Five Ways New Explosion Venting Requirements
For Dust Collectors Affect You (continued)

Given the many NFPA 68 changes and new requirements for explosion venting, here are some useful questions to ask when dealing with dust collector suppliers and installing contractors:

• Is the explosion venting equipment manufactured by a company specializing in such equipment, or is it "homemade" by the dust collector supplier? Either way, ask for documentation proving that the equipment has been manufactured in accordance with NFPA 68.
• Will the supplier provide a calculations sheet on vent sizing and vent discharge ducting?
• Does the supplier have the engineering and testing capabilities to use the performance-based design option where needed?
• Can the supplier perform a hazard analysis or recommend a qualified consultant for this task?
• Does the supplier have access to, and familiarity with, alternative protection technologies such as flameless venting and explosion suppression (see the next subsection)?

Explosion suppression and other protection methods.

If it's not feasible to duct an explosion to the outside through a wall or ceiling in your dust collection application, you'll need an explosion suppression or suppression-isolation system. A system like this may cost more than the dust collector itself.

Suppression methods are covered in a separate document, NFPA 69: Standard on Explosion Prevention Systems,1 which has also just undergone a complete revision. Like NFPA 68, it has evolved from a guideline to a standard. NFPA 69 extends beyond explosion venting to address the whole dust collection system -- that is, inlet and outlet ducting, spark-extinguishing systems, and methods for preventing an explosion from traveling back into the building.

Both now and in the future, these two related standards will have a significant impact on the design and cost of dust collection systems handling combustible dusts. By taking the time today to learn about and comply with these standards, you can keep your plant's dust collection system operating safely.