Stairways - Part I

Flad Architects of 2 Flad Code Forum Notes : DD Month YYYY

Flad Code Forum Notes 17 March 2016 1. Code Forums

a. Notes of past code forums are posted at : i. Flad Home Page / Resources / Codes / Forums / Year / Date of Forum.

b. Next Code Forum: 04/07/2016 : Stairways (Part II). c. This Code Forum will Discuss : Stairways (Part I). d. Additional information is contained in attached power point slides: PP-pages. e. All code references are per the 2012 International Building Code (IBC).

Stairways (Part I).– Refer to PP-01 through PP-89 2. Definitions : PP-04 – PP15

a. Stair and risers are defined by the IBC which require that a stair to have at least (1) tread (horizontal) + (2) risers (vertical). A single step is not a stair.

b. Elevation changes in the Means of Egress (M of E) of less than 12” are required to use sloped surfaces which may or may not involve a ramp.

c. Elevation changes in the M of E of less than 6” are required to use sloped surfaces and either provide handrails and/or contrasting floor finish materials to visually alert occupants of the change in elevation. i. Exceptions include exterior doors, (2) risers + (1) 13” deep tread, and assembly

aisles. ii. Any change in elevation in an I-2 serving non-ambulatory persons must be by a

sloped surface or a ramp. d. Stairways connect one level to another : level is not a story.

i. Example : Mezzanine e. Interior Exit Stairways vs. Exit Access Stairway

i. Interior Exit Stairway (IES) serve as an exit component in the M of E. (1) Exit Access : occupiable portion of a building to an exit. (2) Exit : between the Exit Access and the Exit Discharge. (3) Exit Discharge : between the Exit and the Public Way.

ii. Exit Access Stairway (EAS) is not a required IES. (1) Example : Flad – Madison office

(a) The enclosed and protected East and West Stairways are IES while the open South Stairway and the enclosed but unprotected North Stairway are EAS.

3. Open Stairways : PP-15 – PP24 a. Interior Exit Stairways nomenclature has evolved over time

i. IBC 2000 & IBC 2006 = Vertical Exit Enclosures ii. IBC 2009 = Exit Enclosures iii. IBC 2012 & IBC 2015 = Interior Exit Stairways iv. IBC 2018 = ???

b. Why is knowing this history of the code important? Project teams may encounter open stairways that may or may not meet the code requirements when they were initially installed. i. IBC 2000 & IBC 2006 : Section 1020 Vertical Exit Enclosures (1020.1 Enclosures

required) allowed 50% of egress stairways to be unenclosed or interior egress stairways serving only the 1st & 2nd stories to be unenclosed. Some AHJ’s would still require that the required number of exits from the story to be enclosed to meet the definition of an exit enclosure and an exit.

Flad Architects of 2 Flad Code Forum Notes : DD Month YYYY

ii. IBC 2009 : Section 1021, Exception 3 clarified that the minimum number of exits could include open stairways which were termed “exit access stairways.” EAS were still not in compliance with the definition of an “exit.”

iii. IBC 2012 : (1) Modified the definitions of “Exit” : removed “separated”. (2) Deleted “Exit Enclosure” definition. (3) Added “Exit Access Stairway” and “Interior Exit Stairway” definitions.

iv. IBC 2015 : Modified “Exit” and “Exit Access Stairway” definitions. 4. References : PP25 – PP28

a. The term “Stairways” is referenced in multiple definitions. 5. IBC Section 1009 Stairways : PP29 – PP43

a. Includes (17) sub-sections that are requirements for all stairways. b. Includes (4) specialty stairways :

i. 1009.11 Curved stairways. ii. 1009.12 Spiral stairways. iii. 1009.13 Alt. tread devices. iv. 1009.14 Ship ladders.

c. Stairways that serve occupiable portions of a building. i. All areas of a building are occupiable, except :

(1) Unoccupied accessory areas (corridors, stairways, etc) when determining Net Floor Area.

(2) Crawl spaces, attics, penthouses, equipment platforms d. 1009.1 General

i. Even if the stairway is not a required stairway (e.g. convenience stairway), it must meet this section’s requirements.

