SISTEMAS INSTRUMENTADOS DE SEGURIDAD (SIS):CICLO DE VIDA

Abstract

An Safety Instrumented System

(SIS) is a new term used in the stan

dards that normally also have been

and are known by the majority like:

Emergency Shutdown System (ESD),

Safety Shutdown System, Interlock

System, Emergency tryps System,

Security systems, etc.

The SIS constitutes the last layer

of preventive security and their co

rrect design, installation, tests and

maintenance (life cycle) are the gua

rantee of their suitable operation

when, under demand, it is required. If

this layer fails the dangerous event

will be triggered producing leakages,

explosions, fires, etc with the conse

quences that this can carry in costs

and/or human lost. After this last sin

gle preventive layer they appear those

of mitigation that try to diminish the

consequences (fire and gases sys

tems, plans of emergency, etc.).

An Safety instrumented System

(SIS) can be defined as: "A System

made up of sensors, final logic and

elements in order to take to the deter

mined process to a safe state when

pre-established conditions are viola

ted"

It is therefore critical and funda

mental that the Companies of Pro

cess have in consideration in their

Projects that the industrial safety of

its facilities happens through the

strict fulfillment of each step of the li

fe cycle that the modern international

standards (ISA and lEC) define.

This article tries to expose not

only that is a SIS but also to mean its

importance, to enumerate the best

standards, as well as to as much des

cribe each one of the steps of its life

cycle giving finally recommendations

and identification acronyms.