Means of Egress

Means of Egress (Entry & Exit)

Egress is the action of going out of or leaving a place. Ideally the stairway, ramp, or other type of egress is both strong and large enough to allow use by multiple individuals at the same time, such as in this Lombok building with a stairway width of over six feet wide.

Sufficiently sized egress (185 centimeters; 6 feet 5 inches):
Wide-egress-400.jpg

Insufficiently sized egress (88 centimeters; 35 inches):
too-narrow-400.jpg
too-narrow-zoom-400.jpg

Image everyone in the building attempting to leave at the same time. Can the hallways and other means of egress support that? What if everyone is carrying items with them such as food supplies, cherished items, or similar?

Steps

It is recommended that steps have a riser height (height of an individual step) of 9.5 inches (24 centimeters), a tread depth (depth of an individual step) of 9.5 inches (24 centimeters) and a tread widtih (width of an individual step) of 22 inches (56 centimeters). One should also consider the consistency of the steps. Users are more apt to slip and fall when the width or height of each step is not consistent from other surrounding steps. Samples of such inconsistencies on one staircase are below.

Inconsistent stair heights (15.5 cm and 22 cm):
400px-Stair-heights.jpg

Envision how many people could successfully move from floor to floor in an emergency as compared to this other Lombok building staircase example which is perhaps three feet wide.

Narrow staircase in Lombok:
450px-Narrow-staircase.jpg

Egress Recommendations

Minimum egress recommendations:

  • Ceiling height: 7”6”
  • Floor area in square feet per occupant: residential 200 gross within dwelling units;
  • Egress capacity factor is 0.2 inches per occupant. For example, if the occupant load of a non-sprinklered space is 300 occupants, the required egress width of the exits or exit access doorways serving that space is 300 occupants x 0.2 inches per occupant = 60 inches.
  • Multiple means of egress sized such that the loss of any one means of egress shall not reduce the available capacity to less than 50 percent of the required capacity

Attention should also be paid to the support structures for egresses. In the below image, not only is the concrete breaking away, the internal rebar is rusting. This rust could creep further up into the concrete that remains solid.

Faulty column in Lombok:
faulty-support-column-300.jpg

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