Scaffolding

What are scaffolding structures and why are they a priority risk?

Falls from height are one of the leading causes of fatal accidents in construction and industrial maintenance, and scaffolding is the most commonly used piece of equipment for working at height . Incomplete assembly, the absence of guardrails, the use of improvised platforms, the lack of anchors or bracing, and overloading are recurring causes of serious accidents. For this reason, European regulations (Directive 2001/45/EC, incorporated into Directive 2009/104/EC) and their Spanish transposition established specific requirements for the assembly, use, and dismantling of scaffolding.

Royal Decree 2177/2004 incorporated into Annex II of Royal Decree 1215/1997 the provisions on temporary work at height: selection of the most appropriate equipment, priority of collective protection measures over individual ones, weather conditions, and specific requirements for ladders , scaffolding, and rope access techniques. For scaffolding, it requires that when a structural calculation is not available or does not cover the intended configuration, a strength and stability calculation be performed; that an assembly, use, and dismantling plan be drawn up in the most complex cases; and that conditions of stability, access, platform protection, and inspection be respected.

There are tubular scaffolds made of prefabricated components (the most common for facades), frame scaffolds, multidirectional scaffolds, mobile access and work towers, suspended scaffolds, and mast-mounted platforms. Standards UNE-EN 12810 and UNE-EN 12811 establish the design and performance requirements for facade scaffolds made of prefabricated components and temporary work equipment, and the INSST technical notes (NTP 669, 670, 1015, and 1016) develop the construction and assembly standards.

Main requirements (Annex II of Royal Decree 1215/1997)

• Assembly, use and dismantling plan. Mandatory, depending on the complexity of the scaffolding, in the four cases of Annex II, section 4.3.3: a) suspended platforms of variable level, manually or motorized, temporarily installed on a building or structure for specific tasks, and mast-mounted lifting platforms; b) scaffolding of prefabricated elements supported on natural ground, concrete slabs, floor slabs, cantilevers or other elements whose height, from the lower support level to the top of the scaffolding, exceeds six meters, or which have horizontal elements that span overhangs and distances between supports of more than eight meters, except for trestle or trestle scaffolding; c) scaffolding installed outdoors, on rooftops, domes, roofs or upper structures, when the distance between the support level and the level of the ground or soil exceeds 24 meters; (d) Access towers and mobile work towers where work is carried out at a height of more than six meters from the point of operation to the ground. The plan and, where applicable in accordance with section 4.3.2, the strength and stability calculations must be carried out by a person with a university degree that qualifies them to do so; the plan may take the form of a plan of general application supplemented with details of the specific scaffolding and, in the case of CE-marked scaffolding, it may be replaced by the specific instructions of the manufacturer, supplier or vendor, unless the assembly, use or dismantling is carried out under conditions not provided for therein.
• Assembly and management. Assembly, disassembly or modification under the direction of a person with university or professional qualifications or with certified experience of more than two years and basic level preventive training, and by workers with specific training on the risks and operations.
• Stability. Support elements protected against slippage, support surface with sufficient capacity, bracing and anchoring according to the plan or the manufacturer’s instructions; mobile scaffolding is immobilized during work at height.
• Platforms. Dimensions, shape and arrangement suitable for the work and the loads, with a complete floor that prevents the fall of people and objects and without dangerous spaces between the platform and the fall protection.
• Fall protection. Guardrails with a minimum height of 90 centimeters with an intermediate bar and toe board, or equivalent systems, around the entire perimeter of platforms where there is a risk of falling from more than two meters.
• Access. Integrated interior or exterior stairs, with trapdoors on the platforms and a prohibition on climbing the structure.
• Inspection. By a person with university or professional qualifications before commissioning, periodically and after modifications, periods of non-use, exposure to the elements or earthquakes, with a record of the checks.
• Work area. Signage and delimitation of the area under the scaffolding and its access points, and protection against falling objects.

Risks and complementary measures

• Falls from height. Complete platforms, guardrails, safe access and use of harnesses anchored to suitable points during assembly and disassembly when collective protection is not available.
• Falling objects. Skirting boards, nets or mesh, delimitation of the lower area and order on the platforms.
• Collapse. Calculation or typical configuration, bracing, anchoring to facade according to the plan, adjustable bases on firm supports and load control.
• Electrical contact. Safety distances to overhead lines and taking out of service or isolating the lines when it is not possible to maintain them.
• Weather conditions. Suspension of work in strong wind, ice, snow or storm, and inspection of the scaffolding after these events.
• Coordination. In construction projects, integration of scaffolding into the health and safety plan and coordination between the assembly company and the user companies.

Organizational application: how to manage scaffolding safely

1. Select the appropriate type of scaffolding for the task and check if the intended configuration is covered by the manufacturer’s calculation note or standard configuration, or if it requires specific calculation.
2. Determine if the assembly, use and dismantling plan is required and entrust it to a person with enabling training, adapting it to the real conditions.
3. Appoint the person who directs the assembly and verify the specific training of the assemblers, with documentary evidence.
4. Perform the pre-commissioning inspection, mark the scaffolding as suitable and record the periodic inspections and those following modifications or exposure to the elements.
5. Define the conditions of use: maximum loads, prohibition of modifying the structure, access, use of PPE and action in adverse weather conditions.
6. Coordinate with other companies at the center or construction site the use of scaffolding and lower protection zones.
7. Train users on the risks of working on scaffolding and on reporting anomalies.

Preventive management software allows you to register each scaffold with its plan, the people responsible and their training, the inspections with their results and the incidents, and block the use of scaffolds without a current inspection.

Limits and common mistakes

1. Erecting scaffolding without a plan or standard configuration, or modifying the configuration without recalculating.
2. Using incomplete platforms, loose planks, or without railings and toe boards.
3. Omitting the pre-commissioning inspection or not repeating it after modifications or temporary changes.
4. Entrusting the assembly to personnel without specific training or qualified management.
5. Climb the structure instead of using the integrated access points.
6. Ignoring safety distances to overhead power lines.

The technical requirements are detailed in Annex II of Royal Decree 1215/1997, in the UNE-EN standards and in the INSST technical notes; this sheet is for informational purposes.

Regulatory and reference framework

• Royal Decree 1215/1997, of July 18, Annex II . Provisions relating to the use of work equipment for temporary work at height, including scaffolding.
• Royal Decree 2177/2004, of November 12. Amendment of Royal Decree 1215/1997 regarding temporary work at height.
• Royal Decree 1627/1997, of October 24. Minimum health and safety requirements for construction works.
• NTP 669: Prefabricated work scaffolding (I): construction standards . INSST technical note.
• NTP 670: Prefabricated work scaffolding (II): assembly and use . INSST technical note.
• NTP 1015: Tubular scaffolding of prefabricated components (I): construction standards . INSST technical note.

The UNE-EN 12810 (prefabricated component facade scaffolding) and UNE-EN 12811 (temporary work equipment) standards are acquired through the Spanish Association for Standardization; the INSST also publishes the Technical Guide for the evaluation and prevention of risks related to the use of work equipment.