Prior Communication of Construction Site Opening: When Is It Mandatory and How to Proceed

Prior notice of construction site opening (comunicação prévia de abertura de estaleiro) is a statutory obligation established by Decree-Law no. 273/2003, of October 29, which sets the rules for planning, organization, and coordination to promote occupational health and safety on temporary or mobile construction sites. This legislation applies to building and civil engineering works and arises from the transposition of the European Directive on minimum safety and health requirements at construction sites.

For anyone planning new construction, rehabilitation, or refurbishment, this procedure is mandatory whenever the project reaches specific thresholds of scale, duration, or labor volume. It must not be confused with municipal prior notices submitted to the City Council (under the RJUE) or with the new public notice boards regulated by Ordinance no. 71-B/2024. Site opening notification is strictly dedicated to workplace safety and must be submitted to the ACT — Working Conditions Authority (Autoridade para as Condições do Trabalho).

In practice, this procedure ensures that the construction site is properly registered, that all technical coordinators and stakeholders are formally identified, and that minimum occupational risk prevention conditions are secured before any work begins on the ground.

Fundamental Distinction of Concepts:

The urban planning prior notice submitted to the local council governs the urban compliance and legality of the building. In contrast, the prior notice of site opening submitted to the ACT focuses exclusively on the occupational health, safety, and risk prevention of on-site workers.

What is the prior notice of construction site opening?

The prior notice of site opening is the mandatory formal notification that the project owner (developer/client) must submit prior to the commencement of works whenever construction is expected to meet the statutory duration or labor thresholds.

This document allows inspecting authorities to identify in detail:

• The exact location and complete address of the construction site;

• The nature of the work and the intended use of the building;

• The identification of the project owner and the authors of the architectural and engineering designs;

• The identification of the executing entity (general contractor);

• The site supervision team and safety coordinators (design and execution phases);

• The scheduled start and completion dates for construction;

• The estimated peak number of simultaneous workers and the total cumulative working person-days.

Far more than a mere bureaucratic formality, prior notification is an integral part of the safety framework that must accompany the entire construction lifecycle.

When is prior notice of site opening mandatory?

Under Article 15 of Decree-Law no. 273/2003, the project owner is required to submit prior notification to the ACT whenever the execution of the works meets either of the following conditions:

This means the obligation does not depend solely on project duration. Even a medium-duration project with few daily workers becomes subject to this requirement if the sum of individual working days exceeds 500 person-days.

For this reason, this assessment must be carried out during the technical planning phase, in close coordination with the construction schedule and the architectural schematic design.

Who is responsible for submitting the notice?

Legal responsibility lies entirely with the project owner (client or developer). Decree-Law no. 273/2003 expressly states that it is the project owner’s duty to notify the opening of the site, provide a copy of the notification to the contractor, and ensure compliance with occupational health and safety obligations.

Even if the developer delegates the filing or administrative handling to the architect, safety coordinator, site supervisor, or general contractor, legal ownership of the obligation remains exclusively with the project owner.

The safety coordinator during execution has a statutory duty to provide full technical support in preparing and updating the data, ensuring no required information is omitted from supervisory authorities.

What information must be included in the prior notice?

The prior notice must be duly dated, signed, and contain comprehensive information regarding the project, including:

• Complete address and georeferenced location of the site;

• Nature of the works and the intended use of the building;

• Full identification and tax numbers of the project owner and project designers;

• Identification of the executing entity (contractor license) and technical site supervision;

• Identification of safety coordinators in design and execution phases;

• Identification of technical directors and construction managers;

• Scheduled start and completion dates for construction;

• Estimated peak number of simultaneous workers and total accumulated person-days;

• List of subcontractors and independent self-employed workers already contracted.

The filing must be accompanied by statements of commitment and terms of responsibility from all designated technical participants.

Deadlines and mandatory updates to the notice

The prior notice is not a static document. A construction site is dynamic, which is why legislation imposes strict update deadlines with the ACT:

• Structural changes (directors, deadlines, designers, supervisors): Must be communicated to the ACT within a maximum period of 48 hours, with simultaneous notice given to the safety coordinator and contractor;

• Entry of new subcontractors: An updated list of subcontractors and independent workers operating on site must be submitted monthly.

The contractor is legally required to post a legible copy of the prior notice and all subsequent updates in a clearly visible and sheltered location on the construction site.

Health and Safety Plan (PSS): how does it relate to the site?

Prior notification of site opening is directly tied to the Health and Safety Plan (PSS — Plano de Segurança e Saúde). Under Decree-Law no. 273/2003, a PSS is mandatory for all projects subject to design plans that involve special risks or that are subject to prior notification of site opening.

