At the UEL of 15%, what does this mean for gas combustion?

At the upper explosive limit (UEL) of 15%, this indicates that the concentration of gas in the air is at a level where there is insufficient air to support combustion. When the gas concentration exceeds the UEL, in this case, at 15%, there is not enough oxygen available to allow the gas to ignite and burn effectively. This situation can lead to incomplete combustion and potentially hazardous conditions, as the gas-air mixture is too rich in fuel.

Understanding this concept is crucial for safety inspections and ensuring that gas-burning appliances function correctly. It's important to monitor both gas concentration and air supply to maintain safe combustion conditions, avoiding scenarios where there isn't enough air for combustion, which can lead to safety risks.