Yes, that is right and in practice you can run into a lot of application 
problems which is why this construction needs to be nipped in the bud as early 
as possible if it can be nipped.

The very first fact that needs to be determined is whether or not the building 
code requires a fire or smoke rated separation between that mechanical space 
and the other spaces. There can be a separation requirement, in which case the 
room requires a lid or full height walls having at least one side drywalled. 
The sprinkler issue goes away.

The application problems occur when you run into the other systems where the 
upper sprinkler layer is supposed to be. For example the space above might be 
paved in HVAC ducts.

This open condition occurs in many forms. A simple form is the janitor’s closet 
that was supposed to have a ceiling where the general contractor decides not to 
install. Sometimes we’ll see a sprinkler hanging in the breeze ready for the 
ceiling and sometimes we’ll see an upright placed by a thoughtful fitter.

A more complicated condition is the totally enclosed data center hot aisle 
returning into an above ceiling open plenum return space where the required hot 
return air opening equals all of the ceiling space in the hot aisle. An 
enclosed hot aisle is where walls and doors are at equipment rack aisle ends. 
The racks discharge hot air sideways into the aisle space. A divider closes off 
the space between the rack tops and the ceiling. In this scheme the idea is to 
remove the “used” cooling air so that it cannot mix with cooling air.

This might happen when a conventionally designed data center, i.e. raised floor 
with a ceiling, is upgraded with super high power density server racks that 
require so much heat rejection airflow that by the book the entire ceiling area 
must be egg crate if anything. The enclosed hot aisle condition basically 
creates the same room without a ceiling condition. Applying "the standard" 
spins into endless issues being in a space where most are religiously 
hydrophobic and also where systems might also be a bit exotic.   

Allan Seidel
St. Louis, MO

> On Apr 16, 2018, at 10:17 AM, Nick Maneen <> wrote:
> I’m not going to shoot holes in it.  I like it.  It makes sense.
> Nick Maneen, SET 
> c 704.791.7789
> From: Sprinklerforum [] 
> On Behalf Of Kyle.Montgomery
> Sent: Monday, April 16, 2018 10:49 AM
> To:
> Subject: RE: [EXTERNAL] Re: Mech room sans ceiling & full height walls
> Are we SURE that isn’t intended to be used in these situations?
> I know it says “on only one side”, but I think we might be interpreting that 
> incorrectly. It is saying that the unsprinklered space is adjacent to the 
> sprinklered space on only one side, not the other way around.
> So, while the sprinklered space (the mechanical room in this case) is open to 
> the unsprinklered space on 4 sides (assuming the room is a rectangle)… you 
> could say there are four unsprinklered spaces (north, south, east, and west) 
> that are each open to the sprinklered space on only one side.
> In reality, it’s more like one giant unsprinklered space with a hole in the 
> middle.
> I would say that this scenario doesn’t match up very well with the wording of 
> the code, or the figure, but that is more due to the literary difficulty of 
> explaining this scenario. However, I would think that if you carried 
> sprinkler protection the appropriate distance (half the remote area) out from 
> all sides around the room then that meets the INTENT of this section pretty 
> well. I mean, you would end up with a little more than a full remote area of 
> sprinkler heads above the ceiling, centered around the area we would expect 
> the fire to originate, so how is that not adequate protection.
> Now someone shoot some holes in my theory.
> -Kyle M
> From: Sprinklerforum [ 
> <>] On Behalf Of Ben 
> Young
> Sent: Saturday, April 14, 2018 9:16 AM
> To: 
> <>
> Subject: [EXTERNAL] Re: Mech room sans ceiling & full height walls
> I have to constantly remind the estimators that only works if it's 
> open on one side. 
> Every time this had come up after we are awarded the project we've managed to 
> convince the GC or owner to add a ceiling in these small rooms.
> On Fri, Apr 13, 2018 at 6:49 PM John Irwin < 
> <>> wrote:
>> I've seen this. Never had too much trouble getting a ceiling added when I 
>> give them the add alternate for installing sprinklers at the roof.
>> Checking wall heights is usually one of the first things I do when opening a 
>> fresh set of plans. Half a dozen different color highlighters and a cup of 
>> coffee...
>> John Irwin 
>> DynaFire Inc. 
>> Tampa Fire Sprinkler Division 
>> 727-282-9243 
>> This email was sent from a mobile device. Please forgive brevity, 
>> typographical errors, and grammatical gaffes.
>> On Apr 13, 2018, at 6:42 PM, Ed Kramer < 
>> <>> wrote:
>>> This is something we’re seeing occasionally and I’m wondering if others are 
>>> seeing it also.
>>> A typical office area within a noncombustible building.  All rooms within 
>>> the greater area have lowered finished ceilings, are mostly light hazard, 
>>> and the space above is noncombustible and (almost) concealed.  A small 
>>> mechanical room (or 2 or 3) is located among the various offices.  This 
>>> mech room is less than 130 sf, so the floor area can be protected with 1 
>>> sprinkler.  However, the A/E has decided this room doesn’t need a ceiling 
>>> and the perimeter walls can stop 6” above the ceiling height of the 
>>> adjacent rooms.  This makes the space above the surrounding offices 
>>> noncombustible but not truly concealed.  See below.
>>> NFPA 13 (2013) tells me I have to sprinkler the entire noncombustible space 
>>> above the offices. doesn’t apply since it’s open on all 4 sides. 
>>>  We’re working with GC to convince them to add a ceiling or to extend the 
>>> walls up to the roof deck.  It’s just way too easy to overlook this kind of 
>>> seemingly minor detail when bidding, and difficult to get a change order 
>>> (or walls/ceilings added) after the contract’s signed.
>>> So, just wondering if anybody else is seeing this issue.
>>> Ed Kramer
>>> Bamford Fire
>>> Sprinklerforum mailing list
>>> <>
>>> <>
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> --
> Benjamin Young
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