Background Reference Documents
Functional Requirements for IH Systems provides basic and advanced requirements one may need in a computer database system to be able to make informed exposure judgments. This database tool affords one the ability to incorporate both qualitative and quantitative assessments.
Product Exposure Modeling Toolbox was developed by volunteers with the AIHA and Product Stewardship Society. It is for use by those looking for introductory and comparative information regarding the selection, inputs, outputs and differences between models explored by the team and found to be useful in assessing exposures to humans from products. It should not be considered exhaustive, as there are many models that were explored but found to be inaccessible to the general member (fee-based, other languages, etc.), or were unwieldy or could not be validated as functional. Members are encouraged to participate in the member societies and raise awareness of new or unreviewed models to the AIHA Exposure Assessment Strategies Committee for further consideration.
IH Apps & Tools
The following software tools provide the practicing industrial hygienist with quick and easy access to the information necessary to evaluate exposure profiles and determine if the exposures are acceptable, not acceptable or if more data is needed to make the determination of acceptability. Like all software tools, the results depend on proper tool use and quality data inputs appropriate to the exposure scenario. Users are encouraged to gain expertise in specific tool use via study of the appropriate references as listed and participation in appropriate professional development courses. A new tool (December 2020) is designed to assess oxygen deficiency risks from simple asphyxiant releases.
Legal Disclaimer: These tools were developed by volunteers over the years. As of January 2020, AIHA has been assigned intellectual property rights to all e-tools and, as a result, is now able to enter into agreements with third parties for the production of derivative works (e.g., translations into other languages). With the assistance of legal counsel, we are now in the process of filing for copyright protection through the US Patent & Trademark Office.
TOOLS For the Practicing Industrial Hygienist
These tools are all free and are regularly updated. Several are available in multiple languages.
STEP 1: Data Collection
IH Exposure Scenario Tool (IHEST) guides the assessor through the process of collecting general information about the workplace, specific scenario and agents(s), providing cues for measuring or estimating the important determinants of exposure such as generation and ventilation rates. It also prompts the user to specify the type of engineering controls; this information is needed later when making initial judgments by applying the Qualitative Exposure Assessment Checklist (see below).
STEP 2: Basic Characterization
Basic Exposure Assessment and Sampling Spreadsheet is an Excel-based template for entering air and noise sampling data.
STEP 3: Preliminary/ Initial Exposure Assessment (Tier 1)
The Qualitative Exposure Assessment Checklist (The Checklist) requires only four readily available pieces of information: Occupational Exposure Limit (OEL); Vapor Pressure of the pure chemical (VP) when the agent is gas or vapor form; observed or reported workplace control measures (observed level of control) and required level of workplace control (required level of control). It can be applied in just a few minutes using readily available information and has been shown to be significantly more accurate than subjective intuitive judgments. The user is referred to Chapter 6 of A Strategy for Assessing and Managing Occupational Exposures, 4th edition, AIHA Press.
STEP 4: Refined Assessment (Tier 2)
- IHMOD_2_0© is an Excel-based mathematical modeling spreadsheet similar to the previous IH Mod. 1.0 which is now obsolete. IH Mod 2.0© gives the user the choice between running the model in deterministic (point value parameters as was in IH Mod 1.0) or in Monte Carlo Simulation mode, with choices of distributions of parameter values right in MS Excel with no other software needed. An IHMOD_2_0_Support_File is also available. It includes useful information about IH Mod 2.0©, and a spreadsheet tab to estimate liquid spill pool generation rates via the Hummel-Fehrenbacher equation, a units of measure conversion tool, examples of generation rate estimation, a “Bootstrap” procedure tool, a summary of approaches to estimate ALPHA for the exponentially decreasing emission rate models, and some links to other resources. Please note that the support file is evolving and will be updated periodically with new information. Check back here for updates.
- IHSkinPerm© is an Excel application for estimating dermal absorption. Basic knowledge of Excel is all that is needed to operate IH SkinPerm©. IH SkinPerm© is a work product of the AIHA Exposure Assessment Strategies Committee (EASC) and the Dermal Project Team (DPT) in collaboration with Wil ten Berg, author of the original SkinPerm model. Although various parameters and data outputs have been explained or defined in IH SkinPerm through comments tagged on individual fields, users are encouraged to read Chapter 13 of the Mathematical Models for Estimating Occupational Exposure to Chemicals, 2nd edition, AIHA Press, 2009, C. Keil Editor. This is a useful reference for understanding the science and terminology associated with skin permeation.
- OHDMod© is a Microsoft® Excel workbook for predicting the oxygen content trends in environments where inert gas releases may lead to asphyxiation risks. ODHMOD uses a Near Field-Far Field approach and estimates the oxygen concentration percent by volume and as mmHg partial pressure over time in the two zones. In addition to output graphs, the time required for reaching a target level is provided. Results can be compared to reference values for typical human body reactions due to Oxygen Deficiency Hazards and the need for mitigation measures. Examples provide guidance on input values for multiple industrial scenarios. ODHMOD has a user-friendly multilingual interface like several other AIHA tools. This workbook is a product of collaboration between AIHA and Università degli Studi di Brescia (Italy). The details and description of the mathematical model and workbook can be found here.
STEP 5: Refining/Validating the Exposure Assessment
IHSTAT© is an Excel application that calculates a variety of exposure statistics, performs goodness of fit tests, and graphs exposure data. Multiple languages are available. The book, “A Strategy for Assessing and Managing Occupational Exposures” is intended to accompany this tool as it provides critical detail on the use and interpretation of the various statistical outputs.
The links below will show you how to adjust the macros settings in your version of Excel if needed.