What type of construction is required for vent ducts in vaults containing burning liquids?

Reinforced concrete construction is required for vent ducts in vaults containing burning liquids due to its excellent fire-resistance and structural integrity. Concrete can withstand high temperatures without compromising its strength, making it suitable for environments that may be exposed to fire hazards. Additionally, reinforced concrete is durable and can contain spills and vapors more effectively than other materials. This helps to ensure safety in potentially hazardous environments by preventing the spread of fire and protecting the structural integrity of the vault itself.

Materials like wood or plastic would be unsuitable for this application because they are combustible and could easily catch fire, compromising the safety of the storage area. Steel, while fire-resistant to some extent, may not provide the same level of containment and thermal resistance as reinforced concrete in the context of a vault designed for burning liquids. Thus, the choice of reinforced concrete construction aligns with safety standards and regulations for hazardous locations.