If you can find a specification telling how close a combustible wall NEXT to the range can be, then that would be where you could put the 15 inch deep cabinet, lateral-wise. Think of the cabinet as a combustible wall NEXT to the range that just doesn't go all the way to the counter top.

Hey, Historian, your question got me to thinking...I found this great article on a site called "Code Corner." LOL I love it! They say many, many homes have their cooktop or hood way too close to combustible materials. And in case you were wondering what's considered a combustible material, they provide this helpful definition: "The code defines combustible materials as “any material not defined as non-combustible." Oooookaaaaay. They also say, "In no case can the distance between a solid fuel- (i.e. wood or coal)
burning appliance and a combustible wall surface be reduced to less than
12 inches" Here's the link to the article: http://www.ashireporter.org/HomeInspection/Articles/Code-Corner-Clearance-to-Combustible-Materials/1394

This is an article written for inspectors, and it's actually quite interesting; either that or I am a bigger nerd than I think, and I think I'm a pretty big one, lol. The article also mentions that most backsplashes (which they call decorative stone or tile) are combustible and really have no business being in the kitchen. Huh.

The article goes on to say that you can put a "heat shield" between your heat surface and your combustible materials. And then you can reduce the required clearance to the aforementioned 12", but never, ever more. I don't know if this illustration is helpful:

When a space is required between the combustible material and the
protective material, the same space is required at all edges of the
protective material. Adequate air circulation behind the protective
assembly is critical to proper performance, since this air circulation
is being relied upon to dissipate heat that might otherwise cause a
fire.

You can buy thermal heat shields, also called thermal or heat fillers, online.

I'm wondering now how butcher block counters go right up to the range? I'm guessing (???) there must be some kind of thermal heat shield, but it still goes way closer than 12"; counters go right up to the range. Hmmm...need to do more research,

Hope this helps! I'll update with any new info. :-)

Heatshield Fillers

Heatshield Fillers are recommended for kitchen cabinet
installations where heat sources are a concern. They are pretested to
250º F+ without delamination. Heatshield Fillers are made of postformed
180º profiled components.

Produced from the same thermoplastic as the cabinet doors,
these fillers are a perfect color match. They are available in most
colors.

Available in 4-ft (5315) and 8-ft. (5316) lengths.

Specification: Each length is supplied with a 1"
edgebanding strip. After cutting the Heatshield Filler to size, use the
edgebanding strip to finish the ends.

Installation Information

Base Ovens and Cook Tops: The Heatshield Filler is mounted flush
with the adjoining door parts. The same recommendation applies to cook
tops with front exhaust vents. Fillers provide a barrier to shield
excessive radiant and convective heat. This protects the doors from oven
heat when the oven door is slightly opened and during the self-cleaning
process.

Wall Mounted Ovens: Heatshield Fillers are
recommended in wall mount applications. A horizontal filler should be
placed above the oven units with a 5/8" to 3/4" horizontal lip mounted
just below the doors as shown below.

Wall Mounted Microwave Ovens and Undermount Coffee Makers:
The Heatshield Filler should be mounted flush or protruding slighlty
beyond the face surface of the doors. This prevents possible surface
damage and swelling of the core material from excessive heat or steam.

RESTRICTIONS:
Counter Top Appliances: Care must be taken when using toasters,
toaster ovens, portable grills and other heat/steam generating
appliances to insure that upper wall doors are not subjected to
excessive temperatures.

That article is discussing wood and SOLID fuel fireplaces in a home. It doesn't apply to cooktops or GAS (non-solid fuel) appliances.

How right you are, speaktodeek! However, the basic principle still applies to ranges in the kitchen. Above, I posted some info directly from a kitchen cabinet maker on the use of heat shields in a regular kitchen with cooktops.

But thank you very much for pointing that out to me! When I get my wood burning stove, I'm going to re-read that article to make sure I do it correctly,

Can you just do upper cabs 3" narrower on each side to allow for a 36" hood over 30" range? You'll get better ventilation, the space will feel more roomy, and you can ignore the other stuff about cabs too close.

