Chapeter 8: Means of Egress

Required Ratings of Doors Based on Partition Type

(if a building is fully sprinklered, corridors in Group A, B, E, F, I-2, I-4, M, S, and U occupancies do not have to have a fire rating, so fire-protection-rated doors are not required.)

Corridors must be built of...

-1 hour fire resistive construction when serving and occupant load of 10 or more in R-1 and I occupancies and when serving a load of 30 or more in other occupancies...this includes walls and ceilings.

In buildings four or more stories tall Stairs must be in close with _______; in buildings less than four stories high________is required.

-2-hour-rated walls -1-hour-rated construction ("stories" include basements, but excludes mezzanines)

Doors placed in 1-hour corridors must have a fire rating of at least ___ and include approved smoke- and draft-control seals around the door. The door must also be ___.

-20 minutes -self-closing

Glass may be used in 1-hour-rated corridor walls only if it is listed and labeled as a ___ fire-protection rating and the total area does not exceed ___ of the area of the corridor wall of the room that it is separating from the corridor.

-3/4-hour -25% (but if fire-resistance rated glazing is used, then there is not limitation on the percentage of glazing that may be used)

IBC limits length of dead-end corridors based on occupancy and sprinklering, typically 20'...3 exceptions are:

-Buildings in Group B, E, F, I-1, M, R-1, R-2, R-4, S, and U may have 50 ft (15240 mm) dead-end corridors if the entire building is equipped with an automatic sprinkler system. -Dead-end corridors may be 50 ft (15240 mm) long in Group I-3 occupancies of Conditions 2, 3, or 4. These condition numbers refer to specific security arrangements in detention facilities and are seldom encountered by interior designers. -Dead ends are not limited in length where the length of the corridor is less than 2½ times the narrowest part of the dead-end corridor.

Exit Exceptions

-R-2 or R-3 individual dwelling units with max O.L. of 20 with a sprinkler system -Care suites in Group I-2 occupancies where medical care is provided on a 24 hour basis for more than 4 people who are incapable of self-preservation

Minimum width of Corridors

-absolute minimum for most corridors is 44" is occupant load is 50 or more -if serving an occupant load less than 50, minimum width is 36" -IBC indicates most education spaces to be 72", when serving occupant load of 100 or more -for most situations, plan corridors to 5' wide if possible for commercial design

The interior designer is responsible for making sure the project design complies with...

-all applicable codes and regulations -compliance must be reflected in the construction documents

Common Path of Egress Travel for one exit

-apply to one and two story buildings -For basements and the first three stories above grade, R-2 occupancies with a maximum number of four dwelling units and a maximum common path of egress travel of 125 ft are allowed to have just one exit. -Three exits are required when the occupant load is between 501 and 1000, and at least four exits are required when the occupant load exceeds 1000.

Width of corridor must be unobstructed, with the following exceptions:

-doors opening into the path of egress can reduce the required width up to one-half during the course of the swing, but when fully open, door can project no more than 7" into the required width. -handrails may reduce the required means of egress width no more than 4.5" on each side -nonstructural horizontal projections such as trim and similar decorative features may project a max of 1.5" horizontally from either side -structural elements such as light fixtures or furnishings may project no more than 4" horizontally between 27" and 80" above walking surface

In residential areas, IBC does not allow...

-exiting from a sleeping area through other sleeping areas or toilet rooms. On practicum, residential spaces should be planned so that toilet rooms, kitchens, and bedrooms lead to a corridor within the unit or common living area and then to a corridor or exit.

Inspections are made at specific times during construction. For ID projects, those include;

-framing inspections -gyp wallboard inspections -plumbing -mechanical -electrical -final inspection (contractor is responsible for calling for inspections at appropriate times to not delay work)

Arrangement of Exits

-if 3 or more exits required, two exits must be placed a distance apart equal to not less than one-half or one-third the length of the maximum overall diagonal dimension of the building or area -third and fourth exits must be arranged a reasonable distance apart so that is one becomes blocked, others accessible

Most common exceptions IBC gives to not enclose stairways (4 of 10)

-in other than Group I-2 and I-3 occupancies, exit access stairways that serve only two stories -exit access stairways for a single residential dwelling unit or sleeping unit in Group R-1, R-2, or R-3 occupancies -in Group B or M occupancies if the building has an automatic sprinkler system, the area of the floor opening between stories is not greater than twice the horizontal projected area of the stairway, and the opening is protected by a draft curtain and closely spaced sprinklers in accordance with NFPA 13 -in occupancies other than Group B and M if the occupancy complies with all items in previous exception and the floor opening does not connect more than four stories

The following is required by IBC to submit CDs for review

-must clearly indicate location, nature, extend of work, and how project conforms to code. includes standard floor plan, elevations, sections, details for arch, struc, mech, elect, and other specialty construction, as well as schedules -location plan showing position of space in relation to building -means of egress and occupants -fire rated partitions, doors, and other openings, along with construction details -locations of exit signs and fire extinguishers -fire protection shop drawings -structural calcs (if necessary) -mech and elec drawings -construction specs

