additional scenarios, if needed, or be updated as better information about certain
models becomes available (e.g., aerosolization).
To illustrate the use of Figure D-1, let us assume that an airplane has crashed
into a vessel containing acetone at ambient temperature. This corresponds to
the top scenario on page D-7 of Figure D-1. The analyst is then directed to
page D-8 of Figure D-1, where a number of variations are displayed. The boiling
point of acetone is ~330 K ( 594 R), which is typically well above the ambient
temperature. The temperature on a hot day might be 305 K ( 549 R).
Therefore, the upper branch on page D-8 of Figure D-1 should be selected. The
next question is whether the acetone is under its own static head (i.e., the
pressure is due to its own weight) or under additional pressure from another
A typical condition in which acetone could be under its own static head only is
storage in a vessel at atmospheric pressure. In this case, the analyst is directed
to go to page D-9 of Figure D-1, where the choice is between spillage into a
diked or an undiked area. The analyst is then directed to Section 5.1 or 5.3 of
Reference 6) for spillage into a diked area or to Section 5.6.2 of Reference 6 for
spillage into an undiked area. Section 5.1, for example, gives a detailed analysis
of how to calculate the rate of evaporation of acetone spilled into a diked area
and how to prepare inputs for the Dense Gas Atmospheric Dispersion model
(DEGADIS) (Reference 7) and SLAB (Reference 8). Section 5.6.2 of Reference
6 gives guidance on how to model a spreading pool that is unconfined.
Returning to page D-8 of Figure D-1, the acetone may be under high pressure,
for example, if the vessel is padded with an inert gas. In this case, the analyst
should proceed through the lower portion of page D-9 of Figure D-1 and on to
various sections of Reference 6, as illustrated for the case above. On page 3,
the top branch differs from the lower branch only by the presence of high
pressure. This means that the liquid will be driven out of the vessel at a higher
rate than it would be if it were under static head only.