In today’s episode of the Dust Safety Science podcast, we talk to Brian Edwards, Explosion Protection Consultancy Manager at Fike and Dilip Arulappan, Explosion Safety Consultant for Fike Europe, about how North America and Europe differ in regards to combustible dust.
How is Combustible Dust Handled in North America Under NFPA?
Brian said that in North America, the first step is to identify which NFPA standards apply to your operation.
“Review NFPA 652 and then the various commodity-specific standards to understand which ones are going to apply to a specific facility,” he advised. “But then, in each of those standards, it traditionally starts with understanding the properties of the dust, either by using data from the manufacturers or published data in NFPA or Eckoff’s Dust Explosions in the Process Industries book. If you don’t have any other data, send your dust off for testing to understand those properties as far as explosion severity and ignition sensitivity properties.”
After understanding the properties, you conduct the DHAs to systematically review the process and building to identify where fire and explosion hazards exist. At the same time, you evaluate your current safeguards, determine if those safeguards are adequate, and come up with an action plan. If you find deficiencies during the DHA, develop an action plan to address them. To ensure electrical installations and powered industrial trucks are appropriate for the locations where they are used, you need to use guidelines from NFPA 70 and NFPA 499.
“That’s all part of understanding and identifying the hazards,” Brian said. “As soon as that’s done, NFPA explains the management systems you need to have in place, such as housekeeping protocols, which NFPA provides guidance on – both the methods to use and the dust layer threshold or criteria you can establish to ensure effective housekeeping.”
NFPA also provides guidance in the following areas:
- Hot work permits and inspections
- Testing and maintenance standards for protection equipment and for potential ignition sources
- Employee training
- Contractor management
- Emergency planning and response
- Management of change
“The final part of an effective combustible dust safety strategy is to periodically review what you’re doing,” Brian said. “You’ll update and revalidate your DHAs every five years or when things change. To make sure everything is managed properly, you should conduct periodic inspections and audits of your strategies. That’s a high level overview of how NFPA outlines your strategy.”
How is Combustible Dust Handled in Europe?
Dilip said that there are different approaches to handling combustible dust in Europe and the UK.
“In the UK, there is something called HSG 103,” he explained. “It’s purely for combustible dust strategy to address situations that could arise from operation and process deviation in a facility. Like NFPA, it all starts with dust sampling, and basically that’s the fundamental to determining what the properties of the powder are, and then we can start systemizing and strategizing how to control them.”
With food processing, managers must also conduct risk assessments based on all deviations where the material leaves the facility. From the arriving truck to the finished product, the process has to be assessed in terms of where the material might be compromised.
“So the risk assessment is quite stringent and strict here,” Dilip said. “There are several general obligations like duty of coordination and finding out the hazardous area, storing of materials and preparing explosion documents. There are also special requirements for electrical equipment. Several other articles address miscellaneous provisions like good practices and training for all employees who would have to handle flammables or combustibles materials.”
A facility’s stakeholder responsibility extends from top management to operators. A key aspect of ATEX is a leader-member exchange, where top management and operators need to communicate to understand what is happening in the facility in terms of an inflammable atmosphere, not necessarily combustible dust, but any flammable material handled, moved, or stored within it.
The starting point is an explosion protection document (EPD). If an employer is manufacturing equipment that could potentially use flammable materials or combustible materials, then they have to develop an EPD document. If the facility owner has more than five employees in the facility, it should be a written document EPD.
In Europe, shipments within one country to another should go with an EPD document stating that the flammable atmosphere situations are addressed and all the electrical equipment within those areas are as per ATEX regulations. If it is a silo, hopper, or any other massive vessel, then there should be a design calculation done to determine whether explosion suppression or venting is required.
“If you’re a manufacturer, you have to follow ATEX 95,” Dilip said. “If it is an employer receiving the equipment, then he has to go through ATEX 137 to [confirm that] the equipment is suitable to install within the facility where the employees are going to be.”
What Are Some Key Differences?
Brian identified two main differences between North American and European practice.
“One is the obligation of the EPD. As Dilip explained, [in Europe] the equipment manufacturer needs to come up with that EPD. Whereas in North America, it almost exclusively falls on the responsibility of the facility owner. So we do have cases where maybe an engineering firm that’s designing a process will, you know, prepare a DHA or work with the consultant to prepare a DHA. But, you know, the obligation ultimately falls on the owner.”
The other difference is the contents of the DHA/EPD.
“NFPA is less formal as far as how you can do it,” Brian said. “NFPA specifically says that you can use multiple methodologies: you can use a HAZOP as a DHE, you can do failure modes and effect analysis, or you can use a checklist style DHA. Whereas with an EPD, there’s a more strict guidance on what that exposure protection document should look like and everything it needs to include. It’s not as loose as the DHA requirements are.”
Dilip added that EPDs require dust sampling to identify material properties of each dust.
“Any manufacturer of pigments, powders, or flammable materials should have their properties identified and incorporated into a Safety Data Sheet before shipping or logistics. Europe has several agencies that test combustible dust because it is so prevalent here. Any powder, even one kilo or one ton, has to be identified and recorded into the Safety Data Sheet. Only then can it cross the border.”
In terms of hazardous area classification, Brian said that the main difference he saw between European Hazardous Area classification and North America is that NFPA focuses on building compartments.
“You’re looking at what room and what areas of the room are going to be classified. And when you’re looking at classification, you’re only really looking at it from an electrical standpoint. It also covers powered industrial trucks and maybe some hand tools and whatnot, but you’re really only looking at it from that electrical standpoint and you’re only looking at the building spaces. Whereas with the ATEX standard, you’re looking at basically the entire spaces inside and outside of equipment.”
Conclusion
North America and Europe have different approaches to combustible dust standards. In North America, the NFPA sets standards while in Europe, the ATEX Directive applies to all equipment and protective systems intended for use in potentially explosive atmospheres in the European Union. It’s essential for businesses to be familiar with the applicable standards in their region to ensure compliance and protect workers from the risks associated with combustible dust.
If you would like to discuss further, leave your thoughts in the comments section below. You can also reach Bill Edwards and Dilip Arulappan directly:
Email: [email protected], [email protected]
Website: https://www.fike.ca/
LinkedIn: https://www.linkedin.com/in/brian-edwards-pe-gatech/
https://www.linkedin.com/in/dilip-arulappan-80908970/
If you have questions about the contents of this or any other podcast episode, you can go to our ‘Questions from the Community’ page and submit a text message or video recording. We will then bring someone on to answer these questions in a future episode.
Resources mentioned
Dust Safety Science
Combustible Dust Incident Database
Dust Safety Science Podcast
Questions from the Community
Dust Safety Academy
Dust Safety Professionals
Dust Safety Share
Companies
Standards
NFPA 652
Publications
Eckhoff, Rolf. Dust Explosions in the Process Industries
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