Table 5—Fire Resistance Ratings of Structural Elements in Hours

Notes on page 44
STRUCTURAL ELEMENT

TYPE OF CONSTRUCTION

TYPE 1

TYPE 2

TYPE 3

TYPE 4

FIREPROOF

NONCOMBUSTIBLE Note b

EXTERIOR MASONRY WALLS

FRAME

PROTECTED

Unprotected

Heavy
Timbers
(Mill)

ORDINARY

Protected

Unprotected

Protected

Unprotected

1A

IB

2A

2B

2C

3A

3B

3C

4A

4B

EXTERIOR WALLS Note a

4

3

2

3/4

0

2

2

2

3/4

0

On Street Lot Lines or with
Fire Separation of 30' or More
from Interior Lot Lines or Any
Building

Bearing

Non-Bearing

0

0

0

0

0

0

0

0

3/4

0

On Interior Lot Lines or Less
Than 6' Therefrom or From
Any Building

Bearing

4

3

2

1-1/2

3/4
Note c

2

2

2

3/4

3/4

Non-Bearing

2

2

1-1/2

3/4

3/4
Note c

2

2

2

3/4

3/4

6' or More But Less Than 11'

Bearing

4

3

2

3/4

0

2

2

2

3/4

0

Non-Bearing

2

2

1-1/2

3/4

0

2

2

2

3/4

0

11' or More But Less Than 30'

Bearing

4

3

2

3/4

0

2

2

2

3/4

0

Non-Bearing

1-1/2

1-1/2

3/4

3/4

0

See Sec. 217

1-1/2

1-1/2

3/4

0

2

Interior Bearing Walls and Partitions

4

3

-----------N

2
noncombustible

3/4
-----------

0

2

3/4

0

3/4

0

3

Fire Walls

4

3

2 2
— In No Case Less Than

2
an Fire Grading

2
ing of Use C

2 2

Group--(See Table 16) —

2 2

Noted

4

Fire Divisions

-------------------Fire Resistance Rating Corresponding to Fire Grading of Use Group--(See Table 16)---------------------

5

Fire Enclosure of Exitways, Elevator Hoistways, Exitway
Hallways and Stairways Note e

2

2

2

2 | 2 | 2 2 2

----Noncombustible-------------------------------------------------

3/4

3/4

6

Shafts Other Than Stairways

2 2 | 2

2 | 2
----Noncombustible----

2

2

2

3/4

3/4

7

Exitway Access Hallways & Vertical Separation of Tenant
Spaces

3/4

3/4 | 3/4 3/4
-----------Noncombustible-------Note

1

h-----——

3/4

3/4

1

3/4

0

8

Columns, Girders, Trusses,
(Other Than Roof Trusses) and
Framing

Supporting One Floor

3

2

1-1/2

3/4

0

See Sec. 217

3/4

0

3/4

0

Supporting More Than
One Floor

4

3

2

3/4

0

See Sec. 217

3/4

0

3/4

0

9

Structural Members Supporting Wall

Require

Fire Resistance of Wall Supported But Not Less
Fire Resistance Rating for Type of Construction

Than

10

Floor Construction Including Beams Note g

3

2

1-1/2

3/4

0

See Sec. 217

3/4

0

3/4

0

11

Roof Construction Including Beams— Note g
15' or Less in Height

2

1-1/2

3/4

3/4
— Note h-

0

See Sec. 217

3/4

0

3/4

0

12

Roof Trusses and Framing In-
cluding Arches and Roof Deck

Note f

More than 15' But Less
Than 20' in Height to
Lowest Member

3/4

3/4

3/4

0

0

See Sec. 217

0

0

3/4

0

20' or More in Height
to Lowest Member

0

0 0
----------------- Note h —

0

0

See Sec. 217

0

0

0

0