View Full Version : Aggregate Horizontal Projections

Adam Calhoun
09-28-2013, 11:58 PM
What is the meaning of Aggregate Horizontal Projection?Fire safety code mentioned this in the sprinkler section.

09-29-2013, 02:17 PM
Pretty sure it means your sprinklers will cover everything on a horizontal pattern. Heads are not blocked by props and temp walls that wouldn't allow complete spray coverage.

Adam Calhoun
09-29-2013, 08:47 PM
The question was in reference to NFPA 101" Specialty Amusement Automatic Sprinkler's. Every special amusement building,
other than buildings or structures not exceeding 10 ft (3050 mm) in height and not exceeding 160 ft2 (15 m2) in aggregate
horizontal projection, shall be protected throughout by an approved, supervised automatic sprinkler system"

My question at hand is actually, Do I need sprinklers or not. As in an instant if I didnt exceed 160ft in aggregate horizontal projection.

Hope that maybe helps get more direct to what I mean. Thanks for your post, and hope you guys are able to help.


09-29-2013, 08:55 PM
Your building, tent or trailer is shorter then 10FT high ?

Adam Calhoun
09-29-2013, 11:57 PM
For the most part no, but in some areas it is at 10ft exactly, and Itd be nice to be able to figure out the meaning of this so that I might be able to save some money.

09-30-2013, 07:50 AM
The term "aggregate horizontal projection" is refering to the total area of a multilevel play structure (like the things attached to some fast food restaraunts) and is not really applicable to a Haunted Attraction. The general paragraph above the one you referenced gives more context, it states: "Special amusement buildings, regardless of occupant load, shall meet the requirements for assembly occupancies in addition to the requirements of 13.4.7, unless the special amusement building is a multilevel play structure that is not more than 10 ft (3050 mm) in height and has aggregate horizontal projections not exceeding 160 ft2 (15 m2). "

09-30-2013, 09:28 AM
A horizontal projection is anything that extends beyond the exterior walls of a structure, such as a balcony. The code is stating that you must include all such projects in the total width of the building. For instance if you have a room that juts out from the basic form of a haunted house, that must be included in the total width. Say you have a 40ftx40ft footprint but on the second floor you have a room that juts out 5ft beyond the 40ft wide wall, that extra 5ft would be included in the total width of the building.

Your footprint would be 40x40 but the aggregate horizontal projection would be 45ftx40ft.

Howie Slobber Erlich
09-30-2013, 09:48 PM

The best thing to do is talk to your Fire marshal. They can tell you what will be required. In general, if your location is larger than 1000 sq ft, most places will require a sprinkler system. Or at least that is what they are supposed to do. However, I know of many haunts where the city does not enforce this rule and lets you get away without one. Call and check!

Howie "Slobber" Erlich

Adam Calhoun
10-01-2013, 01:37 PM
Thanks everyone for all your help.