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DB-SUA: safety of use and accessibility in the Spanish building code

📐 Topic5 min read

The Documento Básico de Seguridad de Utilización y Accesibilidad (DB-SUA, the safety-of-use and accessibility basic document of the CTE, Spain's building code) gathers two families of requirements with a common root: that the building can be used without risk and without discrimination. The first family limits the risk of accidents in everyday use; the second, articulated in requirement SUA 9, guarantees accessibility for people with disabilities. Its place within the code as a whole is explained in the complete guide to the Spanish Building Code.

Unlike other basic documents, the DB-SUA works on highly visible elements of the building: stairs, ramps, guardrails, glazing, lifts, toilets. That makes it one of the most checked documents at permit and inspection stage, and one that generates the most user claims when applied poorly.

The nine requirements of the document

Section Risk addressed
SUA 1 Falls: slipperiness, level changes, stairs, ramps, glazing cleaning
SUA 2 Impact or entrapment with fixed and operable elements
SUA 3 Being trapped in enclosed spaces
SUA 4 Inadequate lighting, including emergency lighting
SUA 5 High-occupancy situations in stands
SUA 6 Drowning in swimming pools
SUA 7 Moving vehicles in car parks
SUA 8 Lightning action and the need for protection
SUA 9 Accessibility

Two blocks concentrate most design decisions and have their own article: fall safety, which governs the geometry of stairs, ramps and protective barriers, and the accessibility of requirement SUA 9, with its accessible routes, lifts and facilities. Both condition the geometry from preliminary design and do not admit late adjustment.

The key variable: building use

As in the rest of the CTE, requirements are modulated by use. The same staircase admits different geometries in a single-family house and in a public assembly building; the slip-resistance class required of a floor depends on location and slope; accessible provisions grow with the size and character of the building. The practical consequence is that the DB-SUA is not satisfied with a catalogue of standard details: each design needs its own reading of the tables.

On top of this state-level baseline sits regional and municipal accessibility regulation, frequently stricter. The design rule is always to apply the most restrictive condition and to document in the report which regulation governs each decision, because each territory's technical services check their own first.

Where it hits the budget

The cost of the DB-SUA is spread across three fronts. The first is geometry: stairs with code-compliant treads and risers, ramps with their maximum slopes and landings, guardrail heights and strengths. Direct extra cost is low here, but the opportunity cost in floor area can be high, because an accessible ramp or a properly sized core consumes sellable square metres.

The second is equipment: accessible lifts, adapted toilets with their technical aids, controls at regulation height, floors with the required slip-resistance class, signage. The third is glazing and protection: glazing with the required impact performance and barriers at every relevant level change.

As an indicative order of magnitude, the whole can sit between 2 and 5 % of the PEM (presupuesto de ejecución material, the direct construction cost) in multi-family residential, with the accessible lift as the dominant item in mid-sized buildings. The item-by-item reading is developed in the article on the cost of CTE compliance.

Application errors worth avoiding

The first is designing accessibility as a final add-on. Accessible routes condition the position of cores, clear widths and slopes; incorporating them late forces chain redesigns.

The second is forgetting that requirement SUA 9 also reaches common areas and provisions: accessible parking spaces, accessible dwellings where applicable, controls and signage. The scope is checked across the whole building and not only the dwellings.

The third is neglecting slip resistance: the floor's class is a performance that is specified, purchased and verified, not a happy accident of the chosen finish. The class required depends on where the floor sits and must appear in the design.

The fourth is treating evacuation and accessibility separately: both share routes, and elements such as the refuge areas of the DB-SI only work if coordinated with the accessible routes of the DB-SUA. The coordination is resolved on the plan, not in the report.

Note: percentages and orders of magnitude are indicative and vary with building type, region and market conditions. The reference in force is the consolidated version of the DB-SUA published on the official CTE portal.

Frequently asked questions

Safety in use and accessibility, with requirements on falls, impact, entrapment, lighting, high occupancy situations and the accessibility of requirement SUA 9.

A given class according to where the floor sits and its exposure to water. It is a performance specified in the item, purchased and checked on delivery.

Yes. Requirement SUA 9 covers routes, lifts, accessible parking spaces, controls and signage, as well as accessible dwellings where applicable.

Not always. Regional accessibility rules run alongside the CTE, and only the more restrictive of the two protects the project.

Explore the articles in this guide

The CTE: Spain's building code, its basic documents, requirements and compliance cost