What is the range for the Upper Explosive Limit (UEL) for ammonia?

The Upper Explosive Limit (UEL) for ammonia is a critical safety parameter in industrial settings where ammonia is used as a refrigerant. The UEL indicates the maximum concentration of ammonia in air at which a mixture can ignite. If the ammonia concentration exceeds this limit, it becomes too rich in ammonia for combustion to occur.

The accepted range for the UEL of ammonia is indeed approximately 28% to 30%. This range demonstrates that concentrations within this limit can pose a risk of explosive mixtures if an ignition source is present. Therefore, understanding and monitoring the UEL is essential for maintaining safety protocols in environments where ammonia is present, particularly in refrigeration systems, which operate under specific conditions that could lead to a build-up of gaseous ammonia.

In contrast, the other ranges listed do not accurately represent the established UEL for ammonia, thus highlighting the importance of relying on precise data when assessing hazardous materials and their potential risks.