scope:

The material defined by this specification is a grade of low light transmittance, reflective, laminated float glass which will meet test requirements of the government standards for the country of use. The laminate consists of two pieces of clear or tinted annealed float glass, plus an optional coating on number 2 or 3 surface to obtain the desired color and reflectance, bonded together with one or two pieces of dyed or pigmented polyvinyl butyral (PVB) interlayer WSB-M4D356-B (if two pieces of PVB are used, one may be clear) and so constructed to give low light transmittance and high reflective properties.