Hazards Analysis, Code Compliance & Procedure Development

Services to identify process safety hazards and facilitate compliance with established standards and codes.

Combustible Dust Testing

Laboratory testing to quantify dust explosion and 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


Classification of hazardous materials subject to shipping and storage regulations

Safety Data Sheets

Develop critical safety data for inclusion in SDS documents


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


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 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

10 Tips: Setting Up ARSST Test to Yield Thermal Data and Safe Scale-Up

Posted by The Fauske Team on 06.09.15

By Elizabeth Raines, Chemical Engineer, Fauske & Associates, LLC



  1. Prior to each test, perform electrical resistance checks on the temperature and heater glands as well as the thermocouple and heater. 
  2. When installing the foil layer around the heater and heater belt, ensure that the test cell is evenly coated and press firmly around the whole configuration so the foil lies flatly against the cell.  This improves heat transfer to the cell evenly.
  3. Make sure to ground the thermocouple and vessel to the control box and house ground to lower the possibilities of electrical noise.
  4. Place the ARSSTTM (Advanced Reactive System Screening Tool) vessel square on the center of a stir plate to improve mixing inside the test cell.
  5. When testing a solid sample, ensure that the test cell is full enough and the thermocouple is low enough so the temperature can still be read when/if the solid melts.
  6. Keep in mind that the main factors that change calibration polynomials are sample mass, sample heat capacity, and back pressure.  If any of these variables vastly changes, it is a good idea to generate a new polynomial.
  7. As a rule of thumb, when increasing or decreasing the temperature rate of a polynomial, a 0.1 change in the A coefficient results in a heating rate change of approximately 0.3°C/min.
  8. When installing the thermocouple over the test cell, make sure that there will be no obstruction with the stir bar.  If the stir bar repeatedly hits the thermocouple during the test, it could deter mixing or cause noisy temperature readings.
  9. Remember that the maximum power output for the ARSSTTM is 16.7 W.  When the maximum power is achieved during a test, the test is no longer under adiabatic conditions.
  10. Configuring the test cell setup the same way each test is the key to generating reproducible results.  One way of maintaining the test cell configuration is using the same amount of insulation for each test.


Adiabatic calorimeter testing provides data for relief system design, safe scale-up of chemical processes, and changes to process recipes.  Safe process design requires knowledge of chemical reaction rates, character and energy release - all of which can be obtained from a low phi-factor adiabatic calorimeter such as the VSP2TM (Vent Sizing Package 2) or ARSSTTM (Advanced Reactive System Screening Tool).


The VSP2TM and the ARSSTTM provide thermal data required for safe scale-up of chemical processes and changes to process recipes. A variety of process upset conditions can be tested to quantify hazards identified by a PHA or HAZOP study. The low phi-factor (or thermal inertia) allows the heat and gas generation rates to be measured and directly applied to the process scale, which leads to appropriately designed emergency relief systems.


Fauske & Associates, LLC (FAI) was the principal research contractor for the Design Institute for Emergency Relief Systems (DIERS), an extensive R&D program sponsored by 29 companies under the auspices of AIChE and completed in 1985. Company founder, Hans K. Fauske, D.Sc., served as the principal investigator and overall leader of the DIERS research project. A primary purpose of that effort was evaluation of emergency relief vent requirements, including energy and gas release rates for systems under upset conditions and the effect of two phase flow on the emergency discharge process.

The DIERS program resulted in the development of a bench scale low thermal inertia adiabatic calorimeter, which was first commercialized as the Vent Sizing Package (VSP). Later improvements led to the VSP2TM. The Reactive System Screening Tool (RSSTTM) was introduced by FAI in 1989 to provide an easy, inexpensive approach to the DIERS testing method. Recent enhancements led to the Advanced RSST (ARSSTTM) in 1999. FAI uses the DIERS-based calorimeters to characterize chemical systems and design emergency pressure relief systems. Both instruments provide vent sizing data that are directly applicable to the process scale.

For more information, please contact Elizabeth Raines, eraines@fauske.com or 630-321-4794


Guide to Process Scale Up

#adiabatic test, #process safety, #process hazards


Topics: process safety, process hazards, PHA, ARSST, VSP2, DIERS, chemical reaction, adiabatic calorimetry, relief system design, adiabatic, scale up, relief system, thermal data


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