With the request to enter into a revision cycle approved by the Standards Council, the Preliminary Daft of NFPA 652, Standard on Combustible Dust, is now accepting public input until January 4, 2013. The big question circling this document, what are the fundamentals of combustible dusts?
If you were to go through the different NFPA dust standards, you will notice similar requirements. The requirements may not be exactly the same throughout the standards, but the general underlying ideas are there.
The Technical Committee (TC) started the draft out with four main chapters that circle around four basic concepts in each of the dust standards: hazard identification, hazard assessment, hazard management, and management systems.
The very first thing you are going to do is to Identify whether a hazard exists in your facility. Before getting overwhelmed by the combustible dusts standards, you need to determine if the dust in your facility is a combustible dust and if it presents a flash-fire or explosion hazard. Can the dust burn? Yes, then you will need to determine if it can cause a flash-fire and/or explosion. To determine if the the dust can present an explosion hazard, the simplest test that can be performed is known as the “go/no-go” test or ASTM E 1226 Standard Test Method for Explosibility of Dust Clouds. Further tests may be required based on the hazard management methods you wish to use in your facility. Knowing whether the dust in your facility has a potential for a flash-fire or explosion hazard is essential to determine where you need to go next within the standard and the other standards. If you do not properly manage the hazards, you are increasing the chance (or risk) of an incident occurring in your facility.
After identifying whether the dust in your facility can present a fire, flash-fire, or explosion hazard, the next step to assess the type of hazard you have and where these hazards exist. The method can be as simple as going through your facility and determine where these hazards exist and develop a means in which they can be managed (see hazard management). Simply, this method of accessing your facility for hazards is known as a process hazard analysis. A process hazard analysis (or PHA) is not intended to be complex analysis requiring a facility to hire consultants. There are many ways to preform this analysis and the TC is developing some guidance to better help the user understand how to perform a PHA. However, if you do not know the hazards or process equipment well enough to make informed decisions, it wouldn’t hurt to have a 3rd party assist in the review.
These are going to be your tools on how to manage the different hazards in the facility: building construction, explosion protection, equipment construction, ignition source control, housekeeping, etc. There are requirements that will apply to the facility itself and different pieces of equipment. Some will not apply to your particular facility and other requirements will give you different options that you can apply.
The last major concept when dealing with combustible dusts is management systems. Management systems cover operating procedures, inspection, testing and maintenance of equipment, training for employees and contractors, emergency planning, incident investigation, management of change, and document retention. Basically, make sure that you use and maintain your equipment properly, train your employees and anyone working in your facility, investigate fire and explosion incidents, keep constant documentation, and procedures for managing any changes in the process, equipment, material, facility, etc.
When taking a high-level view at the concepts in each of the dust standards, there are basic concepts that standout no matter what type of dust your facility has.