Abstract: An ignition suppressing enclosure configured to contain an ignition source is disclosed and includes a body portion defining an inner surface, an outer surface, and an enclosed volume containing a flammable gaseous mixture. The enclosed volume is sized to contain the ignition source. The enclosed volume of the ignition suppressing enclosure is surrounded by an exterior combustible environment also containing the flammable gaseous mixture. The ignition suppressing enclosure includes one or more vent paths that extend between the inner surface and the outer surface of the body portion, where each individual vent path includes an effective diameter based on at least a minimum ignition energy of the flammable gaseous mixture. The effective diameter of the individual vent path is selected to quench a flame that occurs within the enclosed volume of the ignition suppressing enclosure.

Abstract: A method, system, and apparatus for flame arresting are provided. In an embodiment, a flame arrestor includes a quenching element disposed within a conduit. The flame arrestor also includes a cooling system in thermal contact with the quenching system. The cooling system cools the quenching element during operation of the cooling system.

Abstract: A method for testing physical properties of a material includes inserting coherent light into a waveguide such that the coherent light exits the waveguide at an end of the waveguide that is embedded within the material, thereby causing the coherent light to interact with the material. The method also includes detecting a reaction of the material to the coherent light.

Abstract: Ignition-quenching covers are configured to quench an ignition event in a combustible environment triggered by an ignition source associated with an ignition-risk structure. Ignition-quenching covers comprise a porous body that includes two or more porous elements and are configured to cover the ignition-risk structure, wherein the ignition-risk structure is associated with a potential ignition source that may produce the ignition event in the combustible environment. The porous body defines passages sized to quench the ignition event. Methods comprise installing a porous ignition-quenching cover over an ignition-risk structure to prevent bulk combustion, e.g., of a fuel vapor in a fuel tank, due to an ignition event associated with the ignition-risk structure.

Abstract: Gas-flammability sensing systems and methods may be used to determine the flammability of gas mixtures in measurement volumes such as a fuel tank (e.g., an aircraft fuel tank). Gas-flammability sensing systems include a test cell structured to receive a gas sample, a heater in thermal communication with the test cell, and a gas meter configured to measure a physical property of the gas sample within the test cell related to the combustion state of the gas sample. The heater is configured to heat the gas sample to an elevated temperature less than the autoignition temperature of the gas sample. Methods of determining the flammability of a gas sample include collecting the gas sample, heating the gas sample to the elevated temperature, measuring the physical property of the gas sample after heating, and determining the flammability of a gas sample based upon the measured physical property.

Abstract: An ignition suppressing enclosure configured to contain an ignition source is disclosed and includes a body portion defining an inner surface, an outer surface, and an enclosed volume containing a flammable gaseous mixture. The enclosed volume is sized to contain the ignition source. The enclosed volume of the ignition suppressing enclosure is surrounded by an exterior combustible environment also containing the flammable gaseous mixture. The ignition suppressing enclosure includes one or more vent paths that extend between the inner surface and the outer surface of the body portion, where each individual vent path includes an effective diameter based on at least a minimum ignition energy of the flammable gaseous mixture. The effective diameter of the individual vent path is selected to quench a flame that occurs within the enclosed volume of the ignition suppressing enclosure.

Abstract: A method for testing physical properties of a material includes inserting coherent light into a waveguide such that the coherent light exits the waveguide at an end of the waveguide that is embedded within the material, thereby causing the coherent light to interact with the material. The method also includes detecting a reaction of the material to the coherent light.

Abstract: A cover that extends over a fastener and methods of installing the cover over the fastener. The cover includes an open end positioned at a member from which the fastener extends. The cover also includes a closed end that extends over the fastener and shields the fastener from the exterior environment that can be combustible. A plurality of holes extend through the cover from the interior space to an exterior environment external to the cap.

Abstract: A cover that extends over a fastener and methods of installing the cover over the fastener. The cover includes an open end positioned at a member from which the fastener extends. The cover also includes a closed end that extends over the fastener and shields the fastener from the exterior environment that can be combustible. The cover includes an outer shell with one or more windows. An inner shell is positioned within the outer shell. The inner shell includes one or more windows that are offset from the windows of the outer shell. One or more flow paths extend through the windows for gas, liquid, and/or some particles to flow through the cover while removing the thermal and/or kinetic energy that may ignite the combustible exterior environment.

Abstract: Systems include a test object that comprises a surface having a non-planar topographical feature, and an electrode comprising a non-linear segment that is proximate to the non-planar topographical feature of the surface of the test object. The electrode is positioned proximate to but not in contact with the surface of the test object such that the perpendicular distances between the electrode and the surface of the test object are uniform across the electrode. The electrode is further configured to (i) be translated across the surface of the test object while maintaining the perpendicular distances between the electrode and the surface of the test object, and (ii) impart a layer of charge across the surface of the test object when the test object is translated across the surface.

