# Will Condensation Form on My Roof's Steel Structure?

• cyn1117
In summary, the conversation discusses the possibility of condensation occurring within a roofing structure due to hot and humid weather conditions. Various calculations and approaches are mentioned, but the main focus is on finding the surface temperature at the steel structure when the temperature of the air gap is unknown. The suggestion is to use steady state heat flow to calculate the temperature drops and find the surface temperature.
cyn1117
Hi ! I need to know whether condensation could appear within this roofing structure.

The top layer (exposed to outside weather, hot and humid) is composed of (1) Glass reinforced fibre cement panels, underneath it is a layer of (2) thermal insulation, (3) an air gap, (4) steel structure, (5) another insulating layer. The inside air is air-conditioned.

I am trying to find out whether condensation would occur within the air gap and condense on the steel structure??

I look up online and found,

t(i) - t(s) = {t(i)-t(o)}/{R(is) + R(os)} x R(is)

to calculate surface temperature, then obtain dew point from psychrometric chart...however, how do I calculate the surface temperature at the steel structure when I don't know the temperature of the air gap (since it is affected by outside hot temperature too)

Also, should I be using another approach which I found, by calculating vapour pressure drop, then calculate surface temperatures etc...but then again, I don't know the temperature of the air gap...?

#### Attachments

• Roof structure.doc
32 KB · Views: 210
cyn1117 said:
how do I calculate the surface temperature at the steel structure when I don't know the temperature of the air gap
Assume steady state heat flow. Given the inside and outside temperatures and all the gaps and conduction coefficients, you can calculate the heat flow rate. Then you can find each of the individual temperature drops.

## What is condensation calculation?

Condensation calculation is a process used by scientists to determine the amount of water vapor that can turn into liquid droplets on a surface due to changes in temperature and humidity.

## Why is condensation calculation important?

Condensation calculation is important because it helps scientists understand and predict the formation of droplets, which can have significant impacts on various processes, such as weather patterns, material degradation, and biological systems.

## What factors are involved in condensation calculation?

The main factors involved in condensation calculation include temperature, humidity, surface area, and surface material. These factors play a crucial role in determining the amount of water vapor that can condense on a surface.

## How is condensation calculation performed?

Condensation calculation is typically done using mathematical equations that take into account the factors mentioned above. These equations are based on the laws of thermodynamics and can be solved using various methods, such as numerical simulations or analytical solutions.

## What are the applications of condensation calculation?

Condensation calculation has a wide range of applications in various fields, including atmospheric science, building construction, chemical engineering, and food science. It can help in designing more efficient systems, predicting weather patterns, and understanding the effects of condensation on different materials.

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