physical and chemical properties, and these properties tend to change significantly during and after a spill with oil aging (weathering). Such properties have a direct bearing on oil recovery operations, influencing the selection of response methods and technologies applicable for clean up, including their effectiveness and capacity, which can influence the time and cost of operations and the effects on natural resources.The changes and variations in physical and chemical properties over time can be modeled using data from weathering studies of specific oils. When combined with performance data for various equipment and materials, tested over a range of weathering stages of oils, windows-of-opportunity can be estimated for spill response decision-making. Under experimental conditions discussed in this paper, windows-of-opportunity have been identified and estimated for four oils (for which data are available) under a given set of representative environmental conditions. These ‘generic’ windows have been delineated for the general categories of spill response namely: (1) dispersants, (2) in situ burning, (3) booms, (4) skimmers, (5) sorbents, and (6) oil-water separators. To estimate windows-of-opportunity for the above technologies (except booms), the IKU Oil Weathering Model was utilized to predict relationships—with 5 m s⁻¹ wind speed and seawater temperatures of 15°C.The window-of-opportunity for the dispersant (Corexit 9527^®) with Alaska North Slope (ANS) oil was estimated from laboratory data to be the first 26 h. A period of ‘reduced’ dispersibility, was estimated to last from 26–120 h. The oil was considered to be no longer dispersible if treated for the first time after 120 h. The most effective time window for dispersing Bonnic Light was 0–2 h, the time period of reduced dispersibility was 2–4 h, and after 4 h the oil was estimated to be no longer dispersible. These windows-of-opportunity are based on the most effective use of a dispersant estimated from laboratory dispersant effectiveness studies using fresh and weathered oils. Laboratory dispersant effectiveness data cannot be directly utilized to predict dispersant performance during spill response, however, laboratory results are of value for estimating viscosity and pour point limitations and for guiding the selection of an appropriate product during contingency planning and response. In addition, the window of opportunity for a dispersant may be lengthened if the dispersant contains an emulsion breaking agent or multiple applications of dispersant are utilized. Therefore, a long-term emulsion breaking effect may increase the effectiveness of a dispersant and lengthen the window-of-opportunity.The window-of-opportunity of in situ burning (based upon time required for an oil to form an emulsion with 50% water content) was estimated to be approximately 0–36 h for ANS oil and 0–1 h for Bonnie Light oil after being spilled. The estimation of windows-of-opportunity for offshore booms is constrained by the fact that many booms available on the market undergo submergence at speeds of less than 2 knots. The data suggest that booms with buoyancy to weight ratios less than 8:1 may submerge at speeds within the envelope in which they could be expected to operate. This submergence is an indication of poor wave conformance, caused by reduction of freeboard and reserve net buoyancy within the range of operation. The windows-of-opportunity for two selected skimming principles (disk and brush), were estimated using modeled oil viscosity data for BCF 17 and BCF 24 in combination with experimental performance data developed as a function of viscosity. These windows were estimated to be within 3–10 h (disk skimmer) and after 10 h (brush skimmer) for BCF 17. Whereas for BCF 24, it is within 2–3 d (disk skimmer) and after 3 d (brush skimmer).For sorbents, an upper viscosity limit for an effective and practical use has in studies been found to be approximately 15,000 cP, which is the viscosity range of some Bunker C oils. Using viscosity data for the relative heavy oils, BCF 17 and BCF 24 (API gravity 17 and 24), the time windows for a sorbent (polyamine flakes) was estimated to be 0–4 and 0–10 d, respectively. With BCF 24, the effectiveness of polyamine flakes, was reduced to 50% after 36 h, although it continued to adsorb for up to 10 d. For BCF 17, the effectiveness of polyamine flakes was reduced to 50% after 12 h, although it continued to adsorb for up to 4 d. The windows-of-opportunity for several centrifuged separators based upon the time period to close the density gap between weathered oils and seawater to less than 0.025 g ml⁻¹ (which is expected to be an end-point for effective use of centrifugal separation technology), were estimated to be 0–18 (ANS) and 0–24 h (Bonnie Light) after the spill. Utilizing the windows-of-opportunity concept, the combined information from a dynamic oil weathering model and a performance technology data base can become a decision-making tool; identifying and defining the windows of effectiveness of different response methods and equipment under given environmental conditions. Specific research and development needs are identified as related to further delineation of windows-of-opportunity.     

