Minimum Sprinklers in NFPA 13R Calculation?

9/1/2020

I have a residential sprinkler calculation out of NFPA 13R 2016.

Do you need to calculate a minimum of 4 residential sprinklers within the dwelling unit?

I have a two-bedroom apartment unit and my most demanding area would be the two that are in the bedrooms and the two that are in the kitchen/living area.

Can I consider the kitchen/living area a compartment separate from the bedrooms and calculate only these two sprinklers?

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6 Comments

Mike

9/1/2020 10:10:48 am

7.1.1.3.1 For each of the following situations, the number of
sprinklers in the design area shall be all of the sprinklers
within a compartment, up to a maximum of four sprinklers,
that require the greatest hydraulic demand:

It is not a minimum of 4 and it is within a compartment.

3.3.2 Compartment. A space completely enclosed by walls
and a ceiling. Each wall in the compartment is permitted to
have openings to an adjoining space if the openings have a
minimum lintel depth of 8 in. (203 mm) from the ceiling and
the total width of the openings in a single wall does not exceed
8 ft (2.44 m) in width. A single opening of 36 in. (914 mm) or
less in width without a lintel is permitted when there are no
other openings to adjoining spaces.

It sounds like an opening greater than 36" unless it's a door.

Nick

9/1/2020 10:11:46 am

No need to calculate 4 sprinklers. It is up to 4 sprinklers in a single compartment.

Patrick Turner

9/1/2020 10:15:32 am

Per NFPA 13R for Number of Sprinklers Required in a Calc Area: "The number of design sprinklers under flat, smooth, horizontal ceilings shall include all sprinklers within a compartment, up to a maximum of four adjacent sprinklers, that requires the greatest hydraulic demand". So as long as your kitchen/living area meets the definition of a compartment: A space completely enclosed by walls and a ceiling. The compartment enclosure is permitted to have openings in walls to an adjoining space if the openings have a minimum lintel depth of 8 in. from the ceiling and the openings do not exceed 8 ft in width. A single opening of 36 in. or less in width without a lintel is permitted when there are no other openings to adjoining spaces", then you only need the two sprinklers in the kitchen/living area.

M.Newell

9/1/2020 10:16:05 am

NFPA 13D says a maximum of 2 in a compartment (10.2.1) NFPA13D - 2019
NFPA 13R says a maximum of up to 4 in a compartment (7.1.1.3.1) NFPA13D - 2019
NFPA 13 says 4 adjacent most demanding sprinklers (19.4.1.1) NFPA13 - 2019

To understand this better read the definition of compartment as listed in NFPA

Louie Lincoln

9/1/2020 10:47:18 am

To make a long story short. If they are separate rooms calculate the larger room.

Mike

9/1/2020 03:53:15 pm

Oops, I was wrong. Misread the opening part. My mistake

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