The impact of condensation on glass wool insulation materials and solutions

The impact of condensation on glass wool insulation materials and solutions

I What is condensation?

Condensation is the phenomenon that water vapor in the air condenses into liquid water when it encounters a cold surface. According to the principles of thermodynamics, the dew point temperature is directly related to the air temperature and relative humidity. For example, when the indoor temperature is 25°C and the relative humidity is 60%, the dew point temperature is about 16.7°C (data source: ASHRAE Handbook). If the surface temperature of the building envelope is lower than this value, condensation will form. This phenomenon is common in high humidity environments or areas with significant temperature differences, such as cold storage, air conditioning ducts, and building exterior walls.

Ⅲ Glass wool anti-condensation solution

1.Internal anti-condensation design

Add moisture-proof layer: Set aluminum foil veneer or polyethylene film (thickness ≥ 0.15mm) on the outside of the glass wool to block water vapor penetration. Experiments show that aluminum foil veneer can reduce the probability of condensation by more than 60% (source: test report of a building materials manufacturer).

Joint sealing treatment: Use special tape or sealant to seal the joints to ensure that the vapor barrier is continuous and complete.

2.External environment control

Ventilation design: Reserve air circulation channels in the sandwich structure, such as roof overhead layers or wall cavities, to accelerate moisture discharge.

Vapor barrier setting: According to the "Building Moisture-proof Design Code" (GB 50037-2013), a vapor barrier is set on the high-temperature side to prevent water vapor from migrating to the insulation layer.

The condensation problem of glass wool can be effectively solved by optimizing material design and environmental control. It is recommended to combine temperature and humidity monitoring data in the project (such as regular testing with a dew point meter) to dynamically adjust the anti-condensation strategy to ensure the long-term stable operation of the insulation system.

Ⅲ Glass wool anti-condensation solution

1.Internal anti-condensation design

Add moisture-proof layer: Set aluminum foil veneer or polyethylene film (thickness ≥ 0.15mm) on the outside of the glass wool to block water vapor penetration. Experiments show that aluminum foil veneer can reduce the probability of condensation by more than 60% (source: test report of a building materials manufacturer).

Joint sealing treatment: Use special tape or sealant to seal the joints to ensure that the vapor barrier is continuous and complete.

2.External environment control

Ventilation design: Reserve air circulation channels in the sandwich structure, such as roof overhead layers or wall cavities, to accelerate moisture discharge.

Vapor barrier setting: According to the "Building Moisture-proof Design Code" (GB 50037-2013), a vapor barrier is set on the high-temperature side to prevent water vapor from migrating to the insulation layer.

The condensation problem of glass wool can be effectively solved by optimizing material design and environmental control. It is recommended to combine temperature and humidity monitoring data in the project (such as regular testing with a dew point meter) to dynamically adjust the anti-condensation strategy to ensure the long-term stable operation of the insulation system.

3.Place other hard insulation materials between the purlins and the color steel plates (or their supports) to avoid cold bridge.

References:

1. ASHRAE Handbook (2022), Chapter 6: Moisture Management.
2. ASTM C1134-23, Standard Test Method for Water Retention of Rigid Thermal Insulation.
3. <建筑防潮设计规范>GB 50037-2013.