Although catastrophic water intrusion on a fire alarm system is rare, it does happen. ­“Preventing Corrosion and Deterioration” in the May 2023 ELECTRICAL CONTRACTOR reminded me of one such ­disastrous water intrusion. I was working on a site with a complete ­renovation to a historical hotel, a visitor’s center and a new hotel. I had designed the fire alarm systems for all three and was reviewing each installation’s progress.

Late one afternoon, I received a frantic call from the owner’s representative that a major flood had occurred in the new hotel, which was days from its grand opening.

What to do with the equipment?

I rushed to investigate and found that the sprinkler contractor had turned on the water for the sprinkler system but had not ­connected the 4-inch pipe network in the attic. The water flooded out a large portion of the second and third floors, and there was additional damage to two rooms and the first-floor hallway. I was not called because of the expensive soaked furniture. In addition to the smoke detectors and other fire alarm devices affected by the water, the fire alarm control units (FACUs) in the electrical rooms on each floor were inundated with water.

As I stared at the water dripping out of one of the FACUs, the owner asked if we could simply use a hair dryer to dry out the equipment. I explained that when electronics get wet, ­they are likely to undergo corrosion and deterioration, and he began to understand the total implications of the water intrusion. 

Drying out the FACU was not the answer, because the water contains contaminants that would cause corrosion in the FACU’s components. Indeed, left to dry on their own, the FACU electronic control boards would begin to show almost immediate ­deterioration. Even if the electronics do not currently appear to have any corrosion issues, it will happen eventually and cause trouble signals in the system and possibly false alarms within the first six months after the incident. The costs incurred at the six-month mark will inevitably be higher due to hotel occupancy. 

Reliable operation is crucial

NEMA’s “Evaluating Water-­Damaged Electrical Equipment” clarifies that “Equipment used in ­signaling, ­protection, and ­communication systems generally contain electronic ­components, and the exposure of such equipment to flooding by water can adversely affect the reliability of those systems. ­Contamination by ­pollutants or debris in flood waters may cause ­corrosion of components of the ­system, shorting of printed circuits, or ­alteration of circuit characteristics. 

“Since some of these types of installations are ­classified as life safety systems, it is ­important that the reliability of those ­systems be ­maintained. Where such systems are damaged by water, it is ­recommended that components of these systems be replaced or returned to the manufacturer for appropriate cleaning, ­recalibration, and testing. Manufacturers of these systems should be contacted for ­information on specific equipment.” 

Additionally, these guidelines warn that sediments and contaminants ­contained in water may find their way into the ­internal components of installed electrical ­products and may remain there even after the ­products have been dried or washed by the user. These may adversely affect the ­products’ performance without being readily apparent to the user community.

Reliable operation of the protective devices inside the electronics boards for the FACUs vital to system safety can be adversely affected by water. The operation of the safety mechanism can be impaired by corrosion, the presence of particles such as silt and lubricant removal. Similarly, the functionality of electronic protective relays in the fire alarm notification power supplies can be impaired.

In this incident, all the fire alarm ­control units and batteries, smoke detectors ­protecting the space where the FACUs were located, all living units and hallway smoke detectors and manual fire alarm pull ­stations located in the affected hallways were replaced.

As stated in the NEMA document, “Wire and cable that is listed for only dry ­locations may become a shock hazard, when ­energized, after being exposed to water.” 

Because the wiring was in metal raceway and impacted by the water, all new wiring was installed.

Two weeks after this incident, in a ­historic hotel renovation, a faulty ­sprinkler head under recall released, causing water damage to living units on three floors. There were no questions after this incident that all fire alarm devices and appliances were going to be replaced. The answer is clear when water intrudes into the fire alarm system or any of its ­component parts—don’t compromise on life safety. Replace everything that gets wet.