---
title: Oxygen
description: "## Oxygen Enrichment The normal oxygen content in the atmosphere is around 20.95%. If a location has a value which exceeds this, its atmosphere is said to be oxygen enriched. E.g.: - gas manufacturing plants, hospital operating theatres, & around…"
url: "https://www.eicstech.com/kb/general-principles/oxygen/"
updated: "2022-05-31"
category: Explosion Proof Basics / General Principles
---

# Oxygen

## Oxygen Enrichment

The normal oxygen content in the atmosphere is around 20.95%. If a location has a value which exceeds this, its atmosphere is said to be oxygen enriched.
E.g.: - gas manufacturing plants, hospital operating theatres, & around oxy-acetylene equipment.

### Oxygen enrichment**has three disadvantages**

1. It can lower the ignition temperature temperature of flammable materials as shown:

| **Material** | **Air** | **Increased Oxygen** |
| --- | --- | --- |
|  | **Ignition temperature °C** | **Ignition Temperature °C** |
| **Hydrogen Sulphide** | **260** | **220** |
| **Acetylene** | **305** | **296** |
| **Ethane** | **515** | **506** |

2. Oxygen enrichment significantly raises the upper explosive limit (UEL) of the majority of gases and vapours, thereby widening their flammable range:

| **Materials** | **Air** |  | **Increase Oxygen** |  |
| --- | --- | --- | --- | --- |
|  | **LEL%** | **UEL%** | **LEL%** | **UEL%** |
| **Methane** | **4.4** | **17.0** | **5.2** | **79** |
| **Propane** | **1.7** | **10.9** | **2.3** | **55** |
| **Hydrogen** | **4.0** | **77.0** | **4.7** | **94** |

3. It can allow an atmosphere to be ignited with much lower values of electrical energy.

**Explosion protected equipment will have been tested in normal atmospheric conditions. Equipment for used in an oxygen enriched atmospheres must be specially tested and certified.**