Safety Insight - DHA Revalidation Process

Jan 21, 2021
Why Should We Be Concerned?
The most recent data published by the National Fire Protection Association (NFPA) indicates there has been a 65% reduction in industrial and manufacturing fires. Despite the decrease in the total number of fires, the sources of ignition for industrial and manufacturing fires remain consistent. The reduction in fires can be attributed to several factors including, but not limited to:
(1.) increased knowledge and awareness of the causes of fires
(2.) improvements in fire protection systems and technology and
(3.) the use of proactive, analytical processes and tools like the Dust Hazard Analysis.
The Dust Hazard Analysis (DHA) is a proven process that helps manufacturers identify potential fire and explosion hazards associated with handling and processing combustible particulate solids. Section 7.1.4 of NFPA 652 requires a review, update, and revalidation of the DHA every five years but does not provide specific guidance on what the five-year review process must include. How are manufacturers, that are already stretched to their limits in terms of time and resources, supposed to satisfy this requirement?
What is a DHA Revalidation?
A DHA Revalidation is a systematic review and evaluation of a facility’s existing DHA with the intention of identifying all process, equipment and/or material changes that may have occurred in the facility in the five years subsequent to the most recent analysis. Proven techniques used for years to Revalidate Process Safety studies (HazOps, What-if Analyses, etc.) can be used to efficiently Revalidate DHAs. These techniques often do not require repeating the full DHA. Here are a few key requirements to consider when performing a DHA Revalidation:
Assemble the right team. The team should be made up of associates from a wide range of responsibilities and disciplines in your facility. Consider including team members from:
  • Maintenance
  • Operations
  • Quality Assurance
  • Engineering
  • Environmental, Health and Safety
Gather as much information on the particulate solids handling or process. Use the site’s current master materials inventory to make sure the team identifies all particulate solids. Information includes but is not limited to:
  • Safety Data Sheets
  • Particle size distribution
  • Flammability data
  • Site raw material inventory
Gather documents and information on your process and all associated equipment in the process. Documents include:
  • Process flow diagrams
  • Original Equipment Manufacture Specifications for equipment
  • Fire protection and other safety systems specifications
Gather copies of all Management of Change (MOC) documentation and a copy of the most recent Dust Hazard Analysis. MOC documents include, but are not limited to:
  • A master list of all MOC’s submitted
  • Risk/Hazard analysis documentation
  • Drawings
  • Equipment specifications
  • Results of material testing
As a team, review the most recent DHA for the site. Confirm the following information:
  • Are all of the processes identified in the DHA still in operation?
  • Are the same materials being processed, handled or stored?
  • Is all of the equipment identified in the DHA still in operation?
  • Is the process operating the same as it was during the most recent DHA?
  • Are the potential credible sources of ignition still the same?
  • Are the dispersion and confinement hazards identified still the same?
If the answer to any of the aforementioned revalidation questions is “no”, the team should review the MOC information to see if a formal assessment of the process, equipment or material change was completed. Once the team confirms the changes were properly assessed, ensure that proposed risk mitigation controls outlined in the MOC were properly implemented and maintained.
If there are new processes, equipment or materials that were introduced without a proper MOC, the team should assess the following:
  • Does a potential hazard exist such as handling new combustible particulate solids, are there new hazards associated with the particulate solids, are there credible sources of ignition present?
  • Where hazards exist, how are they being managed?
  • Is the management of hazards effective?
  • Are there hazards not being managed?
  • What corrective actions need to be taken to: improve existing hazard management systems and/or add hazard management where none exists?
The team should document the entire revalidation process. Documentation includes, but is not limited to:
  • An executive summary document stating what items in the previous DHA are still valid and which items are new that occurred after the previous DHA
  • A master list of MOC’s submitted in the five years after the most current DHA
  • An analysis of all new process, equipment and material added to the process that was not properly assessed with an MOC
Have questions regarding the DHA Revalidation process? Let us be your Trusted Advisor. Contact Us to discuss your DHA Revalidation plan or other consulting needs.