Combustible Dust Testing

Laboratory testing to quantify dust explosion and reactivity hazards

Safety Data Sheets

Develop critical safety data for inclusion in SDS documents

Gas and Vapor

Laboratory testing to quantify explosion hazards for vapor and gas mixtures

Classification of hazardous materials subject to shipping and storage regulations
Testing and consulting on the explosion risks associated with devices and processes which use or produce hydrogen
Safety Data Sheets

Develop critical safety data for inclusion in SDS documents

Thermal Stability

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

Adiabatic Calorimetry
Data demonstrate the consequences of process upsets, such as failed equipment or improper procedures, and guide mitigation strategies including Emergency Relief System (ERS) design
Reaction Calorimetry
Data yield heat and gas removal requirements to control the desired process chemistry
Battery Safety

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

Safety Data Sheets

Develop critical safety data for inclusion in SDS documents

Cable Testing
Evaluate electrical cables to demonstrate reliability and identify defects or degradation
Equipment Qualification (EQ)
Testing and analysis to ensure that critical equipment will operate under adverse environmental conditions
Water Hammer
Analysis and testing to identify and prevent unwanted hydraulic pressure transients in process piping
Acoustic Vibration
Identify and eliminate potential sources of unwanted vibration in piping and structural systems
Gas & Air Intrusion
Analysis and testing to identify and prevent intrusion of gas or air in piping systems
ISO/IEC 17025:2017

Fauske & Associates fulfills the requirements of ISO/IEC 17025:2017 in the field of Testing

ISO 9001:2015
Fauske & Associates fulfills the requirements of ISO 9001:2015
Dust Hazards Analysis
Evaluate your process to identify combustible dust hazards and perform dust explosion testing
On-Site Risk Management
On-site safety studies can help identify explosibility and chemical reaction hazards so that appropriate testing, simulations, or calculations are identified to support safe scale up
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 safely handle the effluent discharge from an overpressure event

FATE™ & Facility Modeling

FATE (Facility Flow, Aerosol, Thermal, and Explosion) is a flexible, fast-running code developed and maintained by Fauske and Associates under an ASME NQA-1 compliant QA program.

Mechanical, Piping, and Electrical
Engineering and testing to support safe plant operations and develop solutions to problems in heat transfer, fluid, flow, and electric power systems
Hydrogen Safety
Testing and consulting on the explosion risks associated with devices and processes which use or produce hydrogen
Thermal Hydraulics
Testing and analysis to ensure that critical equipment will operate under adverse environmental conditions
Nuclear Safety
Our Nuclear Services Group is recognized for comprehensive evaluations to help commercial nuclear power plants operate efficiently and stay compliant
Radioactive Waste
Safety analysis to underpin decomissioning process at facilities which have produced or used radioactive nuclear materials
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 and Parts for the DSC/ARC/ARSST/VSP2 Calorimeters

Products and equipment for the process safety or process development laboratory


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


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


Our highly experienced team keeps you up-to-date on the latest process safety developments.

Process Safety Newsletter

Stay informed with our quarterly Process Safety Newsletters sharing topical articles and practical advice.


With over 40 years of industry expertise, we have a wealth of process safety knowledge to share.

Recent Posts

Safer Scale-Up of Batch and Semi-Batch Reactions Part 3: Applications of Adiabatic Calorimetry

Posted by Fauske & Associates on 11.06.19

Richard Kwasny, Ph.D., Senior Consulting Engineer and Gabe Wood, Manager Thermal Hazards Testing & Consulting, Fauske & Associates, LLC


ARSST equipmentFrom a process safety perspective, we can use stirred-reaction calorimetry to measure the heat of a reaction and calculate the adiabatic temperature rise for an exothermic reaction, assuming there are no heat losses to the environment. The rise in batch temperature can be derived from the experimental data using ΔTad = ΔHr / Cp,s where the adiabatic temperature rise is ΔTad , the heat of the reaction is ΔHr , and the specific heat of the reaction mass Cp,s .

The adiabatic temperature rise provides for a thermodynamic estimate that if cooling were lost, we could predict the maximum temperature of the synthetic reaction (MTSR) using the relationship MTSR = TOP + ΔTad , where TOP is the temperature of the process.

However, this approach needs to be refined using the tempering effect of the batch solvent(s), incorporating the real change in heat capacity with increasing temperature, and accounting for any thermal instability from the reaction mixture at elevated temperature under adiabatic conditions. This type of worst-case-scenario, where the batch heats exponentially, and cooling is a linear function, is commonly referred to as a thermal runaway reaction. In many situations, we know the thermal properties of the desired reaction, but we are not aware of process safety hazards associated with the adverse reaction in terms of reaction kinetics, temperature/pressure rates, and the production of fixed gases and the corresponding maximum temperature/pressure.


