How to Calculate and Increase the Maximum Occupancy of Commercial Premises in Barcelona

The maximum authorised occupancy of commercial premises in Barcelona cannot be calculated by applying one ratio to the total floor area. The expected occupancy of each zone must first be assessed according to its actual use. The exits, doors, escape routes and other evacuation provisions must then be checked to determine whether they can safely accommodate that number of people. Spain’s Building Code fire safety document, CTE DB-SI, provides the technical framework for occupancy densities and evacuation.

The figure that matters operationally is the occupancy accepted under the premises’ activity authorisation and supporting technical documents—not the number advertised by a landlord, the number of chairs installed or an estimate based only on square metres. Before signing a lease, carrying out refurbishment work or adding customer places, obtain the existing file, compare its drawings with the current layout and establish whether a municipal modification procedure is required.

What maximum authorised occupancy means and where to find it

Calculated occupancy is the technical result obtained by examining the different parts of the establishment. Maximum authorised occupancy—commonly called aforo in Spanish and Catalan—is the number ultimately permitted for the activity after considering that calculation, evacuation capacity and the conditions recorded in the administrative file. For certain entertainment and recreational establishments, Catalan legislation requires licences and authorisations to state the maximum permitted occupancy. [5]

Start by requesting the activity licence, prior communication or other municipal authorisation, together with its technical report, drawings and certificates. Barcelona establishments open to the public may also have an occupancy notice at the entrance. That sign is useful as a reference, but it does not replace the official file. If the sign, floor plans and authorisation show different figures, do not simply rely on the highest one; the discrepancy should be resolved through the municipal and technical records. [6]

• Obtain the activity licence, communication or authorisation.
• Review the registered technical report and floor plans.
• Check certificates and any specific conditions in the file.
• Compare the approved drawings with the premises as they stand today.
• Treat advertisements, seating numbers and entrance signs as supporting information, not conclusive proof.

How occupancy is calculated for different zones

The calculation begins by dividing the premises into zones according to their real intended use. A retail area, seated dining room, standing audience area, bar, storeroom and staff service area are not necessarily assessed in the same way. Section SI 3 of CTE DB-SI provides different occupancy densities for different uses and zones. It also requires special or occasional uses to be considered where they could significantly increase normal occupancy. [2]

The relevant criterion is applied to the usable floor area of each zone, after which compatible occupancies are combined. This produces an initial design occupancy rather than an automatically authorised figure. A single density should not be applied to the entire constructed or cadastral area, and an isolated table should not be treated as an online occupancy calculator. The current DB-SI and its official supporting material should always be consulted because the document and its interpretation may be updated. [2] [8]

• Identify every zone and define how it will actually be used.
• Verify the usable area of each zone from accurate measurements.
• Apply the appropriate occupancy criterion to each use.
• Combine zones that may be occupied simultaneously.
• Assess alternative layouts or occasional uses with a higher concentration of people.

Why floor area does not determine the final figure

Two premises with the same floor area can have different permitted occupancies. Once the initial figure has been calculated, the number, location and width of exits must be assessed, together with doors, corridors, stairs, changes in level and escape-route lengths. CTE DB-SI 3 regulates the number of exits, travel distances and the sizing of evacuation provisions. A result derived from floor area may therefore have to be reduced if the escape arrangements cannot support it. [2]

Furniture and operational layouts also matter because they must not obstruct circulation or alter the escape routes assessed in the project. An increase may have consequences for ventilation, accessibility, sanitary facilities and fire precautions as well. These factors explain why there is no reliable universal answer to a question such as “How many people fit in 100 square metres?” The activity, internal configuration and authorised conditions must all be known first.

• Number, position and clear width of exits.
• Door, corridor and staircase configuration.
• Length and arrangement of escape routes.
• Furniture, counters and other potential obstructions.
• Ventilation, accessibility, toilets and fire safety provisions.

Illustrative example: a restaurant with several uses

Consider a hypothetical restaurant containing a dining room with tables, a staffed bar, a small entrance lobby, toilets and a storeroom. The correct method is not to add the whole constructed area and divide it by one density. The usable areas are first separated and assigned their actual functions. Their partial occupancies are then calculated, taking account of which spaces can be used at the same time. This exercise requires accurate drawings rather than an estate agent’s floor-area figure.