6. Types of Stairways : PP44 – PP60 a. Interior exit stairways (IES) must discharge directly to the exterior, except :

i. Areas on the level of exit discharge (50% of the number/capacity) ii. Vestibules (50% of the number/capacity) iii. Horizontal exits

b. Exit access stairways (EAS) shall be enclosed : except : i. Communicate between only 2 stories. ii. Single residential dwelling. iii. Group M & B occupancies with sprinklers and floor opening restrictions. iv. EAS within an atrium. v. EAS in open parking garages. vi. EAS in outdoor facilities. vii. EAS serving stages, platforms and technical production areas. viii. Group I-3 (guard towers)

T:\twyatt\Code\Code Forums\2016 0317\2016 0317 Code Forum Notes.docx

F L A D C O D E F O R U M

Stairways

Code Requirements That May Trip You Up

03/17/2016 Flad Code Forum 1

O U T L I N E

PART I (03/17/16)

• Definitions (IBC 2012)

• Open Stairways

• References (IBC 2012)

• Section 1009 Stairways

• Types of Stairways

PART II (03/24/16)

• Stairway Enclosures

• Stairway Criteria

• Special Conditions

• Related Components

• Stair Width Exercise


Definitions (IBC 2012)


SECTION 202 DEFINITIONS


Are these STAIRS?

Left : NO(Level + Riser + Level =

No Tread)

Right : YES(Riser + Tread + Riser)

STAIR. A change in elevation, consisting of one or more risers.

RISER. Vertical dimension from tread surface to tread surface or treadsurface to landing surface. (Commentary)

Stair riser heights shall be 7 inches maximum and 4 inches minimum.

SECTION 1003 GENERAL MEANS OF EGRESS

1003.5 Elevation change.

Where changes in elevation of less than 12 inches exist in the means of egress, sloped surfaces shall be used.

Where the slope is greater than one unit vertical in 20 units horizontal (5-percent slope), ramps complying with Section 1010 shall be used.

Where the difference in elevation is 6 inches or less, the ramp shall be equipped with either handrails or floor finish materials that contrast with adjacent floor finish materials.


SECTION 1003 GENERAL MEANS OF EGRESS

1003.5 Elevation change. Exceptions:

1. A single step with a maximum riser height of 7 inches (178 mm) is permitted for buildings with occupancies in Groups F, H, R-2, R-3, S and U at exterior doors not required to be accessible by Chapter 11.

2. A stair with a single riser or with two risers and a tread is permitted at locations not required to be accessible by Chapter 11, provided that the risers and treads comply with Section 1009.7, the minimum depth of the tread is 13 inches (330 mm) and at least one handrail complying with Section 1012 is provided within 30 inches (762 mm) of the centerline of the normal path of egress travel on the stair.

3. A step is permitted in aisles serving seating that has a difference in elevation less than 12 inches(305 mm) at locations not required to be accessible by Chapter 11, provided that the risers and treads comply with Section 1028.11 and the aisle is provided with a handrail complying with Section 1028.13.

Throughout a story in a Group I-2 occupancy, any change in elevation in portions of the means of egress that serve nonambulatory persons shall be by means of a ramp or sloped walkway.



FLIGHT. A continuous run

of rectangular treads,

winders or combination

thereof from one landing

to another.

WINDER. A tread with

nonparallel edges.




STAIRWAY. One or more flights of stairs, either exterior or interior, with the necessary landings and platforms connecting them, to form a continuous and uninterrupted passage from one level to another.

“Level” is not a “Story”


STORY. That portion of a building included between the upper surface of a floor and the upper surface of the floor or roof next above.

It is measured as the vertical distance from top to top of two successive tiers of beams or finished floor surfaces and, for the topmost story, from the top of the floor finish to the top of the ceiling joists or, where there is not a ceiling, to the top of the roof rafters.


“Level” is not a “Story”

MEZZANINE. An intermediate level or levels between

the floor and ceiling of any story and in accordance

with Section 505.



STAIRWAY, EXTERIOR. A stairway that is open on at least one side, except for required structural columns, beams, handrails and guards. The adjoining open areas shall be either yards, courts or public ways. The other sides of the exterior stairway need not be open.

STAIRWAY, INTERIOR. A stairway not meeting the definition of an exterior stairway.


STAIRWAY, EXTERIOR



INTERIOR EXIT STAIRWAY. An exit component that serves to meet one or more means of egress design requirements, such as required number of exits or exit access travel distance, and provides for a protected path of egress travel to the exit discharge or public way.

EXIT ACCESS STAIRWAY. An interior stairway that is not a required interior exit stairway.



EXIT ACCESS. That portion of a means of egress system that leads from any occupied portion of a building or structure to an exit.

EXIT. That portion of a means of egress system between the exit access and the exit discharge or public way. Exit components include exterior exit doors at the level of exit discharge, interior exit stairways, interior exit ramps, exit passageways, exterior exit stairways and exterior exit ramps and horizontal exits.

EXIT DISCHARGE. That portion of a means of egress systembetween the termination of an exit and a public way.


Open Stairways


Are open stairways permitted MoE?

