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Soffit Sprinkler Placement

Enter the width and height of the soffit to find required sprinkler placement. Supports NFPA 13-2019 Chapter 10 standard spray and Chapter 12 residential sprinklers — pendent, upright, and sidewall orientations.

Soffit Sprinkler Placement

Find required sprinkler placement for soffits and obstructions against the wall, per NFPA 13-2019 Chapter 10 (standard spray) and Chapter 12 (residential).

Sprinkler type

Uses the obstruction-against-wall formula: A = D − 8″ + B.

Soffit dimensions

Horizontal projection of the soffit from the wall. Soffits wider than 30″ should also be evaluated as a separate ceiling area.

Vertical distance from the sprinkler deflector down to the bottom of the obstruction, per NFPA 13-2019 Fig. 10.2.7.1.2(b). The soffit hangs below the deflector by B. Soffits deeper than 24″ should be checked against beam rules.

Section view

Obstruction against wall

CeilingWallDeflectorD = 24″B = 4″A = 20″A < D — sprinkler falls under the soffit; verify under-soffit placement rules

Engineering disclaimer

Results are for preliminary engineering only. Final designs must be reviewed by a licensed fire protection engineer and verified against NFPA 13/14 and the local AHJ.

Minimum distance from wall to sprinkler

1' 8"

Place the sprinkler at least 1' 8" from the wall.

NFPA 13-2019 Figure 10.2.7.1.2(b)

Calculation

Formula
A = D − 8″ + B
Soffit width (D)
24″
Soffit below deflector (B)
4″
Computation
24″ + 4″ − 8″ = 20″
Required A
20″

Inputs

Sprinkler standard
Standard spray (NFPA 13 Ch. 10)
Orientation
Pendent / upright
Soffit width (D)
2'
Soffit below deflector (B)
4"
Method
Formula
Reference
NFPA 13-2019 Figure 10.2.7.1.2(b)