What is the maximum allowable oxygen amount for an inert atmosphere?

For maintaining an inert atmosphere during the handling of flammable liquids and gases, the maximum allowable amount of oxygen is typically set to around 8%. This restriction is critical because keeping oxygen levels low reduces the risk of combustion and explosions, which are significant hazards in environments where flammable materials are present. An oxygen content of up to 8% is considered sufficiently low to prevent ignition in most cases, while ensuring that the atmosphere remains safe for personnel working in the area.

The other options suggest higher oxygen levels that could potentially lead to increased risks of combustion. For example, 10% and 15% oxygen environments may still support combustion, while 5% could be too low for safe breathing conditions for personnel without proper respiratory protection. Thus, maintaining an oxygen level around 8% balances safety measures and operational needs.