Summary of Development and Field Testing of the Transrec Oil Recovery System

This paper summarizes the development, field testing and performance evaluation of the Transrec oil recovery system including the Framo NOFO Transrec 350 skimmer and multi-functional oil spill prevention and response equipment and presents performance data, not published before, from full-scale experimental oil spills in the North Sea from 1981 to 1990. The rare data provides useful information for evaluation of mechanical clean-up capabilities and efficiency, in particular, for responders who are using this equipment in many countries around the world.The development of the Transrec oil recovery system represents one of the most comprehensive efforts funded to date by the oil industry in Norway to improve marine and open ocean oil spill response capabilities. The need for improvements was based upon early practical user experience with different oil recovery systems, and test results from experimental oil spills in the North Sea.The result of the development efforts increased: (1) skimmer efficiency from approximately 15–75% (it reached 100% under favorable environmental conditions); (2) oil emulsion recovery rate from approximately 20–300 m³/h; (3) recovery system efficiency from approximately 15–85% in 1.5 m significant wave height; (4) oil emulsion thickness from approximately 15–35 cm; (5) weather-window for mechanical recovery operations from 1.5 to 3.0 m significant wave height; (6) capability for transfer of recovered oil residue to shuttle tankers in up to 4 m significant wave height and 45 knot winds; (7) capability for operations at night.The new Transrec oil recovery system with the special J-configuration virtually eliminated skimming operation downtime, and damage to booms and equipment failures that had been caused by oil spill response vessel (OSRV) problems with maintaining skimming position in the previous three-vessel oil recovery system with the boom towed in U-configuration. The time required to outfit OSRVs dropped from approximately 30–<1 h, reducing time from notification to operation on site by more than 24 h.Improvement in oil recovery resulted in the acceptance of a new oil spill preparedness and response plan. The new plan reduced the need for oil recovery systems from 21 to 14, towing vessels in preparedness from 42 to 18, and personnel on stand-by from 135 to 70, which subsequently reduced the total contingency and operational costs by almost 50%. These cost reductions resulted from lower contingency fees for personnel, fewer towing vessels on stand-by, less expensive open ocean training and exercises, less equipment and reduced storage space to lease, and simplified equipment maintenance.     

Physical Properties and Processes that Influence the Clean Up of Oil Spills in the Marine Environment

Based on a study carried out by the Versuchsanstalt für Wasserbau und Schiffbau, Berlin – VWS for the German Environmental Agency, this report represents an attempt to summarize the knowledge in the Federal Republic of Germany and world-wide concerning the control of hazards from discharged oil and other liquid chemicals after casualties on and in the hydrosphere. Because of technical reasons, control measures can be classified into passive and active types; this classification has been adopted for this report in the following order:

• •Part 1: Passive mechanisms: Booms and barriers.
• •Part 2: Active mechanisms: Recovery devices.
• •Part 3: Other means: Dispersion.
• •Part 4: Control of sinking and/or sunken chemicals.

Part 1 not only evaluates the behaviour of liquid chemicals on water, but also considers the physical fundamentals underlying the functioning of booms and barriers. Some widely used definitions and relations (such as the relationship between the blocking of liquid chemicals and boom draught or efficiency) will be refined. The discussion of the physical fundamentals is presented in the broadest sense and concludes with practical advice on the deployment of booms.Part 2 attempts to standardize recovery devices based on the application of fundamental physical principles. Four classes were identified and have been used to classify pick-up devices. Once again basic physical fundamentals have been presented in a way that facilitates deductions on application possibilities. The evaluation showed that practically only those methods that utilize adhesion and “hole-in-the-water” principles can be operated with sufficient efficiency which, in turn, reflects the world-wide state-of-the-art in equipment development. Special attention has been paid to hybrid systems which utilize both passive and active methodologies.In Part 3, the basics of dispersion of oil and other floating liquid chemicals are considered. It can be shown that mechanical dispersion has the same effect as its chemical counterpart. This relationship recognizes the necessity for applying a mechanical agitator for using dispersants effectively. This strategy calls into question the efficiency of chemical dispersion.Part 4 deals with the behaviour and control options for sinking and/or sunken liquid chemicals. Contrary to the general opinion that liquid chemicals which have disappeared from the surface cannot be controlled, it has been found that, under certain conditions, even these chemicals can be “herded” and recovered. It will be shown that practically the same techniques can be applied to submerged chemicals as has been used for the recovery of floating hazardous substances.     

