Windhinder en bezonning rond nieuwbouw (RIS 170509a) – The Hague Building Regulations
The official document Windhinder en bezonning rond nieuwbouw (RIS 170509a), issued by the Municipality of The Hague (Gemeente Den Haag), establishes the regulatory framework for assessing wind nuisance and sun access in the context of new construction projects. This policy, originally formulated by the Commission for Spatial Planning, Urban Renewal, and Housing and the Commission for Traffic, Transport, Inner City, and Monuments, serves as a formal guideline for the technical evaluation of building plans and high-rise developments within the municipal boundaries.
The scope of these regulations covers the urban physical aspects of development, specifically focusing on the impact of new structures on the local wind climate and the availability of direct sunlight for surrounding residences and public spaces. The document defines technical thresholds such as the Lichte TNO-norm for sun access and specific annual average wind speeds for different functional areas. It outlines the requirements for stedenbouwfysische aspecten (urban physical aspects) that must be included in zoning plans (bestemmingsplannen) and building permit applications to prevent wind-related hazards and ensure habitable outdoor environments.
Professional stakeholders, including structural engineers and urban planners, use this document to determine when a formal windtunnelonderzoek (wind tunnel study) or bezonningsonderzoek (sunlight study) is mandatory. The guidelines provide a standardized method for reporting results and integrating architectural solutions to mitigate adverse environmental effects caused by building mass and height.
Sun Access Standards and the Lichte TNO-norm
The municipality employs specific criteria to safeguard the quality of sunlight for residential facades and public areas. The primary standard for urban situations is the Lichte TNO-norm, which specifies minimum sunshine hours for residential facades during the spring and autumn seasons.
- Minimum Duration: At least 2 possible sun hours per day.
- Reference Period: Between February 19 and October 21.
- Sun Altitude: Only sunlight at an angle greater than 10 degrees is counted.
- Target Areas: Residential facades and public or semi-public spaces with a recreational function.
Wind Nuisance and Safety Thresholds
Wind climate is evaluated based on the annual average wind speed and the probability of wind gusts. The document categorizes urban areas by their intended activity level to determine the maximum permissible wind speeds.
- Doorloopgebied (Transit zones): Maximum annual average wind speed of 3.2 m/s.
- Slentergebied (Strolling zones): Maximum annual average wind speed of 2.4 m/s.
- Verblijfsgebied kort (Short-stay areas): Maximum annual average wind speed of 1.9 m/s.
- Verblijfsgebied lang (Long-stay areas): Maximum annual average wind speed of 1.8 m/s.
- General Danger Threshold: Wind speeds exceeding 23 m/s must not occur more than 90 hours per year for general categories and no more than 45 hours per year at main building entrances.
Permit Procedures and Reporting Requirements
Building plans that involve high-rise elements or significantly alter the urban fabric must include a dedicated chapter on urban physics. This reporting must be accessible to non-experts while maintaining technical accuracy through maps and data visualizations.
- Hoogbouw criteria: Buildings taller than 25 meters and more than 50% taller than the surrounding average require detailed studies.
- Reporting Content: Must include an introduction, description of measurement points approved by the municipality, measurements of the current versus the new situation, and an analysis of variants where criteria are exceeded.
- Public Space Mitigation: If street-level interventions (such as wind screens or vegetation) are required, financing and design must be discussed with the municipality beforehand.
Frequently Asked Questions
What is the minimum sun access required for new dwellings in The Hague?
According to the Lichte TNO-norm, new dwellings should have at least 2 possible sun hours per day between February 19 and October 21, assuming a sun altitude of more than 10 degrees.
When is a wind tunnel study mandatory for a building project?
A wind study is typically required for high-rise projects (Hoogbouw) defined as buildings over 25 meters high that stand significantly (50%) above the average height of the surroundings, or when a project deviates from an established zoning plan.
What is the maximum allowed wind speed for a terrace or outdoor pool?
These areas are classified as 'verblijfsgebied voor lange duur', where the maximum annual average wind speed allowed is 1.8 m/s.
How does the municipality define wind danger?
Wind danger is defined by the probability of wind gusts reaching 23 m/s; this must not happen for more than 90 hours per year in general areas and 45 hours per year at main entrances.
Which months are relevant for calculating sun hours?
The regulatory period for assessing sun access runs from February 19 to October 21.
Must a sunlight study be included in the zoning plan?
Yes, for urban development plans, a specific section on urban physics (stedenbouwfysische paragraaf) must highlight sun access and wind climate effects.
