CHARM Software - When Realism Counts

The potential for accidental release of hazardous chemicals (air dispersion and transport), fires (BLEVE, pool fire, and jet fire), and explosions (mechanical failure and air dispersion and transport followed by vapor cloud explosion), poses a risk that must be addressed on several levels. The EPA Risk Management Program (RMP, Rule 112r) requires hazard assessment and emergency response programs. To assure that you have adequate resources and that plans are well organized for any contingency, you need to plan for emergency response. Should such an accident occur, you need real-time data to guide the response activities. CHARM software helps you meet all of these needs.

There are two versions of the CHARM software available; One assumes a single source in flat terrain. The second version allows for multiple sources in complex terrain but requires more input than the first. Both versions are available for downloading for a two week evaluation period on the Downloads page. Registration is required for trial version downloads - no financial information is required or requested if checkout is directly from Your Cart. They both provide calculations of air transport and dispersion, mechanical and vapor cloud explosions, and BLEVE, jet fire, and pool fire radiation. See the Examples page for representative impact results of scenarios calculated using the complex terrain version. Visit YouTube to some some videos on using CHARM, especially the complex-terrain version.

The flat terrain version is also available as a web application, which can be accessed through a browser on the Internet and requires no special software to be loaded on the browser’s computer.

Both versions of CHARM can be used to estimate impacts from the use of chemical WMDs. The expected species that may be used (e.g. chlorine, mustard gas, sarin, soman, and VX) are in both databases. The complex terrain version can do an even more complete simulation. Many chemicals used for WMD are released as aerosol. The complex terrain version of CHARM is capable of simulating all major processes affecting aerosol. Some estimate of the size distribution of the aerosol in the released chemical is needed. After the release has occurred, CHARM can calculate the changes in the size distribution due to coagulation, condensation/evaporation, and deposition.

The aerosol capabilities of the complex terrain version of CHARM also allows impacts from biological WMDs (e.g. anthrax) to be estimated. The impacts can be given as air concentrations or surface deposition.

Carbon Dioxide Source Term Calculation Problem

On June 27, 2023 a problem with the calculated source term for Carbon Dioxide was found. It was found and corrected on June 28. fixed and WebCHARM has been updated.

The problem was for releases from containment. The correction was adding two lines of code. In tests here, it appears that the correction leads to shorter durations and lower total amount released. Of course, those results are from my tests. Configurations that you model may not act in the same way.

Carbon Dioxide (not CO2) releases from containment should be specified as having no liquid in the container. CHARM uses the Span and Wagner 1996 Equation of State to determine phase amounts and other basic parameters. Releases specifying CO2 are treated as a standard CHARM species and uses techniques that use the parameters (e.g. normal boiling point, triple and critical point values, etc.) in the database to calculate the other basic parameters.

We are sorry for any inconvenience that this may bring about.

Nuclear Radiation impacts have been added in the Complex Terrain version. Radionuclides can be included in an emission. Radiation rates and doses are calculated - 2D, 3D, and table displays.

Complex Terrain version can use multi-processor chips. Faster results!

The list with the changes made to the Flat and Complex Terrain versions of CHARM is available here.

WebCHARM

WebCHARM takes the power of CHARM and delivers it right to the web browser of your choice, no matter where you are. We understand that in many situations, especially in the field of accidental releases, you cannot always be by a computer with the proper software loaded. Because WebCHARM is hosted entirely through the web with no software to download, you are always just a few clicks away from conducting your modeling analysis.

If you have already purchased a license, go to WebCHARM