Flow Network example: Shutdown Sequence

The following example illustrates the steps that the system executes in order to shut down all pumps at a Flow Network when a CLOSE command blocks off flow to a pump such that the pump is:

• Upstream blocked.

• Downstream blocked.

• Shut in (blocked on both sides).

Setup

The Flow Network "Acceptance Testing Station 1" is associated with the Protected Location "AT_Protected_Fnet2".

Note: Refer to the following in regards to the "AT_Protected_Fnet2" protectedLocation record (see the "Acceptance Testing Station 1" figure):

• The Flow Network has a configured Shutdown Sequence (an actionSequence record).

• The Uncommanded Shutdown Delay for Closed State timer is enabled with a value of 10 seconds.

• The Uncommanded Shutdown Delay for Closing State timer is enabled with a value of 20 seconds.

• The two-headed arrow icon to the left of the valve "AT_FNET_S1_V06" indicates a critical valve. If a critical valve closes, it blocks flow to a pump and triggers a Shutdown Sequence.

Acceptance Testing Station 1

A Critical Valve

Triggering of a Shutdown Sequence

The critical valve "AT_FNET_S1_V06" enters the CLOSING state.

Valve "AT_FNET_S1_V06" in a Closing State

As per the configured Uncommanded Shutdown Delay for Closing State timer, the system will shut down the pump in 20 seconds, as noted in the Alarm Summary window.

However, a few seconds after entering the CLOSING state, the critical valve "AT_FNET_S1_V06" enters the CLOSED state.

Valve "AT_FNET_S1_V06" in a Closed State

As per the configured Uncommanded Shutdown Delay for Closed State timer, the system will now shut down the pump in 10 seconds, as noted below in the Alarm Summary window.

After the critical valve remains in the CLOSED state for more than 10 seconds, the system shuts down all pumps at the Flow Network.

All Pumps at Acceptance Testing Station 1 Shut Down

Alarm Summary window—Sequence of Steps for Shutdown Complete