Documento Básico HS Salubridad (DB-HS) – Spanish Building Code for Health and Hygiene
The Documento Básico HS Salubridad (DB-HS) is a fundamental technical regulation issued by the Ministerio de Transportes, Movilidad y Agenda Urbana of Spain. It forms a key part of the Código Técnico de la Edificación (CTE), the legal framework governing building standards across the country. Initially approved by Real Decreto 314/2006, this consolidated version incorporates the significant updates established by Real Decreto 450/2022 on June 14, 2022. Its primary objective is to reduce the risk of users suffering discomfort or disease and to prevent the deterioration of buildings and their immediate environment through proper project design, construction, use, and maintenance.
The document is structured into six technical sections that define the objective parameters and procedures for compliance. These include HS 1 Protection against moisture, which regulates the enclosure of walls, floors, and roofs; HS 2 Collection and evacuation of waste, covering storage and disposal systems; HS 3 Indoor air quality, specifying ventilation requirements to eliminate pollutants; HS 4 Water supply and HS 5 Water evacuation, governing plumbing and drainage installations; and HS 6 Protection against radon exposure, which addresses soil gas risks. The code applies to new constructions, building extensions, changes of use, and specific renovations that alter the initial health and hygiene characteristics of the property.
Professional application of the DB-HS ensures that buildings meet the basic requirement of Higiene, salud y protección del medio ambiente. The following sections detail the specific technical criteria for humidity control, ventilation flows, plumbing pressures, and hazardous gas mitigation as defined in the current Spanish legislation.
HS 1: Protection Against Moisture
This section establishes the minimum degree of impermeability required for building elements in contact with the ground or the exterior air, such as walls, floors, facades, and roofs.
- Degree of Impermeability: Determined by factors such as the presence of groundwater (low, medium, high) and the permeability coefficient of the terrain (Ks).
- Facade Performance: Requirements for external coatings are classified from R1 (medium resistance) to R3 (very high resistance) based on rainfall zones and wind exposure.
- Roof Slopes: Flat roofs intended for pedestrians or vehicles must maintain a slope between 1% and 5%, while sloped roofs vary by tile type, such as 32% for curved tiles.
- Moisture Barriers: Mandatory installation of capillary breaks at least 15 cm above exterior ground level for facade starters.
HS 3: Indoor Air Quality and Ventilation
Regulates the supply of exterior air to habitable rooms to ensure CO2 concentrations remain within safe limits. It applies to dwellings, storage rooms, and parking garages.
- CO2 Limits: Annual average concentration must be below 900 ppm, with cumulative annual exposure exceeding 1,600 ppm limited to 500,000 ppm·h.
- Minimum Airflow (qv): Dwellings with 3 or more bedrooms require a minimum total flow of 33 l/s; kitchens specifically require an independent extraction system of at least 50 l/s.
- Garage Ventilation: Natural or mechanical ventilation is mandatory, with CO2 or Carbon Monoxide detectors required in garages with more than five spaces or exceeding 100 m².
- Exhaust Heights: Ventilation outlets on roofs must be at least 1 m high and located 3 m away from any air intake or areas habitually occupied by people.
HS 4 & HS 5: Water Supply and Evacuation
These sections define the technical requirements for the health-safe delivery of water and the efficient removal of wastewater and rainwater.
- Minimum Supply Pressures: At consumption points, a minimum of 100 kPa for common faucets and 150 kPa for fluxors or heaters; maximum pressure must not exceed 500 kPa.
- Hot Water (ACS): Temperature at consumption points should be maintained between 50ºC and 65ºC.
- Drainage Gradients: Horizontal wastewater collectors require a minimum slope of 1%, while buried collectors require at least 2%.
- Siphon Heights: Hydraulic seals must have a minimum depth of 50 mm for continuous use and 70 mm for discontinuous use.
HS 6: Protection Against Radon Exposure
Applies to buildings located in municipalities with significant radon potential, categorized as Zone I or Zone II in Appendix B.
- Reference Level: The maximum annual average radon concentration in habitable rooms is established at 300 Bq/m³.
- Zone I Mitigation: Requires either a protection barrier or a ventilated air chamber between the ground and habitable spaces.
- Zone II Mitigation: Mandatory protection barrier combined with either a ventilated containment space or a soil depressurization system.
- Monitoring Requirements: Passive or active detectors must remain exposed for a minimum of two months to determine average annual concentration.
Frequently Asked Questions
What is the maximum allowed radon concentration in Spanish buildings?
According to Section HS 6, the annual average reference level for radon concentration in the interior of habitable rooms is 300 Bq/m³.
What is the minimum water pressure required for a kitchen sink?
Section HS 4 specifies a minimum pressure of 100 kPa for common faucets at the point of consumption.
How often must building ventilation systems be cleaned?
Section HS 3, Table 7.1, requires the cleaning of vents and mechanical extractors once every year.
What is the minimum required airflow for a kitchen extraction system?
In addition to general ventilation, kitchens must have an independent mechanical extraction system capable of removing at least 50 l/s.
What are the slope requirements for flat roofs in the CTE?
For walkable flat roofs, Section HS 1, Table 2.9, dictates a slope between 1% and 5% toward the drainage elements.
When is a soil depressurization system mandatory for radon protection?
Soil depressurization is a required additional protection measure for buildings located in Zone II municipalities as defined in Appendix B of Section HS 6.
