Definition of Source Terms.

DOE-STD-3014-96

APPENDIX D

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

source.

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.

D-5