We have tested and have the ability to control dampers. But we do not practice it or recommend doing it because the minimum energy savings to be gained does not outweigh the risk and life safety of the facility.
The first priority for a Type 1 grease duct is to extract grease-laden air from the kitchen hood and maintain the safety of the occupants in the building. Any obstructions in the air flow prevent the duct from performing its core life safety mission. And Melink does not advocate the usage of modulating dampers as a control strategy.