Understanding Documented Risk Assessments for Combustible Dust

What Is a Documented Risk Assessment?

In North America, for facilities handling Combustible Dust, we pull guidance and information about Documented Risk Assessments from the NFPA Combustible Dust Standards. NFPA 652 states:

“A documented risk assessment acceptable to the AHJ shall be permitted to be conducted to determine the level of protection to be provided, including, but not limited to, protection measures addressed in Section 9.3.” (NFPA 652 9.3.1)

“A means to determine protection requirements should be based on a risk assessment, with consideration given to the size of the equipment, consequences of fire or explosion, combustible properties and ignition sensitivity of the material, combustible concentration, and recognized potential ignition sources. Where multiple protections are prescriptively required, a risk assessment could determine that an adequate level of safety can be achieved with only some, or possibly none, of the prescribed protective measures. More specifically, while ignition source control without consideration of the potential consequences is generally not an accepted primary means of explosion protection, a risk assessment (which by definition requires consideration of the consequences) could determine that ignition source control provides an acceptable level of safety.” 
(NFPA 652 A.9.3.1)

To put it simply: A Documented Risk Assessment systematically examines the equipment and materials involved, evaluating both the likelihood and potential consequences of a fire or explosion. It’s also important to understand that a Documented Risk Assessment is not necessarily the same as a Dust Hazard Analysis (DHA). A Risk-Based DHA conducted for a full facility or process may closely resemble a Documented Risk Assessment, but we are focusing on using a Documented Risk Assessment as an alternative to prescriptive requirements. They can help supplement DHAs, and when completed, Documented Risk Assessments should be incorporated into or kept alongside the DHA.

If you’re already familiar with this, feel free to skip ahead to “Why Are Documented Risk Assessments an Option?” If not, let's explore a simple analogy to clarify.

A Practical Scenario

Imagine you're standing in an empty room holding a soft, foam ball. Now, if someone asked you to toss the ball in random directions, what are the chances of causing any damage or harm? Virtually none, right? Even if you were to hit something, the foam ball is unlikely to cause any damage.

Now, let's switch out that foam ball for a small, hard rubber ball. The situation changes slightly: the likelihood of causing harm remains low, but the consequences might be a bit more significant. You’d probably exercise a little more caution.

Finally, picture adding a few other people in the room, each holding their own rubber ball. Everyone is now tossing them around. The chances of someone getting hit and the potential for minor injuries have increased significantly.

In this analogy, the foam ball is like a minor risk with minimal consequences, while the rubber ball and additional people represent a situation where both the likelihood and consequences are more serious. Similarly, in a combustible dust hazard scenario, a Documented Risk Assessment examines all variables, including materials, equipment, and operating conditions, to determine the likelihood and potential severity of an incident.

Why Are Documented Risk Assessments an Option?

A Documented Risk Assessment becomes a valuable tool when prescriptive NFPA standards require specific safety measures, but the facility believes those measures may be unnecessary or disproportionate to the actual risk. In these cases, a Documented Risk Assessment offers a more flexible approach, allowing facilities to assess their unique circumstances and justify alternative levels of protection.

For example, take the NFPA 652 requirement:

"Where an explosion hazard exists within any operating equipment greater than 8 ft³ (0.2 m³) of containing volume, the equipment shall be protected from the effects of a deflagration." (NFPA 652 9.7.3.1)

Now, imagine that a facility believes the equipment in question poses minimal risk. The cost of installing explosion protection could be high, but the perceived likelihood of an incident is low. In such a situation, the applicable NFPA standard allows the facility to conduct a Documented Risk Assessment to evaluate whether the required protection is justified based on the level of risk. A Documented Risk Assessment can provide a risk-based approach to ensure safety while considering practical constraints, ultimately offering a balanced solution between cost, risk, and compliance.

It is important to note that many of the allowances for Documented Risk Assessments include the requirement that they must be acceptable to the Authority Having Jurisdiction (AHJ). Understanding what an AHJ will accept is one of the key advantages of working with Dustcon Solutions. Our extensive experience delivering Documented Risk Assessments that have been accepted by AHJs ensures your facility remains compliant while managing costs effectively.

When Can a Documented Risk Assessment Be Used?

To understand when a Documented Risk Assessment is applicable, it’s important to consider the structure of NFPA standards. NFPA 652 serves as the fundamental standard for combustible dust hazards, but industry- and commodity-specific standards (such as NFPA 61, 484, 654, 664) build on this foundation with tailored requirements. Additionally, there are practical “How-to” documents that provide more specific guidance.

