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Also known as reflective barrier, Radiant Barrier inhibits heat transfer through thermal radiation. However, they are ineffective when it comes to convection and conduction, which are two other modes of heat transfer.
Through thermal radiation, energy is emitted by every material and the extent of which depends on surface temperature and the relative ability of the material to emit radiation which in turn is directly proportional to heat radiated at particular wavelengths. At these given wavelengths, the amount of energy that a material reflects measures the Reflectivity of that material.
For those wavelengths at which the Radiant Barrier function, there emissivity is to be maintained low as much as 0.1 or below it. The range of wavelength for buildings lies in the middle of the long infrared spectrum that is between 3-15 micrometers where the range for reflectivity of Radiant Barrier is not fixed because the total of reflectivity and emissivity does not have to be one and therefore, there is no fixed range. It can be said that low thermal emissivity creates dark surfaces and for proper functioning, the Radiant Barrier should be facing open surfaces which are vacuum or air to prevent radiation. The method of applying a radiant barrier:
Application of radiant barrier-
NASA came up with a material that was light, reflective and made up of a plastic substrate that had a vapor deposited coating of aluminum. This is popularly known by the name space blanket. It is used for protection of equipments, astronauts and spacecraft from radiation and also for the retention of heat as temperature fluctuations are a common thing in space. Radiant Barrier is more effective in space than on earth because heat transfer in space only takes by radiation. The heat transfer on earth can take place by conduction and convection even if Radiant Barrier is deployed.
There is another use of Radiant Barrier that is to reduce loss of indoor heat.
There are basically two methods by which Radiant Barrier insulation can be installed-
1. Radiant Barrier Decking
2. Radiant Barrier Attic Foil.
The roof of a building absorbs solar energy on sunny days and this heat is radiated downwards to the floor. If a radian barrier is placed on the floor, it reflects the heat it receives back to the roof again. This causes the surface to remain cooler. It also reduces the amount of heat coming into the rooms and hence is quite an effective device.
The traditional method of insulating an attic and a radiant barrier are different from each other. Despite having the same objective, the two differ in the methods of doing so. The areas near a radiant barrier are cooler as it reduces the heat radiated whereas the traditional method of attic insulation achieves this by means of convection. This technique utilizes air trapping. R-value is the scale which rates this technique. Radiant Barrier has no R-values as they depend on a lot of factors.
Radiant Barrier comes in different ranges. The cost primarily depends upon the one who is installing it. Other factors include the extra features which some people like to incorporate in it. The price is different for a new house and an existing one.
Needless to say, Radiant Barrier is highly effective and desirous. They are of vital importance and preferred these days. Have a look on radiant barrier reviews before you decide to install it.
Find more articles written by Martini Hogiri