Our Solutions: Testing
Dust Explosibility Screening
(Go/No-Go Test)
First Step to NFPA 652/NFPA 660 DHA Compliance
Dust Explosibility Screening
(Go/No-Go Test)
First Step to
NFPA 652/NFPA 660
DHA Compliance
Sigma-HSE’s Dust Explosibility Screening (Go/No-Go Test) follows the approach outlined in NFPA 652/NFPA 660 to qualitatively identify combustible dusts to determine whether your material presents an explosion hazard, a fire hazard, or both.
This initial screening series combines dust cloud explosibility (Go/No Go) and combustibility (Burning Behavior) screening and provides the foundation for hazard identification and risk assessments, equipment design, and compliance with NFPA 652/NFPA 660 Combustible Dust Standards.
Dust behavior can vary significantly based on particle size, moisture content, composition, and process conditions, so assumptions based on appearance, historical use, or generic literature are often not enough. Initial screening testing helps establish whether more detailed testing is necessary. By starting with targeted explosion and fire hazard screening methods, facilities can focus resources on materials that present real hazard potential instead of applying a full testing program to every sample.
Combustible Dust Screening Testing as the First Step
Before a facility can effectively manage combustible dust risk, it must first determine whether its materials meet the definition of a combustible dust under NFPA 652 and NFPA 660. Chapter 5 of these standards requires facilities to evaluate whether particulate materials are combustible or explosible and provides the framework for making that determination.
Materials shown to be explosible when dispersed as a dust cloud are considered combustible for the purposes of NFPA combustible dust hazard management. Likewise, if a dust ignites and continues to propagate combustion after the ignition source is removed, the material is considered combustible under the standard.
As a result, combustible dust screening is often the first step in understanding whether a material may present a combustible dust hazard and whether additional evaluation, such as combustible dust characterization testing or a Dust Hazard Analysis (DHA), may be appropriate.
Explosibility (Go/No-Go) screening is typically the logical starting point. This test evaluates whether a dust sample is capable of propagating an explosion when dispersed as a cloud, providing an initial indication of potential dust explosion hazards. The results help facilities determine whether combustible dust hazards may exist and establish the basis for any follow-on testing, hazard analysis, or risk mitigation efforts that may be required.
However, not all combustible dusts have the particle size, concentration, or confinement needed to cause a dust explosion in every situation, so determining whether a material presents a combustion (fire) hazard in deposited form is also essential. Combustibility (Burning Behavior) screening addresses this by evaluating whether a dust layer or pile can ignite and sustain or propagate flame after the ignition source is removed, helping identify fire hazards from settled dust even when cloud explosibility is limited or absent.
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Industry Relevance
Chapter 5.0 of the U.S. Chemical Safety Board’s (CSB) 2006 Combustible Dust Hazard Study summarizes dust explosion incidents in general industry over a 25-year period from 1980 to 2005.
During this time, the CSB identified 281 combustible dust incidents resulting in 119 fatalities, 718 injuries, and significant material damage to facilities across 44 states and multiple industrial sectors.
This data highlights the persistent and serious nature of combustible dust hazards and underscores the critical importance of conducting thorough Dust Hazard Analysis and implementing proactive risk management strategies in industries handling combustible dust.
Source: U.S. Chemical Safety Board Combustible Dust Hazard Study, 2006 (CSB Report)
Explosibility (Go/No-Go) Screening
What Explosibility (Go/No-Go) Testing Determines
MIE testing follows established laboratory standards that define how testing must be performed. Standardized procedures help produce repeatable results that engineers can rely on during safety evaluations.
Several technical standards are commonly referenced for MIE testing.
- ASTM E2019 provides procedures for determining the MIE of a dust cloud under controlled laboratory conditions. This standard outlines test methods used to generate sparks of known energy levels.
- BS EN ISO IEC 80079-20-2 includes internationally recognized procedures for evaluating ignition characteristics of combustible dusts used in hazardous area classification.
- BS EN 13821 appears in older technical guidance as a legacy reference related to dust ignition testing methods.