AHJ may want to see some or all of the following information listed on the first sheet of the drawings:

-names and addresses of all design professionals responsible for the work -street address or legal description of the property -codes being used -area of the space designed -construction type and occupancy group or groups -occupant load calculations -an indication of whether the space is sprinklered or not -the valuation of new construction represented by the plans and specifications

Residential exiting

-only one exit required from basement or second story of house...however, basements and bedrooms must have an escape window with a minimum openable area of 5.7 ft2, with windowsill no more than 44" above floor -Minimum clear opening height is 24" and minimum clear width is 20"...emergency escape windows required in group R and I-1 occupancies -unlike most commercial construction, residential exits may pass through kitchens, storerooms, and similar spaces. -corridors may be a min of 36" wide because OL under 50, but make sure accessible -doors can swing in since OL less than 10 -can have door knobs -dead bolts/secondary locking, openable from inside without a key and mounted no more than 48"H

Handrails

-provided on both sides of stair -intermediate handrails are required so that all portions of stairway width required for egress capacity are within 30" of handrail (ie if stairways wider than 5', must have intermediate handrails) (The IBC definition of a stair is one or more risers, so even one step requires handrails. The exception to this applies to decks, patios, and walkways, single risers at entrance doors of Group R-3 occupancies, and three or fewer risers in dwelling units of Groups R-2 and R-3 occupancies.)

Handrail Design

-top of handrail must be between 34" and 38" above the nosing of the treads and extend not less than 12" beyond the top riser and not less than the depth of one tread beyond the bottom riser -gripping portion cannot be less than 1 1/4" or more then 2" in cross sectional dimension -must be a space atleast 1 1/2" wide between the wall and the handrail.

The means of egress consists of three parts

1. The Exit Access 2. The Exit 3. The Exit Discharge -These must lead to a public way: any street, alley, or similar parcel of land unobstructed from the ground to the sky and is appropriated for public use, has a clear width of not less than 10'

IBC allows egress to pass through a stockroom that serves a group M occupancy if the following conditions are met:

1. stock in stockroom must be of the same hazard classification as that found in the main retail area 2. not more than 50% of the exit access can be through a stockroom 3. stockroom cannot be subject to locking from the egress side 4. must be a demarcated aisle with a minimum with of 44" defined by a full-or partila-height fixed walls or similar construction that will maintain the required width and lead directly from the retail ara to the exit without obstruction

Egress door opening width must be atleast:

32" and must be measured between the face of the door and the doorstop when the door is open 90 degrees

Stairways serving an O.L. of 49 or less must not be less than:

36" wide

Risers on the stair cannot be less than _ or more than _. treads must be no less than__

4" or more than 7", 11"

Handrails may project into the required width of the stairs _.

4.5" on each side

The maximum width and height of swinging egress doors is

48" and 80"H (several exceptions to this minimum width requirement)

Means of egress

A continuous and unobstructed path of vertical and horizontal egress travel from any point in a building or structure to a public way

Egress Court

A court or yard (considered part of an exit discharge) that provides access to a public way for one or more required exits. (was formally called an exit court)

Exit Access Doorway

A door or access point along the path of egress travel from an occupied room, area, or space where the path of egress enters an intervening room, corridor, unenclosed exit access stair or unenclosed exit access ramp

Exit enclosure

A fully enclosed portion of an exit that is only used as a means of egress and provides for a protected path of egress either in a vertical or horizontal direction. In most instances, however, exit enclosures mean protected stairways. Depending on construction and building type, an exit enclosure must have either a 1-hour or 2-hour rating, and all openings must be protected. An exit enclosure must lead to an exit discharge or public way.

Exit passageway

A horizontal fully enclosed portion of an exit that is only used as a means of egress. Leads from an exit doorway to an exit discharge or public way

Corridors

A portion of an exit access leading to an exit with the purpose of providing a safe means of egress from a room or space to a building exit or another approved exitway, such as a stairway

Area of Refuge

An area were persons unable to use stairways can remain temporarily to await instructions of assistance during emergency evacuation

Corridor

An enclosed exit access component that defines and provides a path of egress travel to an exit. A corridor may or may not be protected depending on the particular requirements of the code.

Horizontal Exit

An exit through a minimum 2-hour rated wall that divides a building into two or more separate exit access areas to afford safety from fire and smoke

Exit Access Stairway

An interior stairway that is not a required interior exit stairway, such as a monumental stair serving two floors of a retail store

Permitting Process

Begins after the interior designer has completed the drawings and specifications. The contractor is responsible for submitting the documents to the local building department

Occupant Load Factor

The amount of floor area presumed to be occupied by one person -gross area includes stairs, corridors, toilets, mech rooms, closets, partition thickness -net area includes space actually used -when occupant load from accessory space exits through primary space, the egress facilitates from the primary space occupant load must include their own occupant load plus occupant load of the accessory space...this just means occupant loads should be cumulative as occupants exit through intervening spaces to an ultimate exit. -if mixed occupancies/uses, each area is calculated with its respective occupant load factor and then all loads are added together.