Introduction/Overview to In Situ Burning of Oil Spills

In situ burning is an oil spill response technique or tool that involves the controlled ignition and burning of the oil at or near the spill site on the surface of the water or in a marsh (see Lindau et al., this volume). Although controversial, burning has been shown on several recent occasions to be an appropriate oil spill countermeasure. When used early in a spill before the oil weathers and releases its volatile components, burning can remove oil from the waters surface very efficiently and at very high rates. Removal efficiencies for thick slicks can easily exceed 95% (Advanced In Situ Burn Course, Spiltec, Woodinville, WA, 1997). In situ burning offers a logistically simple, rapid, inexpensive and if controlled a relatively safe means for reducing the environmental impacts of an oil spill. Because burning rapidly changes large quantities of oil into its primary combustion products (water and carbon dioxide), the need for collection, storage, transport and disposal of recovered material is greatly reduced. The use of towed fire containment boom to capture, thicken and isolate a portion of a spill, followed by ignition, is far less complex than the operations involved in mechanical recovery, transfer, storage, treatment and disposal (The Science, Technology, and Effects of Controlled Burning of Oil Spills at Sea, Marine Spill Response Corporation, Washington, DC, 1994).However, there is a limited window-of-opportunity (or time period of effectiveness) to conduct successful burn operations. The type of oil spilled, prevailing meteorological and oceanographic (environmental) conditions and the time it takes for the oil to emulsify define the window (see Buist, this volume and Nordvik et al., this volume). Once spilled, oil begins to form a stable emulsion: when the water content exceeds 25% most slicks are unignitable. In situ burning is being viewed with renewed interest as a response tool in high latitude waters where other techniques may not be possible or advisable due to the physical environment (extreme low temperatures, ice-infested waters), or the remoteness of the impacted area. Additionally, the magnitude of the spill may quickly overwhelm the deployed equipment necessitating the consideration of other techniques in the overall response strategy (The Science, Technology, and Effects of Controlled Burning of Oil Spills at Sea, Marine Spill Response Corporation, Washington, DC, 1994; Proceedings of the In Situ Burning of Oil Spills Workshop. NIST. SP934. MMS. 1998, p. 31; Basics of Oil Spill Cleanup, Lewis Publishers, Washington, DC, 2001, p. 233). This paper brings together the current knowledge on in situ burning and is an effort to gain regulatory acceptance for this promising oil spill response tool.     

水域泄漏油品回收处理技术

提出了水域泄漏油品回收技术的装备需求,介绍了水域泄漏油品问收处理措施.采用拦油栅来控制漂浮在水上的油品,将泄漏油品集中在相对较小的区域内,并使水面的浮油层加厚,然后使用人工或机械对泄漏油品进行回收.对于水域中的少量泄漏油品,采用吸油材料来进行吸附.在油膜较薄,难以用机械方法回收的情况下,使用消油剂或固化剂进行处理.水域...     

An approach to evaluate the application of the vulnerability index for oil spills in tropical Red Sea environments

The Egyptian national marine oil pollution contingency plan was urgently initiated after the Nabila oil spill in 1982, to provide an estimate of its environmental effects on the Egyptian Red Sea coastal areas and to determine geomorphological features and cuastal processes, together with physical, chemical and biological baseline data for this tropical environment.The ‘Vulnerability Index’ (VI) was applied to evaluate and calibrate the effect of the Nabila oil spill on the Egyptian Red Sea Coastal area. A detailed in situ coastal survey was conducted during two visits in November 1982 and May 1983 to 80 shore sites from Suez to Ras Banas to monitor the oil pollution and to apply the ‘Vulnerability Index’. A comparative assessment of the index over time by comparing it with a quick ground inspection in November 1993 to some sites to evaluate the applicability of this index for oil spills in such environments. In addition, the physical effects of fresh and weathered crude oil and/with dispersant on water filtration by different beaches were preliminary studied.The geomorphological/Vulnerability Index results show that most of the Egyptian Red Sea coastal environments have medium to high vulnerability to immediate and medium term oil spill damage. The oil pollution spread estimated to be 250 km south of the oil spill and about 200 km north of it. The quantity of oil along the shoreline was reduced by about 60% due to natural and authorities clean up. The third survey after 11 years showed that the VI could be used as a predictive tool for assessment of oil spill effects on such tropical environments.     

