• Welcome to The Building Code Forum

    Your premier resource for building code knowledge.

    This forum remains free to the public thanks to the generous support of our Sawhorse Members and Corporate Sponsors. Their contributions help keep this community thriving and accessible.

    Want enhanced access to expert discussions and exclusive features? Learn more about the benefits here.

    Ready to upgrade? Log in and upgrade now.

When is a Penthouse a Story?

F

FyrBldgGuy

Silver Member
Joined
Oct 19, 2009
Messages
356
A building is 74 to the finished floor of the highest story, (from the lowest point of fire department access).

The penthouse floor is at 85 feet, area is less than 30% of a story.

Two thirds of the penthouse has mechanical equipment.

One third of the penthouse is a storage room for consumable materials used in the penthouse.

Is the penthouse a story?
 
It would clearly be a penthouse if it were not for the storage. 1509.2 does not permit penthouses to be used for storage. I have seen local interpretations that permit 1 month, 3 months, 6 months or 1 year's worth of filters within a penthouse. One third of the area might be bit excessive for incidental storage. 100 square feet might be a more appropriate number and somewhat justified and referenced under incedintal uses.

No storage should be within the machine rooms if the rooms are used as return air or fresh air intake plenums.
 
Last edited by a moderator:
From a structural perspective the area and to a lesser extent height limitations are key to the definition of a penthouse. When designing for earthquakes great difficulties could result if a small penthouse with storage was considered another story. This is because the penthouse is often constructed using a different structural system.
 
Reading between the lines, the question is being asked because someone thinks that if the penthouse is a story, the building becomes a high rise subject to IBC 403.

Note however that IBC 403 kicks in for buildings "with an occupied floorlocated more than 75 feet (22 860 mm) above the lowest level of fire department vehicle access." the operative phrase is occupied floor, not story.

Thus it is possible to have an unoccupied floor over 75' without triggering High Rise. The trick is proving the floor is not occupied. I would go along with anyone being skeptical that a floor with "storage" is not unoccupied. "Storage" now, "Facilities Office" after C.O. If you can be convinced this space is truly only accessed for maintenance, you could buy off on it being unoccupied, and therefore the building is not High Rise.
 
The storage area will more than likely have a desk, a chair etc. for the Building Mechanical worker to notate things done during maintenance.

And yes the question is when the Penthouse becomes a story, because it is no longer just a mechanical room does it now create a high rise.

The storage creates a fire hazard at greater than 75 feet from the lowest point of fire department access. If I ask a fire fighter if dragging hose up to the storage room is a high rise I think I know the answer.
 
My 2 cents is that I would measure twice. It's a occupied story due to it being used for storage and maintenance needs. Someone has to occupy the area to add storage and maintain the mechanical equipment. This is the biggest piece of crap with the code section. Does the 5-7 story structure need sprinklers, maybe not but when owners and designers do this, at minimum, protect the mechanical/storage area from the remainder. Call it what it is and and via your/AHJ interpretation and let them argue amongst the suits, you'll have served notice.

Must be one of those days!
 
FMWB is correct. There is a difference between not occupied and not normally occupied. A mechanical or storage room is, by definition, not normally occupied, but it is occupied.
 
IF there is storage its still unoccupied. There's a definition to support this.


OCCUPIABLE SPACE. A room or enclosed space designed for human occupancy in which individuals congregate for

amusement, educational or similar purposes or in which occupants are engaged at labor, and which is equipped with means

of egress and light and ventilation facilities meeting the requirements of this code.

​


IF there is a desk, it's a occupiable since individuals will be engaged in labor = story.

Have them bring a clipboard.
 
"engaged in labor" = stocking storage room, working on mechanical equipment, .... good place for holiday decorations...

Penthouse - good place to hide; or a magazine read in a hiding place.
 
Working on mechanical equipment is never a reason for defining "engaged in labor." Otherwise every attic or interstitial space above the lay-in ceiling would be an occupiable space if there's an air handler there.

What KIND of magazine???? lol!
 
Gene, I can agree with the definition but if there is a solid floor in the space and someone is storing materials (regardless) and maintenance of equipment is being done on that "solid" flooring it's an occupied (granted at times) penthouse in my humble interpretation. My question may be what is the ceiling height :)
 
Gene Boecker said:
Working on mechanical equipment is never a reason for defining "engaged in labor." Otherwise every attic or interstitial space above the lay-in ceiling would be an occupiable space if there's an air handler there.What KIND of magazine???? lol!
Click to expand...
Hey Gene,

You've Posted the clearest analysis I've read here. My thought is that if there's no office/desk on that level it's not occupied. If a plan is submitted that shows no occupancy and someone later, without a permit, adds an office they own any resultant issues. Every time I hear "but what if they do such and such later" I think someone's out in front of their skis a bit too much!

Bill
 
Last edited by a moderator:
You must log in or register to reply here.
Back
Top