Adiabatic Calorimeters

The first lab-scale attempt to study the adverse reaction using adiabatic calorimetry was the Accelerating Rate Calorimeter (ARC™). It was successful in identifying decomposition reactions that were driven by the kinetics of the reaction during a long-hold time under isothermal conditions or at elevated temperatures. However, the test data were obtained with a Φ factor much greater than one; and resulted in an estimated adiabatic temperature rise rather than actual scale-up conditions due to the significant amount of heat which was absorbed by the test cell.

The Φ-factor, or thermal inertia, can be calculated using Φ = 1 + (Mv *Cp,v )/(Ms *Cp,s ), where Mv and Ms are the masses of the test cell and sample, respectively; Cp,v and Cp,s are the corresponding specific heat of the test cell and the sample.

Fauske & Associates, LLC developed low Φ-factor agitated adiabatic calorimeters, which did not require any assumptions, and the adverse reaction was allowed to proceed adiabatically in an unhindered manner. The Advanced Reactive System Screening Tool (ARSST™) and Vent Sizing Package 2 (VSP2™) adiabatic calorimeters allowed for direct scale-up of the calorimetric temperature/pressure data allowing for the measurement of the actual adiabatic temperature rise as opposed to a theoretical calculation requiring several assumptions. These instruments can also be used to simulate various runaway scenarios, and the temperature and pressure rise rate data can easily be used to perform emergency relief sizing using the Design Institute for Emergency Relief Systems (DIERS) methodology.

Get a quote

Practical Applications of ARSST and VSP2 Test Data

These devices can be used to characterize the hazardous properties, tempering, and flow regimes of adverse chemical reactions, fire scenarios, and worst-case scenarios in terms of thermal runaways and thermal decompositions under adiabatic conditions.

Once the adverse reaction is characterized, it is possible to apply DIERS methodology to design engineering controls in terms of adequately sized emergency venting, thereby making the process safer in the event of an unwanted process deviation, e.g., loss of cooling.

Solid powders containing carbonate functional groups are often dried as part of the normal work-up process. Drying these types of organic substrates can suddenly result in decarboxylation resulting in significant pressure and pressure generation rates due to large volumes of evolved carbon dioxide and water during the endothermic decomposition.

The resulting off-gas and vapor can be initiated by exceeding the recommended isothermal drying time or raising the internal temperature of the dryer without knowledge of the consequences; both of which depend upon the kinetics of the decomposition reaction. Understanding the decomposition kinetics and time limits can better allow for proper dryer engineering controls, e.g., vent relief or use of a dryer with an adequate maximum allowable working pressure, etc.

A key advantage of using the ARSST or VSP2 is that the testing can be conducted in a batch or semi-batch mode with agitation as needed. Therefore, a test can be designed to study the adverse reaction(s) under real process conditions. Then the data can be used to determine and design the proper pressure relief needed using DIERS technology.


In summary, low Φ-factor adiabatic testing data can be used to determine:

• Onset temperature, adiabatic temperature rise, and heat of reaction for exothermic events,

• Moles of non-condensable gas generated by the reaction,

• Thermal runaway data, used for DIERS relief sizing,

• Identification of venting behavior (gassy, tempered, and hybrid),

• Determination of flow regime (two-phase or single-phase), and

• Kinetic data, e.g., Time to Maximum Rate (TMR) or Temperature of No Return (TNR).


If you are interested in learning more about how low Φ-factor adiabatic testing data can be used to improve your organization, contact us.

Contact Us



  1. Stoessel, Francis, Thermal Safety of Chemical Processes, Wiley-VCH, (2008).
  2. Grewer, Theodor, Thermal Hazards of Chemical Reaction, Volume 4, Elsevier, (1994).
  3. Barton, John, and Rogers, Richard, Chemical Reaction Hazards, Second edition, Gulf Publishing Company, (1997).
  4. Guidelines for Chemical Reactivity Evaluation and Application to Process Design, Center for Chemical Process Safety of the American Institute of Chemical Engineers,(1995).
  5. Burelbach, J. P., “Advanced Reactive Systems Screening Tool (ARSST),” Presented at the Mary Kay O’Connor Process Safety Center Symposium, College Station, Texas, (October 26-27, 1999).
  6. Fauske, H. K., “Managing Chemical Reactivity-Minimum Best Practice,” Process Safety Progress, Vol. 25, No. 2, (2006).
  7. Fauske, H. K., “Properly Size Vents for Nonreactive and Reactive Chemicals,” Chem. Eng. Progress (February 2000).
  8. Fauske, H. K., “Revisiting DIERS’ Two-Phase Methodology for Reactive Systems Twenty Years Later,” Process Safety Progress, Vol. 25, No. 3, pp. 180-188 (September 2006).
  9. Leung, J. C., Fauske, H. K., and Fisher, H. G., “Thermal Runaway Reactions in a Low Thermal Inertia Apparatus,” Thermochimica Acta, 104, pp. 13-29 (1986).

Topics: Process Safety, ARSST, DIERS, Reaction Calorimetry, Adiabatic Calorimetry


Is My Dust Combustible?

A Flowchart To Help You Decide
Download Now