.wbgt-calculator-container {
font-family: 'Arial', sans-serif;
background-color: #f9f9f9;
padding: 25px;
border-radius: 8px;
box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
max-width: 700px;
margin: 20px auto;
border: 1px solid #ddd;
}
.wbgt-calculator-container h2 {
color: #333;
text-align: center;
margin-bottom: 20px;
font-size: 28px;
}
.wbgt-calculator-container .input-group {
margin-bottom: 15px;
display: flex;
flex-direction: column;
}
.wbgt-calculator-container label {
margin-bottom: 8px;
color: #555;
font-weight: bold;
font-size: 16px;
}
.wbgt-calculator-container input[type="number"],
.wbgt-calculator-container select {
width: 100%;
padding: 12px;
border: 1px solid #ccc;
border-radius: 5px;
font-size: 16px;
box-sizing: border-box;
-webkit-appearance: none; /* Remove default arrow for select in some browsers */
-moz-appearance: none;
appearance: none;
background-color: #fff;
}
.wbgt-calculator-container select {
background-image: url('data:image/svg+xml;charset=US-ASCII,%3Csvg%20xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg%22%20width%3D%22292.4%22%20height%3D%22292.4%22%3E%3Cpath%20fill%3D%22%23000000%22%20d%3D%22M287%2C197.9l-136.2%2C136.2c-4.1%2C4.1-9.6%2C6.2-15.1%2C6.2c-5.5%2C0-11-2.1-15.1-6.2L5.4%2C197.9c-8.2-8.2-8.2-21.5%2C0-29.7c8.2-8.2%2C21.5-8.2%2C29.7%2C0l116.1%2C116.1l116.1-116.1c8.2-8.2%2C21.5-8.2%2C29.7%2C0C295.2%2C176.4%2C295.2%2C189.7%2C287%2C197.9z%22%2F%3E%3C%2Fsvg%3E');
background-repeat: no-repeat;
background-position: right 12px top 50%;
background-size: 12px auto;
padding-right: 30px; /* Make space for the custom arrow */
}
.wbgt-calculator-container button {
background-color: #007bff;
color: white;
padding: 14px 20px;
border: none;
border-radius: 5px;
cursor: pointer;
font-size: 18px;
width: 100%;
margin-top: 20px;
transition: background-color 0.3s ease;
}
.wbgt-calculator-container button:hover {
background-color: #0056b3;
}
.wbgt-calculator-container #wbgtResult {
margin-top: 25px;
padding: 20px;
background-color: #e9f7ef;
border: 1px solid #d4edda;
border-radius: 8px;
font-size: 18px;
color: #155724;
text-align: center;
font-weight: bold;
min-height: 50px;
display: flex;
align-items: center;
justify-content: center;
}
.wbgt-calculator-container #wbgtResult.error {
background-color: #f8d7da;
border-color: #f5c6cb;
color: #721c24;
}
.wbgt-calculator-container .note {
font-size: 14px;
color: #666;
margin-top: 20px;
text-align: center;
}
Wet Bulb Globe Temperature (WBGT) Calculator
Use this calculator to estimate the Wet Bulb Globe Temperature (WBGT) based on environmental conditions. WBGT is a measure of heat stress in direct sunlight, which incorporates temperature, humidity, wind speed, and visible and infrared radiation.
Outdoor with Solar Radiation
Indoor or Outdoor without Solar Radiation
Enter values and click 'Calculate WBGT' to see the result.
Disclaimer: This calculator provides an estimate based on standard formulas. Actual heat stress can vary due to individual factors (acclimatization, clothing, activity level) and specific environmental conditions. Always consult official safety guidelines for heat stress prevention.
Understanding WBGT
The Wet Bulb Globe Temperature (WBGT) is a composite temperature used to estimate the effect of temperature, humidity, wind speed, and visible and infrared radiation on humans. It's a crucial metric for assessing heat stress risk, especially in occupational and athletic settings.
Components of WBGT:
- Wet Bulb Temperature (Twb): This is the temperature read by a thermometer covered in a water-soaked cloth and exposed to air flow. It reflects the cooling effect of evaporation and is a good indicator of humidity.
- Globe Temperature (Tg): Measured by a thermometer inside a black globe, this accounts for radiant heat (e.g., from the sun, hot machinery, or warm surfaces).
- Dry Bulb Temperature (Tdb): This is the standard air temperature, measured by a regular thermometer.
WBGT Formulas:
The WBGT calculation varies depending on the presence of solar radiation:
- Outdoor with Solar Radiation: This formula is used when there is direct exposure to sunlight or significant radiant heat sources.
WBGT = 0.7 * Twb + 0.2 * Tg + 0.1 * Tdb - Indoor or Outdoor without Solar Radiation: This formula is applied in indoor environments or outdoors on cloudy days where solar radiation is not a significant factor.
WBGT = 0.7 * Twb + 0.3 * Tg
Interpreting WBGT Values (General Guidelines):
WBGT values are often used to establish work/rest cycles and hydration protocols to prevent heat-related illnesses. Here are some general interpretation levels (these can vary based on specific guidelines like ACGIH, OSHA, military, or sports organizations):
- Below 25°C (77°F): Generally low risk for most activities.
- 25°C – 29°C (77°F – 84°F): Moderate risk. Caution advised, especially for unacclimatized individuals or strenuous activity.
- 30°C – 32°C (86°F – 90°F): High risk. Increased vigilance, frequent breaks, and hydration are critical. Strenuous activity should be limited.
- Above 32°C (90°F): Very high risk. Extreme caution. Strenuous activity should be avoided or significantly reduced. Close monitoring for heat stress symptoms is essential.
Always refer to specific organizational or national guidelines for precise action thresholds.
function calculateWBGT() { var wetBulbTempInput = document.getElementById("wetBulbTemp").value; var globeTempInput = document.getElementById("globeTemp").value; var dryBulbTempInput = document.getElementById("dryBulbTemp").value; var environmentType = document.getElementById("environmentType").value; var resultDiv = document.getElementById("wbgtResult"); resultDiv.className = "; // Reset class for styling var Twb = parseFloat(wetBulbTempInput); var Tg = parseFloat(globeTempInput); var Tdb = parseFloat(dryBulbTempInput); if (isNaN(Twb) || isNaN(Tg) || (environmentType === "outdoor_sun" && isNaN(Tdb))) { resultDiv.innerHTML = "Please enter valid numbers for all required temperature fields."; resultDiv.classList.add('error'); return; } var wbgt; if (environmentType === "outdoor_sun") { // WBGT = 0.7 * Twb + 0.2 * Tg + 0.1 * Tdb wbgt = (0.7 * Twb) + (0.2 * Tg) + (0.1 * Tdb); } else { // indoor_no_sun // WBGT = 0.7 * Twb + 0.3 * Tg wbgt = (0.7 * Twb) + (0.3 * Tg); } var wbgtRounded = wbgt.toFixed(1); var interpretation = ""; if (wbgt = 25 && wbgt = 30 && wbgt = 32 interpretation = "Very high risk. Extreme caution. Avoid strenuous activity. Close monitoring for heat stress symptoms is essential."; } resultDiv.innerHTML = "Calculated WBGT: " + wbgtRounded + " °C" + interpretation; }