Engineering ToolBox - Resources, Tools and Basic Information for Engineering and Design of Technical Applications!

This is an AMP page - Open full page! for all features.

Heat Index

Equivalent heat index vs. air temperature and relative humidity - in degrees Fahrenheit and Celsius.

Sponsored Links

The heat index can be used to indicate how an average person will perceive temperature and humidity and the human body ability to cool it self.

Heat Index in degrees Fahrenheit

The heat index in degrees Fahrenheit can be calculated as

tHI = -42.379 + 2.04901523 t + 10.14333127 φ

    - 0.22475541 t φ - 0.00683783 t2 - 0.05481717 φ2

    + 0.00122874 t2 φ + 0.00085282 t φ2 - 0.00000199 (T φ)2                                         (1)

where

tHI = heat index (oF)

t = air temperature (oF) (t > 57oF)

φ = relative humidity (%)

Apparent Temperature Heat Stress Index (oF)
Relative Humidity
(% RH)
Temperature (oF)
80859095100105110115120125130135140
0 78 82 87 911) 94 97 100 103 105 107 108 110 110
5 78 82 86 90 94 98 102 106 110 114 117 121
10 78 82 86 902) 95 100 105 110 116 121 128
15 78 82 86 91 96 102 108 115 122 130
20 79 82 86 91 97 104 112 121 130 140
25 79 82 87 93 100 108 117 127 138
30 79 83 88 94 102 112 122 134 148
35 80 84 89 96 106 116 129 143
40 80 84 91 99 109 121 136 152
45 80 85 92 102 114 127 143
50 81 86 95 1053) 118 134 152
55 81 88 97 109 124 141
60 82 89 100 113 129 149
65 82 91 103 118 136
70 83 93 106 123 143
75 84 95 109 1284)
80 84 97 113 134
85 85 99 117
90 86 102 122
95 86 104
100 87 107
  • T(oC) = 5/9[T(oF) - 32]

Sunstroke and heat exhaustion:

1) Caution - Fatigue is possible with prolonged exposure and/or physical activity

2) Extreme Caution - Sunstroke, heat cramps and heat exhaustion are possible with prolonged exposure and/or physical activity

3) Danger - Sunstroke, heat cramps and heat exhaustion are likely. Heat stroke is possible with prolonged exposure and/or physical activity

4) Extreme Danger - Heatstroke/sunstroke is highly likely with continued exposure

Heat Index in degrees Celsius

Heat index in degrees Celsius:

Sponsored Links

Related Topics

Related Documents

Sponsored Links

Share

Search Engineering ToolBox

  • the most efficient way to navigate the Engineering ToolBox!

SketchUp Extension - Online 3D modeling!

Add standard and customized parametric components - like flange beams, lumbers, piping, stairs and more - to your Sketchup model with the Engineering ToolBox - SketchUp Extension - enabled for use with the amazing, fun and free SketchUp Make and SketchUp Pro . Add the Engineering ToolBox extension to your SketchUp from the Sketchup Extension Warehouse!

Privacy

We don't collect information from our users. Only emails and answers are saved in our archive. Cookies are only used in the browser to improve user experience.

Some of our calculators and applications let you save application data to your local computer. These applications will - due to browser restrictions - send data between your browser and our server. We don't save this data.

Google use cookies for serving our ads and handling visitor statistics. Please read Google Privacy & Terms for more information about how you can control adserving and the information collected.

AddThis use cookies for handling links to social media. Please read AddThis Privacy for more information.

Topics

Unit Converters

Temperature

oC
oF


Load Calculator!

Length

m
km
in
ft
yards
miles
naut miles


Load Calculator!

Area

m2
km2
in2
ft2
miles2
acres


Load Calculator!

Volume

m3
liters
in3
ft3
us gal


Load Calculator!

Weight

kgf
N
lbf


Load Calculator!

Velocity

m/s
km/h
ft/min
ft/s
mph
knots


Load Calculator!

Pressure

Pa (N/m2)
bar
mm H2O
kg/cm2
psi
inches H2O


Load Calculator!

Flow

m3/s
m3/h
US gpm
cfm


Load Calculator!

3 10

This website use cookies. By continuing to browse you are agreeing to our use of cookies! Learn more