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Q/A for Using the Beta Version of ChemSTEER

Q:  How can I use ChemSTEER effectively?

A: You should read the Help System thoroughly. Although the beta version of ChemSTEER has been made more user-friendly than the previous version, ChemSTEER remains a complex tool intended to be used by knowledgeable technical users.  You also need to have important information and data about operations for which ChemSTEER does not contain a synonymous industry-specific operation.

Q:  What if some parameters that ChemSTEER uses exist as ranges but ChemSTEER only allows a user to enter a point estimate for each of these parameters?

A: The user must carefully consider how to use ChemSTEER to overcome this limitation. For example, a user may choose a Source/ Activity twice for an operation and run the appropriate model using different parameters for both Sources/ Activities.  Some situations may require the user to run separate assessments with explanation of the differences.  Future updates to ChemSTEER are planned to allow use of ranges of parameters in models, although some of the issues regarding parameter ranges are considered to be too complex to overcome.

Q:  Will ChemSTEER allow evaluation of a mixture?

A: The beta version of ChemSTEER was designed to evaluate a single chemical within a mixture.  In some cases, careful use of models may allow the assessment of a mixture as a whole.  EPA is exploring ways to allow improved evaluation of mixtures for future versions.

Q: How do I evaluate only one process (mfg., processing or a use) and not the whole life cycle of the chemical?

A: You can do this by simply selecting one scenario that best fits your process from the selection on the Operation page and entering appropriate volumes, concentrations, and other relevant parameters for the process.

Q: Can I access a single model without doing a full assessment?

A:  Yes, the beta version allows you to access models with minimal data entry.  Instructions for "short-cut" access to one or more models is in the Using Individual Methods or Developing Partial Assessments page of the Getting Started section of the Help System.

Q:  What happens when you don't know the precise chemical identity (chemical name, CAS number)?

A: Chemical identifiers such as CAS number and chemical name are for record keeping.  The user is not required to enter or use this information for running ChemSTEER.

Q: What do I do when the precise physical properties are unknown?

A:  Physical properties are important as they may be used by release and exposure estimation methods or models residing in ChemSTEER.  When physical properties of the substance are unknown or known as a range, the user must make best point estimates.

Q: Can ChemSTEER adjust the vapor pressure if a release or exposure occurs at a temperature other than the reference temperature?

A: No, the beta version is not able to automatically extrapolate and calculate vapor pressure at other temperatures than this reference temperature.  Models in ChemSTEER that require a temperature and vapor pressure input will use the default values, and if other temperatures are appropriate, the user must manually calculate and enter vapor pressure adjustments.

Q:  What if my chemical is dispersible or reacts in water?

A: The beta version of ChemSTEER allows use of water solubility in one of the models.  However, the Water Saturation model that uses the water solubility of the chemical is not appropriate for assessing releases of chemicals that are dispersible or that react with water.  The user must determine other methods for estimating releases for these types of chemicals.

Q:  Why would I want to rename a "User defined" operation?

A:  This simply allows you to use a more descriptive term to describe the operation.

Q: Why do I have to establish an "Operations Relationship" (Scenario relationship)?

A:  You do not have to, but if you do not, ChemSTEER cannot track chemical volumes, concentrations, and densities of the chemical (or mixture containing the chemical) being assessed entering and exiting each operation, and some default values which are used by the models to estimate exposure and release will not be calculated.  In the future, ChemSTEER may track types and numbers of transport containers and volumes.

Q:  Are there any considerations for use of ChemSTEER for international assessments?

A:  ChemSTEER uses some occupational exposure models that are based on compliance with U.S. regulatory limits.  Use of these models may not be appropriate for workplaces outside of U.S. when different regulatory standards may apply, and another approach will have to be determined for use in such situations.
 
 

 


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