Related Experiment Video

Updated: Dec 11, 2025

Experimental Methodology for Estimation of Local Heat Fluxes and Burning Rates in Steady Laminar Boundary Layer Diffusion Flames

Experimental Methodology for Estimation of Local Heat Fluxes and Burning Rates in Steady Laminar Boundary Layer Diffusion Flames

Published on: June 1, 2016

Comparison of correction factor for both dynamic total thermal insulation and evaporative resistance between ISO 7933

¹Japan Organization of Occupational Health and Safety, National Institute of Occupational Safety and Health, 6-21-1 Nagao, Tama-ku, Kawasaki, Kanagawa, 214-8585, Japan. ueno@h.jniosh.johas.go.jp.

Journal of Physiological Anthropology

|August 25, 2020

Abstract

Background:

Thermal insulation and evaporative resistance of clothing are the physical parameters to quantify heat transfer and evaporative dissipation from the human body to the environment, respectively. Wind and body movement decrease thermal insulation and evaporative resistance of clothing, which is represented as correction factors for dynamic total thermal insulation (CF_i) and evaporative resistance (CF_e), respectively. Then, CF_i and CF_e are parts of the key parameters to predict heat strain of workers by computer simulation. The objective of this study was to elucidate the difference of CF_i and CF_e between ISO 7933 and ISO 9920 and compare the difference of predicted rectal temperature, water loss, and exposure time limit calculated by using each correction factor.

Methods:

CF_i of ISO 7933 (CF_i7933) and ISO 9920 (CF_i9920), and CF_e of ISO 7933 (CF_e7933) and two kinds of CF_e of ISO 9920 (CF_e9920a, CF_e9920b) were compared in terms of relative air velocity, walking speed for three kinds of thermal insulation of clothing. Next, two modified predicted heat strain (PHS) models were developed: modified PHS integrated with CF_i9920 and CF_e9920a (PHS_mA) and modified PHS integrated with CF_i9920 and CF_e9920b (PHS_mB). We calculated the rectal temperature, water loss, and exposure time limit by PHS, PHS_mA, and PHS_mB and compared the results.

Results:

CF_i7933 and CF_i9920 were almost similar in terms of V_ar and walking speed, while CF_e9920a and CF_e9920b were larger than CF_e7933 when V_ar was more than 1.0 m·s^-1. Intrinsic clothing insulation (I_cl) diminished the effects of V_ar on CF_i7933, CF_i9920, CF_e7933, and CF_e9920b. However, CF_e9920a was not influenced by I_cl. The predicted rectal temperature and water loss difference were larger between PHS and PHS_mA as CF_e difference got larger. The duration time when limit of rectal temperature of 38 °C was reached (D_limTre38) calculated by PHS was significantly longer than PHS_mA, PHS_mB at higher V_ar.

Conclusions:

Precise correction factors for evaporative resistance are required to predict rectal temperature, water loss, and work-time limits.

Keywords:

Correction factor Evaporative resistance Predicted heat strain (PHS)Thermal insulation

More Related Videos

Characterization of Thermal Transport in One-dimensional Solid Materials

Characterization of Thermal Transport in One-dimensional Solid Materials

Published on: January 26, 2014

Production and Testing of Moisture Behavior and Thermal Properties of Rapeseed Straw and Ganoderma resinaceum Mycelium Bio-Composites

Production and Testing of Moisture Behavior and Thermal Properties of Rapeseed Straw and Ganoderma resinaceum Mycelium Bio-Composites

Published on: September 5, 2025

Related Concept Videos

Thermal Insulation in Masonry Walls

Thermal Insulation in Masonry Walls

In hot, dry climates, the thermal mass of masonry walls can be beneficial, absorbing heat during the day and releasing it at night, thereby stabilizing indoor temperatures. However, in most other climates, additional insulation is necessary to enhance thermal resistance.
External insulation can be applied using an Exterior Insulation and Finish System (EIFS), which involves affixing panels of plastic foam to the wall and covering them with a polymeric stucco reinforced with glass fiber mesh....

Conduction, Convection and Radiation: Problem Solving

Conduction, Convection and Radiation: Problem Solving

There are three methods by which heat transfer can take place: conduction, convection, and radiation. Each method has unique and interesting characteristics, but all three have two things in common: they transfer heat solely because of a temperature difference; and the greater the temperature difference, the faster the heat transfer.
In order to solve a problem related to heat transfer, first of all, the situation needs to be examined to determine the type of heat transfer involved. This could...

Thermodynamics: Activity Coefficient

Thermodynamics: Activity Coefficient

Activity is the measure of the effective concentration of the species in solution. It can be expressed as the product of the molar concentration of the species and its activity coefficient. The activity coefficient is a dimensionless quantity and depends on the total ionic strength of the solution.
The activity coefficient is a measure of the deviation from ideal behavior. When the ionic strength of the solution is minimal, the activity coefficient of an ionic species is close to unity, making...

Thermal expansion and Thermal stress: Problem Solving

Thermal expansion and Thermal stress: Problem Solving

San Francisco's Golden Gate Bridge is exposed to temperatures ranging from -15 °C to 40 °C. At its coldest, the main span of the bridge is 1275 m long. Assuming that the bridge is made entirely of steel, what is the change in its length between these temperatures?
To solve the problem, first, identify the known and unknown quantities. The initial length (L) of the bridge is 1275 m, the coefficient of linear expansion (α) for steel is 12 x 10-6/°C, and the change in temperature (ΔT) is 55...

Measurement of Air Content in Concrete

Measurement of Air Content in Concrete

Air content measurement in concrete is critical for ensuring structural integrity and durability of concrete structures, especially in environments prone to severe weather conditions. Accurate air content analysis optimizes concrete's resistance to freeze-thaw cycles and enhances its workability and strength. Several methods are standardized under ASTM guidelines to measure the air content in fresh concrete, each suitable for different concrete types and conditions.
The pressure method,...

Calorimetry

Calorimetry

When objects at different temperatures are placed in contact with each other but isolated from everything else, they attain thermal equilibrium. A container that prevents heat transfer in or out is called a calorimeter, and the use of a calorimeter to make measurements is called calorimetry. Generally, these measurements involve heat or specific heat capacity. The term "calorimetry problem" is used for any problem where the specified objects are thermally isolated from their...

Articles linked to this work by shared authors, journal, and citation graph.

Investigating age and regional effects on the relation between the incidence of heat-related ambulance transport and daily maximum temperature or WBGT.

Environmental health and preventive medicine·2021

Effects of ventilation openings in industrial safety helmets on evaporative heat dissipation.

Journal of occupational health·2019

See all related articles