Thanks everyone,

It is actually considered an open grid ceiling (Thanks for directing me to 
Sec.8.15.3).

George Medina Jr. 




-----Original Message-----
From: George Church <[email protected]>
To: [email protected]
Sent: Wed, Apr 14, 2010 6:14 am
Subject: RE: Grating


Boxes are placed on grated floors, creating obstructions to spray that
ren't apparent at final inspection.
-----Original Message-----
rom: [email protected]
mailto:[email protected]] On Behalf Of
[email protected]
ent: Wednesday, April 14, 2010 8:29 AM
o: [email protected]
ubject: RE: Grating
Grating is grating.  It deflects and is an obstruction to the sprinkler
pray pattern.  Heads need to be below.
Open grid ceilings are a different animal as they typically occur moreso in
ight or possibly ordinary hazard occupancies. 
Ceilings are one thing and floor grating is another.  Don't confuse the two.
If you have 2007, look at 8.5.5.3.3 and A.8.5.5.3.
8.5.5.3.3* Sprinklers installed under open gratings shall be of the
ntermediate level/rack
torage type or otherwise shielded from the discharge of overhead
prinklers.
Commentary:
 FAQ:Where open grating is utilized, are additional sprinklers required
elow the open grating? 
Sprinklers installed under open gratings are addressed in 8.5.5.3.3.
lthough open grating 
llows heat from a fire to pass through it and reach a sprinkler, the
penings are not adequate 
o compensate for obstructions to the sprinkler spray pattern. Thus,
upplemental sprinklers 
nder the open grating deck are necessary. Gratings or slatted decks and
alkways are
requently covered with goods in storage or by a light surface dust stop.
prinklers are
equired under such gratings and walkways. Sprinklers located below the open
rating must
e provided with a water shield or be of the intermediate level/rack storage
ype to prevent
ater from sprinklers that are operating above from wetting the thermal
lement and delaying
prinkler operation.

raig L. Prahl, CET   
ire Protection Specialist
echanical Department
H2MHILL
ockwood Greene
500 International Drive
O Box 491, Spartanburg, SC  29304-0491
irect - 864.599.4102
ax - 864.599.8439
[email protected]
ttp://www.ch2m.com 

----Original Message-----
rom: [email protected]
mailto:[email protected]] On Behalf Of George Medina
r
ent: Tuesday, April 13, 2010 7:06 PM
o: [email protected]
ubject: Grating
What is the dimensions of grating when sprinklers are required underneath? I
ooked under NFPA-13 (2007 ed.) index for Grating and found no
pecifications.

George Medina Jr. 
=
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