The tests described on this page are the most common process safety tests quoted by DEKRA.
- We have additional tests that we quote that do not show up on this list including UN/DOT tests and customized testing to meet client’s specific needs. Please reach out to us if you need a test that does not show up on this list.
- In addition, we can customize testing to meet the client’s needs on a case-by-case basis unless regulations require a specific method (e.g. DOT testing for classification).
Dust Explosion Testing
Go / No-Go - Explosibility Screening Test
The explosibility screening test determines whether a powder or dust will explode when exposed to an ignition source when in the form of a dust cloud. The test results in a material being classified as either GO – explosible or NO-GO -- non-explosible.
DEKRA Services, Inc., performs explosibility screening testing first using the Modified Hartmann Tube apparatus. The apparatus consists of a 1.2-liter vertical tube mounted onto a dust dispersion system. Initially, powder or dust samples of various sizes are dispersed in the tube and attempts are made to ignite the resultant dust cloud by 10 J constant arc ignition source. If the material fails to ignite in the Modified Hartmann Tube apparatus, GO / NO-GO testing is continued in the 20-litre sphere apparatus in general accordance with ASTM E1226. Powder or dust samples of various sizes are dispersed inside the sphere and are exposed to a 10 kJ, 5kJ, or 2.5kJ ignition source (chemical igniters).
Dust Testing Bundles
This bundle of tests includes the following individual tests:
Electrostatic Testing (Liquids)
Electrostatic Chargeability Test – Liquid
The concept of chargeability refers to the propensity of a liquid to become charged when flowing through conveyances, filters or when handled in mixing vessels. Chargeability is measured by flowing samples through tubes -- and measuring the resultant electrostatic charge. The test provides data which can be used to develop appropriate materials handling guidelines.
Because of the effect of flow velocity on liquid chargeability, this test is performed at a number of flow velocities.
Due to the potential electrostatic ignition risks, this test is conducted under an inert atmosphere.
Electrostatic Testing (Powders)
Electrostatic Chargeability Test – Powder
The concept of chargeability refers to the propensity of a powder or dust to become charged when flowing through conveyances or when handled in containers. DEKRA Services, Inc. measures powder chargeability in general accordance with ASTM D4470 Standard requirements. Chargeability is measured by flowing samples through tubes of uniform length and made from different materials -- specifically stainless steel, plastic, and glass -- and measuring the resultant electrostatic charge. The test provides data which can be used to develop appropriate materials handling guidelines.
Because of the effect of atmospheric and absorbed moisture on powder chargeability, this test is performed at ambient and low relative humidity conditions. For low humidity testing, samples are conditioned for at least 12 hours.
Electrostatic Testing (Films, Fabrics, Liners, Clothing, & Flooring Samples)
Electrostatic Accumulation and Discharge Testing
Insulating materials and conductive materials isolated from ground can become electrostatically charged. Accumulated charge can produce electrostatic discharges when exposed to ground. Electrostatic discharges from insulating materials are known as brush discharges, while discharges from isolated conductors are known as spark discharges.
The purpose of electrostatic discharge testing is to determine whether a material or object is capable of producing electrostatic discharges. Samples are electrostatically charged using a variety of methods and attempts to produce electrostatic discharges are made. Trials are performed under both ambient and low humidity conditions.
Electrostatic Testing (FIBCs, Drums, Sacks)
Discharge Incendivity Testing – FIBC
DEKRA Services, Inc., performs discharge incendivity testing, in general accordance with IEC 61340-4-4, by suspending an FIBC in a test rig and filling and emptying the FIBC with test powder. The test is intended to simulate a FIBC that becomes charged during filling and represent a reasonable worst-case electrostatic charging scenario. Electrostatic voltage on the FIBC surfaces is measured using an electrostatic voltmeter (fieldmeter).
Discharge incendivity is measured by approaching the FIBC surfaces with a gas-emitting probe. Discharges exhibiting an effective energy greater than the minimum ignition energy (MIE) of the flammable atmosphere within the probe shroud will cause an ignition. The MIE of the flammable atmosphere will be 0.14mJ. The purpose of discharge incendivity testing is to assess the potential hazard posed by the use of FIBCs in flammable atmospheres.
A total of 200 discharge incendivity tests (filling trials) will be carried out on the FIBC. Because atmospheric and absorbed moisture affects the propensity of a material to produce electrostatic discharges, these tests are performed at ambient and low relative humidity conditions. For low humidity testing, samples are conditioned for at approximately 12 hours.
Aerosol Foam Test-per UN DOT Standard
The test method is used to determine the flammability of an aerosol spray emitted in the form of a foam, mousse, gel or paste. An aerosol that emits a foam, mousse, gel or paste is sprayed on a watch glass and an ignition source is placed at the base to observe if ignition and sustained combustion of foam, mousse, gel or paste occurs.
Thermal Stability Testing
Aerated Solid Screening Test
The Aerated Powder Test is used to evaluate the thermal stability of powders and dusts during drying operations in which a heated air stream passes through the material, such as in circulating band and fluidized bed dryers. DEKRA Services, Inc., performs aerated powder testing in an explosion-protected laboratory oven in accordance with the Institute of Chemical Engineers (UK) "Guide to Prevention of Fires and Explosions in Dryers" (1990).
A 150 mL sample is loaded into a sintered glass sample cell which is fitted with an air inlet adapter. The cell is inserted into the oven, where it is suspended and exposed to increasing temperatures ramped at 0.5 °C (0.9 °F) per minute for 14 hours. Heated air is passed through the sample at a rate of 0.6 liters per minute or other rate specified by the client. The temperature of the sample and oven are measured at several locations. The sample temperatures over the duration of the test are analyzed to determine any exothermic activity.
