Looking into Surface Temperatures with Speed Wrap® ESi
With safety becoming more and more of a concern around facilities, it becomes increasingly important to minimize the risk of burns caused by exposed steam and/or process piping. There are a lot of variables that influence Surface Temperature, and we take a shot at providing some clarity to the situation.
Variables that influence Surface Temperature:
- Ambient Temperature
- Process Temperature
- Pipe Size
- Wind Speed
- Insulation Material (k-values)
- Insulation Thickness
- Surface Emissivity
By using Speed Wrap® ESi for our study, Insulation Material, Insulation Thickness, and Surface Emissivity remain constant, so we look at how Ambient Temperature, Process Temperature, Pipe Size, and Wind Speed affect Surface Temperature.
As expected, when the temperatures around the outside of the insulation increase, the surface temperature of the insulation increase. Under the conditions examined (1/2 mph wind speed, 1 1/2″ IPS Pipe), the increase in surface temperature was about 8°F for every 10°F increase in ambient temperature, regardless of process temperature changes.
Similar to changes in ambient temperatures, changes in the process temperatures yielded almost linear results. At the same process temperature, smaller pipes have a lower surface temperature than larger pipes, and surface temperatures increase more slowly as process temperatures increase on smaller pipes vs larger pipes
This is where it starts getting interesting. Pipe size has a pretty substantial effect on surface temperature as it increases from 1/2″ IPS up to around 2″ IPS. However, this effect becomes less pronounced as process temperature gets closer to the ambient temperature.
Wind Speed is another big contributor. As colder air blows across the insulation, the surface temperature will decrease. The decrease in surface temperature from stagnant to even 1/2 mph wind speed is pretty dramatic. Especially at higher process temperatures.
It is important to keep in mind that the information in these graphs represent a controlled environment. “Real World” conditions can, and usually will, vary so it is important to take that into consideration when evaluating individual applications.
Disclaimer: The information presented above was calculated using 4E Plus® software using insulation property data provided by suppliers. SpeedTech USA, LLC makes no warranty with respect to the accuracy of the information provided by their suppliers, and disclaims all liability reliance thereon.