Final answer:
The question is about the minimum number of extra sprinkler heads and wrenches that should be available for easy replacement in case of damage.
Step-by-step explanation:
The subject of this question is Fire Safety. The question is asking about the minimum number of extra sprinkler heads and appropriate wrenches that should be available to replace damaged ones.
Each building equipped with a sprinkler system should have a certain number of extra sprinkler heads on hand that can be easily replaced if a sprinkler becomes damaged. This is important because damaged sprinkler heads may not function properly and could compromise the effectiveness of the entire system in suppressing a fire.
For example, the National Fire Protection Association (NFPA) recommends that a minimum of six spare sprinkler heads, along with the appropriate wrenches, should be available for easy replacement. These spare sprinkler heads should match the type, temperature rating, and response characteristics of the system being used.