What is the difference between Kst and Pmax?

Kst describes the normalized maximum rate of pressure rise from a standardized dust deflagration test, while Pmax is the maximum explosion pressure measured in that test context. They answer different design questions and neither describes ignition sensitivity on its own.

Rate-of-pressure-rise index Maximum test pressure Ignition sensitivity and actual process conditions

The source links below support the regulatory, standards-development, investigation, or test-characteristic context stated on this page. DustDHA does not reproduce paywalled standard text and does not turn general source material into a facility-specific engineering conclusion. Where a fact depends on the current NFPA 660 edition, use the official NFPA publication and record the edition reviewed.

Record the material form, process conditions, equipment and enclosure, current safeguards, authority having jurisdiction, and the evidence used. Separate verified facts from assumptions. If a decision affects life safety, explosion protection, code compliance, or a signed engineering deliverable, have a qualified professional evaluate the actual site rather than relying on this summary.