R-9 UCRC Index of Sections


SECTION 370B SPECIFIC USE PROVISIONS
Code Plain English

370B.1 Room and Space Dimensions

370B.1.1 General.

Room dimensions and floor areas of Group R Division 9 Occupancies shall be as for an R-1 Occupancy.

341B.1.1 General.

A reading of Section 310.7, the "efficiency dwelling unit" provision in the UBC, in the context of work/live suggests that the designated residential portion of a unit could be as little as 220 square feet–leaving out bathroom and closet, which can be considered work space– for a maximum of two residents. This conforms exactly to 1/3 of the minimum unit size, which is 660 square feet.

The designated work portion of an F-7 or F-8 unit is not considered habitable space and therefore have less rigorous ceiling height, room area, light and ventilation requirements than residentially oriented live/work (R-7 or R-8) or the designated residential portion comprising the remainder of that F-7 or F-8 unit. Nevertheless, said work portion must be a minimum of 2/3 of the unit's area.

Section 334B.2 simply refers back to the planning approval criteria for JLWQ.

370B.1.2 Sleeping Mezzanine Space Dimensions.

A sleeping mezzanine shall have space dimensions as provided herein.

341B.1.2 Sleeping Mezzanines.

"Sleeping Mezzanines" are an invention of the Oakland Live/Work Building Code. They can be accessed by ladders, they can have a lower ceiling–5’-8" if flat or 4’-0" minimum if they have a sloping ceiling with a minimum slope of 4" vertical to 12" horizontal–and a maximum area of 120 square feet. There are minimum dimensions, amount of open area, and railing requirements which are detailed in the body text . (Section 341B1.2)

370B.1.2.1 Headroom.

The minimum sleeping mezzanine headroom shall be a headroom "envelope" clearance to the ceiling or any projections from the ceiling that has a height of 4' with an increasing height of 4" vertical to 12" horizontal or steeper running towards the access to the loft. A horizontal ceiling shall be a minimum of 5'-8" above the sleeping mezzanine floor. See Figures A-3B-1A & 1B.

370B.1.2.2 Floor Area.

The area dimensions of a sleeping mezzanine may be 5' minimum deep by 7' minimum long or 7' minimum deep by 5' minimum long with a maximum area of 120 square feet. At least fifty percent (50%) of the sleeping loft area perimeter shall be open to the common atmosphere of the space in which it is located unless mechanical ventilation or openable window pursuant to Section 1203.2 is provided. The floor area of a sleeping mezzanine shall not exceed the allowable floor area for mezzanines pursuant to Section 364C.2. See Figures A-3B-1A & 1B.

370B.1.3 Built-in Sleeping Bunk Space Dimensions.

A built-in sleeping bunk shall have space dimensions as provided herein.

341B.1.2.2 Built-in Sleeping Bunks.

"Built-in sleeping bunks" are also an invention of the Oakland Live/Work Building Code. They can be accessed by ladders, they can have a lower ceiling– 3’-6" if flat or 3’-0" minimum if they have a sloping ceiling with a minimum slope of 4" vertical to 12" horizontal––and a maximum area of 60 square feet. There are minimum dimensions, amount of open area and railing requirements which are detailed in the body text. (Section 341B1.2.2)

370B.1.3.1 Headroom.

The minimum built-in sleeping bunk headroom clearance shall be a headroom "envelope" clearance to the ceiling or any projections from the ceiling with a height of 3' and with an increasing height of 4" vertical to 12" horizontal or steeper running towards the access to the built-in sleeping bunk. The minimum clearance for a flat ceiling shall be 42 inches above the built-in sleeping bunk floor. See Figures A-3B-2A & 2B.

370B.1.3.2 Floor Area.

A built-in sleeping bunk shall meet the area dimensions requirements for a sleeping mezzanine pursuant to Section 364C.1.2.2. However, the area of the built-in sleeping bunk may not exceed 60 square feet. See Figures A-3B-2A & 2B.

370B.2 Mezzanines in Individual JLWQ.

370B.2.1 General.

Mezzanines shall conform to other requirements of this code or as herein provided.

370B.2.2 Mezzanine Ceiling Height.

The ceiling height of a sloping ceiling above a mezzanine may be measured in accordance with 1998 CBC Section 310.6.1.

341B.2.2 Mezzanine Ceiling Height.

