1. Technical Standard for Smoke Management Systems of Buildings, GB 51251-2017
4.4.10 A smoke fire damper shall be fitted on a smoke duct at: 1 the horizontal section where a vertical duct meets each floor horizontal duct; 2 a smoke branch serving several smoke compartments; 3 the inlet of the smoke exhaust fan; 4 a fire-compartment crossing.
[Note] The smoke fire damper has these four fitting positions.
2. Technical Standard for Smoke Management Systems of Buildings, GB 51251-2017
5.2.2 The smoke exhaust fan and make-up fan shall be controlled by: 1 local manual start; 2 automatic start by the fire alarm system; 3 manual start at the fire control room; 4 automatic start of the fan when any smoke valve or outlet opens; 5 the smoke fire damper closes by itself at 280°C and interlocks to close the smoke exhaust fan and the make-up fan.
[Note] The smoke fire damper here is usually taken as the one at the fan inlet.
3. Code for Fire Protection Design of Garages, Repair Garages and Parking Lots, GB 50067-2014
8.2.8 On a smoke branch duct crossing different smoke compartments, fit a smoke fire damper that closes automatically when the gas temperature exceeds 280°C; the damper shall interlock to close the corresponding smoke exhaust fan.
[Note] 1. The smoke fire damper here means the damper on a smoke branch serving several smoke compartments.
2. For a garage, any smoke fire damper in Figure 1 must close by itself at 280°C and interlock to close the smoke exhaust fan.
4. Conclusion
For garage and non-garage mechanical smoke systems, the set of smoke fire dampers that must interlock to close the exhaust fan is quite different.