How many sprinklers must be sent off for testing if a sample size of quick response sprinklers fails the initial testing and are over 20 years old?

When a sample of quick response sprinklers fails initial testing and these sprinklers are over 20 years old, industry standards and regulations stipulate that all the sprinklers in that batch must be sent off for testing. This is because the failure of the sample indicates potential issues with the entire batch, particularly given the age of the sprinklers.

The rationale behind this approach is centered on safety and reliability. Sprinklers that are over 20 years old may not just have localized issues but could have systemic problems affecting all units. Thus, sending all the sprinklers for testing ensures that any potentially faulty units are identified and addressed, maintaining the integrity and effectiveness of the fire protection system.

In contrast, sending a smaller sample size would not adequately ensure safety, as there may be hidden defects in other sprinklers that did not get tested. By opting for a comprehensive approach, it aligns with best practices for fire safety and compliance with codes that demand thorough evaluation in situations where components under prolonged use have shown signs of failure.