BS 493 is applicable to thermoplastics materials for wall ventilation.
BS 493 specifies requirements for two classes of wall ventilating units as follows:
class 1: Airbricks for use in external walls;
class 2: Wall ventilators or gratings for internal use.
BS 493 on airbricks and gratings for wall ventilation is useful for:
Wall ventilator or grating is a unit having apertures to allow for the passage of air which is either built into or fixed to internal walling, normally in conjunction with an external airbrick.
BS 493 provides you with the specifications of materials for wall ventilation that will assist you while purchasing the materials. Also, BS 493 assists you to check the durability of thermoplastics materials this will help you to protect from fire hazards as well as improve the masonry strength.
Overall, BS 493 helps you to improve the durability of walls by providing specifications for internal and external use walls.