---
title: Typical I.S. system layout
description: "![typical layout of I.S system](https://www.eicstech.com/wp-content/uploads/2022/06/typical-layout-of-I.S-system.png) An IS system usually consists of safe area equipment, a safe to hazardous area interface, cables and junction boxes, and field (hazardous area) equipment. The system is designed to guard against the possibility of particular…"
url: "https://www.eicstech.com/kb/intrinsic-safety-ex-i/basics-on-typical-layout-of-i-s-system/"
updated: "2022-06-01"
category: Explosion Proof Basics / Intrinsic Safety (Ex i)
---

# Typical I.S. system layout

![typical layout of I.S system](https://www.eicstech.com/wp-content/uploads/2022/06/typical-layout-of-I.S-system.png)

An IS system usually consists of safe area equipment, a safe to hazardous area interface, cables and junction boxes, and field (hazardous area) equipment. The system is designed to guard against the possibility of particular faults occurring.

**The intrinsic safety concept applies to the whole system and not to any one item only.**

#### **Associated apparatus (interface)**

The equipment in the safe area is connected to equipment in the hazardous area via the interface, which is the **associated apparatus.**

The **function of the interface** is to **limit the energy** into the hazardous area and is often called as the **I.S. Safety Barrier.**

There are two types of I.S barriers:

- Zener barrier
- Galvanic isolation barrier

The interface may be incorporated inside the safe area apparatus (e.g. a recorder with an energy-limited input from a sensor I the hazardous area).