Production of Polysilicon using a Modified Siemens Process

Flow of Events:
1. Maintenance operator inspects temperature sensor, testing its
capability to detect known temperatures within the acceptable
accuracy and its ability to determine the correct course of action based
on what it senses
2. Temperature sensor is recalibrated or replaced if not detecting the
correct temperature or taking the right action after detecting
temperature
3. Maintenance is documented
Post-condition: Temperature sensor is able to detect the correct temperature
within the specified accuracy and able to take the correct course of
action based on its readings and process is able to continue without
increased operation hazard levels
Scenario (3.1.2): Piping Leak Maintenance
Description: Pipe tested for leaks
Primary Object: Reactor Piping
Primary Actors: Maintenance Operator
Pre-condition: Process not running
Flow of Events:
1. Maintenance operator inspects pipes for leaks, most likely by running
pressure or flow tests
2. Any presence of leaks is detected and their severity determined
3. If problem is sever, pipe may have to be replaced immediately, if it is
minor, patching of pipe may be acceptable
4. Maintenance is documented
Post-condition: Pipe leak is eliminated and process is able to continue without
increased operation hazard levels
Requirements and Traceability