What is the formula used to calculate dilution air for lower explosive limit (LEL)?

The correct answer involves the calculation of dilution air necessary to ensure that the concentration of a flammable vapor is kept below the lower explosive limit (LEL). The formula used is designed to determine the amount of air needed to dilute a given volume of flammable vapor to a safe concentration.

The formula 4(100-LEL)(vapor release)/LEL effectively addresses the need for sufficient dilution by taking into account the percentage of the lower explosive limit and the rate of vapor release. In this case:

• The term "100 - LEL" represents the percentage of the air in the mixture that is safe and does not contribute to the explosive potential. This has to be multiplied by the vapor release rate to establish how much air is needed for dilution.

• Dividing by the LEL helps to adjust the values in relation to the actual concentration of the explosive vapor, ensuring that the calculation accurately reflects the ratio of the vapor present against the threshold that could indicate risk.

Thus, this formula successfully combines these elements to achieve the objective of maintaining safety in environments where flammable vapors are present. The result is a practical method for calculating the dilution air necessary to keep concentrations of hazardous vapors below an exploitable threshold, thus preventing potential ignition