Rated corridors UBC

[Sifu]

In high-rise buildings constructed under the 1994 UBC, corridors may be required to be rated even if they are sprinklered per UBC 1005.7. So my question is with the term "within office spaces". Does this mean within a tenant space, or does it include the entire group of separate office spaces on a given floor?
The IBC basically provides an exception for corridors if the building is sprinklered, but the UBC stops short of that by limiting the occupant load to 100, just not sure where the limitation applies.

1994 UBC
1005.7 Construction. Walls of corridors serving a Group R, Division 1 or Group I Occupancy
having an occupant load of 10 or more and walls of corridors serving other occupancies having an
occupant load of 30 or more shall be of not less than one-hour fire-resistive construction and the
ceilings shall not be less than that required for a one-hour fire-resistive floor or roof system.

EXCEPTIONS:
1. One-story buildings housing Group S, Division 2 and Group F, Division 2 Occupancies.
2. Corridors more than 30 feet (9144 mm) in width where occupancies served by suc1 corridors have at
least one exit independent from the corridor. (See Chapter 4 for covered malls.)
3. Exterior sides of exterior exit balconies.
4. In Group I, Division 3 Occupancies such as jails, prisons, reformatories and sim1lar buildings with
open-barred cells forming corridor walls, the corridors and cell doors need not be fire re~ istive.
5. Corridor walls and ceilings need not be of fire-resistive construction within office spaces having an
occupant load of 100 or less when the entire story in which the space is located is equipped with an automatic sprinkler system throughout and an automatic smoke-detection system installed within the corridor. The actuation of any detector shall activate alarms audible in all areas served by the corridor.
6. In other than Type I or II construction, exterior exit balcony roof assemblies may be of heavy-timber
construction without concealed spaces.
7. Within office spaces occupied by a single tenant, partial height partitions which form corridors and
which do not exceed 6 feet (1829 mm) in height need not be fire resistive, provided the) are constructed in
accordance with Section 601.5 and are not more than three fourths of the floor-to-ceiling height.
8. Corridor walls and ceilings need not be of fire-resistive construction within office spaces having an occupant load of 100 or less when the building in which the space is located is equipped with an automatic sprinkler system throughout.

 

[cda]

I would say yes

Being an old ubc/ufc person

I would say yes you can have a corridor in an office

Than goes back to occupant load as for code requirements

 

[mtlogcabin]

The IBC basically provides an exception for corridors if the building is sprinklered,

The IBC requires the heads to be quick response which became part of the NFPA 13 in 1996. Be careful when applying IBC codes to older sprinklered buildings when trying to reduce the prescriptive requirements in the legacy codes.

The UBC is referring to the individual office space not the corridor serving multiple tenants. So yes you can have an unrated corridor within an individual office space fully sprinklered building

The IBC has exceptions to fire ratings of corridors in all non H, I-1 and I-3 occupancies See Table 1018.1

[F] 903.3.2 Quick-response and residential sprinklers.
Where automatic sprinkler systems are required by this code, quick-response or residential automatic sprinklers shall be installed in the following areas in accordance with Section 903.3.1 and their listings:

1. Throughout all spaces within a smoke compartment containing care recipient sleeping units in Group I-2 in accordance with this code.

2. Throughout all spaces within a smoke compartment containing treatment rooms in ambulatory care facilities.

3. Dwelling units and sleeping units in Group I-1 and R occupancies.

4. Light-hazard occupancies as defined in NFPA 13.

In 1996, the NFPA 13 standard, which deals specifically with fire sprinkler systems, was updated to require quick response fire sprinklers in all light-hazard occupancies. As a result of this change, most newer office buildings, restaurants, hotels, and schools now employ quick response sprinklers instead of the traditional standard response sprinkler.

 

[Sifu]

Thanks MT, I am trying to be careful about applying new provisions to old buildings. In my ignorance I have been totally disregarding the rating requirement for these corridors because it never occurred to me to look back at the old requirements. Ironically, it was the architect who enlightened me. By your response I am gathering the 94 code means exactly what it says: the rating within office spaces (inside the individual spaces) might be dropped if the building (or floor) is sprinklered, but the corridors leading from the space to the exit is not exempt.

 

[mtlogcabin]

Correct

 

[Paul Sweet]

It would be worth asking the building official if the corridors could be unrated if you changed the sprinkler heads to quick-response. This might cost less than providing smoke dampers, gasketed doors, and other requirements the IBC has added for rated corridors.

 

[JPohling]

Paul there are several other changes to NFPA13 that are not so easily remedied other than the heads.
Seismic bracing, decreased support distances, flexible couplings and pipe clearances to address.