Return air grill location

[ICE]

311.3 (6) exception (3)(c)
Return-air inlets shall not be located within 10 feet (3048 mm) from an appliance firebox or draft diverter in the same enclosed room or confined space.

Here is a furnace in a closet with a return air grill located directly under the door to the closet. We have always treated this as a violation (less than 10' away from a firebox) unless the door to the closet has a gasket that seals it from the hallway.

Here you can see the gasket material.

I have always been skeptical of this code. In reading it I see that it says, "firebox or draft diverter in the same enclosed room or confined space" and that is not the case once the door is shut.

I am looking for opinions.

 

[mtlogcabin]

Was that an old UMC code section? Todays IMC and IRC are different.
IMC
601.5 Return air openings.
Return air openings for heating, ventilation and air-conditioning systems shall comply with all of the following:

1. Openings shall not be located less than 10 feet (3048 mm) measured in any direction from an open combustion chamber or draft hood of another appliance located in the same room or space.

 

[klarenbeek]

I've always been OK with this setup without gasket as long as it is a solid door (not louvered) that can close and latch shut, provided it doesn't open into a bathroom or bedroom. No bi-fold doors. At that point it's in a separate room.

Is there combustion air in the closet? Does the top picture have enough room in front of the furnace when the door is closed? At least from this angle it looks like there's not much, and most standard efficiency furnaces have a minimum clearance on the front to allow combustion air through the openings in the furnace panel.

 

[Gregg Harris]

311.3 (6) exception (3)(c)
Return-air inlets shall not be located within 10 feet (3048 mm) from an appliance firebox or draft diverter in the same enclosed room or confined space.

Here is a furnace in a closet with a return air grill located directly under the door to the closet. We have always treated this as a violation (less than 10' away from a firebox) unless the door to the closet has a gasket that seals it from the hallway.

Here you can see the gasket material.

I have always been skeptical of this code. In reading it I see that it says, "firebox or draft diverter in the same enclosed room or confined space" and that is not the case once the door is shut.

I am looking for opinions.

It does not appear that there is enough combustion air in the closet. If the door has a seal around it you would be good to go.