In situ burning of emulsions R&D in Norway

SINTEF Applied Chemistry has been working in the field of in situ burning since 1988, beginning with the first open water testing of the 3M fire proof boom which took place on Spitsbergen. In recent years, the focus of SINTEF's research activities in this area has been on the burning of emulsions. An experimental programme was initiated by NOFO in 1990 to study the in situ burning of water-in-oil (w/o) emulsions, as part of a wider NOFO programme ‘Oil spill contingency in Northern and Arctic waters’ (ONA). The research conducted under this programme has addressed many areas of in situ burning including:

• &#x02022;• study of processes governing burning emulsions
• &#x02022;• development of ignition techniques for emulsions
• &#x02022;• effect of environmental conditions on burning
• &#x02022;• burning crude oil and emulsions in broken ice
• &#x02022;• uncontained burning of crude oil and emulsions.

     

Reutilization of thermostable polyester wastes by means of agglomeration with phenolic resins

We report on the possibility of obtaining organic polymeric matrixes allowing the development of new high performance fire-resistant products by recycling downsized thermostable waste materials. Phenolic resins have been used as binders for recycled waste. Furthermore, considering that reinforced plastic triturations have superior properties (chemical, mechanical, water resistance, etc.) to wood agglomerates, significant advantages over conventional materials are anticipated. In summary, we propose a viable solution to some of the known problems caused by the consumption of wood and to the needs of strengthened plastic processing engineering. Using resins as a binder, several fire-resistant prototypes were prepared from polyester waste, and their mechanical properties, thermal stability, and fire-resistant properties were analyzed.     

Recent developments in cleanup technologies

A recent draft report from the U.S. Environmental Protection Agency's Robert S. Kerr Environmental Research Laboratory in Ada, Oklahoma, entitled ?General Methods for Remedial Operation Perforrmance Evaluation,”? establishes protocols for evaluating and optimizaing the performance of groundwater pump-and-treat systems (EPA 1992). For the first time, EPA proposes guidelines for determining when these systems can be terminated, regardless of whether a site's remediation goals are met. This column reviews the chemical and physical limits of pump-and-treat technology and discusses how these protocols can improve pump-and-treat performance and determine when it may be time to pull the plug.     

Accelerated Stability Testing of a Polyherbal Transdermal Patches Using Polyvinyl Alcohol and Hydroxypropyl Methylcellulose as a Controlling Polymer Layer

The present work was to evaluate the stability potential of (E)-4-(3,4-dimethoxyphenyl)but-3-en-l-ol (Compound D) in polyherbal transdermal patches. The polyherbal formulation composed of the rhizomes of Zingiber cassumunar and Curcuma longa, leaves and stems of Cymbopogon citratus, rind and leaves of Citrus hystrix fruit, and leaves of Acacia rugata and Tamarindus indica. Polyvinyl alcohol and hydroxypropyl methylcellulose were used as a matrix film, and glycerine was used as a plasticizer. Stability testing was established for 6 months under accelerated conditions as according to International Conference on Harmonisation guidelines. Mechanical properties, moisture uptake, swelling ratio, and in vitro studies were evaluated. New Zealand white rabbits were used as the animal model. Results obtained after 6 months showed that the polyherbal transdermal patches were stable, with a good mechanical properties and hydrophilicity. In vitro study kinetics for active Compound D fitted to the Higuchi model for both release and skin permeation. The transdermal patch containing polyherbal formulation was safe to apply on the skin without irritation. Thus, transdermal patches containing this polyherbal formulation had good stability potential, with no irritation on application.     

