Plans 9 75(5 Wa 4 x /09'
1994 UNIFORM BUILDING CODE 508 -509.1
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See Chapters 3 and 4 for special occupancy provisions.
SECTION 507 — MEZZANINES
A mezzanine need not be counted as a story for determining the allowable number of stories when
constructed in accordance with the following:
1. The construction of a mezzanine shall be consistent with the requirements for the type of con-
struction in which the mezzanine is located, but the fire - resistive time period need not exceed one
hour for unenclosed mezzanines. The clear height above and below the mezzanine floor construc-
tion shall not be less than 7 feet (2134 mm).
2. There shall not be more than two levels of mezzanines in a room. However, there is no limita-
tion on the number of mezzanines within a room.
3. The aggregate area of mezzanines within a room shall not exceed one third of the area of the
room in which they are located.
4. All portions of a mezzanine shall be open and unobstructed to the room in which they are lo-
cated, except for columns and posts and protective walls or railings not more than 44 inches (1118
mm) in height.
EXCEPTIONS: 1. Partitioning may be installed if either of the following conditions exist:
1.1 The aggregate floor area of the enclosed space does not exceed 10 percent of the mezzanine area
1.2 The occupant load of the enclosed area of the mezzanine does not exceed 10.
2. A mezzanine having two or more exits need not be open into the room in which it is located, provided
at least one of the exits gives direct access to a protected exit corridor, an exit court, enclosed exit stairway,
exterior exit, exterior exit balcony or exit passageway.
3. In industry facilities, mezzanines used for control equipment may be glazed on all sides.
5. Two exits shall be provided from a mezzanine when two exits are required by Table 10 -A.
6. If any required exit enters the room below, the occupant load of the mezzanine shall be added
to the occupant load of the room in which it is located.
SECTION 508 — FIRE - RESISTIVE SUBSTITUTION
When an approved automatic sprinkler system is not required throughout a building by other sec-
tions of this code, it may be used in a building of Type II One -hour, Type III One -hour and Type V
One -hour construction to substitute for the one -hour fire - resistive construction. Such substitution
shall not waive or reduce the required fire- resistive construction for:
1. Occupancy separations (Section 302.3).
2. Exterior wall protection due to proximity of property lines (Section 503.2).
3. Area separations (Section 504.6).
4. Dwelling unit separations (Section 310.2.2)
5. Shaft enclosures (Section 711).
6. Corridors (Sections 1005.7 and 1005.8).
7. Stair enclosures (Section 1009).
8. Exit passageways (Section 1011.1).
9. Type of construction separation (Section 601.1).
10. Boiler, central heating plant or hot -water supply boiler room enclosures (Section 302.5).
• •
SECTION 509 — GUARDRAILS
509.1 Where Required. Unenclosed floor and roof openings, open and glazed sides of stairways,
landings and ramps, balconies or porches, which are more than 30 inches (762 mm) above grade or
floor below, and roofs used for other than service of the building shall be protected by a guardrail.
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1994 UNIFORM BUILDING CODE b06 -b09.1
See Chapters 3 and 4 for special occupancy provisions.
SECTION 507 — MEZZANINES
A mezzanine need not be counted as a story for determining the allowable number of stories when
constructed in accordance with the following:
1. The construction of a mezzanine shall be consistent with the requirements for the type of con-
struction in which the mezzanine is located, but the fire- resistive time period need not exceed one
hour for unenclosed mezzanines. The clear height above and below the mezzanine floor construc-
tion shall not be less than 7 feet (2134 mm).
2. There shall not be more than two levels of mezzanines in a room. However, there is no limita-
tion on the number of mezzanines within a room.
3. The aggregate area of mezzanines within a room shall not exceed one third of the area of the
room in which they are located.
4. All portions of a mezzanine shall be open and unobstructed to the room in which they are lo-
cated, except for columns and posts and protective walls or railings not more than 44 inches (1118
mm) in height.
EXCEPTIONS: 1. Partitioning may be installed if either of the following conditions exist:
1.1 The aggregate floor area of the enclosed space does not exceed 10 percent of the mezzanine area
1.2 The occupant load of the enclosed area of the mezzanine does not exceed 10.
2. A mezzanine having two or more exits need not be open into the room in which it is located, provided
at least one of the exits gives direct access to a protected exit corridor, an exit court, enclosed exit stairway,
exterior exit, exterior exit balcony or exit passageway.
3. In industry facilities, mezzanines used for control equipment may be glazed on all sides.
5. Two exits shall be provided from a mezzanine when two exits are required by Table 10 -A.
6. If any required exit enters the room below, the occupant load of the mezzanine shall be added
to the occupant load of the room in which it is located.
SECTION 508 — FIRE - RESISTIVE SUBSTITUTION
When an approved automatic sprinkler system is not required throughout a building by other sec-
tions of this code, it may be used in a building of Type II One -hour, Type III One -hour and Type V
One -hour construction to substitute for the one -hour fire- resistive construction. Such substitution
shall not waive or reduce the required fire- resistive construction for:
1. Occupancy separations (Section 302.3).
2. Exterior wall protection due to proximity of property lines (Section 503.2).
3. Area separations (Section 504.6).
4. Dwelling unit separations (Section 310.2.2)
5. Shaft enclosures (Section 711).
6. Corridors (Sections 1005.7 and 1005.8).
7. Stair enclosures (Section 1009).
8. Exit passageways (Section 1011.1).
9. Type of construction separation (Section 601.1).
10. Boiler, central heating plant or hot -water supply boiler room enclosures (Section 302.5).
SECTION 509 — GUARDRAILS
509.1 Where Required. Unenclosed floor and roof openings, open and glazed sides of stairways,
landings and ramps,.balconies or porches, which are more than 30 inches (762 mm) above grade or
floor below, and roofs used for other than service of the building shall be protected by a guardrail.
1-89