Resonate Testing Ltd. are playing with fire….

We provide Systems Fire Protection testing using our oil burner. Materials testing for Seat Cushions, Cargo liners and insulation and Flammability testing for all your material needs.

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    Fire testing for safety and reliability

    At Resonate Testing we offer a sophisticated, custom-built fire testing facility in addition with the in-depth technical and professional knowledge to fully understand your specific fire or flammability test requirements with precision. When it comes to ensuring the integrity of your products or components under fire conditions, demonstrating compliance with customer and international regulations becomes paramount. An equally critical consideration is the impact of over-designed components, leading to increased costs, weight, or even non-compliance. Our fire testing services enable you to simulate the performance of your products during exposure to real-life fire scenarios. You will have the ability to evaluate your product's capacity to continue to function, self-extinguish promptly, and prevent re-ignition.

    In aerospace fire and flammability testing, our skills extend to certification of interior cabin cargo compartment and insulation materials to fire testing of powerplant systems and fire walls. Operating a fire test facility with the ability to expose parts to a complete range on environmental and operational conditions applied for both flight and on-ground conditions. Our particular forte is fire penetration testing for aircraft powerplant certification (AC20-135, ISO 2865, AS1055), where a range of operational conditions, from additional loading and vibration to airflows or internal fluids/oils at temperature and pressure can be included within the test. We can also carry out material fire testing for Seat Cushions, Cargo Liners and Insulation and Flammability testing (vertical, horizontal and 45 degrees) in accordance with FAA Fire Test Handbook.

    Our capabilities can be extended to other industries including construction, rail, automotive, energy, marine etc. and we are open to diversification into other sectors. Fire testing to other industry standards or your own bespoke testing requirements can all be catered for.

    Resonate Testing provide a complete range of AC20-135 ISO2685 compliant propulsion level fire testing for large airplanes (FAR25, CS25, CAR525) Aircraft engines (FAR 33, CS-E, CAR 533), Helicopter (FAR27, CS27, CAR527 / FAR29, CS29, CAR529), small airplanes (FAR23, CS23, CAR523) etc. Testing includes propulsion systems and externals including structures, seals, TRU’s and a wide range of fluid and electrical systems.

    Using both approved Kerosene burners and Sonic Burners we support a range of R&D, product development, and validation including certification level testing. We are happy to work to customer Qualification Test Procedures (QTP’s), although increasing clients realise significant benefits from discussing their requirements and compliance means with our engineers.

    Governing standards for powerplant testing

    They are varied and complexity arises due to differing requirements and subsequent interpretation of a means of compliance.

    The approaches are similar and seek to achieve an appropriate level of testing for the testing to demonstrate compliance with national and international airworthiness requirements, i,e FAA EASA, Transport Canada, JCAB, ENAC etc.

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    Fire Testing for Civil Aircraft Certification

    Various test methods, advisories and guides are used to provide criteria used in determining the flame characteristics required to test various components used in aircraft engines, their nacelles and their other supporting structures.

    Primary documents for propulsion-grade fire testing

    ISO2685: Environmental Test Procedures for Airborne Equipment – Resistance to Fire in Designated Fire Zones, International Standards Organisation

    AC 20-135: Powerplant Installation and Propulsion System Component Fire Protection Test Methods, Standards and Criteria, Revised 1990 – NOTE AC 20-135:Change 1

    FAA Power Plant Engineering Report No. 3A: Standard Fire Test Apparatus and Procedure (For Flexible Hose Assemblies), Revised March 1978

    Guidance documentation

    FAA Aircraft Material Fire Test Handbook: Chapter 11 Powerplant Hose Assemblies Test and Chapter 12 Powerplant Fire Penetration Test - used to determine the fire resistance components used in designated fire zones to damage due to flame and vibration for showing compliance with TSO C42, C53A, and C75. April 2000.

    SAE AIR 1377A: Fire Test Equipment for Flexible Hose and Tube Assemblies, Revised January 1980.

    SAE AS 1055: Fire Testing of Flexible Hose, Tube Assemblies, Coils, Fittings and Similar System Components, Revised 1978.

    AS4273: Fire Testing of Fluid Handling Components for Aircraft Engines and Aircraft Engine Installations

    RTCA DO -160G: Environmental Conditions and Test Procedures for Airborne Equipment Section 26.0 Fire, Flammability.

    SAE ARP5757: Fire Guidelines for Engine Component Tests Section 5.24.