Explosion Severity Test (Gases) – 20 Liter
DEKRA Services, Inc., performs explosion severity testing using the 20-Liter Sphere apparatus. A known concentration of the fuel is prepared in the sphere, ignited with an energetic ignition source and the pressure of the resulting explosion is measured. The sample concentration is varied to determine the optimal fuel concentration. The maximum pressure and rate of pressure rise are measured and used to determine the KG value of the material. These data can be used for the purpose of designing explosion protection measures and equipment.
Explosion severity testing is performed in accordance with American Society for Testing and Materials (ASTM) Method E 1226, National Fire Protection Association (NFPA) Standard 68 (1994), German Society of Engineers (VDI) Method 3673 (1995), and International Standards Organization (ISO) Method 6184/1.
Chemical Reaction Hazard Testing
Accelerating Rate Calorimeter (ARC)
DEKRA Services, Inc. performs ARC tests in accordance with the methods described in ASTM standards E1981 and ASTM E2086, to determine appropriate reactivity-hazard ratings for individual chemicals per NFPA 704 and registration criteria for individual chemicals and mixtures for the New Jersey Toxic Catastrophe Prevention Act (NJTCPA), where applicable.
The ARC is an automated laboratory instrument, which aids in experimentally determining the time, temperature, and pressure relationships of any exothermal reaction in a confined adiabatic environment. In operation the ARC uses an automatic heat-wait-search step scanning mode to determine the onset of exothermic reaction. When detected, the calorimeter will follow this reaction adiabatically, storing time, temperature, and pressure data. The data produced by the ARC can be applied to the evaluation of thermal and pressure hazard potentials of reactive chemicals. The ARC generates data such as heat generation rates, adiabatic self-heating parameters, temperature vs. real time plot, adiabatic reaction temperature, adiabatic reaction pressure, pressure rate data, kinetic data, reaction rate constants, and time to maximum rate. The calorimeter package consists of an insulated aluminum canister package which houses the calorimeter jacket, sample bomb assembly, and connections for thermocouples, heating elements, pressure transducer and jacket cooling air.
Samples usually 1- 10 grams are contained in pressure rated holders (bombs) of various masses and materials of construction such as titanium, tantalum, Hastelloy – C and 316 stainless steel.
OSHA NEP Testing For Combustible Dust
Class II Test
National Materials Advisory Board (NMAB) 353-3-80, Classification of Combustible Dusts in Accordance with the National Electrical Code, defines dusts having Ignition Sensitivity (IS) greater than or equal to 0.2 or Explosion Severity (ES) greater than or equal to 0.5 to be explosion hazards requiring electrical equipment suitable for Class II hazardous electrical locations. Ignition Sensitivity and Explosion Severity of the sample is determined by comparing explosibility and sensitivity test data to the same parameters of Pittsburgh Coal dust.
UN/DOT Test Bundles
Bundle – UN/DOT Series 1 Determination Test
This bundle of tests includes the following individual tests depending on if the test material is classified as a class 1 or class 2 material.
UN/DOT Transportation Testing
There is a difference between the UN and 49CFR DOT regulations for Division 4.3 materials. The UN test only measures the rate of flammable gas evolution, while the 49CFR regulation covers both flammable or toxic gas evolution. For 49CFR DOT testing, the gas evolution rate is measured and the presence of a toxic gas is determined through chemical analysis. Many toxic gases can be economically detected using Draeger tubes. Draeger tubes are not available for every gas. For gases without an available Draeger tube, or for samples where the identity of the gas produced is unknown, DEKRA would use a mass spectrometer to identify the gas.
- Dangerous When Wet Test - UN Test N.5 (Division 4.3) (emits flammable gas)
- Dangerous When Wet Test – 49CFR (Division 4.3) (emits toxic gas) (detection by Draeger tubes)
- Dangerous When Wet Test – 49CFR (Division 4.3) (emits toxic gas) (detection by mass spectrometer)
UN/DOT Test Descriptions for testing in accordance with the test methods described in the United Nations (UN) Recommendations on the Transport of Dangerous Goods, Manual of Tests and Criteria 7th Edition 2019. These descriptions were last updated: 11/16/2021.
UN/DOT Test Series 1(a): Gap Test for Detonation Propagation
The test is used to assess the ability of a substance to propagate a detonation. The test involves filling a cold-drawn, steel tube (400 mm L x 48 mm OD x 4 mm t) with the sample material. The top of the vertical tube is covered with a mild steel witness plate. The bottom of the tube is fitted to a booster charge and detonator. Test uses no gap between the booster assembly and the tube. A positive (+) result is indicated by complete fragmentation of the tube and/or a hole punched through the witness plate. If a negative (-) result is obtained during the first trial, a second trial is performed.
Required amount of material: 1-L (typically 1 to 1.5-Kg)
Corrosion Testing Study Using Metal Coupons – ASTM G31
To measure the corrosion rate of a metal when exposed to a potential corrosive substance, corrosion immersion tests are performed in accordance with ASTM G31,Standard Practice for Laboratory Immersion Corrosion Testing of Metals. Selected test conditions such as temperature and duration should reflect those anticipated for the actual service (e.g. the highest anticipated service temperature). Following the exposure, the corrosion rates will be calculated and the coupons examined for the evidence of localized corrosion.
The assignment of a packing group of the material or mixture (after testing is completed) will be recommended according to 49 CFR Part 173.137 and UN Recommendation on the Transport of Dangerous Goods Chapter 2.8 “Corrosive Substances” 2003. The corrosion test will be conducted for seven (7) days at a test temperature of 55°C.
Many corrosive substances can react with metals, with natural or synthetic fibers and with some other substances. Therefore, it is important to store or transport corrosive substances with only compatible substances to avoid any violent or adverse reactions. Optional customized coupons may be tested if it is desired (see note below) at the same time.