• IBC 2000 : Section 1005.3.2 Vertical Exit Enclosures – Part of Section 1005 Exits

C H A N G E

• IBC 2003/2006 : Section 1019/1020 Vertical Exit Enclosures

C H A N G E

• IBC 2009 : Section 1022 Exit Enclosures

C H A N G E

• IBC 2012

– Section 1009 Stairways • Section 1009.2 Interior Exit Stairways

• Section 1009.3 Exit Access Stairways

– Section 1022 Interior Exit Stairways and Ramps

• IBC 2015

– Section 1011 Stairways

– Section 1019 Exit Access Stairways & Ramps (see also 1006.3)

– Section 1027 Interior Exit Stairways and Ramps

• IBC 2018 : ???



Why the code history lesson?

“Those who don't know history are doomed to repeat it.”

Edmund Burke

You may encounter open stairways in existing buildings that may or may not

meet the code requirements when they were initially installed.



• IBC 2000 - 2006 : Exit enclosure– EXIT ENCLOSURE. An exit component that is separated from other interior spaces of

a building or structure by fire-resistance-rated construction and opening protectives, and provides for a protected path of egress travel in a vertical or horizontal direction to the exit discharge or the public way.• Vertical (Stairways + Ramps) + Horizontal (Exit Passageway)

• SECTION 1020 VERTICAL EXIT ENCLOSURES– 1020.1 Enclosures required, EXCEPTIONS:

– 8. In other than H and I occupancies, a maximum of 50 percent of egress stairways serving one adjacent floor are not required to be enclosed, provided at least two means of egress are provided from both floors served by the unenclosed stairways. Any two such interconnected floors shall not be open to other floors. Unenclosed exit stairways shall be remotely located as required in Section 1015.2.

– 9. In other than H and I occupancies, interior egress stairways serving only the first and second stories of a building equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1 are not required to be enclosed, provided at least two means of egress are provided from both floors served by the unenclosed stairways. Such interconnected stories shall not be open to other stories. Unenclosed exit stairways shall be remotely located as required in Section 1015.2.



• IBC 2000 - 2006 : Exit enclosure

• AHJ Interpretation – An open egress stair is not in compliance with the definition of

“Exit” as “a portion of a means of egress system which is separated from other interior spaces.”

– In some jurisdictions, once the stair was unenclosed, it was notconsidered an Exit and did not count as an Exit. Another enclosed stair had to be installed to meet the required number of exits from a story.

• C H A N G E : IBC 2009– 1020.1 Enclosures required, Exception #8 & #9 relocated to

1016.1 Travel distance limitations, Exception #3 & #4



• IBC 2009 : Section 1021, Exception 3 reference added

– 3. Exit access stairways and ramps that comply with Exceptions 3 or 4 of Section 1016.1 shall be permitted to provide the minimum number of approved independent exits required by Table 1021.1 on each story.

• 1st time “open stairs” referred to as “exit access stairways”

• EAS still not in compliance with the definition of Exit BUT they can be used to provide the minimum number of exits from a story.

• C H A N G E : IBC 2012



• IBC 2012

• EXIT. That portion of a means of egress system which is separated from other interior spaces of a building or structure by fire-resistance-rated construction and opening protectives as required to provide a protected path of egress travel between the exit access and the exit discharge or public way. Exits componentsinclude exterior exit doors at the level of exit discharge, vertical exit enclosures interior exit stairways, interior exit ramps, exit passageways, exterior exit stairways, and exterior exit ramps and horizontal exits.

• EXIT ENCLOSURE. An exit component that is separated from other interior spaces of a building or structure by fire rated construction and opening protectives and provides for a protected path of egress travel in a vertical or horizontal direction to the exit discharge or the public way.

• EXIT ACCESS STAIRWAY. An interior stairway that is not a required interior exit stairway.

• INTERIOR EXIT STAIRWAY. An exit component that serves to meet one or more means of egress design requirements, such as required number of exits or exit access travel distance, and provides for a protected path of egress travel to the exit discharge or public way.



• IBC 2015

• EXIT. That portion of a means of egress system between the exit access and the exit discharge or public way. Exits components include exterior exit doors at the level of exit discharge, vertical exit enclosures interior exit stairways, interior exit and ramps, exit passageways, exterior exit stairways and exterior exit ramps, and horizontal exits.

• EXIT ACCESS STAIRWAY. An interior stairway that is not a required interior exit stairway. with the exit access portion of the means of egress system.

• INTERIOR EXIT STAIRWAY. An exit component that serves to meet one or more means of egress design requirements, such as required number of exits or exit access travel distance, and provides for a protected path of egress travel to the exit discharge or public way.


