What is the maximum concentration of flammable gas allowed before entry into a confined space for hot work is prohibited?

The maximum concentration of flammable gas allowed before entry into a confined space for hot work is set at 20% of the Lower Explosion Limit (LEL). This is a critical safety measure as it ensures that the atmosphere within the confined space is not conducive to combustion. At concentrations above this level, there is a significant risk of igniting a flammable mix, which can result in explosions and fires during hot work activities such as welding, cutting, or grinding.

Prior to entering a confined space for hot work, it's essential to monitor the atmosphere and confirm gas levels are well below this threshold to ensure the safety of workers. Hot work can introduce sparks and heat, both of which could trigger an explosion if flammable gases are present in unsafe concentrations. Therefore, adhering to this limit is crucial for maintaining safety and preventing hazardous situations in confined spaces.