NFPA 652: Essential Requirements for Owners & Operators

In this episode of the DustSafetyScience Podcast, we’re talking about dust hazard analysis requirements for owners and operators as specified in NFPA 652. This is an important topic for a couple of reasons:

Not everyone is as familiar with the 2019 NFPA 652 requirements for facility owners and operators as they should be.
September 7, 2020, is the deadline for all facilities to carry out a dust hazard analysis.

NFPA 652 is the central document for the prevention of combustible dust explosions and fires. There are also standards that are specific to certain commodities and industries:

NFPA 61 for fires and dust explosions in agricultural and food processing facilities
NFPA 665 for sulphur fires and explosions
NFPA 484 for combustible metals
NFPA 664 for wood processing and woodworking facilities
NFPA 654 for combustible particulate solids

What Are The Requirements For Owners and Operators?

NFPA 652 imposes certain requirements on owners and operators of facilities that handle combustible dust.

Hazard Identification

Chapter 4, Section 4.1 and Chapter 5 indicate that those responsible for facility operations must know the combustibility and deflagration properties of materials, either by testing them or looking at historical data.

We’ve covered combustible dust testing in earlier episodes of the podcast, such as Episode #21 with Martin Clouthier. A new guidebook, Methods of Chemical Process Safety Volume 3, includes a chapter by Dr. Ashok Dastadar about dust explosion test methods. (Dr. Chris Cloney also contributed a chapter to this volume.) The Resource section on the DustSafetyScience website also includes examples and guidelines for combustible dust hazard analysis released by the Center for Chemical Process Safety.

Chapter Seven of NFPA 652 covers the requirement to identify and assess any fire, flash fire, and explosion hazards. Its opening sections feature important points of consideration for owners and operators.

7.1.1 states that a dust hazard analysis (DHA) must be completed for all new processes and facility compartments.
7.1.2 specifies that DHAs must be carried out for all existing processes and facility compartments by September 7, 2020.
7.1.3 indicates that an absence of previous incidents will not be used as a reason for not performing a DHA.
7.1.4 states that DHAs shall be reviewed and updated every five years.

Dust Hazard Analysis

By September 7, 2020, a DHA must be carried out on all processes in facilities handling combustible dust. Although the NFPA 652 documentation does not specify how to do a DHA, Annex B provides a good example using a typical powder processing operation.

There are different methods for carrying out a DHA:

Node-based analysis
‘What if’ analysis
Checklist-based
Hazard and operability (haz-op) study

Owners and operators should work with a combustible dust expert or a specialist in the field to come up with the best approach for their facility.

What Is Included In A Dust Hazard Analysis?

The NFPA 652 guidance states that a DHA is a systematic review to identify and evaluate the potential fire, flash fire or explosion hazards associated with the presence of one or more combustible dust or combustible particulate salts in a processing facility. It will likely include the following:

Identification and evaluation of locations where hazards exist.
Identification and evaluation of specific hazards scenarios
Identification of existing safeguards.
Recommendations of additional safeguards where warranted
A plan for implementation of additional safeguards.

In the body of the NFPA 652 documentation, it states that each part of the process shall be evaluated. This means all equipment and each line between equipment units (such as conveyors and ducts) and each building or building compartment shall be evaluated for things like fugitive dust accumulations.

The annex provides guidance on what could or should constitute a process, building or compartment, such as ducts, conveyors, silos, bunkers and hidden areas above drop ceilings. It also states that the elimination of accumulated fugitive dust is critical and the single most important criteria for a safe workplace.

Who Can Perform a DHA?

NFPA 652 specifies who can perform a DHA. Section 7.2.2 stated that it must be performed or led by a qualified person. According to the definition in the front matter, this is someone “who, by possession of skill, recognized degrees, certificate of professional standing or who, by knowledge, training, and experience, has demonstrated the ability to deal with the problems related to the subject matter, the work or the project.”

The annex material expands on this definition, stating that the person should be familiar with conducting a DHA and the hazards of combustible dust. It also says that a team should be involved. For a small process, this could be a two-person team consisting of a combustible dust expert and someone from the processing operation who is familiar with its operation, maintenance, and any history of previous incidents.

The subject of a qualified person has been discussed in previous episodes of the podcast, specifically Episode #12 with Jason Reason and #15 with Michael Marrington, who recommended the implementation of a system that certifies people to do DHAs.

Conclusion

How do we start making facilities safer? If we focus on the incident sequences (in particular, the fugitive dust accumulations), it may be possible to prevent a single fire or explosion from escalating into a disaster. Perhaps the biggest component, however, is doing a dust hazard analysis. With DHAs becoming mandatory on September 7th, 2020, they will be a key driver in outlining facility risks and coming up with ways to improve safety.

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.