Publicly-available Models

Note: Users should carefully evaluate applicability of these models to pre­vailing conditions.

A list of some publicly-available models that can be used to address special site-specific scenarios follows:

DEGADIS—(\5. S. Coast Guard): DEGADIS, the Dense Gas Dispersion Model, is designed to simulate dispersion of heavier-than-air gas releases. It can handle both evaporative emissions from liquid spills and jet emissions. It is basically steady-state but simulates transient conditions by a series of steady-state calculations. Vapor generation rate, spill area, and meteorological parameters are important inputs to the

model. Information available through National Technical In­formation Service (NTIS), U. S. Department of Commerce, Springfield, VA 22161.

HEGADAS—(Shell Research B.V.): HEGADAS is a dis­persion model for neutrally-buoyant and dense gases. The basic model components are solutions to the advection/diffu-sion equations and are in the standard form of Gaussian dis­persion models. The model can handle a wide variety of source types, including transient horizontal jets. Information available through National Technical Information Service, U. S. Department of Commerce, Springfield, VA 22161.

SLAB—(Lawrence Livermore National Laboratory): SLAB is designed for application to dense gases that are emitted from liquid spills. The model considers the concen­tration integrated over a cross-section perpendicular to the plume centerline. The downwind variation of the integrated concentration is calculated. The size and emission rate of the liquid spill are required inputs to the model. Information available through Lawrence Livermore National Laboratory, Box 808, Livermore, CA 94550, or contact American Petroleum Institute, Health & Environmental Sciences De­partment, 1220 L Street, NW, Washington, D.C. 20005.