User manual

11
Functional Safety Manual
IP101/FSM, Rev AA
January 2012
Horizontal Float Switch
OPERATION AND
MAINTENANCE
Proof-test Requirement During operation, a low-demand mode SIF must be proof-tested. The objective of
proof-testing is to detect failures within the equipment in the SIF that are not detected
by any automatic diagnostics of the system. Undetected failures that prevent the SIF
from performing its function are the main concern.
Periodic proof-tests shall take place at the frequency (or interval) defined by the SIL
verification calculation. The proof-tests must be performed more frequently than or as
frequently as specified in the SIL verification calculation in order to maintain the
required safety integrity of the overall SIF. A sample procedure is provided in the
section “Proposed Proof-test Procedure” on page 13.
Results from periodic proof tests shall be recorded and periodically reviewed.
Repair and Replacement Repair procedures in the Mobrey product document M310 must be followed.
Notification Of Failures In case of malfunction of the system or SIF, the Mobrey level switch shall be put out of
operation and the process shall be kept in a safe state by other measures.
Mobrey Limited must be informed when the Mobrey level switch is required to be
replaced due to failure. The failure shall be documented and reported to Mobrey
Limited using the contact details on the back page of this safety manual. This is an
important part of Emerson Process Management’s SIS management process.