Abstract: An ignition testing system including a test article testing chamber, and at least one gas mixture verification chamber being communicably coupled to the test article testing chamber and being configured to verify at least a content of a gas mixture content provided to the test article testing chamber.

Abstract: A method, system, and apparatus for flame arresting are provided. In an embodiment, a flame arrestor includes a quenching element disposed within a conduit. The flame arrestor also includes a cooling system in thermal contact with the quenching system. The cooling system cools the quenching element during operation of the cooling system.

Abstract: Gas-flammability sensing systems and methods may be used to determine the flammability of gas mixtures in measurement volumes such as a fuel tank (e.g., an aircraft fuel tank). Gas-flammability sensing systems include a test cell structured to receive a gas sample, a heater in thermal communication with the test cell, and a gas meter configured to measure a physical property of the gas sample within the test cell related to the combustion state of the gas sample. The heater is configured to heat the gas sample to an elevated temperature less than the autoignition temperature of the gas sample. Methods of determining the flammability of a gas sample include collecting the gas sample, heating the gas sample to the elevated temperature, measuring the physical property of the gas sample after heating, and determining the flammability of a gas sample based upon the measured physical property.

Abstract: Systems include a test object that comprises a surface having a non-planar topographical feature, and an electrode comprising a non-linear segment that is proximate to the non-planar topographical feature of the surface of the test object. The electrode is positioned proximate to but not in contact with the surface of the test object such that the perpendicular distances between the electrode and the surface of the test object are uniform across the electrode. The electrode is further configured to (i) be translated across the surface of the test object while maintaining the perpendicular distances between the electrode and the surface of the test object, and (ii) impart a layer of charge across the surface of the test object when the test object is translated across the surface.

Abstract: Incendivity test systems and methods are disclosed. Incendivity test systems include a non-flammable gas mixture and a test article. The non-flammable gas mixture includes a thermally reactive reagent that is formulated to thermally react to produce a reaction product. Incendivity test systems also include an energy source configured to apply an energy discharge such as a simulated lightning strike to the test article. Incendivity test systems also include a detection device configured to measure an indicator species in the non-flammable gas mixture (e.g., the thermally reactive reagent and/or the reaction product). Incendivity test methods include contacting the test article with the non-flammable gas mixture, applying the energy discharge to the test article, and then measuring the amount of the indicator species and determining the incendivity of the test article in response to the energy discharge based upon the amount of the indicator species.

Abstract: A combustion test system includes a power source and a corona generator coupled to the power source. The combustion test system also includes a charge storage device. The charge storage device includes a charging surface spaced apart from the corona generator such that charge carriers, motivated by an electric field of the corona generator, intersect the charging surface to charge the charge storage device. The combustion test system also includes a first electrode coupled to the charge storage device and a second electrode coupled to a reference ground. The second electrode is spaced apart from the first electrode to produce an electrical arc between the first electrode and the second electrode based on a voltage difference between the first electrode and the second electrode.

Abstract: Ignition-quenching covers are configured to quench an ignition event in a combustible environment triggered by an ignition source associated with an ignition-risk structure. Ignition-quenching covers comprise a porous body that includes two or more porous elements and are configured to cover the ignition-risk structure, wherein the ignition-risk structure is associated with a potential ignition source that may produce the ignition event in the combustible environment. The porous body defines passages sized to quench the ignition event. Methods comprise installing a porous ignition-quenching cover over an ignition-risk structure to prevent bulk combustion, e.g., of a fuel vapor in a fuel tank, due to an ignition event associated with the ignition-risk structure.

Abstract: A cover that extends over a fastener and methods of installing the cover over the fastener. The cover includes an open end positioned at a member from which the fastener extends. The cover also includes a closed end that extends over the fastener and shields the fastener from the exterior environment that can be combustible. A plurality of holes extend through the cover from the interior space to an exterior environment external to the cap.

Abstract: A cover that extends over a fastener and methods of installing the cover over the fastener. The cover includes an open end positioned at a member from which the fastener extends. The cover also includes a closed end that extends over the fastener and shields the fastener from the exterior environment that can be combustible. The cover includes an outer shell with one or more windows. An inner shell is positioned within the outer shell. The inner shell includes one or more windows that are offset from the windows of the outer shell. One or more flow paths extend through the windows for gas, liquid, and/or some particles to flow through the cover while removing the thermal and/or kinetic energy that may ignite the combustible exterior environment.

Abstract: Methods of incendivity testing include applying a flexible sheet over a test article to form a sealed space between the flexible sheet and a surface region of the test article. Methods further include filling the sealed space with an indicator gas mixture, applying an energy discharge to the test article, and determining whether the indicator gas mixture in the sealed space reacted in response to the energy discharge. The indicator gas mixture may be flammable and may be formed while filling the sealed space. Incendivity test systems include the test article, the flexible sheet sealed to the test article to form the sealed space, a gas control module configured to fill, flush, purge, and/or sample gas in the sealed space, and an energy source configured to apply the energy discharge to the test article.