The purpose of MIL-STD-810 standard testing method 511 is to show the ability of materials to operate in fuel-air environmental conditions without causing ignition. As a MIL-810 certified lab, we realize the importance of MIL-STD-810 explosive atmosphere testing. Meeting the MIL-810 explosion risk requirements can be difficult. We understand the challenges and guide companies through the process.
When products do not meet the requirements, we assist with finding solutions. Keystone Compliance partners with customers to achieve MIL-STD-810 product compliance. We provide comprehensive reports shortly after completion of the MIL-810 standard testing. Keystone takes a consultative approach throughout the entire test program.
The Importance of Explosive Atmosphere Compliance Testing
MIL 810 method 511 testing applies to all material designed for use in the vicinity of fuel-air explosive atmospheres. This MIL-810 standard is associated with aircraft, automotive, and marine fuels at or above sea level.
Explosive testing demonstrates that an explosive or burning reaction occurring within encased materials will be contained.
It is important to note that the flammable test conditions may come from the equipment itself or from an outside source.
The expected life cycle sequence of events is a risk assessment used by applying the least potentially explosive atmospheres. Vibration, shock, and temperature stresses may distort seals and reduce their effectiveness, thus making ignition of flammable atmospheres more likely.
Limitations of test method 511, explosive atmosphere test, must be noted. First off, this test procedure uses a relatively low flashpoint mixture. Moreover, this may not be representative of some actual fuel-air aerosol. Next, explosive atmosphere testing is conservative.
There is a low probability of the material igniting prevailing the fuel vapor mixture. This method is not intended to test high surface temperatures. However, it does not preclude this possibility.
Differences Between MIL-810 Explosive Atmosphere Testing Procedures
Before conducting these 810-tests, complete the tailoring process by selecting a procedure and variations. These shock testing procedures are based on the documents provided below. Some effects of these procedures include low levels of energy discharge or electrical arcing. These effects are caused by devices that can ignite mixtures of fuel vapor and air.
Procedure I – Explosive Atmosphere – lab testing is useful to all types of sealed and unsealed material. The MIL-STD 810 test evaluates the ability of the test item to be run in a fuel vapor environment without igniting the environment.
Procedure II – Explosion Containment – This procedure determines the ability of the test item’s case or other enclosures to contain an explosion or flame. The procedure failure is a result of an internal material malfunction. Procedure II relates to atmospheres in an area where flammable fluids or vapors exist either constantly or occasionally.
Common Terms of Explosive Atmosphere Method 511
Fuel – Unless otherwise specified, use n-hexane as the test fuel. The fuel is used either as reagent grade or 95 percent n-hexane with 5 percent other hexane isomers. This fuel is used when its ignition properties in flammable atmospheres are equal to or more sensitive than the similar properties of aviation gasoline and jet engine fuel.
Fuel-Vapor Mixture – This MIL-STD-810 testing method recommends the use of a fuel-air mixture in the correct ratios. The required information to determine the fuel weight is as follows. Chamber air temperature during the test, fuel temperature, specific gravity of n-hexane, test altitude and net volume of the test chamber.
Temperature – Heat the fuel-air mixture to the highest ambient air temperature at which the material is required to operate. The material should be heated during deployment and provide the greatest chance of ignition. Perform all testing at this maximum air temperature.
Effect of Humidity on Flammable Atmosphere – There is no need to consider the effect of humidity if the ambient air dew point temperature is 10 degrees C or less. The concentration of water vapor increases the n-hexane fuel concentration. Tailoring may be required to simulate specific geographic areas.
Altitude Simulation – This MIL-STD 810 lab test evaluates whether a test item can operate safely in a fuel/air mixture. The purpose is to operate without creating a spark that could ignite the atmosphere. This test is not performed above the altitude of 16 km due to the lack of oxygen in the atmosphere.
Keystone Compliance Provides Explosive Atmosphere Testing Services
Keystone Compliance is one of the best Explosive Atmosphere and military testing labs in the country. We employ expert MIL-810 test engineers and properly equip our laboratory to provide MIL-STD 810 compliance certifications.
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