How much space do we need?

This section provides you with a tool to help with space requirement assessments and discusses the following issues in considering space allocations:

• Understanding Area Calculations
• "Rule of Thumb" Calculations
• Factors Impacting on Area Calculations
• Individual Allocations
• Support Spaces
• Regulatory Requirements
• Building Factors

Understanding Area Calculations

Area calculations or space budgets are utilised to provide a "first pass" at identifying an agency's total area requirements. They are useful for providing a general sense of how much space an agency needs and for seeking initial approvals.

"Rule of Thumb" Calculations

The general "rule of thumb" used by most people in the industry is to multiply the number of staff by a density rate of 15m2/person.

The density rate will be higher for agencies/groups with a higher number of executives/senior managers in a CBD location requiring increased numbers of formal meeting spaces and may be as high as 20-22m2/person. Conversely it will be lower for predominantly call centre functions and/or groups with principally administrative functions and may be reduced to 10sqm/person or less. This is very much an industry "rule of thumb" and is often a useful beginning point and also a final check after a more thorough calculation. It does not include specific operational spaces required for a particular agency such as a dedicated library, equipment laboratory or task force suites, etc.

The calculation provides a gross area that includes the so called group support spaces including meeting, conference, team, project, utility and storage areas together with circulation routes, team zones, open discussion areas, etc.

Factors Impacting on Area Calculations

The more precise the variables, the more the calculation can be relied on to give an accurate understanding of the total space required. Refer to the following INDICATIVE SPACE BUDGET for a more accurate identification of Total Area Requirements.

Download Indicative Space Budget as an excel spreadsheet.

When calculating area requirements the following points should be taken into consideration.

• Available building stock will vary the "building factor" allocation and may be critical in fitting your requirements into the available space - more complex buildings require a higher "building factor".
• Window to core dimensions may be too small or too large to suit your requirements and will alter primary and secondary circulation percentages dramatically.
• Column sizes and placement may not allow efficient planning and dramatically increase the building factor allocation beyond acceptable percentages.
• Compactus storage allocation as a percentage of the floor may exceed the available building allocation, and storage may need to be accommodated in open "static" shelving which will require additional space.
• Secure zones and secondary secure circulation may need to be allocated to accommodate secure routes into specific areas.

Note

• Density calculations are based on seated staff plus support spaces. Staff may share desks at ratios which would be known (eg in 24 hour operations) or could be developed for hot desking/hotelling. Only the actual seats are utilised in the calculation, not the total staff number.

Individual Allocations

Individual worksettings per person are averaged over any fitout and generally more space is allocated to shared resource space than to specific individual space. Actual individual space will vary depending on workstation size, shape and circulation requirements. This is usually worked through on an as needs basis, depending on the level of technology and paperwork required to support the role/job function.

Generally, however, worksettings will vary from approximately 2.5-8m2 for a workstation to 12-20m2 for an office. This range is only an approximation and will vary according to individual circumstances.

Support Spaces

Support spaces will include typical office space needs as well as operational space requirements. These spaces may be under-utilised areas that could double for other uses or they may require very specific access that needs more circulation allocation.

Typical support spaces might include:

• Utility zones in open plan area, printers, fax, small photocopier, etc.
• IT areas in open plan areas for shared desks with specialist IT requirements.
• Resource rooms/space for large equipment with layout area.
• Compactus rooms/space (requires heavy floor load area - limited depending on building construction).
• General storage areas.
• Meeting rooms - small/medium/large.
• Training rooms - computer (specialist) or general.
• Quiet rooms.
• Project areas.

Regulatory Requirements

Circulation and access is required around worksettings - generally based on primary and secondary circulation.

Primary circulation is generally nominated as being around the core, two people passing each other in opposite direction.

Secondary circulation is the space allocated between worksettings or may be allocated within the worksettings depending on the calculation technique.

• Escape paths to fire exits/stairs - Building Code of Australia (BCA) fire code.
• Minimum clearances for general access for the disabled, AS 1428 Part 1-1m (pinch points .85m) and AS 1428 Part 2 -1.2m

When dealing with new buildings/fitouts the scope of the Disability Discrimination Act requirements must be carefully considered (see Design for Access and Mobility) as they can be onerous and the circulation space impacts are dramatic in secondary circulation and corridors.

Building Factors

A building factor is an allocation of a percentage to reflect the inefficiency of the floorplate. The factor is used as a multiplier of the total space. It provides for the allocation of areas that are unusable in a floor plate but are still paid for on a rental basis. For example, older buildings which have large intricate facades that are difficult to lay out workstations; existing buildings with walls that cannot be removed but don't fit the agreed module; buildings on triangular or irregular footprints, or just intricate base building planning. It can be worked out quickly if any previous layout has been designed for the space or reviewed with a designer.

To calculate the building factor:

• Review existing floor layouts (if they exist)
• If using rectilinear workstations, calculate the total of all non-usable zones and/or any additional circulation zones, and divide this into the total NLA. This figure is usually between 3-10%.
• If using non-rectilinear or non-standard shaped workstations, approximate the non-usable zones and/or any additional circulation zones and divide this into the total NLA. This figure is usually between 3-10%.
• Selecting a workstation size that does not fit the building grid well, particularly in relation to column spacings will create pockets of non-usable zones, and this should also be included in the calculations

The building factor calculation is part of the overall total area requirements for the agency, so it is relevant to building selection. A generalised rule of thumb is that the building factor will be about 5%.

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