Mysterious Obstruction and Sprinkler Spacing Issue 2

[az5333]

Hi Fellows,

I am working on designing a sprinkler system and have encountered an issue regarding how to classify the obstruction as and which NFPA 13 rule would apply to it. The obstruction is as shown in the picture below:
Can anyone please guide me how to space sprinklers around this obstruction? The obstruction is a double-door entrance with 5'X5'X9'(high). The ceiling of the entrance room is provided, so I am providing an additional sprinkler inside the small room to cover that area. Need some guidance on sprinkler spacing around the obstruction? One of the branch lines is passing right above this room (1.5' from the wall).

 

[cdafd]

Put a sprinkler above the door area??

Like if there was a short freezer in a restaurant.

Looks like there is about five feet front front of door to wall

 

[az5333]

Hi cdafd,

Thanks for your response. I have a sprinkler inside the enclosed doorway (short freezer , however are you saying to put a sprinkler in the small space above? As per the dimensions I took, the space depth below the ceiling is ~8 inches. I heard that if the space is less than 18" deep (measured between the deflector and the top of the obstruction), and since it is a Extra Hazard Group 2 occupancy for me, I would treat it as a wall? Can you shed some light on this? Or would you still propose I need to cover the space with an extra sprinkler head? Yes the dimensions are 5 ft. by 5 ft.. Thanks.

 

[UFT12]

I would keep my sprinkler design as is regardless of this enclosure. In other words, if my design had a line running from above, I would run and install the sprinklers as if this enlcosure wasn't there given that an additional sprinkler is installed inside the enclosure and that the next sprinkler row from that enclosure in this room is maximum half the maximum allowable distance of sprinklers away for the given hazard.

 

[cdafd]

""""Thanks for your response. I have a sprinkler inside the enclosed doorway (short freezer bigsmile, however are you saying to put a sprinkler in the small space above? As per the dimensions I took, the space depth below the ceiling is ~8 inches. I heard that if the space is less than 18" deep (measured between the deflector and the top of the obstruction), and since it is a Extra Hazard Group 2 occupancy for me, I would treat it as a wall? Can you shed some light on this? Or would you still propose I need to cover the space with an extra sprinkler head? Yes the dimensions are 5 ft. by 5 ft.. Thanks. """""""


Do you have a code section for """ I heard that if the space is less than 18" deep ""


I could see going with the storage shelve against the wall rule.


It is one sprinkler add it.

 

[az5333]

Hi UFT12,

Thanks for your response and this is exactly what I have done!

Hi cdafd,

Okay I will consider that! Thank you.