The PSS originates in the design phase (drafted by the design phase safety coordinator) and is subsequently developed and specified by the contractor for the execution phase.

Golden Rule Before Commencing Work:

Before site setup and installation, the PSS for construction execution must be technically validated by the site safety coordinator and formally approved by the project owner. The contractor cannot initiate any works on site without this approval.

What if the project does not require a Health and Safety Plan?

In smaller-scale projects where a PSS is not legally required, but specific high-risk operations are involved (such as work at heights, demolition, excavation, or shoring), the contractor is required to prepare safety procedure sheets.

These sheets identify existing risks, collective and individual preventive measures, site constraints, and emergency response procedures, and must remain accessible on site for consultation by all workers and inspection teams.

Step-by-step guide: how to proceed without errors

To ensure legal compliance and avoid severe ACT administrative fines, follow this workflow:

• 1. Threshold Assessment: Calculate estimated cumulative person-days and peak simultaneous workers during the planning phase;

• 2. Appointment of Stakeholders: Formalize contracts and collect statements of responsibility from designers, safety coordinators, and the general contractor;

• 3. PSS Development & Approval: Secure technical validation from the safety coordinator and formal approval from the project owner;

• 4. Submission to ACT: Submit the prior notice of site opening before any earthworks or site mobilization take place;

• 5. On-Site Display: Post a copy of the prior notice on a visible board at the construction site;

• 6. Continuous Management & Updates: Notify ACT of major changes within 48 hours and update subcontractor records monthly.

Public notice boards under Ordinance no. 71-B/2024 (Urban Planning Simplex)

Alongside the safety notice sent to the ACT, there is another on-site requirement that must not be confused: displaying the new public notice boards for urban planning operations, regulated by Ordinance no. 71-B/2024, of February 27, under the Urban Planning Simplex (Decree-Law no. 10/2024).

These boards provide public transparency from the street regarding the planning title of the development (municipal permit or prior notice).

Mandatory notice board models and dimensions

The models provided in Annexes XIX to XXII of Ordinance no. 71-B/2024 include:

• Annex XIX: Notice of application for urban planning license/permit (remains on site until project completion);

• Annex XX: Notice of submission of urban planning prior notice (operation not yet titled);

• Annex XXI: Notice of submission of urban planning prior notice (operation already titled);

• Annex XXII: Notice of execution of urban planning operations promoted by Public Administration.

Notice boards must be rectangular with minimum dimensions of 0.80 m x 1.20 m (or 0.40 m x 0.60 m for existing autonomous units facing public streets or commercial walkways) and be made of weather-resistant materials to remain fully legible from the public road throughout the entire build.

Comparison Table: Notice to ACT vs. Ordinance 71-B/2024 Boards

To eliminate confusion regarding on-site responsibilities, review the structured comparison:

How MJARC Arquitetos ensures rigor on site

At MJARC Arquitetos, we view construction supervision and site preparation as the natural extension of rigorous project design. From developing solutions for sustainable buildings to complex housing or boutique hospitality projects, we coordinate technical teams to ensure all legal and safety requirements are rigorously met.

Frequently asked questions about site opening

• Is prior notice of site opening mandatory for all construction projects? No. It is only mandatory when the estimated duration exceeds 30 days with more than 20 simultaneous workers, or when cumulative labor exceeds 500 person-days.
• Who legally submits the site opening notification? The legal obligation rests with the project owner (developer/client), supported by the site safety coordinator.
• Does notification to the ACT replace the municipal building permit? No. Notice to the ACT is strictly for occupational health and safety, whereas municipal licensing or prior notice authorizes urban construction.
• Is a Health and Safety Plan (PSS) always mandatory? It is mandatory for all projects subject to design plans that involve special risks or that trigger the prior notice of site opening.
• Where can Ordinance no. 71-B/2024 notice boards be acquired? They can be purchased through construction sector trade associations, specifically via the AICCOPN online store.

References and legal framework

• Decree-Law no. 273/2003, of October 29 — Occupational Health and Safety Regime in Temporary or Mobile Construction Sites.
• Article 15 of Decree-Law no. 273/2003 — Prior notice of site opening and posting duties.
• Ordinance no. 71-B/2024, of February 27 — Public notice board models for urban planning operations under the Simplex.
• Decree-Law no. 10/2024, of January 8 — Reform and simplification of urban planning licensing (Urban Planning Simplex).

Note: The content of this article is for general informational purposes only and does not replace consultation with applicable legislation, official ACT guidelines, or technical advice from qualified safety coordinators and site managers.