Heat Stress

The following materials are intended to support and expand the application of ACGIH® TLV® for heat stress and strain. The worksheets are intended for training and are not offical interpretations of the TLV®. 

The materials are copyrighted by me and are intended for personal and professional use with appropriate recognition. It would be nice to hear from you by email about materials you find helpful.

The TLV® for heat stress and strain was described in a webinar offered by the ACGIH® in April 2006 and June 2013. Please see the ACGIH® website for information on obtaining a copy of the webinar.

  • Basic Tools (Click to expand)
    Psychrometric Relationships

    Can be used to determine other psychrometric properties from any two and can be used to estimate natural wet bulb temperature. This workwork provides a method to estimate WBGT from ambient data.

    Analysis Package
    v 1.0 (1/22/05)
    Estimation of Metabolic Rate

    Methods include ISO and Qualitative Descriptors plus equations for selected activities.

    The newest versions (v3 for Analysis Package and v2 for Manual Method) have an expanded set of equations including an adaptation of Garg's equations to estimate metabolic rate.



    Analysis Package
    v 3.1 (7/28/05)


    Manual Method
    v 2.0 (8/6/06)
    Estimation of WBGT from Dry Bulb Temperature and Dew Point or Relative Humidity

    Tables are provided in °C-WBGT and °F-WBGT and can be copied into other documents.

    The tables use air temperature and a measure of humidity (either dew point or relative humidity).

    Excel Workbook
    Tables
    v2.0
    (5/4/2013)
  • Screening (Click to expand)
    Qualitative Exposure Assessment

    Two methods are provided. One has been published and the other reflects some of my thoughts (unpublished).
    Qual Exp Ass't
    v 1.0 (8/19/01)
    WBGT Screening for Heat Stress

    Manual Screen
    v 2.2 (4/14/06)
  • Analysis (Click to expand)
    WBGT

    The basic time-weighted average method for exposure assessment. Analysis Package has routines to estimate WBGT.

    Analysis Package
    v 4.0 (4/1/06)



    Manual Method
    v 3.2 (4/14/06)
    Rational Heat Stress Analysis Package

    The Excel workbook is built on the Predicted Heat Strain model described in ISO 7933 (2004) and papers published by Prof. J. Malchaire. An additional feature is the inclusion of clothing adjustments based on ISO9920 (2007). Imperial (Traditional US) units are not supported.
    Analysis Package
    v 1.1 (3/25/09)
    PrevHeat: Qualitative PHS Exposure Assessment

    PrevHeat is an Excel-based qualitative exposure assessment method based on the ISO 7933 (2004) Predicted Heat Strain. Click on Prevheat under the desired language and follow the directions carefully.
    Link to Prof. Jacques Malchaire
    Recovery Allowances

    This is a major revison in terms of presentation of the allowances. The user specifies five metabolic rates, clothing adjsutment factor and the WBGT of the recovery area. Both tables and graphs are provided for recovery in the same area and recovery in a different area with work clothes. WBGT is presented in °C-WBGT and °F-WBGT.

    If WBGT instrumentation is not available, see tables in Basic Tools for estimating the WBGT.
    Short-Term Exposure Limit

    An empirical relationship to recommend time limits for high heat stress exposures based on WBGT and allowing for metabolic rate and clothing.

    This is currently under review in JOEH.


    Analysis Package
    v 1.0 (3/13/09)
    Estimation of Exposure Time with Ice Cooling Personal Protection

    An estimate of the amount of time a person can stay in a hot environment while wearing a personal cooling system with an ice heat sink.
    Manual Method
    v 1.0 (2/5/07)
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