How to classify fire doors based on their fire resistance performance?

Update:Jan 15,2024
Summary:How to classify fire doors based on their fire resistance performance?Fire doors are classified into heat-insulated/partially heat-insulated/non-heat-......
How to classify fire doors based on their fire resistance performance?
Fire doors are classified into heat-insulated/partially heat-insulated/non-heat-insulated fire doors according to their fire resistance.
The fire doors we usually refer to are all heat-insulated fire doors,
which are classified into three types based on their fire resistance limit:
Class A (1.5h), Class B (1.0h) and Class C (0.5h).