A Documented Risk Assessment can be used whenever an NFPA standard permits a risk-based approach as an alternative to prescriptive requirements. Here are some common areas where Documented Risk Assessments may be applied:

• Housekeeping
• Ignition Source Control
• Explosion Protection
• Explosion Prevention
• Explosion Isolation
• Automatic Fire Extinguishment

For instance, NFPA 652 details various situations where a Documented Risk Assessment can help determine the necessary level of protection. Industry-specific standards also outline scenarios where a Documented Risk Assessment is useful. For example:

• NFPA 484: Allows Documented Risk Assessments when evaluating risks associated with additive manufacturing powder weighing and sieving.
• NFPA 664: Permits Documented Risk Assessments when assessing the use of compressed air for cleaning.

Understanding when to follow NFPA 652, an industry-specific standard, or a “How-to” document is crucial. If you're uncertain, you can always reach out to our team at Dustcon Solutions for expert guidance.

Conducting a Documented Risk Assessment Involves Several Critical Steps:

• Define the Scope:
  • Identify the area or system being assessed, including any equipment, processes, or facilities that could potentially be involved in a combustible dust event.
• Identify Hazards:
  • Review the materials and processes to determine where combustible dust may be present. This includes identifying potential ignition sources, dust accumulations, and areas where dust might become airborne.
• Assess Risk:
  • For each identified hazard, evaluate the likelihood of an event occurring and its potential consequences. This step often involves qualitative or quantitative assessments to rank risks.
• Control Measures:
  • Once risks are assessed, determine the control measures needed to mitigate or eliminate them. This can involve ignition source control, dust collection systems, explosion venting, and the installation of passive or active explosion protection measures.
• Document Findings:
  • Record every step of the process, from the initial hazard identification to the final control measures implemented. This documentation should include justifications for the measures chosen and any risk-based decisions.
• Review and Update:
  • A Documented Risk Assessment is a living document that should be reviewed regularly. As processes, equipment, or regulations change, the assessment must be updated to reflect the current risk landscape.

What Makes a Good Documented Risk Assessment?

A successful Documented Risk Assessment includes the following elements:

• Clearly Defined Risk Tolerance and Evaluation Method: Establishing a clear risk tolerance and using a structured method (i.e., risk matrix) is essential for evaluating potential hazards. This ensures that risks are assessed consistently and in line with the facility’s safety objectives, providing a strong foundation for informed decision-making.
• Comprehensive Hazard Identification: Every potential hazard related to combustible dust should be considered, including the less obvious ones.
• Clear Documentation: A good Documented Risk Assessment is clearly written, with every risk and control measure thoroughly documented. This not only ensures compliance but also makes it easier to update the assessment as needed.
• Stakeholder Involvement: The best Documented Risk Assessments involve input from multiple stakeholders, including engineers, safety professionals, and plant operators, ensuring that all perspectives are considered.
• Evidence-Based Reasoning: When using evidence-based solutions, the reasoning behind the decisions should be explicitly detailed, including references to relevant NFPA standards or other guidelines.

One additional benefit of a well-executed Documented Risk Assessment is having a clearly defined record of the decisions made and the reasoning behind them. We have worked with clients who, unfortunately, did not keep their Documented Risk Assessment on file. Over time, new staff made changes that inadvertently increased their risk because they were unaware of the original assessment. Keeping your Documented Risk Assessment readily accessible helps prevent such issues and ensures continuity in your safety measures.

Considerations for Conducting a Documented Risk Assessment with Dustcon Solutions

Working with Dustcon Solutions to conduct a Documented Risk Assessment offers several advantages:

• Expertise in Combustible Dust Hazards: Our team includes engineers who serve on NFPA technical committees, bringing deep knowledge of the standards governing combustible dust safety.
• Tailored Approach: We understand that no two facilities are the same. Dustcon works closely with you to ensure that the Documented Risk Assessment is customized to your specific needs and processes.
• Comprehensive Documentation: Dustcon provides clear, actionable reports that are easy to understand and implement. We avoid cookie-cutter reports, instead focusing on providing recommendations that make sense for your facility’s unique risk profile.
• Proactive Safety Planning: In addition to helping you meet current safety requirements, we assist in identifying areas where proactive measures can reduce future risks, often leading to cost savings over time.

Conclusion

A well-executed Documented Risk Assessment is a valuable tool in managing combustible dust hazards. By clearly identifying risks, evaluating mitigation options, and documenting every step of the process, you ensure a safer working environment while remaining compliant with NFPA standards. When choosing to conduct a Documented Risk Assessment, consider working with a team like Dustcon Solutions, where expertise, experience, and a tailored approach ensure your assessment provides real value.

At Dustcon Solutions, we are ready to help you navigate the complexities of combustible dust safety and ensure your facility is both safe and compliant. Reach out today to discuss how we can assist you in conducting a thorough Documented Risk Assessment.