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

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

Effects of Temperature on LOC of Dimethyl Sulfuxide Mixed With Higher Vapor Pressure Solvent

Posted by The Fauske Team on 11.29.17

By: T.J. Frawley, Flammability Project and Lab Manager, Fauske & Associates, LLC

Dimethyl Sulfoxide (DMSO) is an extremely versatile solvent with uses spread across multiple industries. It is a by-product of the wood industry, has many uses in the medical field (although some uses are controversial), is an effective solvent due its high solubility, and can be used as a reaction solvent in manufacturing (DMSO.com).

DMSO’s effectiveness is partially due to the relatively nonvolatile nature of the substance when compared to other solvents. It has a high boiling point of 189°C and a low vapor pressure. The vapors are quite dense, with a vapor density of 2.70. Air has a vapor density of 1.0. The combination of dense vapors and low vapor pressure contribute to its, again, relatively high flash point temperature of 87°C.

Solvent - Flashpoint Chart

From a process safety standpoint, as long as the process is ran below the 87°C with DMSO alone, there is little risk. However, once another solvent with a lower flash point is mixed with DMSO, the flash point of that mixture will drop below 87°C, creating an explosive environment. If the process requires higher temperatures and high pressures, the danger increases with additional each degree and millibar.

If you are reading this, I feel safe in assuming that you are aware of the fire triangle and the hazards that exist working with the boundaries of that three-corners geometric shape of fire and fury. Before you think to mitigate the hazard through vent sizing or any other method, let us discuss prevention.

Your product is fuel. Cannot eliminate that leg of the triangle. And while you can attempt to reduce the exposure of your process to an ignition source, it is near impossible to eliminate every single, minute, possible, feasible, conceptual, source of ignition.

This leaves our final leg of the triangle, Oxygen. Here is where the Limiting Oxygen Concentration (LOC) test comes into play. If the process is anaerobic, you can completely inert your process with Nitrogen or Argon. This can get expensive as Nitrogen is not cheap, Argon less so. So you perform an LOC test to determine the lowest percentage of oxygen needed to sustain flammable propagation. And you run your process beneath that number. You are now on the off ramp exiting the danger zone.

But engineer beware. As the temperature increases, the amount of Oxygen needed to propagate an ignition decreases.

Assuming at 1:1 ratio mixture by volume of DMSO and another solvent with a flash point lower DMSO, the LOC of the mixture will decrease as the temperature increases. At lower temperatures the partial pressure of the mixture’s vapors will consist mostly of the other solvent. Not enough of the DMSO has vaporized to propagate an ignition in environments that are starved of oxygen. For example, say Sample A has an LOC of 10% O2 at 14.7 psia at 100°C and DMSO has an LOC of 6.5% O2 at 14.7 psia at 100°C. The LOC of the mixture of Sample A and DMSO will be closer to 10% O2 because the partial pressure will consist of a greater percentage of the less dense vapors of Sample A.

Oxygen - Temperature Ratio DMSO


However, as the temperature increases, so too does the vapor pressure of the DMSO. Thus, the partial pressure of the vapor is comprised more of DMSO molecules. The LOC of the mixture will begin to drastically decrease, moving away from the LOC of Sample A and beginning to reflect an LOC closer to that of DMSO.

The moral of the story is to beware when working with DMSO within a process. It is a very useful and diverse product that spans industries. The presence of DMSO drastically lowers the LOC of a mixture as temperatures increase.

For more information on FAI flammability services, contact T.J. Frawley at 630-887-5289 or frawley@fauske.com. www.fauske.com 





Topics: flammability, flash point, limiting oxygen concentration, vapor


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