References (IBC 2012)



AREA OF REFUGE. An area where persons unable to use stairways can remain temporarily to await instructions or assistance during emergency evacuation.

ATRIUM. An opening connecting two or more stories other than enclosed stairways …

SMOKEPROOF ENCLOSURE. An exit stairway designed and constructed so that the movement of the products of combustion produced by a fire occurring in any part of the building into the enclosure is limited.



FLOOR AREA, GROSS. The floor area within the inside perimeter of the exterior walls of the building under consideration, exclusive of vent shafts and courts, without deduction for corridors, stairways …

FLOOR AREA, NET. The actual occupied area not including unoccupied accessory areas such as corridors, stairways …



INTERIOR FLOOR FINISH. The exposed floor

surfaces of buildings including coverings applied

over a finished floor or stair, including risers.

NOSING. The leading edge of treads of stairs and

of landings at the top of stairway flights.


IBC Section 1009 Stairways


SECTION 1009 STAIRWAYS

• 1009.1 General.

• 1009.2 Interior exit stairways.

• 1009.3 Exit access stairways.

• 1009.4 Width.

• 1009.5 Headroom.

• 1009.6 Walkline.

• 1009.7 Stair treads and risers.

• 1009.8 Stairway landings.

• 1009.9 Stairway construction.

• 1009.10 Vertical rise.

• 1009.11 Curved stairways.

• 1009.12 Spiral stairways.

• 1009.13 Alt. tread devices.

• 1009.14 Ship ladders.

• 1009.15 Handrails.

• 1009.16 Stairway to roof.

• 1009.17 Stairway to elev equip.


1009.1 General

Stairways serving occupied portions of a building shall comply with the requirements of this section.

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.


Human Occupancy ?


Unoccupied Accessory Areas

FLOOR AREA, NET. The actual occupied area not

including unoccupied accessory areas such as

• Corridors

• Stairways

• Toilet Rooms

• Mechanical Rooms

• Closets


Unoccupied Areas

• CRAWL SPACES

• ATTICS– Space between the ceiling beams of the top story and the roof

rafters

• PENTHOUSES– An enclosed, unoccupied rooftop structure used for sheltering

mechanical and electrical equipment, tanks, elevators and related machinery, and vertical shaft openings.

• EQUIPMENT PLATFORM– An unoccupied, elevated platform used exclusively for

mechanical systems or industrial process equipment, including the associated elevated walkways, stairs, alternating tread devices and ladders necessary to access the platform


1009.16 Stairway to roof

In buildings four or more stories above grade plane, one stairway shall extend to the roof surface, unless the roof has a slope steeper than four units vertical in 12 units horizontal (33-percent slope).

In buildings without an occupied roof, access to the roof from the top story shall be permitted to be by an alternating tread device.


Occupied roofs



1009.16.1 Roof access.

Where a stairway is provided to a roof, access to the roof shall be provided through a penthousecomplying with Section 1509.2.

Exception: In buildings without an occupied roof, access to the roof shall be permitted to be a roof hatch or trap door not less than 16 square feet (1.5 m2) in area and having a minimum dimension of 2 feet (610 mm).



1009.16.2 Protection at roof hatch openings.

Where the roof hatch opening providing the

required access is located within 10 feet (3049

mm) of the roof edge, such roof access or roof

edge shall be protected by guards installed in

accordance with the provisions of Section 1013.


1009.17 Stairway to elevator equip

Roofs and penthouses containing elevator

equipment that must be accessed for

maintenance are required to be accessed by a

stairway.


1009.1 General

Stairways serving occupied portions (and special unoccupied portions) of a building shall comply with the requirements of this section.

• Intended for ANY stairway (required AND “convenience” stairways)

• Intended for ANY stairway (and steps) in the Exit Access, Exit, Exit Discharge all the way to the Public Way.


All the way to the Public Way (?)


Types of Stairways


1009.2 Interior exit stairways

Interior exit stairways shall lead directly to the exterior of the building or shall be extended to the exterior of the building with an exit passageway conforming to the requirements of Section 1023, except as permitted in Section 1027.1.

1009.2.1 Where required. Interior exit stairways shall be included, as necessary, to meet one or more means of egress design requirements, such as required number of exits or exit access travel distance.

1009.2.2 Enclosure.

All interior exit stairways shall be enclosed in accordance with the provisions of Section 1022.


Section 1027 Exit Discharge

1027.1 General.

Exits shall discharge directly to the exterior of the building.

The exit discharge shall be at grade or shall provide direct access to grade.

The exit discharge shall not reenter a building.

