Tips on Sprinklers for Water Curtains

Q: Got any tips for a novice on how to navigate through the Life Safety Code? I’m interested in specifics on sprinkler placement for water curtains.

A: NFPA 13 (1999 edition) is the standard for the installation of water-based sprinklers referenced by the 2000 edition of the Life Safety Code. There are many rules on how to install sprinklers, such as:

  • The maximum distance a sprinkler can be installed below a ceiling is 12 inches (with some exceptions)
  • The minimum distance a sprinkler can be installed below a ceiling is 1 inch
  • The maximum spacing between two sprinklers is determined by the rating on the sprinkler head (usually 15 feet, but there are other spacing distances depending on the manufacturer)
  • The minimum spacing between two sprinkler is 6 feet
  • The maximum distance a sprinkler can be installed from a wall is ½ the maximum spacing between two sprinklers
  • The minimum distance a sprinkler can be installed from a wall is 4 inches
  • The coverage area (measured in square feet) of a single sprinkler is determined by the design density and the manufacturer’s rating of the sprinkler
  • The horizontal distance between a sprinkler head and a ceiling mounted obstruction is a sliding ratio based on the vertical distance the obstructions is mounted below the sprinkler deflector
  • The minimum vertical distance a shelf or items stored on a shelf can be to a sprinkler deflector is 18 inches
  • Sidewall sprinklers cannot be installed more than 6 inches or less than 4 inches below a ceiling (with some exceptions)
  • Maximum area of protection, maximum wall length and maximum spacing between horizontal sprinklers is different than pendant or upright sprinklers, and is dependent on the design density
  • Baffles are permitted between sprinklers when the sprinklers are mounted less than the minimum allowable distance allowed
  • The values mentioned above change for extended coverage sprinklers

I tell you all of the above to show you that there are many individual factors about installing sprinklers that have to be considered in order to design a fire protection system. The bottom line… This is a job for a professional engineer. That is why most AHJs require a PE stamp on all sprinkler designs submitted to them for approval.    

The best way to learn about the Life Safety Code is to experience it on a daily basis. What I mean by that is to have a position in an organization that actively works for compliance with the LSC, such as a Safety Officer or a Facility Manager position… someone who oversees the compliance with the LSC in their facility. Pick up the LSC book and read it, starting with one of the occupancy chapters (12 – 42; chapter 19 is reserved for existing hospitals). Understand that the first 11 chapters are considered basic chapters (or ‘core’ chapters) that apply to all occupancy chapters. Also understand that when there is a conflict between the core chapters and an occupancy chapter, the occupancy chapter rules. Look for some basic Life Safety Code Boot Camp seminars, taught by ASHE, NFPA and Joint Commission Resources.

I hope this information is helpful. Welcome to the world of Life Safety Code compliance. It is a learning experience that will last a lifetime.