Combustible Dust Testing

Laboratory testing to quantify dust explosion & 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

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Engineering and testing to support safe plant operations and develop solutions to problems in heat transfer, fluid flow, electric power systems

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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

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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 (DSC/ARC supplies, CPA, C80, Super Stirrer)

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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Recent Posts

Explosion Protection for Volumes Greater Than 8 ft3

Posted by Zachary Hachmeister on 06.19.19

 By Zachary Hachmeister, Chief Operating Officer, Fauske & Associates, LLC

20 Liter Chamber

20 Liter Chamber

NFPA 652 provides a prescriptive approach and a performance based approach as compliance options to mitigate dust explosion hazards. The prescriptive approach requires that air-material separators with a dirty side volume greater than 8 ft3 are equipped with explosion protection. Air-material separators with dirty side volumes less than 8 ft3 do not require explosion protection to achieve compliance with NFPA 652. This volume exemption also applies to other process equipment with small volumes (< 8 ft3).

The 8 ft3 exemption does not mean that an explosion hazard does not exist. In fact, the majority of data used for addressing dust explosion hazards is generated in a test apparatus with a volume of  20 L  (~0.7 ft3). The exemption exists because it can be difficult to provide these small vessels with explosion protection equipment and that the hazard risk is considered to be modest. As an illustration, let us assume an 8 to 1 volumetric expansion from a typical dust deflagration, an 8 ft3 enclosure (sphere with a radius of 1 ¼ feet) can produce a fireball with a volume of 64 ft3.  If the fireball is spherical then the radius would be ~2.5 ft.  Therefore, the decision to strike a balance between the economic impact and potential consequence justified the exemption.

The important take away is; per NFPA, you’re not required to protect these small volume units. However, we would strongly encourage to take a risk based approach when making this decision. This approach should include (but not limited to) consideration of consequences to personnel, property, and operations and probability of ignition give the ignition sensitivity of the material and how the equipment is being used.

Hopefully, this provides some clarification to a frequently asked question. If you'd like to learn more about dust hazard analysis and mitigation, check out FAI's 3 Step Approach by clicking below.

FAI's 3 Step Approach to DHA


Topics: Combustible dust, NFPA 652, explosion protection, dust explosion


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