Fig. 1.1 shows a cross-section of a cavity wall before and after foam insulation is injected into the gap. How does the foam reduce the rate of energy trans...
Question 1 Report
Fig. 1.1 shows a cross-section of a cavity wall before and after foam insulation is injected into the gap.
How does the foam reduce the rate of energy transfer through the wall?
Answer Details
In the unfilled cavity wall, the air gap allows convection currents to form: warm air near the inner wall rises and cool air near the outer wall sinks, transferring energy across the gap. Injecting foam into the cavity traps the air in small pockets, preventing convection. The foam itself and the trapped air are poor conductors, so conduction through the cavity is also reduced. Together these effects significantly lower the rate of energy transfer through the wall.
Download The App On Google Playstore
Everything you need to excel in your exams