Occupant Load

The number of people that a building code assumes will occupy a given building or portion of a building. -based on occupancy classification

When the final inspection has been successfully completed....

a Certificate of occupancy is issued which allows the client to occupy the space (ie letter of occupancy or a use of occupancy letter (U & O) -Temporary Certificate of Occupancy (TCO) may be issued when problems have arise or for large projects. ie Partial Certificate of Occupancy

Stairways serving an O.L of 50 or more must be:

at leat 44" wide or a wide as determind by multiplying occupant load by .3 or .2

stair defined by IBC

change in elevation consisting of one or more risers

Occupant load of areas with fixed seating:

determined by taking the actual number of fixed seats and adding occupant load of areas in which fixed seating is not installed, such as waiting spaces and wheelchair spaces -for fixed seating without dividing arms, the occupant load is based on one person for each 18" of seating length -for seating booths, the assumed unit is one person for each 24" of seat booth length

Occupant Load of areas without fixed seating:

determined by taking the area assigned to a particular use and dividing by occupant load factor as given by the code.

Interior exit stairway (interior exit ramp)

exit component that serves to meet one or more means-of-egress requirements

Most codes allow a room to have one exit through adjoining or intervening room or space, but not through...

kitchens, storerooms, rest rooms, closets or spaces used for similar purposes (in the IBC, foyers, lobbies, and reception rooms constructed as required for corridors (with 1 hour wall) are not considered intervening rooms, so occupants can exit through these spaces)

1. The Exit Access

leads to the entrance of an exit -may or may not be protected, -include components such as rooms, spaces, aisles, intervening rooms, hallways, corridors, ramps, and doorways -in concept, exit access does not provide a protected path of travel -In IBC, fire rated corridors are considered exit access -the portion of the building where travel distance is measured and regulated

dead end corridor

limited to max length of 20', but when building is equipped with an automatic sprinkler system, the dead end corridor limit is increased to 50' for groups B, E, F, I-1, M, R-1, R-2, R-4, S and U -when doing practicum spaces should be planned to avoid dead-end corridors altogether if possible

Residential stairs for occupancies less than 10 people:

max riser: 7 3/4" min run tread: 10"

Required minimum widths of exits is determined by...

multiplying the occupant load served by a factor of .3" for stairways and .2" for egress components -stairs serving more than one story calculated using occupant load of each story separately, rather than combined. -Exception: Group H and I-2 occupancies, if equipped with automatic sprinkler system and emergency voice/alarm communication system, multiplying factors are .2" for stairways and .15" for egress components other than stairways.

stairway

one or more flights of stairs, with the necessary landings and platforms connecting them, forming a continuous passage form one level to another

Egress doors must be:

pivoted or side hinged swing in the direction of travel when serving any hazardous area or occupant load of 50 or more

3. The Exit Discharge

portion of the egress system between the termination of an exit and the public way -typ include portions outside of the exterior walls, such as exterior exit balconies, exit courts, exterior exit stairways -may also include building lobbies of multistory buildings if one of the exit stairways opens onto the lobby and certain conditions are met -conditions require exit door in the lobby is clearly visible, the level of discharge is sprinklered, and that the entire area of discharge is separated from areas below by the same fire-resistance rating as for the exit enclosure that it opens onto it. -IBC indicates exterior exit stairways and ramps are considered exits, not exit discharge areas

2. The Exit

provides a protected path of egress between the exit access and the exit discharge -fully enclosed and protected from all other interior spaces by fire-resistance-rated construction with protected openings (doors, glass, etc) -must have either a 1 or 2 hour fire rating

Positive Pressure Fire Testing

simulates actual fire conditions where there is positive pressure above and below a certain point on the door (called neutral pressure level) and negative pressure below this point. during such conditions, there is a greater tendancy for smoke and gases to be forced through the crack between the door and frame. To meet the requirements of positive pressure fire testing, a door must have approved gasketing or intumescent material along its edge or frame. An intumescent material is one that swells and chars when exposed to heat to form a barrier to smoke and fire.

The Appeals Process

sometimes AHJ denies a permit for reasons such as codes, designer using new material, new code too expensive for an old building, etc -if agreement cannot be reached with the local official, an appeal can be made to the board of appeals -formal process by which a request is made in writing stating the reasons why the designer feels the proposed design meet the intent of the board

Travel Distance (or exit access travel distance in the IBC)

the distance that an occupant must travel from the most remotes point in the occupied portions of the exit access to the entrance to the nearest exit -once person is safelty in exit, travel distance not an issue

Common Path of Egress Travel

the portion of the exit access travel distance measured from the most remote point within a story to the point where the occupants have separate access to two exits or exit access doorways and can make a choice about which direction to go

Landings must be provided at the top and bottom of every stairway. Min dimension in the direction of travel must not be less than...

the width of the stair but need not be more than 48' if the stair is a straight run.

If two or more exits are required...

total width must be divided such that the loss of any one means of egress does not reduce the available capacity to less than 50% of the required capacity