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


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Process Safety Newsletter

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

Recent Posts

Peak Pool Boiling Critical Heat Flux True Hydrodynamic Limitation

Posted by Fauske & Associates on 05.21.19

By Hans K. Fauske, D.Sc., Emeritus President, ANS Fellow, AIChE Fellow, NAE Member

Hydrodynamic instabilityAs often claimed, the classic hydrodynamic instability theory by Zuber (1958) does not provide the upper external hydrodynamic limitation to onset of the heat transfer crisis for well-wetted horizontal surface,

formula 1     (1)


where formula 2= pool boiling critical heat flux, Formula 3 = latent heat of evaporation, ρ(kg m-3) = vapor density, g (9.8 m s-2) = gravitational constant, Untitled-6-2(kg s-2) = liquid surface tension, and ρl (kg m-3= liquid density. Here, I propose that the upper limiting value of the heat flux (independent of surface conditions such as porous, polished, or nanoscopically smooth surfaces) is determined by the onset of fluidization, i.e., change in flow regime from liquid to vapor continuous condition.

The superficial vapor velocity jcorresponding to fluidization can be estimated from (Wallis, 1969), 

Formula 4     (2)

where α is the volume fraction of liquid droplets, and Formula 5 is the terminal droplet velocity given by (Levich, 1962),

Formula 6     (3)

Combining Eqs. (2) and (3) and setting CD = 1 and α = 0.6 (corresponding to a state when spherical liquid droplets no longer are touching each other) results in the minimum fluidization velocity,

Formula 7     (4)

and the peak critical heat flux Formula 8     (5)

It follows that Formula 9 . Here we note that the highest measured deviations from Zuber’s instability theory is a factor of 1.78 obtained on microporous surfaces with the highly-wetting FC-72 fluid (Rainey et al., 2003).

In summary, considering an appropriate hydrodynamic limit based upon a flow regime change from liquid to vapor continuous condition due to incipient fluidization (Eq. 5), this limit is clearly substantiated based upon the highest reported heat flux values obtained with well-wetting surfaces at different pressures. As such, the microporous surfaces used by Rainey et al., provide the maximum possible heat removal rates.

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Levich, V. G., 1962, “Physiochemical Hydrodynamics,” Prentice Hall .

Rainey, K. N., et al., 2003, “Pool Boiling Heat Transfer Microporous Surfaces in Surfaces in FL-72,” Journal of Heat

Transfer, Vol. 125/75 (February).

Wall is, G. B., 1969, “One-Dimensional Two-Phase Flow,” McGraw-Hill .

Zuber, N., 1958, “On the Stability of Boiling Heat Transfer,” ASME J. Heat Transfer 80(2), pp . 711-720.

Topics: Reactive Chemicals


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