Hazardous Material Offsite Exposure Determination

DOE-STD-3014-96

instantaneously onto the ground and either spread to a depth of

1 cm (0.4 in.) or cover a well-defined diked area if there is one.

The rate of evaporation will then be calculated using standard

formulas such as those provided by the Center for Chemical

Process Safety (CCPS) (Reference 6).

3. For refrigerated liquids, the material will likewise be assumed to

spill onto the ground and either spread to a depth of 1 cm (0.4 in.)

or cover a well-defined diked area. The rate of evaporation will

again be calculated using standard formulas such as those

provided by CCPS.

4. For a pipeline rupture, the complete contents of the pipeline up to

the nearest undamaged isolation valve(s) will be assumed to be

released as a puff.

5. For materials that can burn and form toxic products of

combustion, the burning will be assumed to be instantaneous,

with 100 percent efficient production of the toxic products.

In the above determinations, the respirable fraction will be assumed to be

100 percent. For releases that are potentially buoyant, the buoyancy will

be ignored for the purposes of the screening calculation.

Hazardous Material Offsite Exposure Determination. Reference 3

7.2.4.2

contains a series of nomographs for common hazardous chemicals that

provide dosage estimates under various conditions relevant to aircraft

crash scenarios. These nomographs serve to guide analysts and simplify

the screening process. They can be used to provide a screening value

for the site boundary Level of Concern for the materials and conditions

specified. If a particular facility has materials or conditions not covered by

the nomographs, an acceptable technique is given by the U.S.

Environmental Protection Agency's (EPA's) TSCREEN Code