What considerations need to be made when defining occupant capacity?

In general, the maximum occupancy of a room or venue is determined by considering the available space, the number and location of exits and the total exit width after discounting the largest exit.

Other considerations include, but are not limited to;  the type of building/structure, travel distances, smoke detection systems, alarms, fire loads, sight lines, projected occupant flow rates (alcohol may effect speeds which people flow through an exit, or perception of risk) topography of the site (if outdoor) mobility impaired persons on site etc.

Are people standing, seated, dancing, or eating, laying down or a blend of all of these?

How to calculate venue capacity?

To calculate the occupancy figure you will need to consider the following:

  • The use of the premises
  • The type of premise
  • Your exit capacity (after discounting the largest exit)
  • Travel distances
  • The findings of your fire risk assessment

There are two factors that determine the figure used for venue capacity:

  • The maximum number of persons it is designed to hold. This can be determined by dividing the area of the venue/room/field (m2) by an occupancy factor. Occupancy factor has been illustrated in the table below.
  • The number, width and location of the available exits allowing occupants to escape to a place of safety, after discounting the largest exit.
Room/Area Occupant capacity based
on floor space factor (m2/person)
Amusement arcade, assembly hall, bingo hall, club concourse, crush hall, dance hall, venue for pop concert and like occasion, queuing area and bar areas without fixed seating 0.5
Dining Room, Restaurant 1.0
Exhibition room or studio (radio, film, television, recording) 1.5
Sports Hall (not used for assembly or examinations etc) 5.0
Committee room, common room, conference room, dining room, licensed betting office (public area), lounge or bar (other than in 1 above), meeting room, reading room, restaurant, staff room or waiting room 1.0
Standing spectator areas, bar areas (within 2m of serving point) similar refreshment areas 0.3

To calculate, segment each area by its use then measure (length x width) to calculate the total area:

In this example we will calculate the total capacity of area with a restaurant/function room, a bar and a lounge.

Firstly, we need to measure the size of the room, then divide it by occupant capacity based upon the floor space factor as outlined in the table above.

  1. Restaurant/Function Room = 85m2
    This area has been identified of having two uses – a restaurant and a function area, therefore two different occupancy factors need to be applied, and the figure that gives the highest occupancy figure should be used. For Example:85m2 ÷ 1m2 per person = 85 persons(The Occupancy factor for the room when used for dining)85m2 ÷ 0.5m2 per person = 170 persons(The occupancy factor for the room when used for functions. This figure will not apply if a large seated audience is attending the function. The occupancy factor for this type of event will depend on the number of seats available).
  2. Bar = 30m2
  3. Lounge = 50m2

The total occupancy capacity for these premises is:

  1. Restaurant/Function Room (If used as a Function Room)
    85m2 ÷ 0.5m2 per person = 170 persons
  2. Restaurant/Function Room (If used as a Dining Room)
    85m2 ÷ 1m2 per person = 85 persons
  3. Bar
    30m2 ÷ 0.5m2 (0.3m2 within 1m of the bar*) per person = 60 persons
  4. Lounge
    50m2 ÷ 0.5m2 (if fixed seating 1m2) per person = 100 persons

So the premises capacity is for the restaurant used as a function room will be:

170 + 60 + 100 = 330 persons.

Fire exit capacity

Careful consideration should also be given to calculating the capacity of fire exits. There should be enough exists of adequate width, to allow people to evacuate a room or venue safely in the event of an emergency, as quickly as possible.

If a building is to be used to its full capacity, exits should be sufficient in both number and width to allow safe evacuation of everyone in the building working on the basis that full capacity has been reached.

Exit capacity can be calculated by gathering information such as the amount and width of the available exits. When taking measurements, the width of an exit and projections into the doorway or in the immediate vicinity of the doorway should be taken into consideration.

It can be assumed that for a:

  • 750mm opening, 100 people can safely exit in a specified time
  • 1050mm opening, 200 people can safely exit in a specified time
  • 1500mm opening, 300 people can safely exit in a specified time
  • 2000mm opening, 400 people can safely exit in a specified time

This number should then be stress tested using a worst case scenario where the largest exit is removed from the calculation. With the largest exit blocked (potentially by fire) there should be sufficient provision for the highest occupancy figure to exit via the remaining doors.

Crowd Safety can help you with Fire Risk Assessments, Crowd Calculations and an independent report that demonstrates the capacity calculations in preparation for your event. Contact us to find out exactly how we can contribute to the safety of your next event.