Z77 Safeguard and Switchgear Ventilation

Question 1

What is the timeline once a fire is detected in the Z77 ventilation system?

Answer 1

5 sec delay supply and exhaust fans trip
30 seconds fire dampers close
45 sec CO2 valves open flooding area
50 sec Z77 fans restart

Question 2

What will trip a supply fan if it is manually started?

Answer 2

Nothing, it must be manually stopped

Question 3

What will de-energize the heating coil?

Answer 3

Low flow or if fan trips

Question 4

How is System Z77 balanced to battery room and why?

Answer 4

Provide outside air at a rate of 10 changes per hour to prevent accumulation of hydrogen

Question 5

How to air operated dampers fail Z77?

Answer 5

Fail open on loss of air so fans can still be operated

Question 6

How does the 10-times an hour air swap for battery rooms work?

Answer 6

The exhaust fans suck directly from battery rooms

don’t blow batteries

Question 7

Z77 How to Unit 2 fans work in relation to unit 1?

Answer 7

Unit 2 is slave to unit 1

Question 8

How does the red and green light indication work in the control room for supply fans?

Answer 8

Both must be running (same speed) to get a red light. Green light means either no units are running or only Unit 1 is running

Question 9

Z77 How does the light indication work in the control room for the dampers?

Answer 9

Both must be open to get a red light. Green means either one or both are closed.