Grafo-Therm:How it works
What is condensation
Air is a mixture of gases. There is always vapour in the air, and there is more of it when the temperature is high.
When vapour meets a cold surface it condenses into water. Condensation always occurs when the surface temperature is down to and below the so-called dew point.
In buildings with a single skin roof system, condensation occurs during the quick changes in weather. The surface temperature of a steel roof may fall as much as 5 degrees below the inside temperature.
The Grafo-Therm Treatment
In the dry state Grafo-Therm is an efficient thermal insulant, albeit that a 1.5mm thickness would not be efficient against heat loss, it does put back the time before dew point occurs, thereby preventing or considerably reducing the periods during which condensation forms. Thereby reducing the amount of condensation formed during any one 24 hour period.
Whenever dew point is reached on the surface coated, condensation will form and this will immediately be absorbed by the coating. A 1.5mm thickness can absorb and control against dripping up to 1.0 litres moisture per m². Having absorbed moisture it is most important to effect rapid evaporation and removal from the cavity, when conditions change to drying.
For this Grafo-Therm is superb, for example, when sprayed onto a 1000m² corrugated roof the textured finish of the compound effectively increases the specific drying surface by at least 10 times = 10,000m², on most corrugated sheets this can be increased by 20% to allow for the corrugations – 12,000m² of drying surface.
Grafo-Therm having proven absorption and capillary capabilities assures maximum benefit from this large specific drying surface, enabling fast and efficient cyclic drying.
The release properties of Grafo-Therm are faster per thickness and area than competitive materials which rely on greater thickness being applied.
Grafo-Therm has passed the CONDENSATION CONTROL TEST
The effect of Grafo-Therm can be proved with a British testing method (Ministry of supply SSF B 111)
A cone-shaped copper vessel is sprayed on the outside with Grafo-Therm and placed together with an identical untreated cone in a room at 20 degrees and 60% relative humidity.
Both cones are filled with ice water. RESULT:
First drop after 35 minutes
After 6 hours collected 33cl of water
Surface treated with Grafo-Therm
No condensation water collected
Typical areas for application
This single skin roof must have condensation control. During a single frosty night condensation can run to drip from purlins and saturate goods below. Grafo-Therm is the protection.
Single-skin roof over insulated suspended ceiling
The single skin roof over a highly insulated suspended ceiling is the most cost effective mineral fibre insulation system allowing “u” values better than 0,25w/m²C. If this system is subjected to dripping condensation the wet insulation will loose it’s value and the ceiling panels may collapse, if a vapour check membrane is used, the weight of the water collected could also bring down the ceiling. A simple coating of Grafo-Therm will complete this excellent specification.
Single-skin roof over purlin system
When condensation is controlled on the single skin roof sheet, this built up over purlin system is very cost effective in both the short and long term. Grafo-Therm will provide protection for the life of the steel sheets.
Concrete structures such as hardened aircraft shelters, multi-story car parks may also benefit from a coating of Grafo-Therm to provide condensation control, light reflection, and noise dampening.