# Question: What Is A Safe LEL Level?

## What is the difference between LEL and PPM?

Different combustible gases have different lower explosive limit concentrations.

The lower explosive limit (100% LEL) concentration for hydrogen is about 4.0% volume, which is equal to 40,000 ppm.

So, 1.0% LEL hydrogen = 40,000 ppm X 0.01 = 400 ppm.

So, a concentration of 2000 ppm hydrogen = 2000 ÷ 400 = 5.0% LEL..

## What is the LEL of LPG?

19,000 ppmThe chosen IDLH, based on the “estimated” LEL for L.P.G. (19,000 ppm), is the concentration above which only the “most protective” respirators are permitted.

## What Is percent LEL?

One hundred percent lower explosive limit (100% LEL) denotes an atmosphere in which gas is at its lower flammable limit. The relationship between percent LEL and percent by volume differs from gas to gas. The example below demonstrates the flammability of Methane (Natural Gas) in Air.

## What is a safe LEL levels for welding?

Work must not proceed if oxygen level is above 23%, or the LEL is greater than 10% (note that oxygen must be above 19.5% in order to accurately measure LEL/LFL).

## What percent of oxygen is safe?

19.5 percentHuman beings must breathe oxygen . . . to survive, and begin to suffer adverse health effects when the oxygen level of their breathing air drops below [19.5 percent oxygen]. Below 19.5 percent oxygen . . . , air is considered oxygen-deficient.

## What is Lel in confined space?

An LEL Confined Space refers to Lower Explosive Limit within the confined space, which will be a percentage of combustible material in a gas or vapor state, that if mixed in the right proportion with air can create a hazardous fuel/air mixture that can be ignited and explode.

## What is the acceptable oxygen level in a confined space?

19.5 %19.5 % Minimum acceptable oxygen level. 15 – 19% Decreased ability to work strenuously. Impair coordination.

## How is LEL measured?

How is LEL measured? Known combustible gasses have a determined LEL expressed as a volume %Vol. As the amount of detectable combustible gas rises, an LEL sensor will display a readout from 0 – 100% LEL. For example: Methane has an LEL of 5.0% Vol in air.

## What is a safe UEL level?

The maximum concentration of a gas or vapor that will burn in air is defined as the Upper Explosive Limit (UEL). Above this level, the mixture is too “rich” to burn. The range between the LEL and UEL is known as the flammable range for that gas or vapor. Methane – LEL: 5% by volume in Air / UEL: 17% by volume in Air.

## What is the LEL of oxygen?

Normal Oxygen Level 21% in air. LEL and UEL will change as oxygen level changes. FLAMMABLE RANGE. Flammable Range of Selected Gases and Vapors. Flammable Vapor or Gas LEL UEL.

## What is LEL & UEL?

The minimum concentration of a particular combustible gas or vapor necessary to support its combustion in air is defined as the Lower Explosive Limit (LEL) for that gas. … The maximum concentration of a gas or vapor that will burn in air is defined as the Upper Explosive Limit (UEL).

## How many ppm of hydrogen is dangerous?

It has also been reported that 50 to 100 ppm causes mild conjunctivitis and respiratory irritation after 1 hour; 500 to 700 ppm may be dangerous in 0.5 to 1 hour; 700 to 1,000 ppm results in rapid unconsciousness, cessation of respiration, and death; and 1,000 to 2,000 ppm results in unconsciousness, cessation of …