Working Systems, Human Failures: Why Fire Protection Depends on the People Around It

For property owners, operators, and the brokers who help protect them, a working fire protection system can be the difference between a contained incident and a major property loss. However, installing the right system is only the beginning. Its effectiveness ultimately depends on how well it is maintained, monitored, and managed as the property changes over time.

Automatic sprinkler systems are among the most reliable safety technologies available. According to NFPA's U.S. Experience with Sprinklers report, from 2017 to 2021 sprinklers operated in 92 percent of U.S. structure fires large enough to activate them and were effective at controlling the fire in 97 percent of those incidents. Often, very little is needed: in 77 percent of the structure fires where sprinklers operated, only one sprinkler operated.

That record raises an obvious question. If the technology works this well, why does it ever fail? The NFPA data points to a clear answer: the problem is rarely the system itself. It is usually the people around it.

What the numbers show

NFPA estimates an annual average of 771 fires where the sprinkler system failed to operate from 2017 to 2021, plus an estimated 311 fires per year where the system operated but was ineffective. When NFPA broke down why systems failed to operate, the pattern was clear: 

Reason for failure to operate	Share of failures
System shut off	61%
Manual intervention defeated the system	15%
Lack of maintenance	9%
System component damaged	9%
Inappropriate system for the type of fire	6%

Source: NFPA, "U.S. Experience with Sprinklers," 2017 to 2021 data.

NFPA summarizes the takeaway directly: in 79 percent of incidents in which sprinklers failed to operate, the system had been accidentally shut off, damaged, or not maintained. None of those causes involves a defect in how sprinkler technology works. Each involves a decision, an oversight, or a gap in care. 

Human intervention defeats working systems

Shut off systems: A closed valve turns a fully functional sprinkler system into overhead decoration. Valves get closed for legitimate reasons: a leak repair, a tenant renovation, winterization of a vacant building. The failure happens when no one tracks the closure, no one watches the protected area while it's out of service, and no one confirms the system is restored.

Manual intervention: This happens after a fire starts. Staff see water flowing, assume the fire is out or minor, and close the valve to limit water damage. The fire, still smoldering or hidden in a concealed space, regains strength with nothing to stop it.

Deferred maintenance: Sprinkler systems sit idle for years and must still work on demand. Corrosion, obstructed piping, painted sprinkler heads, and neglected fire pumps all degrade performance quietly. NFPA 25, the Standard for the Inspection, Testing, and Maintenance of Water-Based Fire Protection Systems, exists because these problems stay invisible until someone looks for them.

Fire protection is dynamic, not static

A fire protection system is designed for a specific building, occupancy, and hazard at a specific point in time. Buildings don’t stay that way. Tenants change, storage heights rise, processes shift, walls move, and new equipment arrives. Each change can quietly push a system outside its design basis.

Special hazard systems show how little it takes to compromise protection. For a clean-agent system to suppress a fire in a server room, the enclosure must retain an effective concentration of the agent for the required duration. A contractor who runs a new cable through a wall and leaves the penetration unsealed can compromise that protection without touching the system itself. That is why NFPA 2001 requires the protected enclosure to be inspected at least annually unless a documented program monitors its barrier integrity.

Fire protection must therefore be managed as an ongoing program, not treated as a one-time installation. A system correctly designed ten years ago may be inadequate today, not because it broke, but because the exposure or the building around it changed.

What property owners and managers can do

• Follow NFPA 25 and NFPA 72 ITM schedules. Use qualified contractors, correct deficiencies promptly, and maintain current inspection and testing records.

  
  

• Establish a formal impairment program. Tag each impairment, make the required notifications, implement appropriate precautions such as a fire watch and restrictions on hazardous operations, and complete the required inspections and testing before returning the system to service, including a valve status test to verify that affected valves have been restored to their proper operating position.

  
  

• Supervise and secure control valves. Electronic valve-supervisory switches provide notice when a valve is moved from its normal position, while approved locks or seals help discourage unauthorized closure.

  
  

• Train staff not to shut off flowing sprinklers. Train staff not to prematurely shut down an operating sprinkler system during a fire. Waterflow should continue until authorized emergency personnel determine that sprinkler protection can safely be shut down.

  
  

• Review protection whenever the building changes. New tenants, storage arrangements, and renovations should trigger a protection review.

The bottom line

Fire protection systems work. The data shows that sprinklers operate and control fires in the overwhelming majority of incidents where they are called upon. When protection fails, the problem is often not the technology itself, but what happened around it: a closed valve, deferred maintenance, an impairment that wasn't restored, or a building that changed while its protection did not.

A sprinkler system installed today and ignored for ten years results in an unprotected building. Reliable protection requires owners and managers to inspect, test, and maintain these systems and to reconsider them whenever the building or its hazards change. The technology is proven. Keeping it ready is the human part.

At ARU, we know strong property risk management often comes down to these details. The technology may be proven, but keeping it ready takes people who understand the risk, recognize when conditions have changed, and take action before an impairment becomes a loss.