Residential and commercial fire sprinkler systems present differences in design and capabilities that are important to consider in risk assessment. Awareness of these differences in system design and water supply requirements make considerable differences in evaluating values at risk and risk assessment of pure property protection versus the safety of occupants. To consider commercial and residential fire sprinkler systems identical in a risk assessment invites gaps in the assessment. This paper is not intended to cover both commercial and residential sprinkler system design in detail - beyond a brief recap of the purpose and functions of fire sprinklers. Certain knowledge of commercial automatic fire sprinkler systems is assumed.

Overall Purpose of Fire Alarm Systems

Any fire alarm system provides three critical functions:

  • Detect - sense a fire event

  • Alarm - provide a warning to occupants that the system has activated so they may take action

  • Communicate - provide a notification away from the occupants that the system has activated.

These three functions are the same for any fire protection system. Smoke detectors have the same basic function as automatic fire sprinklers. The difference is the application of control measures by fire sprinklers in addition to the alarm.

Arguments against Fire Sprinklers

As safety professionals, being prepared to dispel unfounded rumors and misunderstandings are important when discussing automatic fire sprinklers. This list has the most common arguments against fire sprinklers and points that can be used to overcome each.

  • They are unsightly

  • Sprinklers go off accidentally and leak

  • They all go off at the same time

  • They cause water damage

  • They are too expensive

  • They don't save lives

They are Unsightly

Current sprinkler design uses painted and coated sprinkler heads that blend in easily to almost any environment. Sprinklers can be recessed and covered with plates that hide the entire unit - important for residential applications.

Sprinklers Go off Accidentally and Leak

The actual experiences of accidental sprinkler discharges are remote. Factory Mutual reported that the probability of an accidental sprinkler discharge due to a manufacturing defect is 1 in 16 million sprinklers per year in service. Where sprinklers do discharge accidentally, it is most often caused by direct physical damage - using a sprinkler as a coat hanger for example. Actual occurrences of leaks are remote. But, even if a sprinkler does accidentally go off, will insurance respond? Most policies are structured to include a sprinkler discharge under the same definitions as any other plumbing leak.

They All Go off at the Same Time

Sprinkler heads are individually activated unless of a specialized design, such as deluge or exposure protection heads. A thermal element within each sprinkler head must "fuse", or melt. This allows the existing water pressure in the pipes to push off the cap and flow water from that specific sprinkler head.

They Cause Water Damage

The best argument against this is through calculation. A typical sprinkler head for a light hazard occupancy, like an office, is designed to discharge 0.10 gallons per minute.

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