Lessons Learned From Sprinkler System Investigations

Sprinkler contractors and contractor associations might want to consider the potential educational opportunities that come from the results of fire and loss investigations conducted by fire protection engineers.  Based upon investigations into the operation of sprinkler systems and failures of sprinkler systems (did not control a fire, sprinkler operated without a fire, water loss from a failure of a component or components) many important lessons can be learned from both the good and the bad things that happen.

Bad things tend to outweigh the good things, but good things do happen almost daily with sprinkler saves.  I investigated a fire in 2010 that, initially, some on the scene of the fire thought it was a sprinkler system failure because at least 41 sprinklers operated in a three-story residential apartment building.  I think it was a sprinkler save because there were several hundred units and all of the residents were back in the building a few days after the fire, except those in the 42 units affected by smoke, fire, and water damage.

The fire started with a cigarette in a planter on the ground level patio, extended up the building exterior, into the eave, and then into the attic.  The fire entered through the balcony doors into the first-floor apartment, through the balcony doors into the second-floor apartment, and through the third-floor balcony doors and eaves into the third-floor apartment and combustible attic above that unit. The sprinkler system was designed based upon the National Fire Protection Association (NFPA) 13R Standard for the Installation of Sprinkler Systems in Residential Occupancies Up to and Including Four Stories in Height in the apartments and a dry NFPA 13 Standard for the Installation of Sprinkler Systems in the attic.

One sprinkler operated in the first-floor unit.  Three sprinklers operated in the second-floor unit.  Nine sprinklers operated on the third floor (eight in the unit and one in the corridor) and 28 sprinklers operated in the attic.  The fire damage to the building structure was limited to the complete destruction of the two unprotected balconies, and to the third-floor unit and a few of the roof trusses directly above the third-floor apartment only.  In other words, there was very little structural repair that was necessary after this fire and only smoke and water damage to the other 39 units.

What is the Good Lesson?

We only design for four residential sprinklers (on one floor) or maybe as many as 23 or so in the attic to operate; however, this fire had more than 40 sprinklers operate on FOUR levels, started and grew on the building exterior, and still the fire was contained by the sprinklers and the fire department.

Bad Design or Installation Decisions

On the opposite side of that story are the bad things that happen.  Many of the investigations I’m involved with include one or more bad design or installation decisions such as:

  • water-filled sprinkler piping in unheated or potentially unheated spaces or areas;
  • water-filled piping installed in blown-in insulation;
  • glycol in CPVC pipe;
  • connections to underground water mains that have not been properly flushed;
  • installation cost savings by trapping dry systems instead of using other options;
  • installation of low point drains on dry systems in unheated areas;
  • improper or no pitch on the pipe in dry systems;
  • schedule 10 pipe with roll grooves in dry systems (the roll groove traps condensation and can expedite corrosion);
  • low point drains in walls (not always the sprinkler contractors choice);
  • air compressors without tanks (air compressor runs more frequently, more potential condensation);
  • hanger rings that don’t restrain the piping (simply running the rod down to the pipe will hold the pipe, maintain the slope, and minimize the possibility that the pipe slope can change);
  • failure to secure the alarm bypass valve on alarm valves or dry valves;
  • lack of accurate as-built drawings;
  • failure to install a small scale sprinkler system drawing or “key” plan in the valve room showing the locations of all low point drains and control valves.

Lessons to Learn

There are important lessons to learn from the observation of the installation of dry pipe sprinkler systems.  Although NFPA 25, Standard for the Inspection, Testing, and Maintenance of Water-Based Fire Protection Systems puts the obligation on the building owner or manager to maintain their sprinkler systems, the choices made by the installing contractor impact the life expectancy and decrease or increase the odds of problems in the system.

Unquestionably, some of the items in the partial list above will add cost to the sprinkler system; however, those costs become relatively small when a dry sprinkler system freezes and breaks in cold weather and the owner and sprinkler contractor are forced to defend decisions they’ve made.

The educational opportunities, or lessons learned, from the fire and loss investigations should benefit building owners, sprinkler contractors, and insurance carriers.  Loss control and risk management involving the design and installation of automatic sprinkler systems could raise profits and lower insurance costs as well as potentially minimizing maintenance costs, reducing the odds of a failure or property damage loss, and relieve long-term headaches for the building owner.


ABOUT THE AUTHOR: Scott A. Futrell, PE, FSFPE, CFPS, SET, CFEI, is a fire protection consultant with Futrell Fire Consult & Design, Inc., in Osseo, Minnesota and has over 40 years’ experience designing, specifying, and investigating fire protection systems. He is a Fellow in the Society of Fire Protection Engineers and co-author of “Designers Guide to Automatic Sprinkler Systems”.