Toxicity Evaluation with the Microtox Test to Assess the Impact of In Situ Oiled Shoreline Treatment Options: Natural Attenuation and Sediment Relocation

Changes in the toxicity levels of beach sediment, nearshore water, and bottom sediment samples were monitored with the Microtox^® Test to evaluate the two in situ oil spill treatment options of natural attenuation (natural recovery--no treatment) and sediment relocation (surf washing). During a series of field trials, IF-30 fuel oil was intentionally sprayed onto the surface of three mixed sediment (pebble and sand) beaches on the island of Spitsbergen, Svalbard, Norway (78°56^′ N, 16°45^′ E). At a low wave-energy site (Site 1 with a 3-km wind fetch), where oil was stranded within the zone of normal wave action, residual oil concentrations and beach sediment toxicity levels were significantly reduced by both options in less than five days. At Site 3, a higher wave-energy site with a 40-km wind fetch, oil was intentionally stranded on the beach face in the upper intertidal/supratidal zones, above the level of normal wave activity. At this site under these experimental conditions, sediment relocation was effective in accelerating the removal of the oil from the sediments and reducing the Microtox^® Test toxicity response to background levels. In the untreated (natural attenuation) plot at this site, the fraction of residual oil remaining within the beach sediments after one year (70%) continued to generate a toxic response. Chemical and toxicological analyses of nearshore sediment and sediment-trap samples at both sites confirmed that oil and suspended mineral fines were effectively dispersed into the surrounding environment by the in situ treatments. In terms of secondary potential detrimental effects from the release of stranded oil from the beaches, the toxicity level (Microtox^® Test) of adjacent nearshore sediment samples did not exceed the Canadian regulatory limit for dredged spoils destined for ocean disposal.     

Hindcast of a Japan Sea oil spill

An oil spill model was applied to the Nakhodka tanker spill accident that occurred in the Japan Sea in January 1997. The amount of oil spilled was estimated to be around 5000 kl, released over 1 day. Under a 2-m wave height condition, and a 3.5% of drift factor, the model simulated the oil slick to hit the shoreline after 6 days. This was in good agreement with the observed conditions. After drifting to the shoreline, the oil slick moved northeastward with the current. In the model, the simulation where the shoreline absorbs 100% of stranded oil failed to reproduce the actual oil slick trajectory. The simulation in which oil resuspended after stranding indicated a similar trend to the actual case. Therefore, it is likely that a considerable amount of oil that hit the shoreline may have returned to the sea and moved with the current. The effects of current pattern and wind drift angle on the oil slick trajectory were also examined. It is suggested that the wind parameters were of prime importance in reproducing a realistic distribution.     

Value addition of vegetable wastes by solid-state fermentation using Aspergillus niger for use in aquafeed industry

Vegetable waste typically has high moisture content and high levels of protein, vitamins and minerals. Its value as an agricultural feed can be enhanced through solid-state fermentation (SSF). Two experiments were conducted to evaluate the nutritional status of the products derived by SSF of a mixture of dried vegetable waste powder and oil cake mixture (soybean flour, wheat flour, groundnut oil cake and sesame oil cake at 4:3:2:1 ratio) using fungi Aspergillus niger S₁4, a mangrove isolate, and A. niger NCIM 616. Fermentation was carried out for 9 days at 35% moisture level and neutral pH. Significant (p < 0.05) increase in crude protein and amino acids were obtained in both the trials. The crude fat and crude fibre content showed significant reduction at the end of fermentation. Nitrogen free extract (NFE) showed a gradual decrease during the fermentation process. The results of the study suggest that the fermented product obtained on days 6 and 9 in case of A. niger S₁4 and A. niger NCIM 616 respectively contained the highest levels of crude protein.     

Boom failure mechanisms: Comparison of channel experiments with computer modelling results

A large outdoor flowing water channel has been used to obtain experimental data on boom failure mechanisms. Oil containment and failure around a simple barrier has been observed for oil viscosities from 10 to 5600 cSt at relatively low flow velocities from 0.10 to 0.20 m/s. The centre line profiles of stable contained slicks have been measured and underwater videos of escaping oil have been made when the barrier failed. These experiments have been duplicated with a computational fluid dynamics model of the channel and barrier, and satisfactory agreement between the simulated and the experimental measurements has been obtained. The study indicates that computer simulations of these complex processes can be used to obtain data about failure mechanisms that would be difficult to measure experimentally.