Means of Egress

Egress Capacity Factors

1.Number of exits 2.Exit width 3.Arrangement of exits 4.Travel distance

Area of Refuge

A space or area providing protection from fire and/or smoke where persons who are unable to use a stairway or elevator can remain temporarily to await instructions or assistance during an emergency evacuation.

Public Way

The area outside a building between the exit discharge and a public street.

Dead- End Corridors

A dead-end corridor is a corridor with only one direction of exit. •In other words -if a person turns down a corridor with a dead-end, there is no way out except to retrace his or her path. •Codes set maximum lengths for dead-end corridors because they can be deadly in an emergency. The most common maximum is 20'.

Means of Egress

Acontinuous and unobstructed path of travel from any point in a building to its exterior or a public way.

Five Egress Components

Exit access Exit Area of refuge Exit discharge Public Way

Number of Exits

Most codes require a minimum of two exits, whether they are for an entire building or a space within the building. •The number of exits is based on the Occupant Load of the space or building. •First determine the Occupant Load, to then determine the number of exits required. •If there are mixed-occupancies, you count the entire occupant load.

Defend in Place

Occupants will go to a specific area to wait for assistance, i.e. Area of Refuge

Means of Egress Capacity

Reflects the number of people that can safely exit a building in an emergency.

Exit Widths

Set by the building codes as a minimum width requirement for each of the means of egress. Different components will require different exit widths. •This is a minimum width and cannot be reduced anywhere along the route of egress. •Based on Occupant Load of an area or floor. •Multi-story buildings that may have the largest occupant load on the 3rdfloor require that all floors below it meet the same exit width throughout.

Common Paths of Travel

Some of the codes set maximum lengths for common paths of travel. •The specified length depends on the occupancy and types of travel. •One example is the Dead-end Corridor where you can only go in one direction to reach an exit. •The second definition of a Common Path of Travel is an exit access where two paths merge to become one. The merged pathbecomes the Common Path of Travel.

Travel Distance

The measurement of an exit access. The measurement of the distance between the most remote, occupiable point of an area, room, or space to the exit that serves it. •Two types of travel distance are regulated by codes. a.The code limits the length of travel distance from within a single space to the exit access corridor -known as the common path of travel, because all occupants of that space will have to travel in approximately the same direction before they come to two options for exiting. b.Codes also regulate the length of travel distance from anywhere in a building to the exit of the building or floor. c.Typically, if the travel distance within a tenant space exceeds 75', then an additional exit is necessary even if the Occupant Load does not require it.

Evacuation

The occupants will be provided a direct path out of the building.

Exit Discharge

The portion of a means of egress between the termination of an exit and the public way. Can be inside the building such as a main lobby, or an outside courtyard.

Exit Access

The portion of a means of egress that leads to the entrance of an exit. Includes any room or space occupied by a person and any doorway, aisle, corridor, stair, or ramp traveled on the way to the exit.

Exit

The portion of the means of egress that is protected and fully enclosed, and is between the exit access and the exit discharge or public way.

Half- Diagonal Rule

When two or more exits are required, at least two of the exits must be a certain distance apart. This is referred to as the half-diagonal rule. -The distance between two exits be at least one-half of the longest diagonal distance within the building or building area the exits are serving. Measure the length of the diagonal in a straight line from one corner of the floor plan to the other corner. Then take one-half of that length. This results in the distance the exits must be positioned from each other, which is measured to the centerline of each door per the IBC. THIS IS THE MINIMUM DISTANCE ALLOWED.

Arrangement of Exits

a.Half-diagonal rule b.Travel distance c.Dead-end corridors d.Common paths of travel