The combined use of Exceptions 1 and 2 shall not exceed 50 percent of the number and capacity of the required exits.

Exceptions:

1. Areas on the level of exit discharge

2. Vestibule

3. Horizontal exits



Exceptions:

1. A maximum of 50 percent of the number and capacity of interior exit stairways and ramps is permitted to egress through areas on the level of exit discharge provided allof the following are met:

1.1. Such enclosures egress to a free and unobstructed path of travel to an exterior exit door and such exit is readily visible and identifiable from the point of termination of the enclosure.

1.2. The entire area of the level of exit discharge is separated from areas below by construction conforming to the fire-resistance rating for the enclosure.

1.3. The egress path from the interior exit stairway and ramp on the level of exit discharge is protected throughout by an approved automatic sprinkler system.

All portions of the level of exit discharge with access to the egress path shall either be protected throughout with an automatic sprinkler system installed in accordance with Section 903.3.1.1 or 903.3.1.2, or separated from the egress path in accordance with the requirements for the enclosure of interior exit stairways or ramps.


Exit Discharge : Exception #1



Exceptions:

2. A maximum of 50 percent of the number and capacity of the interior exit stairways and ramps is permitted to egress through a vestibule provided all of the following are met:

2.1. The entire area of the vestibule is separated from areas below by construction conforming to the fire-resistance rating for the enclosure.

2.2. The depth from the exterior of the building is not greater than 10 feet (3048 mm) and the length is not greater than 30 feet (9144 mm).

2.3. The area is separated from the remainder of the level of exit discharge by construction providing protection at least the equivalent of approved wired glass in steel frames.

2.4. The area is used only for means of egress and exits directly to the outside.


Exit Discharge : Exception #2



Exceptions:

3. Horizontal exits complying with Section 1025

shall not be required to discharge directly to the

exterior of the building.


1009.3 Exit access stairways

Floor openings between stories created by exit access stairways shall be enclosed.

Exceptions:

1. In other than Group I-2 and I-3 occupancies, exit access stairways that serve, oratmospherically communicate between, only two stories are not required to be enclosed.

2. Exit access stairways serving and contained within a single residential dwelling unit or sleeping unit in Group R-1, R-2 or R-3 occupancies are not required to be enclosed.

3. In buildings with only Group B or M occupancies, exit access stairway openingsare not required to be enclosed provided that the building is equipped throughout with an automatic sprinkler system in accordance with Section 903.3.1.1, the area of the floor opening between stories does not exceed twice the horizontal projected area of the exit access stairway, and the opening is protected by a draft curtain and closely spaced sprinklers in accordance with NFPA 13.


1009.3 Exit access stairways

Floor openings between stories created by exit access stairways shall be enclosed.

Exceptions:

4. Exit access stairways within an atrium complying with the provisions of Section 404 are not required to be enclosed.

5. Exit access stairways and ramps in open parking garages that serve only the parking garage are not required to be enclosed.

6. Stairways serving outdoor facilities where all portions of the means of egress are essentially open to the outside are not required to be enclosed.

7. Exit access stairways serving stages, platforms and technical production areas in accordance with Sections 410.6.2 and 410.6.3 are not required to be enclosed.

8. Stairways are permitted to be open between the balcony, gallery or press box and the main assembly floor in occupancies such as theaters, places of religious worship, auditoriums and sports facilities.

9. In Group I-3 occupancies, exit access stairways constructed in accordance with Section 408.5 are not required to be enclosed.


Exit access stairways : Exception #1


1. In other than Group I-2 and I-3 occupancies, exit access stairways that serve, or atmospherically communicate between, only two stories are not required to be enclosed.



1. In other than Group I-2 and I-3 occupancies, exit access stairways that serve, or atmospherically communicate between, only two stories are not required to be enclosed.

Figure 708.2(2) SHAFT ENCLOSURE - SHUTTERS

EXCEPTION (2009 IBC)




1. In buildings with only Group B or M occupancies, exit access stairway openings

are not required to be enclosed provided that the building is equipped

throughout with an automatic sprinkler system in accordance with Section

903.3.1.1, the area of the floor opening between stories does not exceed twice

the horizontal projected area of the exit access stairway, and the opening is

protected by a draft curtain and closely spaced sprinklers in accordance with

NFPA 13.

Part II : Sneak Peek

How is the clear width of

the stairway determined

for occupant load calcs?

A) Wall to wall

B) Handrail to handrail

C) Inside of stringers

D) Outside of stringers

E) None of the above


F L A D C O D E F O R U M

T H A N K Y O U F O R

AT T E N D I N G


Stairways - Part I

Engineering

Transcript of Stairways - Part I