First layer sprinkler above suspended ceiling 1

[mechanicblues]

We are designing a sprinkler system for a shopping mall. The height of the shops are 6 m. and there is a suspended ceiling 4 m. above the floor. The height between the suspended ceiling and the ceiling is 2 m. There will be sprinklers installed for the fire protection of shops. Do we have to design a first layer sprinkler system above the suspended ceilings to protect the space between the suspended ceiling and the ceiling?
Thanks.

 

[SpkCont]

What type of construction is above the ceilings (combustible or non-combustible)? This includes wall construction if they extend above the ceiling.

 

[TravisMack]

If the space above the ceiling is non combustible, then you don't according to NFPA 13. If it is combustible, then you need to.

 

[mechanicblues]

SpkCont, It is combustible. So it is necessary.
Thanks

 

[SprinklerDesigner2]

At least it is light hazard.

8.14.1.3 Concealed Space Design Requirements. Sprinklers in concealed spaces having no access for storage or other use shall be installed in accordance with the requirements for light hazard occupancy.

 

[TravisMack]

It is light hazard for the density. If your structural members are <36" on center, you are limited to 130 sq ft per sprinkler. If you have obstructed construction with members greater than 3' on center, you are limited to 168 sq ft per sprinkler. Also, pay attention to requirements for steeply sloped structures >=4:12 as this greatly affects the requirements.

 

[stookeyfpe]

How the heck is a shopping mall a Light Hazard occupancy? I'm in an airport right now but I am pretty sure that the discharge density and design area should be Ordinary Hazard Group II.

Or are we saying the sprinkler protection above the ceiling is designed as Light Hazard?

 

[TravisMack]

Stookey:

Yeah. The system for the concealed spaces above the ceiling are Light Hazard. The system for space below the ceiling would be OH2 or greater if dictated by the insurance carrier.

I hope that makes more sense now

 

[stookeyfpe]

You get the stars.

I understand now. I just wanted to make sure that everyone else did because a Light Hazard Mall is not contemplated in the world I live in.