There are two kinds of depressurization alarm:
- ΔP/ΔT (rapid depressurization)
- ATM PRESS (slow leak, or pressure hitting the thresholds)
Main steps that are taken:
- Record incident and contact mission control
- Take pressure gauge
- Evacuate into the Soyuz
- Check if Soyuz descent module is leaking
- If time remaining (T.res) is less than X minutes, say "Bye-bye" to the station, prepare the Soyuz for flight and undocking. Contact Mission control
- If T.res is more than X minutes and the Descent module is leaking, return to the ISS, and deactivate the station orderly
- If T.res is more than X minutes and the Descent module is safe, return to the ISS, close vacuum valves through the laptop and pinpoint leak
- Isolate the leaking compartment
Roughly speaking, X is the time to deactivate the station.
How to spot the leak:
- Use the ISS computer to find the leaking compartment
- If fails, use pressure gauge in each compartment with closed hatches to determine the culprit.
Any steps to patch leaks are taken only after consulting Mission Control
CREW SURVIVAL IS THE HIGHEST PRIORITY
- International Space Station Emergency Operations
- Integrated Russian Segment Emergency Operations
- International Space Station Complex Operations Emergency Procedures All Expedition Flights
Note: if anybody knows where to find an up-to-date SODF please let me know.