Hi,
I have what I thought was an easy one, but the more I look at FM 2-0, the more confused that I get!
I have an 18-inch diameter LED light in a warehouse. It’s located 12-inches below the sprinkler head deflector. It’s a non EC, upright head.
Question..
How far (horizontally) from a storage sprinkler does the light need to be?
There are really only two sections – 2.2.3.5.1 (Umbrella Discharge Pattern) and 2.2.3.5.2 (Inner Core Discharge Pattern). Looking at the first one, it appears that the light would have to be 40-inches away from the head horizontally. Looking at the second one, Table 20 seems to indicate that it only needs to be 12-in. away. Footnote B: If the object is up to 24 in. (600 mm) wide in its maximum dimension, the object must be located a minimum 12 in. (300 mm) horizontally from the nearest sprinkler. Table 20 is "to avoid the sprinkler’s inner core distribution pattern being obstructed by individual objects located below the sprinklers"
It seems like Footnote B of Table 20 would apply as this is an individual object (per the definition) which would mean that the 18-inch diameter light could be located 12-inches or more horizontally from the deflector. However….. If I go back to Figure 31, it would appear that it has to be 40-inches. If the intent of the DS is that both have to be met, why even have have Table 20?
I feel like I must be misunderstanding something. Any help would be appreciated.
Also, I assume that based on Footnote A in T-20, the placement of upright heads from bar joists is not a concern – assuming <4-inch chords. That’s the way I interpret it, but since the DS also says that pipe hangers have to be a minimum of 12-in. from upright heads, I question my interpretation.
Thank you for your time.
I have what I thought was an easy one, but the more I look at FM 2-0, the more confused that I get!
I have an 18-inch diameter LED light in a warehouse. It’s located 12-inches below the sprinkler head deflector. It’s a non EC, upright head.
Question..
How far (horizontally) from a storage sprinkler does the light need to be?
There are really only two sections – 2.2.3.5.1 (Umbrella Discharge Pattern) and 2.2.3.5.2 (Inner Core Discharge Pattern). Looking at the first one, it appears that the light would have to be 40-inches away from the head horizontally. Looking at the second one, Table 20 seems to indicate that it only needs to be 12-in. away. Footnote B: If the object is up to 24 in. (600 mm) wide in its maximum dimension, the object must be located a minimum 12 in. (300 mm) horizontally from the nearest sprinkler. Table 20 is "to avoid the sprinkler’s inner core distribution pattern being obstructed by individual objects located below the sprinklers"
It seems like Footnote B of Table 20 would apply as this is an individual object (per the definition) which would mean that the 18-inch diameter light could be located 12-inches or more horizontally from the deflector. However….. If I go back to Figure 31, it would appear that it has to be 40-inches. If the intent of the DS is that both have to be met, why even have have Table 20?
I feel like I must be misunderstanding something. Any help would be appreciated.
Also, I assume that based on Footnote A in T-20, the placement of upright heads from bar joists is not a concern – assuming <4-inch chords. That’s the way I interpret it, but since the DS also says that pipe hangers have to be a minimum of 12-in. from upright heads, I question my interpretation.
Thank you for your time.