Standardized testing methods allow laboratories to produce consistent and defensible results. This repeatability is important for engineering evaluations, safety documentation, and regulatory reviews. MIE data may also support combustible dust safety documentation used during NFPA-based hazard analyses, including NFPA 652 and NFPA 660 programs.
How Go/No-Go Explosibility Testing Works
Go/No-Go explosibility testing is typically conducted using a 20‑liter explosion vessel designed to evaluate the explosibility of dispersed dust clouds under controlled conditions. During the test, a measured dust sample is dispersed into the chamber to create a suspended dust cloud representative of potential process conditions.
The cloud is then exposed to an ignition source, often in the 5–10 kJ range, while pressure transducers monitor the pressure‑time history inside the vessel. The data are used to determine whether flame propagation or explosion behavior occurs. Unlike quantitative explosion severity testing, Go/No-Go explosibility testing does not generate Kst or Pmax values; it is strictly qualitative and focused on whether the dust is explosible under the specified conditions.
This makes Explosibility (Go/No-Go) Screening testing particularly valuable as an initial hazard-screening tool prior to performing more detailed explosion-severity and ignition-sensitivity testing.
Standards and Compliance Context
Go/No-Go explosibility testing is performed in accordance with recognized industry standards used throughout combustible dust and process safety programs, including ASTM E1226 and BS EN ISO 80079‑20‑2. These standards establish procedures for evaluating dust cloud deflagration behavior and support alignment with recognized and generally accepted good engineering practice (RAGAGEP).
Explosibility (Go/No-Go) screening is often the first step in determining whether a material should be treated as a combustible dust and whether a Dust Hazard Analysis (DHA) is required under NFPA 652 and NFPA 660. If a material is found to be explosible in Go/No-Go screening, additional testing is needed to characterize its explosion‑hazard properties. Tests such as ignition sensitivity (MIE), safe operating temperatures for dust clouds (MIT Cloud), and explosion severity parameters (Kst/Pmax) are then used to design and justify appropriate safeguards.
Even when a dust is screened as non‑explosible, understanding its behavior near hot surfaces can still be critical. Determining the minimum ignition temperature of a dust layer (MIT Layer) helps assess whether deposits might smolder or ignite on hot equipment surfaces; a dust that does not burn at room temperature might still smolder or ignite on a 400 °C motor housing or other heated components.
Benefits of Go/No-Go Explosibility Testing
Go/No-Go testing provides several practical advantages for facilities handling combustible powders and particulate solids.
As an initial screening tool, the procedure offers a fast and cost-effective method for identifying combustible dust hazards before committing to more extensive testing programs. Facilities can quickly assess whether additional explosibility characterization is necessary and focus resources on materials presenting actual explosion hazards.
Key benefits include:
Early identification of combustible dusts
Support for NFPA 652/NFPA 660 compliance efforts
Reduced unnecessary testing costs for non-explosible materials
Improved process safety decision-making
Faster combustible dust identification during process changes
Support for AHJ and insurance preparedness
Combustibility (Burning Behavior) Screening
What Burning Behavior Testing Determines
Understanding how powders and dusts behave under ignition conditions is also critical for managing fire risk within industrial processes. Combustibility (Burning Behavior) Screening testing is a laboratory‑based method used to evaluate how a material deposit responds when exposed to an ignition source, with a focus on whether combustion propagates across its surface.
During burning behavior combustibility testing, materials are assessed for their ability to sustain or spread flame in layer or pile form. Some powders resist ignition entirely, while others propagate combustion rapidly across a surface. This behavior provides an early indication of fire hazard potential from dust accumulations on floors, equipment surfaces, beams, or inside enclosures.
As part of a broader process safety strategy, combustibility (burning behavior) screening serves as an initial fire‑hazard identification tool. The results help inform housekeeping, hot‑surface management, and other controls where dust layers or deposits may be exposed to ignition sources.
How Combustibility (Burning Behavior) Testing is Performed
Burning behavior combustibility testing is conducted under controlled laboratory conditions designed to simulate dust deposits. A small strip or layer of the powder is formed on a heat‑resistant plate, creating a consistent sample for evaluation. An ignition source—typically a platinum wire heated to a defined temperature (around 1000 °C)—is applied to one end of the sample for a specified period.