    AC 33.17-1 33.17-1 - Fire Prevention (Cancelled)

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    Common themes of AC20-135 / ISO2685 compliant fire testing (the fundamental basics)
    Significant considerations
    The Questions

    Flame temperature– 2000°F minimum average (ISO 2685 doesn’t define this as a requirement. This is will be clarified)

    What, How and Where do you measure?

    Approved Equipment

    Best Practice? Whose best practise?

    Heat flux density >4500 Btu/hr (> 10.6 W/cm² (9.3 Btu/ft².s)

    What, How and Where do you measure?

    Approved Equipment

    Best Practice? Whose best practise?

    Almost without exception we can expect vibration

    4g or 7g

    Why any vibration

    Temperatures: the actual and recorded.
    Table 0-1 Comparison of flame temperature - AC20-135 ISO2685
    FAA: North American Preferences
    EASA: European Preferences (Partially)
    The Questions

    Primary Unit
    FAA (2000F minimum Average )
    ± 150F) 1850F-2150F

    2012F Note No minimum average )
    (1868F- 2156F )

    Note the obvious possible error 80C=176F
    (1836F-2176F) Which is incorrect.

    1093C min average
    (1010F- 1177F )

    Primary Unit
    ISO2685 (1100C:
    Note No minimum average )
    ± 80C) 1020C-1180C

    Comparative location of TC’s
    (Exposed Tip) AC20-135 / ISO2685 flame calibration and flame mapping

    Resonate are almost exclusively asked to calibrate at 1” above Centreline.

    ISO2685 sketches may be misleading and be interpretated as 1” below the centre line. Due to flame buoyancy, typically flame temp is measured 1” (25.4mm) above the cone centreline.

    Vertical Burner orientation and AS1055/ AS1377 define testing require flame calibration along the centreline of the cone.

    AC20-135 / ISO2685
    Flame Mapping

    Comparison of Burner Calibration- 1” above centre line Centre line.

    What would the map look like with 2000F min average and ≥4500 BTU/Hr?

    Comparative assessment of flame temperature with Cone, Area and Temp

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    Flammability Testing

    The requirements for use of materials in aircraft, and especially in aircraft interiors are quite similar all over the world, and are clearly described by various regulatory agencies. Materials and composites used in the construction of transport category aircraft must comply with national and international regulations with most countries having adopted the U.S. Federal Aviation Regulations (FAR). These regulations consider that limiting flammability and smoke density will adequately control the toxic fume production. Aircraft Interiors are covered by section “853” of the regulations. Aircraft interior materials designated for use in an aircraft cabin environment must meet certain flammability requirements. All the materials have to pass the vertical burn test. Some aircraft interior components such as interior ceiling, wall panels, partitions, galley structure, large cabinets or cabin stowage compartments must pass as well smoke emission and toxicity tests, as well as a heat release test.

    Best Practice- Actual Temperature against Measure Temperature. All is not what is seems.

    7 type K thermocouples

    1-inch apart (25mm)

    1-inch above centreline

    4-inches away from cone

    3mm external sheath

    4-6mm exposed tip

    24 AWG (0.5mm) wire


    Comparison of Thermocouple requires with Engineering report 3A, AC20-135, ISO2685 and FAA Fire etst handbook.

    TC Requirements from the standards ISO2685 and AC20-135

    Thermocouples for use in flame calibration

    Type K thermocouples are being used at the top end of their range

    The actual specified thermocouples are not available, and the thermocouple industry has moved away from this definition

    Exposed tip thermocouple, while giving fast response time and therefore a more accurate representation of the flame temperature have a finite life and should be replaced often

    Thermocouples should be specified to meet international standard for their manufacture to ensure consistency and a minimum accuracy

    Age has the biggest impact of the temperature measurement

    The thermocouple reading temperature maybe significantly lower than the theoretical gas (flame) temperature in the high-temperature environment

    A smaller TC indicates a higher TC temperature and provides quicker response time than the bigger TC

    Application and relevant of RTCA DO 160F / G to the accepted AC20-135 & ISO2685 approaches.

    Resonate testing draws clients to AC No: 21-16G - RTCA Document DO-160 versions D, E, F, and G, “Environmental Conditions and Test Procedures for Airborne Equipment”. Caution is advised in light of the following clarification

    h. RTCA/DO-160F, Section 26, Fire, Flammability, is not sufficient for 14 CFR parts 25 and 33. RTCA/DO-160G, Section 26, is sufficient for 14 CFR part 25 but not for 14 CFR part 33. Fire and flammability guidance for 14 CFR part 33 is provided in the latest revision of AC 33.17-1

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