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

Recommendations on the Maximum Operating Pressure of ARC Test Cells

Posted by Fauske & Associates on 02.19.19

by Ken Kurko, Chief Technology Officer, Fauske & Associates, LLC


Ken Kurko
Chief Technology Officer
Fauske & Associates, LLC

At Fauske & Associates, LLC (FAI), we are commonly asked about the burst pressures of the Accelerating Rate Calorimeter (ARC) test cells that we offer. The ARC is a high thermal inertia adiabatic calorimeter that is used to obtain runaway chemical reaction data and thermal stability properties.As a runaway reaction occurs in this apparatus, the pressure within the test cell naturally rises whether it be due to vapor pressure effects, the generation of non-condensable gas, or both. The pressure generated by the runaway reaction must be contained by the test cell. As a result of this requirement, the mass of the test cell is relatively large compared to the mass of test sample used. This means that as a runaway reaction progresses, heat from the reaction is absorbed by the test cell and the data are not directly applicable to the process scale.

The standard ARC test cell is approximately 10 ml in volume and is typically constructed of stainless steel, Hastelloy C, titanium, or tantalum. This size of test cell has an internal diameter of 1.0 inches. The wall thicknesses of test cells can be 0.020, 0.025, or 0.035 inches. A diagram of a test cell is provided in Figure 1.

Arc Test Cell Thermal Stability
Figure 1 Standard 10 ml
ARC Test Cell

The reasoning behind the desire to know the burst pressure is so that as much sample material can be added to the test cell as possible without causing a rupture during the test. This reduces the thermal inertia (or essentially, the amount of heat absorbed by the test cell) and ensures lower energy exothermic activity isn’t masked. However, regardless of how much sample is loaded to a test cell, the resulting thermal inertia will never be representative of the process scale (1.05 - 1.10).

The ARC isn’t, and never was, intended to be a low thermal inertia calorimeter. The data from this apparatus will require correction for the thermal inertia. If low thermal inertia data are desired, a calorimeter intended for operation at low thermal inertias Vent Sizing Package 2 (VSP2TM) or Advanced Reactive System Screening Tool  (ARSSTTM) should be used.

Furthermore, this issue isn’t as simple as telling an ARC user the burst pressure of a particular test cell. When designing a test, one must balance a number of variables to ensure optimal results: the sample mass, the maximum temperature that could be achieved during the test, the maximum pressure that could be achieved during the test, the maximum self-heat rate under which adiabatic conditions are maintained, and material compatibility between the test cell and sample.

In order to address the original question regarding test cell burst pressure, we’ll focus on how the ultimate tensile strength of a given test cell material and the wall thickness are related to the peak temperature and peak pressure resulting during a test. The ultimate tensile strength decreases with increasing temperature. Figure 2 illustrates the effect of temperature on the ultimate tensile strengths of common test cell materials. Based on those tensile strengths, the theoretical burst pressures can be calculated for spheres with the specified dimensions provided in Table 1 using Equation 1 below.

σt Untitled-1-22

σt = ultimate tensile strength (Pa)

tw = wall thickness of spherical portion of test cell (m)

r = inner radius of test cell (m)

P = internal gauge pressure (Pa)


Ultimate Tensile Strength as a Function of Temperature for ARC Test Cell Materials
Figure 2 Ultimate Tensile Strength as a Function of Temperature for ARC Test Cell Materials


These are, of course, “ideal” calculations for a sphere that don’t account for the actual geometry of the test cell, nor imperfections that invariably occur during the manufacturing process. For example, the presence of a weld seam and the inhomogeneous microstructures within the welded metal leads to higher corrosion rates when compared to wrought products. Types of factors such as this need to be taken into account. For this reason, the theoretical burst pressures should not be used for test design - a safety factor of 2 to 3 should be used. Table 1 summarizes the theoretical burst pressures and our recommended maximum operating pressures for the various ARC test cells we offer.

Table 1 Theoretical Burst Pressure and Recommended Maximum Operating Pressure as a Function of Maximum Test Temperature for Standard ARC Test Cells
Theoretical Burst Pressure thermal stability


If you enjoyed learning about ARC and its purpose, check out our case study on low thermal inertia adiabatic calorimetry.  In this case study, FAI performs tests to determine what is the self accelerating decomposition temperature of a 50 kg package of azodicarbonamide. Download the case study now to to learn more about AKTS software, self accelerating decomposition temperature, the United States SADT test, and much more.

Download Now



Haynes International, “Hastelloy C-276 Alloy Tensile Strength and Elongation.” Retrieved September 5, 2018
from -C-276-Alloy/tensile-strength-and-elongation

North American Stainless, “Flat Product Stainless Steel Grade Sheet 316 - 316L.” Retrieved September 5, 2018
from https://www.northameric

Kobelco, Kobe Steel Group, “Highest Specific Strength of Existing Metallic Materials - Characteristic s.” Retrieved September 5, 2018

Pick PM , Metal Powder Industries Federation, “What Are Refractory Metals?” Retrieved September 24, 2018
from https://www.pick

Davis, J.R., ASM Specialty Handbook - Heat-Resistant Materials - Part I. Introduction. ASM International.(1997). Retrieved September 5, 2018
from 0YB /asm-speci alty-handbook/part-i-introduction


Is My Dust Combustible?

A Flowchart To Help You Decide
Download Now