Experimental study on effect of vapor penetration on thermal performance of light metal insulating sandwich building envelope

Using the steady heat transfer testing method in the guarded hot box, conducts heat and humidity transfer experiments for the light metal insulating sandwich building envelope, which adopts rock wool as the thermal insulation material, and studies the effect of vapor penetration on the thermal performance. Measures the temperature, humidity and heat flow rate for the typical light metal insulated constructions in steady heat transfer condition, and obtains the temperature and humidity distribution in rock wool of the specimen with different vapor penetration cases. Compares the difference of the heat flow rate of the specimen in five cases, and analyses the correlation between the heat transfer coefficient and humidity. The results show that the heat flow rate through the specimen with vapor penetration increases by many times than that without vapor penetration, and there is an exponential relationship between the heat transfer coefficient of building envelope and the average humidity of thermal insulation material.