Combustion Hazard Testing of Dusts

Maximum Deflagration Pressure and KST for Combustible Dusts (ASTM E1226)

Standard Test Method for Pressure and Rate of Pressure Rise for Combustible Dusts. This test method is used to determine the maximum deflagration pressure, rate of pressure rise, and KST. This information is required to design explosion protection systems and pressure relief vents (per NFPA 68).   Sample size:  1000g.

Determination of Dust Classification (OSHA CPL 03-00-008)

OSHA Explosion Severity. This test method is used to determine if a combustible dust meets the criteria of a Class II dust as defined by explosion severity, and ignition sensitivity if needed. Sample size:  200g.

Minimum Explosible Dust Cloud Concentration, MEC (ASTM E1515) 

Standard Test Method for Explosible Concentration of Combustible Dusts. This test method is used to determine the minimum explosible concentration of a dust cloud. Dust samples are ignited at progressively reduced dust cloud concentrations until the concentration is reached at which flame propagation will no longer occur.  Sample size: 500g.

Minimum Ignition Energy, MIE (ASTM E2019)

Standard Test Method for Minimum Ignition Energy of a Dust Cloud in Air. This test method is used to determine the minimum ignition energy of a dust cloud. Small quantities of dust are pneumatically dispersed into suspension and ignited with an electric spark. The energy content of the spark is progressively reduced until the dust will no longer ignite. Minimum ignition energy is reported in milli-Joules (mJ).  Sample size: 200g.

Minimum Dust Cloud Ignition Temperature, MIT (ASTM E1491)  

Standard Test Method for Minimum Ignition Temperature of Dust Clouds. This test method is used to determine the minimum temperature at which a dust cloud will ignite and is measured by pneumatically conveying a dust sample through a vertically-oriented cylindrical electric furnace. The minimum ignition temperature is the lowest furnace temperature that results in propagation of flames from the bottom of the furnace.  Sample size:  100g.

Limiting Oxygen Concentration, LOC (ASTM E2931)

Standard Test Method of Limiting Oxygen Concentration of Combustible Dust Clouds. This test method is designed to determine the limiting oxygen concentration of a combustible dust dispersed in a mixture of air with an inert/nonflammable gas in a near spherical closed vessel of 20 L or greater volume. Data obtained from this method provide a relative measure of the deflagration characteristics of dust clouds. Sample size: 500g.

Hot Surface Ignition Temperature of a Dust Layer, MIT Layer (ASTM E2021)  

Standard Test Method for Hot-Surface Ignition Temperature of Dust Layers. This test method is used to determine the minimum temperature at which a dust layer will self-heat and ignite. The test material is placed within a metal ring on the top surface of a pre-heated hot plate.  Sample thickness may be varied from 0.25” to 1.0” depending on customer needs.  The sample’s temperature and appearance are monitored for signs of oxidation and/or decomposition reactions. The temperature of the hot plate is varied from test to test in order to determine the minimum temperature at which the sample self-ignites or shows any signs of oxidation or decomposition.  Sample size: 500g.

Auto-Ignition Temperature (Immersion) of a Dust Layer, TL (CRC SD-11) 

This test method is used to determine the auto-ignition temperature of a dust layer. A dust sample is placed in a holder and lowered into a cylindrical electric furnace. Thermocouples are used to measure the temperature of the dust layer and furnace.  At various furnace temperatures the dust-layer time-temperature curves are analyzed to determine the lowest temperature at which the sample spontaneously ignites. Follows Bureau of Mines RI5624 protocol. Sample size: 100g.

Packaging Classification of Dust (Class 4 Division 4.1, Test N.1) 

Test Method for Readily Combustible Solids – U.N. Test N.1 is used to determine the rate of flame propagation in dusts for the purpose of determining packaging classification. A sample is placed in a 250 mm x 20 mm x 10 mm triangular mold and an ignition source is applied at one end in order to determine the burn rate. Sample size: 500g.

Substances Liable to Spontaneous Combustion (Class 4 Div. 4.2, Test N.4)

Test Method for Self Heating Substances. This test method evaluates the ability of a substance to undergo oxidative self-heating as determined by exposure of it to air at temperatures of 100°C, 120°C, or 140°C in a 25mm or 100mm wire mesh cube. Sample size: 2500g.

Volume Resistivity & Volume Resistance of Powders (ASTM D257)

DC Resistance or Conductance of Insulating Materials. This test method is used to describe the conductive, dissipative, or insulative range of static control of material. Volume resistance is expressed in ohms.  Sample size: 50g.

Percent Combustible Dust (OSHA)

This test method provides the percent of combustible material of a dust sample by heating it in a furnace for a specified amount of time and taking weight measurements before and after heating. It is performed in accordance with OSHA requirements as described in CPL 03-00-008, the OSHA Combustible Dust National Emphasis Program. Sample size:  200g.

Bulk Density (ASTM D1895, Method A)

Test Method for Apparent Density of Materials. This test method determines the apparent density of fine granules and materials and provides useful indexes of performance of materials such as powders and granules with respect to their handling in packaging and fabrication. Apparent density is a measure of the fluffiness of a material. Sample Size: 150g.

Particle Size (Sieve) Analysis (CRC SD-4)

This test determines the particle size distribution of a dust sample through sieve analysis. The combustibility and reactivity of materials increases with decreasing particle size. Sample Size: 50g.

Moisture Content (CRC SD-5)

This test method determines the moisture content of a dust sample. Sample Size: 50g.

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