What is often insufficient to remove smoke and heat from large commercial buildings?

The effectiveness of naturally occurring air currents in removing smoke and heat from large commercial buildings is often limited due to several factors. While natural ventilation relies on the movement of air that occurs without additional mechanical assistance, it can be slow and unpredictable. This means that in scenarios where there's a significant fire load or confined spaces, relying solely on natural air currents might not provide adequate control over smoke and heat.

Advanced fire scenarios often result in rapid smoke accumulation and heat buildup that require more reliable and forceful methods of ventilation. Mechanical ventilation systems are designed to actively remove smoke and heat, while emergency exits are crucial for safety but do not contribute to smoke removal. Portable fans can assist, but they are generally less effective in large, open spaces compared to dedicated mechanical systems. Thus, naturally occurring air currents alone do not offer a sufficient means of ensuring the safety and effective fire control needed in such significant structures.