If the dining room is occasionally cleared of tables and used for standing customers, that alternative arrangement may materially increase occupancy and must be assessed. The resulting figure is then checked against the exits and escape routes. This example demonstrates the method but does not provide a number that can be transferred to another restaurant: a defensible calculation requires measured areas, an exact layout and a clear definition of the proposed activity. [2]

• Seated customer area.
• Bar and staff service zone.
• Entrance lobby and circulation areas.
• Storeroom and other ancillary rooms.
• Toilets and spaces not normally intended for customer occupation.

How to assess and authorise an occupancy increase

Increasing occupancy involves more than adding tables or replacing an entrance sign. Define the proposed operation and layout, recalculate occupancy by zone and reassess evacuation and any other affected technical conditions. If the distribution, use of a zone or a condition in the existing activity authorisation changes, a municipal modification may be necessary before the higher figure is used. Canal Empresa, the Catalan business portal, identifies municipal procedures for non-substantial modifications that affect people or the environment. [7]

For certain restaurants, entertainment venues and recreational activities, authorised occupancy may also affect the type of administrative procedure. Canal Empresa identifies 150 people as a relevant threshold in specific circumstances, subject to conditions and exceptions. It is not a general limit or licensing rule for every commercial activity. Confirm the classification through Canal Empresa and Barcelona City Council’s electronic office, as procedure names, forms, fees and submission channels may change. [1]

A practical sequence is to compare the proposal with the existing file, identify layout or use changes, and verify exits, travel distances, ventilation, accessibility, toilets and fire precautions. A competent technician can then determine the documentation and whether the change is treated as substantial or non-substantial under the applicable procedure. Submit the required modification before operating at the increased occupancy, and update signs or counting systems where the relevant rules require them. [6] [7]

• Confirm the currently authorised figure and conditions.
• Prepare an accurate proposed layout and schedule of uses.
• Recalculate occupancy and check all evacuation provisions.
• Assess other affected technical requirements.
• Identify and complete the applicable municipal procedure before implementing the increase.

Documents and checks before leasing or refurbishing

The exact documentation depends on the activity, the extent of the changes and the administrative route. A review may require the existing authorisation, current and proposed floor plans, a schedule of usable areas and uses, the occupancy calculation and an evacuation assessment. Ventilation, accessibility and fire safety may also need to be justified. Depending on the case, the submission could include a technical report, full project or technician’s certificate; this list should not be treated as universal.

The available official sources do not support a single cost or completion time for increasing occupancy. Municipal fees, forms, required documents and processing routes can vary and may be updated. Check the current procedure with Barcelona City Council and Canal Empresa before budgeting or scheduling the project. The official CTE portal should likewise be used to confirm the current version of DB-SI and any ministry comments or supporting documents relevant to the assessment. [7] [8]

Before committing to premises, ask for the authorisation and registered plans, verify the occupancy recorded in the file and compare the drawings with the physical layout. Pay particular attention to basements, mezzanines, enclosed terraces and alterations that may not appear in the approved documentation. Also check whether the proposed use changes the expected occupancy or crosses a relevant administrative threshold. Do not sign solely on the strength of advertised capacity, existing furniture or cadastral area.

• Request the activity authorisation and all registered drawings.
• Confirm the occupancy and any specific operating conditions.
• Check that the physical premises match the approved plans.
• Identify later alterations and areas omitted from the file.
• Make technical and administrative feasibility a condition of the lease where appropriate.

Frequently asked questions

Where is the authorised occupancy of premises recorded?

Look first in the activity licence, prior communication, authorisation and technical documents held in the activity file. Certain establishments must also display a visible occupancy sign at the entrance. If that sign conflicts with the authorisation or approved drawings, the discrepancy should be clarified before treating either figure as valid.

Is occupancy calculated from usable or constructed floor area?

The technical assessment uses the relevant usable areas of individual zones and their actual functions. It does not apply one density to the entire constructed or cadastral area. The initial result must then be checked against evacuation capacity and any other applicable technical or administrative conditions.

Is a technical project required to increase occupancy?

It depends on the activity, the proposed changes and the applicable municipal procedure. A new layout, a change from seated to standing use or altered safety conditions may require a technical report, project, certificate and formal modification. Check the existing file and the current Barcelona City Council procedure before implementing the increase.