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3 years ago

Which of the following has the lowest U value?

Physics

1 answer:

jarptica [38.1K]3 years ago

4 0

Answer:

c. expanded polyurethane

Explanation:

Thermal performance of a building fabric is measured in terms of heat loss and is expressed as U-value or R-value. U-value is the rate of heat transferred through a structure divided by the difference in temperature across the structure with a unit of measurement of W/m²K.You can calculate the U-value of a by getting the reciprocal of the sum of thermal resistances , R, making the building material.

If you have the value of R, then U=1/R

Material size R U

plywood 1" 1.25 0.8

Poured concrete 2" 0.99 1.010

Expanded polyurethane 1" 6.5 0.1538

Asbestos shingles 1" 0.03 33.33

The material with lowest U-value is expanded polyurethane

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