Sea Tech Week® 2022
      • Le 28/07/2022
      • Discover the content of the session: "HNS Spill prevention: study, inform and train"

      • The maritime traffic of Hazardous and Potentially Hazardous Substances is constantly increasing. In order to better understand the risks in case of accidental spills, we will describe this traffic and then focus on the chemical substances that are transported in liquid form and evaporate in case of a spill at sea. The authorities in charge of the response must then face a toxic cloud, potentially explosive, risking to reach the civilian population. The session will present different preparation tools: a synthesis of work on the behavior of HNS in the aquatic environment (behavioral modeling, laboratory analysis and floating cell tests), presentation of results following the captations by hyper spectral camera) and training tools (e-learning modules, chemical operational guides, etc).
      • Session2.jpg
      • Picture: Cedre



        CEDRE (France)



        WEDNESDAY 28th September 2022

        9.30am – 12.30am including a coffee break

        Stéphane Le Floch




        • Manifest Project : HNS Field trial with the support of the French Navy
          Stéphane Le Floch(199)
          (199) Cedre, France








        Laura Cotte
        • Tackling the behaviour of volatile HNS: A key challenge for Marine Pollution response
          Laura Cotte(199)
          (199) Cedre, France

        Release of volatile Hazardous and Noxious Substances (HNS) at sea can lead to the formation of toxic, flammable or even explosive gas plumes that can travel large distances and pose risks over a wide area in relatively short timescales.

        Evidence-based decisions are thus needed to inform maritime authorities in terms of detection and monitoring, and to protect crews, responders, coastal populations and the environment. Unfortunately current limitations regarding data, decision support tools and proper training and exercise resources challenge response.

        In the case of maritime accidents, knowledge about any chemical released in open sea (e.g. physical and chemical properties, behaviour in the environment) is essential to predict potential environmental consequences. The MANIFESTS project aims to address uncertainties by developing modelling tools and providing new experimental data on evaporation and dissolution kinetics of volatile HNS and gas cloud fate[1].

        This paper presents new experimental results for several HNS, selected to represent key chemical groups and with reference to literature reviews undertaken in the MANIFESTS project. First, physical and chemical properties are assessed at various temperatures. Then, the data collected using Cedre’s chemical test bench provide evaporation and dissolution kinetics, enabling evaluation of the competition between mass transfer processes under controlled environmental conditions. The findings will help to inform modelling and response strategies.


        [1] MANIFESTS (MANaging risks and Impacts From Evaporating and gaseous Substances To population Safety) is co-funded by the European Union Civil Protection Mechanism of DG-ECHO (call UCPM-2020-PP-AG – Prevention and preparedness for marine pollution at sea and on shore.




        William Giraud

        • Quantification of gas evaporation from HNS spills at sea by a multispectral infrared remote sensing system: SIMAGAZ
          William Giraud(199)
          (199) Cedre, France

        SIMAGAZ is a cryogenic camera working in the thermal infrared range and producing four images of different spectral content with a high signal-to-noise ratio and a high frame rate. This gas monitoring camera was deployed during the IPOMAC and MANIFEST campaigns in 2021 and 2022.

        These measurement campaigns were carried out several miles off the west coast of France as part of the response to pollution at sea. Various chemicals, legally classified as HNS (Hazardous Noxious Substances), were released on the sea surface and SIMAGAZ measurements were made from the ship and by air. The camera data processing is based on a physical radiometric model, a spectroscopic database containing the compounds of interest and includes a morphological analysis of the images.

        SIMAGAZ has thus enabled the detection, identification and quantification of several gases evaporating from spilled slicks (acetone, butyl acetate, propyl acetate, MTBE and heptane), sometimes for over half an hour. For other products with absorption lines outside the SIMAGAZ spectral range, no gas was seen as expected. On the basis of this success, the analysis of the concentration fields obtained and their dynamics can be compared with the results of evaporation and atmospheric dispersion modelling tools for HNS.





        • Modelling of volatile HNS
          Sébastien Legrand(201)
          (201) Royal Belgian Institute of Natural Sciences, Belgium
  • Campus mondial de la mer
  • Union Européenne
  • Région Bretagne
  • Brest Métropôle
  • Technopôle Brest Iroise
  • Crédit Mutuel ARKEA
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