Under unobstructed construction, the distance between the sprinkler deflector and the ceiling shall be a minimum of 1 in. (25 mm) and a maximum of 12 in. (300 mm) throughout the area of coverage of the sprinkler. The requirements of 10.2.
To comply with NFPA 13, sprinklers are required above the obstruction at a distance not less than 1 in. and not more than 12 in. from the ceiling above, assuming unobstructed construction.
The answer is that you should follow the general obstruction rules of NFPA 13. For obstructions below 18 inches for standard pendent and upright spray sprinklers this means that as long as the obstruction is less than 4ft (1.2 m) wide that it is not considered an obstruction.
In a nutshell, NFPA 25: Standard for the Inspection, Testing, and Maintenance of Water-Based Fire Protection Systems says that objects that can block a sprinkler's spray must be at least 18 inches away from the deflector.
5.2. 1 of NFPA 13, which states that the distance from the sprinkler to the wall can be no more than one-half the allowable distance between sprinklers. The max distance between standard spray sprinklers in light hazard settings is 15 ft. (4.6 m) (with exceptions for light-hazard, combustible concealed spaces).
Sprinkler heads must be a maximum of 12-15 feet apart, depending on the hazard rating of the space (it ranges from Light Hazard to Extra Hazard 1&2), and at least half that distance from the nearest walls (typically 7.5 feet away).
3.1, 18.4(d) and 19.1.2.3, where the maximum ceiling/roof height is 40 feet.
Pendent sprinklers shall be located at least 36 in. (900 mm) away from obstructions such as ceiling fans and light fixtures unless the requirements of 8.2. 5.3 are met. The distance shall be measured from the center of the sprinkler to the center of the obstruction.
Nothing should be in that area between the bottom of the sprinkler heads and the imaginary horizontal plane parallel to the ceiling that is 18 inches below. This is done to allow an even and unobstructed spray pattern from the sprinklers when triggered to extinguish the fire.
NFPA-13 states that sprinkler protection is NOT required above hung ceilings if the area above has non-combustibles even with small openings in the ceiling.
3.2.3 “The Four-Foot and Wide Obstruction Rule”
For obstructions wider than 4 feet (1.2192 m), sprinkler protection is required below the obstruction with deflectors to be located less than 12 inches (0.3048 m) from the bottom of the obstruction.
The “three times rule” to limit the impact of obstructions on water distribution requires that standard sprinklers be located a distance away from the obstruction of at least three times the width of the obstruction. The standard notes a maximum clearance of 24 in. from an obstruction.
All storage, regardless of the type, shall be kept at least 24 inches below a ceiling in non-‐sprinklered areas and at least 18 inches below the ceiling in sprinklered areas of the building.
NFPA 101 – Life Safety Code: Headroom is generally required to be at least 7 feet 6 inches, however, projections are allowed as long as a minimum of 6 feet 8 inches of headroom is provided at these projections. The code states that the measurement is taken from the finished floor and allows a tolerance of -3/4-inch.
NFPA 13 also requires the use of false or dropped ceilings, if ceiling inclines exceed 2-in-12 slopes. However, NFPA 13 requires sprinkler deflectors to have parallel-to-the-ceiling mounting.
4, NFPA 13 clarifies that the maximum distance also varies with the hazards involved: Light-hazard areas allow a maximum distance of 14 feet (4.3 meters). Ordinary-hazard areas permit a distance of only 10 feet (3 meters).
It's against NFPA code: Hanging items from sprinklers or pipe heads is a violation of two National Fire Protection Association codes – and codes are in place for a reason.
OSHA does not impose penalties or require abatement of de minimis violations. Question 1: 29 CFR 1910.159(c)(10) in part states, "The minimum vertical clearance between sprinklers and material below shall be 18-inches (45.7 cm)." Does this apply only to materials placed directly below the sprinkler heads?
Hanging Teaching Aids, Child Prepared Art work, etc. from the Ceiling ( IFC 703.3) Do not attach anything to a light fixture, fire alarm sensors, fire strobe lamps, sprinkler heads, or overhead pipe runs. Proper T-grid hangers are required to keep the integrity of the plenum rated ceiling.
Each sprinkler has a radius of throw of 40 ft (12 m) at 40 psi (3 bar), a discharge of 4.4 gpm (1 m3/h) and the sprinklers are spaced at 40 ft (12 m) square spacing.
1.2 are met, sidewall sprinkler deflectors shall be located not more than 6 in. (150 mm) or less than 4 in. (100 mm) from ceilings.
They provide protection for the sprinklers - making them less prone to accidental knocks, tampering, and the potential water damage that can result. They simplify sprinkler design at clouds and other design features as the sprinklers are located above the dropped ceiling.
According to NFPA 13, Standard for the Installation of Sprinkler Systems, any type of obstructions should be kept at a minimum of 18in. from standard spray sprinklers and 36in.
Keep the spray at least 2 feet away from the house. Change your timing. Your system doesn't need to run every day. Haslem suggests setting it to run for 30 minutes, three times per week.