The response is observed closely, including whether ignition occurs, how far and how fast combustion propagates across the sample, and whether the flame continues after the ignition source is removed. This behavior is used to categorize burning severity and to indicate whether the material presents a fire hazard as a combustible dust in layer or pile form. Testing can also be conducted at elevated temperatures to better reflect process conditions in which heat buildup may influence the combustion risk.
Standards and Methods Used
Combustibility (Burning Behavior) Screening testing in the Sigma‑HSE laboratory is conducted using internationally recognized burning‑behavior methodology, BS EN 17077. This standard describes test methods for determining whether a fire initiated by an external heat source will propagate in a dust layer under defined conditions.
Materials are assigned a Combustibility Class rating between 1 and 6, which provides a structured way to interpret test results and understand fire risk:
CC1: | No combustion propagation observed |
CC2: | Limited or localized combustion |
CC3: | Moderate combustion propagation |
CC4: | Strong combustion with visible spread |
CC5: | Intense combustion with rapid propagation |
CC6: | Very intense combustion with aggressive flame spread |
Using standardized methods ensures that burning behavior and combustibility results are consistent, reproducible, and comparable across industries and regulatory frameworks. Interpretation still requires an understanding of how laboratory behavior translates to real process conditions, so results are typically considered alongside process temperatures, housekeeping practices, and equipment configuration.
How Combustibility (Burning Behavior) Influences Fire and Dust Hazards
Even a small accumulation of dust can present a significant fire hazard if it supports combustion. Burning behavior testing is performed to identify materials that can sustain ignition or allow flame to spread across a deposited layer.
In many facilities, ignition sources are unavoidable. Hot surfaces, friction heat, and equipment failure can all provide enough energy to initiate combustion. Once ignited, materials with higher combustibility may allow flames to propagate, increasing the likelihood of fire spread.
By identifying these characteristics early, combustibility screening testing helps inform process safety evaluations and mitigation strategies for combustible dust hazards. It provides actionable insights into how materials behave under real-world conditions and supports decisions regarding handling, storage, and processing controls.
Sigma-HSE Live: Combustibility Screening Test
[Embed YouTube Video] https://www.youtube.com/watch?v=RuP2_rNmmQw
This demonstration shows how combustion propagates across a powder strip during testing. The ignition source initiates a reaction, and the resulting behavior reveals how the material responds under controlled conditions. Observing this process highlights the variability between materials and reinforces why laboratory testing is essential. Visual confirmation of combustion propagation provides valuable context when interpreting classification results.
Why Choose Sigma-HSE for Dust Explosibility Go/No Go Testing
We provide process safety consulting and laboratory testing services focused on identifying, evaluating, and reducing fire, explosion, and chemical process hazards across industrial operations. Our combustible dust testing programs combine technical rigor with practical process safety expertise to help facilities make informed operational and compliance decisions. We support clients across manufacturing, pharmaceutical, food processing, chemical, metal, energy, and other high-hazard industries where combustible dust risks require structured evaluation and defensible technical data.
Organizations work with us because we provide:
Expertise in combustible dust and process safety
Testing aligned with ASTM, ISO, and NFPA standards
Fast turnaround times, typically 7–10 business days, where applicable
Clear, actionable laboratory reporting
Integration with DHA and hazard mitigation services
Support for global regulatory frameworks and compliance initiatives
Industrial Applications for Dust Explosibility Go/No Go Screening
Dust Combustibility Go/No Go testing is widely used across industries where powders and dusts are handled, processed, or stored. These include:
- Food and beverage manufacturing safety
- Pharmaceutical manufacturing process safety
- Specialty chemical process safety
- Wood products and biomass dust hazards
- Metal powder process safety
Testing is typically initiated when new materials are introduced, during hazard analyses, or when evaluating process changes. It is also used to support material classification and transportation safety requirements
Request Dust Explosibility Go/No Go Screening Testing
Combustible dust behavior varies significantly depending on material properties and operating conditions. Early identification of explosion risks and fire potential allows organizations to take proactive steps to reduce risk and improve process safety.
