The Healthiest Start: Municipal Health Service (GGD) Advice on the Indoor Climate in Childcare

The advisory document from the Municipal Health Service (GGD) of The Hague, prepared in August 2010, emphasizes the crucial importance of a healthy living environment for young children, whose organ systems are still developing. Unfavorable conditions in childcare can lead to the development or worsening of respiratory complaints. The brochure offers comprehensive advice for new construction and renovation of childcare facilities to create the healthiest possible indoor environment. The key themes are ventilation, environmental factors, thermal comfort, and humidity control.

Part 1: The Foundations of a Healthy Indoor Climate

1. Ventilation and Airing: Continuous Air Replacement is Essential

The Municipal Health Service (GGD) makes a clear distinction between ventilation and airing. Ventilation is the continuous, 24-hour removal of pollutants and the supply of clean air. Ventilation (or purging) is the rapid replacement of all air by opening all windows and doors wide for at least five to fifteen minutes, which is necessary at least twice a day.

The Critical Role of CO2-Monitoring

This recommendation deviates significantly from the legal minimum requirements (at the time, the Building Decree) for ensuring a healthy climate:

The legal requirement was based on a ventilation capacity per square meter of floor area (1.3 l/sec/m2).

The Municipal Health Service (GGD), on the other hand, recommends a ventilation requirement per person: at least 54 m3 per person per hour for good air quality, and more than 90 m3 per person per hour for very good quality.

The GGD emphasizes that air quality must be monitored with a CO2-meter. This is the measure to demonstrate whether sufficient ventilation is being provided. The guideline values for CO2 are:

A CO2 level below 800 ppm indicates good air quality.

A level below 650 ppm indicates very good air quality.

At concentrations above 1000 ppm, increased ventilation is required.

These values illustrate the need for continuous and accurate monitoring. The Room You 1 sensor is a perfect tool for displaying CO2 levels directly and visually.

Requirements for Ventilation Systems

The Municipal Health Service (GGD) sets the following requirements for ventilation systems:

The system must be designed to be at least twice as spacious as the legal minimum.

The air supply must come from outside, not from another indoor space.

The ventilation must be adjustable and easy to operate for each room.

Night ventilation is crucial to prevent the accumulation of harmful substances (such as solvents from building and finishing materials), as these substances take a long time to ventilate away.

Cross-ventilation (through more than one facade) is recommended to reduce the airflow velocity for a given air volume, which reduces draft complaints.

2. Environment and Pollution

Indoor air quality is strongly influenced by the outdoor environment.

Traffic: Ideally, the childcare center should be located more than 300 meters from a busy road. If this is not feasible, an airtight, soundproof facade and a mechanical ventilation system with the intake at the rear of the building are required, with additional filtration being considered.

Floor coverings: Smooth, low-odor floor finishes (linoleum, laminate, wood, or stone) are preferred. Textile floor coverings are a source of harmful substances (dirt and plasticizers), the latter of which can increase the risk of respiratory problems.

Part 2: Comfort, Maintenance, and Risk Management

3. Drafts and Cold Downdrafts

While drafts themselves are more unpleasant than dangerous (illness is caused by germs, which ventilation actually removes), prolonged local cooling can lead to complaints.

Drafts are caused by air flowing too fast or too cold.

Cold downdrafts are cool air flowing down a cold window pane.

Radiation asymmetry is the cooling of the skin due to a lack of heat radiation on the side of a cold window pane.

To prevent this, the Municipal Health Service (GGD) recommends:

Windows must be stepless and finely adjustable.

Openings for natural ventilation should be as close to the ceiling as possible to minimize the distance to the living level.

Double glazing and underfloor heating (or concrete core activation) help prevent cold downdrafts and radiation asymmetry.

With mechanical ventilation, a uniform airflow (for example, via a suspended ceiling as a plenum) must be achieved to prevent drafts.

4. Heat Management

Overheating is a common problem, with temperatures reaching up to 30°C.

External screening is essential: a good sunshade (outside the glass) or a substantial overhang are necessary on the south, east, and west facades. Screens should be installed with a gap of at least 7 cm and be light-colored.

Night ventilation is crucial for cooling the building. The alarm system must be activated for this purpose.

The system must be adjusted to avoid unnecessary alarms.

With mechanical ventilation with heat recovery (HRV), a bypass must be present to supply cool outside air during warmer periods instead of preheated air.

The air intake for the HRV must be on the north side (cool side) of the building. Air intake from a flat roof should be avoided, as the roof can become extremely hot in summer, causing the HRV to blow in very warm air.

Thermometers must be present in every room to monitor the temperature.

5. Maintenance and Quality Assurance of Mechanical Ventilation

Lack of maintenance can quickly reduce the capacity of mechanical ventilation (on average 10% per year).

Supply filters must be cleaned or replaced frequently (monthly, sometimes weekly).

The supply ducts themselves must not release any substances (no plastic) and must be degreased upon installation.

The fan's capacity during normal use must be achievable in the medium setting. This means selecting a size larger than the minimum so the fan doesn't have to run at top speed, which prevents noise.

Noise pollution must be limited to a maximum of 35 dB(A) in group rooms and a maximum of 30 dB(A) in sleeping areas.

After installation and each maintenance session, a calibration report from a certified agency must be requested to verify that the system is functioning properly and has been calibrated.

Conclusion: The Role of CO2 Monitoring in a Healthy Indoor Climate

The Municipal Health Service (GGD) advisory report makes it clear that the legal minimum is insufficient for healthy childcare. The core of a healthy indoor environment lies in ample and continuous ventilation, combined with active monitoring. In this context, the CO2 meter is the most essential tool for daily management and quality assurance, with a level of 800 ppm or lower being the benchmark for good air quality. The RoomYou1's features, including accurate CO2 measurement and portability (electric power supply), are directly relevant to meeting these strict GGD recommendations for childcare.

Reference 

GGD The Hague. (2010, August). Healthy indoor environment for childcare: Advice for renovation and new construction. GGD The Hague.