What are the requirements for the discharge from a required exit?

Two type of required exits are defined in the National Construction Code ("NCC"). This includes a "exits" and "fire rated exits". This articles describes
Russ Porteous
CEO, Firewize

Most Occupancy Permits or Maintenance Schedules set out a periodic inspection of "Means of Egress" for the Building Owner.  Means of Egress is a suite of Essential Safety Measures described in some editions of the National Construction Code, Volume One for and Practice Note 23, published by the Victorian Building Authority ("VBA"). Means of Egress includes the following categories;

  • Paths of travel to exits
  • Discharge from exits (including paths of travel from open spaces to the public roads to which they are connected)
  • Exits (including fire-isolated stairways and ramps, non-fire isolated stairways and ramps, stair treads, balustrades and handrails associated with exits, and fire isolated passageways)
  • Smoke lobbies to fire-isolated exits 
  • Open access ramps or balconies for fire-isolated exits 
  • Doors (other than fire or smoke doors) in a required exit, forming part of a required exit or in a path of travel to a required exit, and associated self-closing, automatic closing and latching mechanisms.

 

Exit means

  1. any, or any combination of the following if they provide egress to a road or open space:
    1. An internal or external stairway.
    2. A ramp.
    3. A fire-isolated passageway.
    4. A doorway opening to a road or open space.
  2. A horizontal exit or a fire-isolated passageway leading to a horizontal exit.

DP4 Exits

Exits must be provided from a building to allow occupants to evacuate safely, with their number, location and dimensions being appropriate to—

  1. the travel distance; and
  2. the number, mobility and other characteristics of occupants; and
  3. the function or use of the building; and
  4. the height of the building; and
  5. whether the exit is from above or below ground level.

DP5 Fire-isolated exits

To protect evacuating occupants from a fire in the building exits must be fire-isolated, to the degree necessary, appropriate to—

  1. the number of storeys connected by the exits; and
  2. the fire safety system installed in the building; and
  3. the function or use of the building; and
  4. the number of storeys passed through by the exits; and
  5. fire brigade intervention.

 

DP6 Paths of travel to exits

So that occupants can safely evacuate the building, paths of travel to exits must have dimensions appropriate to—

  1. the number, mobility and other characteristics of occupants; and
  2. the function or use of the building.

The NCC outlines specific criteria for the discharge from a required exit as follows;

D1.10 Discharge from exits

  1. An exit must not be blocked at the point of discharge and where necessary, suitable barriers must be provided to prevent vehicles from blocking the exit, or access to it.
  2. If a required exit leads to an open space, the path of travel to the road must have an unobstructed width throughout of not less than;
    1. the minimum width of the required exit; or
    2. 1 m,
      whichever is the greater.
  3. If an exit discharges to open space that is at a different level than the public road to which it is connected, the path of travel to the road must be by—
    1. a ramp or other incline having a gradient not steeper than 1:8 at any part, or not steeper than 1:14 if required by the Deemed-to-Satisfy Provisions of Part D3; or
    2. except if the exit is from a Class 9a building, a stairway complying with the Deemed-to-Satisfy Provisions of the BCA.
  4. The discharge point of alternative exits must be located as far apart as practical.
  5. In a Class 9b building which is an open spectator stand that accommodates more than 500 persons, a required stairway or required ramp must not discharge to the ground in front of the stand.
  6. In a Class 9b building containing an auditorium which accommodates more than 500 persons, not more than 2/3 of the required width of exits must be located in the main entrance foyer.
  7. The number of persons accommodated must be calculated according to D1.13.