Enter temperature, relative humidity, and optional global temperature to find wet bulb temperature and wet bulb globe temperature (indoor/outdoor).
Access this wet bulb calculator to determine the wet bulb and wet bulb globe temperature (WBGT) for indoor and outdoor environments. It is an Ideal tool that helps to assess heat stress, optimize HVAC systems, and ensure worker safety by calculating WBGT temperature.
This meteorological parameter is widely used to measure the cooling effect of evaporation on the human body. Wet bulb temperature merges the effect of temperature and humidity in one single value.
Key-Points:
How Is It Measured?
Using A Psychrometer:
This is a specific tool that is designed to calculate the humidity. It contains two thermometers:
DIY Method:
Why Is It Important?
Wet bulb temperature helps to determine the body's ability to cool itself through sweating. When you are in a more humid environment, then the water evaporates more slowly. Therefore, the body can't cool down easily. In this kind of environment, humans need to calculate the wet bulb temperature. The high wet bulb temperature indicates a greater risk of low cooling efficiency and getting ill (heatstroke, hyperthermia).
In industries like construction, agriculture, and sports, wet bulb temperature helps to provide the right working environment to the workers who are exposed to outdoor and indoor high-temperature areas.
| Wet Bulb Globe Temperature From WBGT and Relative Humidity% | |||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Humidity% | Temperature in Degrees Farenheit | ||||||||||||||||||||||||||||||
| 0 | 59.0 | 60.8 | 63.4 | 60.8 | 62.6 | 64.4 | 66.2 | 68.0 | 69.8 | 71.6 | 73.4 | 75.2 | 77.0 | 78.8 | 80.6 | 82.4 | 84.2 | 86.0 | 87.8 | 89.6 | 91.4 | 93.2 | 95.0 | 96.8 | 98.6 | 100.4 | 102.2 | 104.0 | 105.8 | 107.6 | 109.4 |
| 10 | 59.0 | 60.8 | 62.6 | 64.4 | 66.2 | 68.0 | 69.8 | 71.6 | 73.4 | 75.2 | 77.0 | 78.8 | 80.6 | 82.4 | 84.2 | 86.0 | 87.8 | 89.6 | 91.4 | 93.2 | 95.0 | 96.8 | 98.6 | 100.4 | 102.2 | 104.0 | 105.8 | 107.6 | |||
| 20 | 60.8 | 62.6 | 64.4 | 66.2 | 68.0 | 69.8 | 71.6 | 73.4 | 75.2 | 77.0 | 78.8 | 80.6 | 82.4 | 84.2 | 86.0 | 87.8 | 89.6 | 91.4 | 93.2 | 95.0 | 96.8 | 98.6 | 100.4 | 102.2 | 104.0 | 105.8 | 107.6 | ||||
| 30 | 62.6 | 64.4 | 66.2 | 68.0 | 69.8 | 71.6 | 73.4 | 75.2 | 77.0 | 78.8 | 80.6 | 82.4 | 84.2 | 86.0 | 87.8 | 89.6 | 91.4 | 93.2 | 95.0 | 96.8 | 98.6 | 100.4 | 102.2 | 104.0 | 105.8 | ||||||
| 35 | 64.4 | 66.2 | 68.0 | 69.8 | 71.6 | 73.4 | 75.2 | 77.0 | 78.8 | 80.6 | 82.4 | 84.2 | 86.0 | 87.8 | 89.6 | 91.4 | 93.2 | 95.0 | 96.8 | 98.6 | 100.4 | 102.2 | |||||||||
| 40 | 66.2 | 68.0 | 69.8 | 69.8 | 71.6 | 73.4 | 75.2 | 77.0 | 78.8 | 80.6 | 82.4 | 84.2 | 86.0 | 87.8 | 91.4 | 93.0 | 95.0 | 96.8 | 98.6 | 102.2 | |||||||||||
| 45 | 66.2 | 68.0 | 69.8 | 71.6 | 73.4 | 75.2 | 77.0 | 78.8 | 80.6 | 82.4 | 84.2 | 86.0 | 89.6 | 91.4 | 95.0 | 96.8 | 98.6 | 98.6 | 102.2 | ||||||||||||
| 50 | 68.0 | 69.8 | 71.6 | 73.4 | 75.2 | 77.0 | 78.8 | 80.6 | 82.4 | 84.2 | 86.0 | 87.8 | 89.6 | 91.4 | 95.0 | 96.8 | 98.6 | 102.2 | |||||||||||||
| 55 | 68.0 | 69.8 | 71.6 | 73.4 | 75.2 | 77.0 | 78.8 | 80.6 | 82.4 | 84.2 | 86.0 | 87.8 | 89.6 | 95.0 | 96.8 | 98.6 | 100.4 | ||||||||||||||
| 60 | 69.8 | 71.6 | 73.4 | 75.2 | 77.0 | 78.8 | 80.6 | 82.4 | 86.0 | 87.8 | 89.6 | 91.4 | 95.0 | 96.8 | 98.6 | 100.4 | |||||||||||||||
| 65 | 69.8 | 71.6 | 73.4 | 75.2 | 77.0 | 78.8 | 80.6 | 82.4 | 87.8 | 89.6 | 91.4 | 95.0 | 96.8 | 98.6 | 100.4 | ||||||||||||||||
| 70 | 71.6 | 73.4 | 75.2 | 77.0 | 78.8 | 80.6 | 82.4 | 84.2 | 86.0 | 87.8 | 91.4 | 96.8 | 100.4 | 102.2 | |||||||||||||||||
The wet bulb globe temperature(WBGT) is a measure of the heat stress in direct sunlight, which affects humans. WBGT measures heat by considering all the four major environmental heat factors:
To calculate wet bulb temperature, determine:
\(\ T_w = T * arctan[0.152 * (rh + 8.3136)^{1/2}] + arctan(T + rh\%) – arctan(rh – 1.6763) + 0.00391838 *(rh)^{3/2} * arctan(0.0231 * rh) – 4.686\)
Where:
