An object’s color significantly affects the level of heat it absorbs once it is exposed to sunlight. In fact, studies have shown that black-colored objects will absorb more heat and become hotter than white-colored ones. This is the reason why people living in tropical climates prefer to wear light-colored clothes, especially whites.
The same is true for roofs of steel buildings. Uncontrolled interior temperatures will most likely be higher for steel buildings with dark-colored roofs. However, white or any other light color is not the most popular color for roofs among designers, architects and even consumers.
In light of this observation, the metal industry has introduced “cool roofs”, which are coated with colors made from pigments that assist in making the roofs of steel buildings to be minimally affected by solar-induced heating.
Factors that affect the absorption of heat going into steel buildings include the construction of the roof, type of roof material, roof slope and especially color. A hot building, no matter what material it is made of, also radiates heat and warms the air in its surroundings. Imagine the effect of having a large concentration of buildings and the result is called “urban heat island effect”, a phenomenon, which has been observed in cities worldwide. The “heat island effect” is both real and measurable as proven by studies done by the EPA.
The EPA’s Heat Island Reduction Initiative also reported that 70% of the solar energy is absorbed by dark-colored pavements and roofs. More heat going into steel buildings means more energy is needed to keep the interiors comfortable to live and work in. That is why the need for a cooler roof is very desirable. It nor only reduces solar-induced heat but also significantly lessens the need for electricity to power air-conditioning equipment.
In layman’s terms, “cool roofs” for steel buildings minimize the amount of energy absorbed by reflecting most of the sun’s energy.
(to be continued)