Free-Fall Spill and Impaction Stress

DOE-HDBK-3010-94

4.0 Solids; Summary

gas through the powder. Large volume deflagrations (flammable gas

volume > 25% of confinement volume) use the value for large

deflagrations given under blast effects.

Median

ARF 5E-2/RF 0.4

Bounding

ARF 1E-1/RF 0.7

F ree-F all S p ill an d I mp action S tres s

For the free-fall spill of cohesionless powders:

Fall distance <3 m, air velocity normal to powder flow, general forced

enclosure ventilation or general low-wind outside conditions.

Median

ARF 3E-4/RF 0.5

Bounding

ARF 2E-3/RF 0.3

Fall distance >3 m, air velocity normal to powder flow. Apply the

calculations outlined in subsection 4.4.3.1.3 provided ARF and RF values

exceed 2E-3 and 0.3.

Suspended solid dispersed into flowing air for enhanced air velocities normal

to direction powder flow. The mass airborne in the RF is limited by the total

mass of material in this size fraction in the source material.

ARF = 0.0134 U + 0.00543

(4-2)

where U = windspeed, m/s.

Suspension of bulk powder due to vibration of substrate from shock-impact to

powder confinement (e.g., gloveboxes, cans) due to falling debris or external

energy (e.g., seismic vibrations).

Bounding

ARF 1E-3/RF 0.1

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