NFRC 201: Standard Test Method for Measuring the Solar Heat Gain Coefficient of Fenestration Systems

Standard: NFRC 201 – Procedure for Interim Standard Test Method for Measuring the Solar Heat Gain Coefficient of Fenestration Systems Using Calorimetry Hot Box Methods

Scope: This test applicable to both residential and commercial fenestration products.

Applicable Products: Non-standard glazing systems such as domed plastic skylights, U-channel glass, multi-wall polycarbonate panels and Windows, Doors, Skylights, and Curtain Walls using non-standard glazing systems.

Test Procedure: The test utilizes an apparatus known as a solar calorimeter. The solar calorimeter is an outdoor device which consists of a room side chamber mounted to a frame capable of tracking the sun’s position in the sky and maintaining normal incidence of the product to the sun. The room side chamber contains heat extraction devices to maintain a specified interior temperature of 75ºF (24ºC) while the device tracks the sun. Clear sky conditions with full sunlight are required throughout the test. The heat gain through the product is measured to determine the Solar Heat Gain Coefficient (SHGC) of the product.

End Result: The Solar Heat Gain Coefficient (SHGC) of the product is determined. The SHGC can be used to determine heat gain through the products and the corresponding cooling energy demand. This typically is used to certify windows, doors, skylights and curtain walls for SHGC. This is almost always done in conjunction with ANSI/NFRC 100 testing for U-Factor.

Special Notes: This method is used when non-standard glazing is used in a fenestration product. It is used only for products which cannot use ANSI/NFRC 200 computer simulation methods. When NFRC 201 is required for SHGC, NFRC 202 or NFRC 203 may be applicable to determine Visible Transmittance (VT) of those products.


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