Combustible Dust Testing

Laboratory testing to quantify dust explosion & reactivity hazards

Flammable Gas & Vapor Testing

Laboratory testing to quantify explosion hazards for vapor and gas mixtures

Chemical Reactivity Testing

Laboratory testing to quantify reactive chemical hazards, including the possibility of material incompatibility, instability, and runaway chemical reactions

DIERS Methodology

Design emergency pressure relief systems to mitigate the consequences of unwanted chemical reactivity and account for two-phase flow using the right tools and methods

Deflagrations (Dust/Vapor/Gas)

Properly size pressure relief vents to protect your processes from dust, vapor, and gas explosions

Effluent Handling

Pressure relief sizing is just the first step and it is critical to safety handle the effluent discharge from an overpressure event

Thermal Stability

Safe storage or processing requires an understanding of the possible hazards associated with sensitivity to variations in temperature

UN-DOT

Classification of hazardous materials subject to shipping and storage regulations

Safety Data Sheets

Develop critical safety data for inclusion in SDS documents

Biological

Model transport of airborne virus aerosols to guide safe operations and ventilation upgrades

Radioactive

Model transport of contamination for source term and leak path factor analysis

Fire Analysis

Model transport of heat and smoke for fire analysis

Flammable or Toxic Gas

transport of flammable or toxic gas during a process upset

OSS consulting, adiabatic & reaction calorimetry and consulting

Onsite safety studies can help identify explosibility and chemical reaction hazards so that appropriate testing, simulations, or calculations are identified to support safe scale up

Mechanical, Piping, and Electrical

Engineering and testing to support safe plant operations and develop solutions to problems in heat transfer, fluid flow, electric power systems

Battery Safety

Testing to support safe design of batteries and electrical power backup facilities particularly to satisfy UL9540a ed.4

Hydrogen Safety

Testing and consulting on the explosion risks associated with devices and processes which use or produce hydrogen

Spent Fuel

Safety analysis for packaging, transport, and storage of spent nuclear fuel

Decommissioning, Decontamination and Remediation (DD&R)

Safety analysis to underpin decommissioning process at facilities which have produced or used radioactive nuclear materials

Laboratory Testing & Software Capabilities

Bespoke testing and modeling services to validate analysis of DD&R processes

Nuclear Overview

Our Nuclear Services Group is recognized for comprehensive evaluations to help commercial nuclear power plants operate efficiently and stay compliant.

Severe Accident Analysis and Risk Assessment

Expert analysis of possible risk and consequences from nuclear plant accidents

Thermal Hydraulics

Testing and analysis to ensure that critical equipment will operate under adverse environmental conditions

Environmental Qualification (EQ) and Equipment Survivability (ES)

Testing and analysis to ensure that critical equipment will operate under adverse environmental conditions

Laboratory Testing & Software Capabilities

Testing and modeling services to support resolution of emergent safety issues at a power plant

Adiabatic safety calorimeters (ARSST and VSP2)

Low thermal inertial adiabatic calorimeters specially designed to provide directly scalable data that are critical to safe process design

Other Lab Equipment (DSC/ARC supplies, CPA, C80, Super Stirrer)

Products and equipment for the process safety or process development laboratory

FERST

Software for emergency relief system design to ensure safe processing of reactive chemicals, including consideration of two-phase flow and runaway chemical reactions

FATE

Facility modeling software mechanistically tracks transport of heat, gasses, vapors, and aerosols for safety analysis of multi-room facilities

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Recent Posts

Self-heating Screening Tests – Thermal Ignition of Bulk Powder

Posted by The Fauske Team on 10.25.16

By: Dr. Ashok Ghose Dastidar, PhD, MBA, Vice President, Dust & Flammability Testing and Consulting Services, Fauske & Associates, LLC

While dust explosions can lead to large and devastating losses in industry, they are not the only form of loss related to the combustion of powders. Often overlooked is the loss from dust/powder fires of related to a phenomenon called self-heating. Under special circumstances, the heat from the general environment may be enough to cause material to spontaneously auto react. This auto reaction results in the smoldering combustion of the powder/dust pile without an external ignition source such as open flame, electric/electrostatic spark or burning embers. The smoldering combustion can then lead to the burning of the powder/dust material with visible flames or even result in a dust explosion.

Thermograph1   Figure 1The self-heating potential of powders/dusts can be evaluated using several complex methods, but this can be very time consuming and may result in costly testing of materials that don’t have any self-heating potential at practical temperatures. Many times, a quick screening test is all you really need to assess a material's self-heating potential. You can then screen out materials that auto-ignite at unlikely temperatures in a given environment and focus on materials that have some self-heating potential; thereby saving time and expense. 

One such screening tool is the Grewer Oven. In this test, six 8-ml wire-mesh baskets are concurrently placed in a heated air stream. With this arrangement, five test samples and a reference material can be studied. The reference sample is typically graphite. Each of the six baskets is affixed with a thermocouple to monitor the internal temperature. The temperature of the oven and air stream can then be ramped from ambient temperatures to 300°-400°C at a rate of 1°C/min. 

Figure 1 illustrates some typical results. In this figure the temperature history of Lycopodium and Soy Flour is plotted and compared with graphite. The Lycopodium starts to self heat at approximately 180°C while the Soy Flour starts to self-heat at 200°C. This indicates that Lycopodium and soy flour do have self-heat potential at temperatures commonly found in industrial settings. Further thermal hazards analysis is warranted for these materials with studies tailored to the specific temperature environment at a given facility.

The Grewer Oven method may not be as quick or as simple as a Differential Scanning Calorimetry (DSC) test (a more modern scientific technique), but it has one advantage in that the sample is constantly exposed to a heated air-stream. In the DSC test the sample is in a sealed pan where the potential of oxygen starvation of the self-heating reaction exists. Once starved of oxygen the fire potential of the material may be masked and the hazard risk may be dismissed prematurely.

For more information on characterizing and assessing the dust explosion and fire hazards at your facility, please feel free to contact me at dastidar@fauske.com or (630) 887-5249 

Is My Dust Combustible?

Topics: Combustible dust, explosive dust, flammable dust, fire hazard, dust hazard, explosibility test, combustible hazard, comdust, dust test, DSC, Differential Scanning Calorimetry, dust explosion, dust cloud, dust control, fugitive dust, Grewer oven, thermal ignition, bulk powder

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