ČSN EN 16475-3

This European Standard specifies the requirements and test methods for draught regulators, standstill opening devices and combined secondary air devices that are used as components, carrying flue gases, in order to limit the draught in chimneys and provide secondary air to the chimney.
Draught regulators, standstill opening devices and combined secondary air devices for positive pressure chimneys are not covered by this standard.
It also specifies the requirements for marking, manufacturers' instruction, product information and attestation and verification of constancy of performance (AVCP).