True mezzanines, defined as intermediate levels placed within a room, are often used in live/work space, and have specific requirements, such as area (normally 1/3 of the room into which they are open), and degree of open-ness. They also normally are required to have 7’ 0" clear height above and below them at all points. This provision allows sloping ceilings above mezzanines such as are normally allowed in rooms in residences. It is important because were this exception not made, some lofts and so-called mezzanines would actually be considered a story, and could cause the building to exceed the allowable or desirable number of stories. Private mezzanines (i.e. within units), sleeping mezzanines and built-in sleeping bunks can be ladder accessed. See Section 345B.
370B.2.3 Mezzanine Area.

370B.2.3.1 The area of a mezzanine within a R-9 Occupancy may be one third of the gross area of the individual JLWQ if the building is fire-sprinklered throughout.

341B.2.3 Mezzanine Area in Individual JLWQ.

Several other provisions have been adopted to relax mezzanine size requirements in existing JLWQ sprinklered buildings. The first permits a mezzanine to be 1/3 of the area of the entire "gross footprint" of the JLWQ as opposed to the room into which it opens.

370B.2.3.2 The area of a mezzanine within an individual R-9 Occupancy may be one half of the gross area of the individual residential space if the building is fire-sprinklered throughout and fire-sprinklers are not otherwise required, including the requirement for fire-sprinklers due to inadequate fire flow in the water supply serving the building. The total area of the mezzanines within and outside the individual residential space on any floor or story of the building shall not exceed one-third of the area of the floor or story.

 

341B.2.3.2

Under a number of rigorous conditions (see body text), mezzanines may be 50% of the gross footprint of the unit. To summarize, these conditions are:

  1. The building must be sprinklered,
  2. Extra layers of 5/8" sheet rock must be applied to demising and corridor walls of the unit,
  3. Any corridor serving the unit is constructed "as for an extent of stairway enclosure"
  4. Glazed openings into the corridor are limited, and
  5. The conversion qualifies as a JLWQ.
  6. The aggregate area of all of the mezzanines of a floor does not exceed 1/3 of that floor. Therefore, it is unlikely that all units on a given floor could avail themselves of this 50% provision.

370B.2.3.3

If the area and type of construction of an existing building and/or the use of area separation walls pursuant to Section 504.6 will not permit additional number of stories for the building, the area of the mezzanine of an individual R-9 Occupancy may be one half of the gross area of the individual residential unit without being classified as an additional story when the building is fire-sprinklered throughout and all of the following conditions exist:
1. the individual residential space has a layer of 5/8" Type 'X' gypsum board applied to the existing ceiling and wall on the unit's side of a common ceiling or wall with another unit and also with any corridor;
2. the building’s interior exit path (corridor, etc.) serving the individual residential space has been constructed as for an extent of stairway enclosure appropriate to the configuration of the building, including requirements for smokeproof enclosure as applicable, pursuant to Section 1005.3.3.3. When a stairway enclosure is not required, the interior exit path shall be constructed as for an exit passageway pursuant to Section 1005.3.4. Unless otherwise required, other individual residential spaces in the building not using the requirements of this section need not be provided with fire-resistive protection on their side of the corridor or exit passageway.
3. glazed openings are allowed between the unit and the building's interior exit path (corridor, etc.) if they are double glazed wire glass in steel frames of no more than 15 square feet per unit fronting on the exit path outside of the individual residential space (corridor, etc.).

See Figure A-3B-4.

370B.3 Yards and Courts.

Yards and courts with required windows for natural light and ventilation shall be provided pursuant to Section 1203.4.

341B.3 Yards and Courts.

This simply states that these should be adequate clearance outside of windows into yards and courts as per residential "interior environment" standards.

370B.4 Eaves.

Eaves over required windows for natural light and ventilation shall be pursuant to Section 1204.

341B.4 Eaves.

It is worth noting that the 1999 code has a use permission requiring that eaves (i.e roof overhangs) over windows required for light or ventilation are not permitted to be closerto a property line than 30".

370B.5 Smoke Detectors.

Smoke detectors shall be provided in individual spaces that shall conform as applicable for new construction and R occupancy to Sections 310.9.1.1, 310.9.1.3, and as appropriate either 310.9.1.4 or 310.9.1.5.

341B.5 Smoke Detectors.

All units shall have smoke detectors as per a residential apartment unit, which means at least one in proximity to the sleeping portion of the designated residential area.

370B.6 Heating.

370B.6.1 General.

The habitable area of an R-9 Occupancy shall conform to the requirements of Section 310.11

341B.6 Heating.

341B.6.1 General.

Section 310.11 refers to minimum requirements for "efficiency dwellings." The 220 square foot minimum residential portion discussed elsewhere complies with 310.11, in part because bathrooms are considered work space. The heating portion of 341B.6.1 is self-explanatory.

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