How to Determine Obstructions with Beam Rule?

One of the most common and basic issues many of us encounter in fire sprinkler design or during on-site review is whether a sprinkler is considered to be obstructed. While the premise of the obstruction tables within NFPA 13 is fairly straightforward, there are a handful of variations in the tables that are dependent upon the edition of 13 being used, the sprinkler type, and in some cases the orientation of the sprinkler.

We built a cheatsheet to show all the options for providing code-compliant sprinkler spacing near obstructions. We call is our Obstruction Cheatsheet. Click the button here to download a copy:​

GET THE SPRINKLER OBSTRUCTION CHEATSHEET (PDF)

We also took this a step further, and developed what we call our Ceiling Obstruction Calculator. This reference tool below was built to quickly determine whether a ceiling-mounted element is considered an obstruction. It can be especially helpful during sprinkler layout or during site review where lugging the entire code volume might not be practical.

Common examples of where obstructions are considered are with sprinklers adjacent to surface-mounted lights, soffits (not against a wall), mechanical equipment in walk-in coolers and freezers, signage, banners, lowered ceilings, thresholds above large openings, raised ceiling pockets, or exit lighting.

To use this tool, you can use your downloadable version of the Toolkit, or you can see it online here: Ceiling Obstruction Calculator. If you don't know your activation code, or have trouble installing the downloadable version, go here: www.meyerfire.com/support.

TRY THE CEILING OBSTRUCTION CALCULATOR

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TL501 SERIES:

1. What is the Sprinkler Database?
2. How to Use the Obstruction Calculator for Beams?
3. How to Use the Obstruction Calculator for Soffits?
4. How to Use the NFPA 13 Translator?
5. What is Driving Design; the K-Factor or Density?
6. How to Estimate Clean Agent Quantities?
7. How to Calculate a Domestic Demand?
8. How to Select an Optimal K-Factor?
9. How to Quickly Calculate Friction Loss?
10. How to Analyze Fire Pump and Water Supplies from a "Big Picture" perspective?
11. How to Determine Fire Flow with the IFC Method?
12. How to Quickly Estimate Hydraulics for a Sprinkler System?
13. How to Estimate a Water Storage Tank Size?
14. How to Calculate Hanger Spacing by Weight?
15. How to Calculate the Size of a Trapeze Member?
16. How to Summarize Notes for Fire Alarm and Suppression?
17. How to Calculate Thrust Block Size?
18. How to Quickly Classify Combustible & Flammable Liquids?
19. Calculate the Volume & Air Compressor Size for a Dry System?