When can Clean Agent fire extinguishing systems be accepted by the Fire Commissioner?

The acceptance of Clean Agent fire extinguishing systems by the Fire Commissioner is based on their effectiveness where traditional water-based systems may not be suitable or effective. Clean agents are typically used in environments where water could cause damage to sensitive equipment or materials, such as in data centers, libraries, and historical buildings.

In situations where water is ineffective—such as in the case of electrical fires or fires involving sensitive electronic equipment—Clean Agent systems provide a necessary alternative. They work by interrupting the chemical reactions of combustion, thus extinguishing the fire without causing water damage.

The other options reference alternative extinguishing agents, like halon, steam, and carbon dioxide, but do not align with the primary consideration for using Clean Agent systems. Clean Agents are specifically designed to complement or replace water, making option A the most relevant and correct response regarding the circumstances under which these systems can be accepted by the Fire Commissioner.