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Environmentally Friendly Fire Suppression System for Cargo using Innovative Green Technology

Periodic Reporting for period 3 - EFFICIENT (Environmentally Friendly Fire Suppression System for Cargo using Innovative Green Technology)

Reporting period: 2019-02-01 to 2020-07-31

Fire suppression and explosion protection have used halons in many applications because they are electrically non-conductive, dissipate rapidly without residue, are safe for limited human exposure and are extremely efficient in extinguishing most types of fires. However, they have a very strong Ozone Depletion Potential (ODP). The Montreal Protocol on Substances that Deplete the Ozone Layer was designed to reduce the production and consumption of ozone-depleting substances in order to reduce their abundance in the atmosphere and thereby protect the earth’s fragile ozone Layer. Many international organisations like the United Nations Environment Programme (UNEP) have mandated earliest production and import phaseout of halons. Substitutes are reviewed on the basis of ozone depletion potential, global warming potential, toxicity, flammability, and exposure potential.
The main objective of the specified work was the development and testing of an environmentally friendly and sustainable fire suppression system intended for use on board aircraft for aircraft cargo hold fire protection, in accordance with the minimum performance standards promulgated by the Federal Aviation Administration (FAA).. The work conducted has contributed to making substantial progress in finding an adequate replacement agent for those currently used Halons and in designing an economically viable halon-free fire suppression system while maintaining an equivalent level of safety compared to any state-of-the-art system in this area.
Keeping in line with the SRIA future requirements, EFFICIENT identified and develop innovative Environmentally Friendly Fire Suppression System configurations with the potential to fulfil the Strategic Research & Innovation Agenda (SRIA) key challenges relating to European industrial leadership, prioritizing research, the environment and the energy supply, while meeting the impact of market needs, environmental protection and flight safety requirements. The succeeding paragraphs bring out the objective of the project linked to SRIA’s key drivers. Based upon the work performed by RISE, the most suitable agent for use in the EFFICIENT project system was identified as being nitrogen gas. Test work was therefore carried out for nitrogen using suitable experimental cup burner and explosion vessel rigs developed at LSBU. In conclusion, an operational fire suppression system was designed and tested, using Nitrogen as an alternative agent.
WP1: Requirements and Concepts
The requirements and concepts were defined, as well as the overall system boundaries and the interfaces. The candidate suppression agents were pre-selected and characterised and also a risk and opportunity analysis were completed by RISE.

WP2: System Design
The design and the specification of the system, the sub-systems, the components and their interfaces, taking into account the boundary conditions formulated under WP1, were obtained.
WP3: Demonstrator Development
During WP3, detailed demonstrator design with consideration to RTCA-D0160 took place. In this context, the fire suppression test rig was built in accordance with FAA's Minimum Performance Tests.

WP4: System Design
During WP4, and based upon the work performed by RISE, which identified nitrogen as the most suitable agent for use in the EFFICIENT project, test work was carried out for nitrogen using suitable experimental cup burner and explosion vessel rigs developed at LSBU.
Hence, the LSBU test work was able to determine the required extinguishing agent concentration (T4.1) and verify the fire suppression capability of the concept in an explosion vessel by determining that there were no adverse effects of the suppression agent upon the rate of explosion overpressure rise. Thus, it was established that nitrogen represented a suitable suppression agent to use in the main EFFICIENT fire suppression test work program.
Based on the studies of RISE and LSBU, Cranfield designed and developed the cargo compartment simulator, where the 4 test scenarios described in the MPS, were carried out.

WP5: Project Management
The Proof of signature of Implementation Agreement and Consortium Agreement, among the EFFICIENT consortium which is constituted by the Institutes: Cranfield University – Coordinator (CU), London South Bank University (LSBU) and Research Institutes of Sweden (RISE) was accomplished.

A dedicated communication plan was prepared and achieved:
- A common project graphical identity was developed (logo, standardised templates, etc.) and implemented throughout the project.
- A public website was created, with dedicated sections targeting the different audiences described above.
- Three Workshops were organised in which guests with relevant expertise were invited to provide their knowledge and discuss about various issues encountered during the project tasks. Guests with relevant expertise were invited to provide their knowledge and discuss about various issues encountered during the project tasks. They were open to public workshops so that external guests with interest in aviation fire safety could join. They were also very useful to Academics and Research students working within the fire safety field.
- A 5th workshop along with the project final review and closure meeting was planned at Fraunhofer institute to conclude the project. However due to Covid-19 restrictions this could not be held and the consortium had to resort to an online meeting.
- Five article publications were achieved in relevant scientific journals
- Two conference presentations took place, including Ninth Triennial International Aircraft Fire and Cabin Safety Research Conference
- A dedicated article has been published on the Community Research and Development Information Service (CORDIS)
- There were a few more presentations organised, where the work of the EFFICIENT project was presented to the FAA and other relavant organisations
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The tests were successfully completed and the results have shown potential for nitrogen to be used as a replacment suppression agent for Halon 1301. The surface burning tests showed high consistency in terms of fire temperature profiles in all the test runs. Containerised and bulk load test runs had some randomness but overall, they passed the acceptance criteria. Finally, the aerosol explosion scenario was performed without any evidence of explosion and unexpected pressure rise.
Based on the configuration of the system at Cranfield, Fraunhoffer Intitute in Germany, completed non-fire tests for testing the Low Rate Discharge System of Nitrogen under a high altitude flight environment.
In addition, CFD simulation of the tests and the distribution of the agent was conducted from Cranfield. The surface-burning fire scenario required by MPS was modelled, combined with the concept of fire design for uncertainty analysis. This work has produced a software tool that can be used for future tests simulation, providing an accurate preview of the expected results and possible outcomes for various suppression agents.

As a general conclusion, all the original objectives were achieved and the selected technologies were matured to TRL 6, hence providing a roadmap for further development and sustenance of these technologies.
Workshop at Cranfield University
The cargo compartment simulator
Workhop at LSBU
Aerosol Can Explosion simulation test