In my case, the two sensible options I see would be:

(1) Keep the current plan - 30" concealed vent flanked by two 30" upper cabinets [with those three cabinets cut down to the specified 13"]

(2) Go to a 36" wide exposed or concealed vent flanked by two 24" cabinets. To get this to line up with the 30/range/30 arrangement of lowers beneath, I guess we'd use a little filler

But of course, option 2 is only open to me if moving the cabinets 3" laterally away from the range makes for an "approved" installation. GE wouldn't tell me this idea was acceptable, they skirted the question by sending language about cabinet heat tolerance requirements. The only thing they would confirm is exactly what is on their diagram, I can have 13" deep uppers (or less) running right up to the range.

It makes sense to me that this would work, and there are 100 pictures showing that everyone does it. But I'm curious how to confirm it.

"If you can find a specification telling how close a combustible wall
NEXT to the range can be, then that would be where you could put the 15
inch deep cabinet, lateral-wise. Think of the cabinet as a combustible
wall NEXT to the range that just doesn't go all the way to the counter
top."

In the specifications, the distance for the nearest side wall (right or left) is a minimum of 6". So, if the same rule applies to upper cabinets, I would need to clear 6" up on either side the range.

But according to this rule, this would be true of any cabinet of any depth sitting too close to the range, wouldn't it? Why can 12" or 13" deep uppers sit directly next to the appliance, but not 14" or 15"?

Since the principle at work in GE's specs is not clear to me, I know I can copy exactly what is on the spec sheet since its there in black and white - but I don't know how to extrapolate from it to see what my closest good alternative is.

Edit to add: For the curious, here is a link to the spec sheet.

If you have a 36" hood over a 30" range I think you will be fine with 15" deep uppers flanking the hood. In fact, the recommendation is that your hood be at least 6" wider than your cooking appliance (and 24" deep) anyway.

You might even consider 3" of open space b/w the hood and upper cabinets for "breathing" space (or "paint" space, as my KD called it). I have found that it makes it much easier to clean the hood surface w/that 3" b/c my hand and/or cloth will fit in the gap.

If you want to, you could also check your local municipality to see what their Code is - most likely they will tell you to follow your manufacturer's specs, but it couldn't hurt to try. (I assume you are pulling permits and having the work inspected...)

Just so you know, 13" is the total depth of a 12" deep upper cabinet: 12" deep box + 1" door = 13".

It's my guess, that the 13" spec aligns with where the grid for the front high-powered burners start. It does on mine. I don't know which range you have, but I have the GE Cafe dual fuel and the front two burners have high BTU's. 14 or 15" cabs would be directly over that high heat and be a safety and liability issue for GE. It would also be extremely close to a tall pot. I just snapped this photo to show how close the 13" install is. And see how the cabinet lines up with the center dividing grid?

"It's my guess, that the 13" spec aligns with where the grid for the front high-powered burners start."

Oh, that might be it! This is the GE profile gas range, which probably has the same measurements. (It is in my living room so I can measure later on and see.)

Meganmca, I haven't wanted to say so, lest I sound remiss, but I have been quietly wondering if this might be also the case. Perhaps, once upon a time, someone did a nice safety test with 12" uppers. Now everyone is using those guidelines. No one has done a follow up test for anything else, and as a result no one is willing to go on record as saying it is safe.

Sadly, I don't know for sure there isn't a reason so I guess I have to assume there is one. Even if I am happy to ignore the guidance, I suppose the inspector and anyone else doing appliance or cabinet installation should theoretically be noticing my inattention.

Mine says, "13" MAX. depth of unprotected
overhead cabinets (when no
hood or microwave is installed)"

I have 15" deep cabinets flanking my cooktop, but I also have a 42" hood over a 36" cooktop. But, I have electric radiant, not gas - so there may very well be different specs.

I still think you'll be fine - but if you're really worried, check with your municipality or your GC - either of them should be able to tell you.

I am actually not really worried - I suspect we'd be fine. However, I am a little afraid of missing some important small detail and screwing up the project.

Perhaps it makes the most sense to get further advice from the cabinet installers and GC (who is managing demo, drywall, insulation, and floor installation for us) and see if their experience can be a guide. Then tweak as necessary.

Note that the 13" includes the door. Standard uppers are 12" deep, and a typical overlay door will add a hair more than 3/4" to that. 13" is the nearest whole number, and allows a margin of error for shimming, etc.

I've been reading more gas range installation specs than I care.

Right now, GE has specs with no more than 15" deep uppers. https://s2.img-b.com/build.com/mediabase/specifications/ge/1486543/ge-jgbs30e-installation-instructions.pdf

Whirlpool, for instance, still has 13", even though Ikea appliances are made by Whirlpool. Go figure.