Sigma-HSE provides fast, accurate, and accredited combustible dust testing to help industrial facilities evaluate powders and particulate solids for these hazards before they affect operations. Our approach combines standardized methods with practical insight to help you better understand combustible dust within your process.
From new material evaluations to DHA initiatives and process change reviews, our team delivers responsive technical support, rapid turnaround times, and actionable laboratory data aligned with ASTM, ISO, and NFPA methodologies.
Contact us to discuss your testing requirements or to develop a tailored dust combustibility Go/No Go testing program.
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FAQ
What is Go/No-Go explosibility testing, and what does it determine?
Go/No-Go explosibility testing is a qualitative screening method used to determine if a dust or powder can form a flammable atmosphere when dispersed and exposed to an ignition source. The test classifies materials as either explosible or non-explosible and provides an initial indication of combustible dust hazard potential.
How does Go/No-Go explosibility testing differ from KSt/Pmax and explosion severity testing?
Go/No-Go testing provides a qualitative (yes or no) result that identifies if a material is capable of explosion under defined conditions. Kst and Pmax testing are quantitative methods used to measure explosion severity through the rate of pressure rise and the maximum explosion pressure to determine how fast and how severe an explosion can be.
When is Go/No-Go explosibility testing sufficient, and when is additional testing required?
Go/No-Go testing may be sufficient for initial hazard screening or evaluation of unknown materials. If a material is classified as explosible, additional testing such as KSt/Pmax, MEC, MIE, or MIT for cloud and layer evaluations is typically required to support engineering design and NFPA 652/NFPA 660 hazard analysis activities.
What standards are used for Go/No-Go explosibility testing?
Go/No-Go explosibility testing is conducted in accordance with recognized standards, including ASTM E1226 and BS EN ISO/IEC 80079-20-2. These methodologies support consistency with recognized and generally accepted good engineering practices (RAGAGEP).
How does Go/No-Go explosibility testing support NFPA 652/NFPA 660 Dust Hazard Analysis (DHA)?
Go/No-Go explosibility testing is often the first step in determining whether a material should be treated as a combustible dust and whether a Dust Hazard Analysis (DHA) is required under NFPA 652 and NFPA 660. If a material is found to be explosible, additional testing should be performed to evaluate explosion risks, assess hazard potential, and determine if additional mitigation measures are necessary.
What is combustibility (burning behavior) testing?
Burning behavior testing evaluates how a powder or dust layer deposit responds to an ignition source, specifically whether it can sustain combustion (ignite) and propagate flame (spread fire) across its surface.
What is a Combustibility Class (CC)?
A combustibility class is a rating from 1 to 6 that indicates the severity of combustion propagation, with higher values representing greater fire spread potential.
When should combustibility screening testing be performed?
Testing is typically conducted when introducing new materials, performing hazard analyses, or evaluating fire risks within a process.
What factors influence combustibility (burning behavior) in powders or dusts?
Particle size, moisture content, chemical composition, and process conditions all influence how a material behaves during combustion.
Why is burning behavior combustibility testing important for combustible dust safety?
It provides early insight into fire propagation risks, helping facilities implement appropriate safety measures and determine whether further testing is required.
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Complete Guide to Dust Hazard Analysis: Protecting Your Facility from Combustible Dust Risks
Not sure if Go/No-Go Explosibility Screening is the right test? Contact our team, and we’ll help you determine the most appropriate combustible dust testing for your material.
Identify Combustible Dust Hazards with Go/No-Go Explosibility Screening
Determine whether your dust can form an explosible dust cloud before investing in more extensive testing. Sigma-HSE’s Go/No-Go Explosibility Screening helps organizations identify combustible dust hazards, support NFPA 660 Dust Hazard Analysis (DHA) programs, and make informed decisions about additional combustible dust testing. Our laboratory provides fast, reliable screening to help reduce risk and support safer process operations.