In order to determine the wet bulb globe temperature (WBGT), you have to measure:
WBGT Formula:
For outdoor conditions (with direct solar radiation):
WBGT = 0.7Tw + 0.2Tg + 0.1T
For indoor conditions:
WBGT = 0.7Tw + 0.3T
Calculate wet bulb temperature, also find outdoor and indoor WBGT index for the following values:
Solution:
\( \text{Calculate}\ 0.151977 \cdot (\text{rh}) + (8.313659)^{1/2}: \)
\(\ =\ 0.151977 \cdot (80 + 8.313659)^{1/2} \approx 0.151977 \cdot (88.313659)^{1/2} \approx 0.151977 \cdot 9.399 \approx 1.428 \)
\(\text{Find arctan(1.428):}\)
\(\text{= arctan(1.428) ≈ 0.963 radians}\)
\(\text{Calculate arctan(T + rh):}\)
\(\text{= arctan(40 + 80) = arctan(120) ≈ 1.563 radians}\)
\(\text{Calculate (arctan(rh} - 1.676331):\)
\(\text{ = arctan(80 - 1.676331) = arctan(78.323669) ≈ 1.558 radians}\)
\(\text{Solve}\ 0.00391838 \cdot \ (rh)^{3/2} \cdot \arctan(0.023101 \cdot \ (rh): \)
\(\ =\ (rh)^{3/2} = 80^{3/2} = 80^{1.5} \approx 715.5 \)
\(\text{ = 0.023101 * 80 = 1.848 arctan(1.848) ≈ 1.072 radians}\)
\(\ = 0.00391838 * 715.5 * 1.072 ≈ 3.010\)
\(\text{Now, combine all the calculated parts in the formula:}\)
\(\ T_w = 40 \cdot 0.963 + 1.563 - 1.558 + 3.010 - 4.686 \)
\(\text{Calculate the final result:}\)
\(\ T_w = 38.52 + 1.563 - 1.558 + 3.010 - 4.686 \)
\(\text{Natural Wet Bulb Temperature (NWB)} ≈ 36.85°C\)
The wet-bulb temperature is approximately 36.85°C, which is high and poses a significant risk of heatstroke.Therefore, it is necessary to take immediate action such as seeking shelter in an air-conditioned environment, staying hydrated, and minimising physical activity to protect yourself. Still, if there are symptoms of heatstroke, get medical attention instantly!
\(\text{Now, for calculating outdoor WBGT, add values in the given formula:}\)
\(\text{WBGT(Outdoor) = 0.7 * 36.85 + 0.2 * 35 + 0.1 * 40}\)
\(\text{WBGT(Outdoor) = 25.795 + 7 + 4}\)
\(\text{WBGT(Outdoor) = 36.795°C}\)
\(\text{Put values in the wet bulb globe temperature (Indoor) formula:}\)
\(\text{WBGT(Indoor) = 0.7(36.85) + 0.3(40)}\)
\(\text{WBGT(Indoor) = 25.795 + 12 = 37.795°C}\)
WBGT is a treasured metric for shielding human fitness in warm and humid environments. So, the high-quality practice is to discover the WBGT and it can be effortlessly found out with a wet bulb temperature calculator.
Be aware: A moist bulb temperature better than 35°C(ninety five °F), can be risky for people.
It helps to understand the environmental heat situations. This mixture of high warmness and humidity is potentially harmful to people. consequently, it's miles vital to determine the WBGT temperature and measure it.
This data is essential for:
The wet bulb temperature and dew point parameters are each associated with the moisture content material in air however they measure specific factors. The moist bulb measures the air's potential to chill thru evaporation even as the dew point shows the amount of moisture content in the air.
It has first-rate importance in HVAC structures because it's far related to the capability of the air to absorb moisture. This relationship appreciably affects HVAC gadget design, operation, and performance.
Here are the key roles of moist bulb temperature in HVAC:
consequently, measuring the wet bulb temperature is important for HVAC experts, which may be without problems calculated using our wet bulb calculator. It automates the size technique and gives you the data had to optimize HVAC structures.
exposure to extraordinarily excessive wet bulb temperatures is existence-threatening. there may be no actual restriction for survival. factors including man or woman fitness, bodily exertion, get right of entry to to cooling, and acclimatization can have an impact on the time it takes for warmth-related infection to occur.
In extremely excessive temperatures, using an air conditioner is vital for survival. while the moist bulb temperature reaches an high temperature threshold (e.g., above 35°C), then it poses a superb risk to human life.
Eight here’s what you want to do:
