There are several standards that collect test methods for haze measurement. In the following subsections we will discuss UNE-EN 2155-9, ASMT D 1003 and ISO 1782.
UNE-EN 2155-9
The UNE EN 2155-9 standard refers to "Aerospace Materials" by its own title. Test methods for transparent materials used in glass in aerospace construction. Determination of turbidity.
The purpose of this standard is to describe a method for the determination of turbidity in flat parts of transparent plastic materials using an integrating sphere-based device. The integrating sphere is used to collect the transmitted light flux. However, according to the standard, this method is not recommended for determining turbidity when values greater than 30% are obtained.
The UNE EN 2155-9 standard states that the percentage of turbidity is obtained from the following formula:
According to the standard, this percentage needs to be expressed in an approximate value of 0.1%, while the thickness of the specimen needs to be measured in millimeters, which is an approximate value of 0.02 mm.
ASTM D 1003
ASTM D1003, "Standard Test Method for Haze and Light Transmission of Transparent Plastics," provides two procedures for light transmission and haze measurements. This method covers the evaluation of specific light transmission and wide-angle light scattering properties of planar sections of materials such as substantially transparent plastics. With regard to the two procedures indicated by the standard, procedure A uses a haze meter and procedure B uses a Spectrophotometer .
International Organization for Standardization ISO 14782 Certification
Regarding ISO 14782, "Plastics. Determination of haze of transparent materials", specifies a method suitable for measuring haze values of less than 40%. In this method, turbidity is determined by an integrating sphere, which keeps the efficiency constant through compensation.
This method implies the need to perform the four measurements given in the table below:
Like UNE-EN 2155-9, the ISO 14782 standard also indicates the following formula to calculate the haze:
τ1 is the intensity of the incident light.
τ2 is the intensity of light transmitted by the sample.
τ3 is the intensity of light scattered by the instrument.
τ4 is the intensity of light scattered by the instrument and sample.
