Creating controlled indoor climates for laboratories and research environments

Buildings are increasingly viewed holistically and are subject to stricter requirements, not least when it comes to indoor climate and sustainability. With indoor environmental quality (IEQ) now included in the European Energy Performance of Buildings Directive (EPBD), the topic has moved even further into focus. Our expert, Dr. Markus Schomaker, Laboratory Manager at Swegon, explains this further below.

Research facilities, hospitals and university laboratories form a special category of buildings. Laboratory buildings, in particular, call for careful consideration of the indoor climate, as they include a wide variety of indoor spaces and rooms with different climatic and air-conditioning requirements. These room types range from standard offices and meeting rooms to analysis rooms, cleanrooms and wet laboratories with specific safety levels.

Air quality and temperature

Laboratory, operating and cleanroom spaces are subject to stringent air quality requirements, such as air exchange rates, air purity and consistent climatic conditions. External influences, such as solar radiation, therefore, need to be considered already in the planning phase. Automatic shading systems can be used to counteract temperature fluctuations caused by radiant heat, while rooms for imaging procedures that need a dark environment can be located inside the building.

“Every experiment requires individual but stable conditions to ensure accurate and reproducible results, therefore, controlled indoor climate is the most fundamental factor in a laboratory setting.”

Consistent and controlled conditions are essential in the laboratory. A scientific article in the journal BioTechniques* describes the effects of room temperature and humidity on experimental results and the reproducibility of biological experiments.

Without controlled ventilation, room temperature can fluctuate significantly depending on region and season. Even in more controlled environments, the indoor climate can vary due to user behaviour and vertical temperature differences resulting from the ventilation system. The article calls for monitoring room temperature, highlighting the importance of a controlled indoor climate.

Air technology for the protection of people and equipment

In addition to the parameters mentioned above, air velocity plays a particularly important role in laboratories which is why high air exchange rates may be required. The air exchange rate is defined by the laboratory type, the hazard level and the applicable standard, such as TRBA 100, DIN EN 12128 or ASHRAE 62.1, and can vary considerably.

The supply air volume must be matched to the exhaust air volume. As an example, biology and chemistry laboratories operate with slight negative pressure to prevent hazardous substances, pathogens or pollutants from escaping the room. In contrast, positive pressure may be required in cleanrooms, for example in pharmaceutical manufacturing or microelectronics, and in certain sterile areas to prevent particles or germs from entering.

To introduce large volumes of fresh air in a comfortable way for the user, and to achieve complete room ventilation, the selection of suitable air outlets and the air distribution principle is central. Different room types may have different requirements and therefore require different air distribution methods.

Wet laboratories often use mixing ventilation via ducted outlets, while operating rooms or recovery rooms, which can also include animal housing, may have higher requirements regarding air velocity and the risk of draughts. These spaces may therefore use low-turbulence displacement ventilation. Another advantage of displacement ventilation is that it allows for the targeted removal of odours or generally contaminated air.

In laboratories, it may also be necessary to manage high heating and cooling loads. A steep drop in cold air pressure or high air velocities at fume hoods can create turbulence that introduces contaminants into the laboratory. Undesirable air currents can also occur at laminar flow hoods/boxes, which function as recirculating air units. This can lead to contamination of biological samples or the introduction of biological material into the room.

Mock-ups for safe laboratory operation

To ensure that the planned air distribution system, whether based on mixed or displacement ventilation, maintains comfortable air velocities and prevents cold air drops near fume hoods, practical room simulations, mock-ups, play an important role in the air handling laboratory.

In a mock-up, the original situation and room layout, including the room furnishings, are replicated 1:1. The air handling parameters are then systematically determined at precisely defined positions in the room using sensitive comfort probes. This helps ensure that laboratory users can work in a comfortable environment and that no undesirable air currents occur.

Another typical air handling situation in research facilities is the handling of high heat loads, often in smaller rooms. Here, too, moderate air velocities are required, along with a comfortable environment for laboratory users. Examples include storage rooms with -80°C ultra-low temperature freezers or microscopy rooms where users spend extended periods of time. Appropriate room temperatures are also necessary to protect the equipment.

High heat loads are usually handled using water as a cooling medium rather than centrally conditioned ventilation, since water can transport 3,475 times more energy than an equivalent volume of air. Operation in dry conditions should be the goal, as otherwise, at water temperatures below the dew point, the available energy is converted into condensate. Accessible ceiling-mounted induction units, such as chilled beams, or fan / coil combinations operated with recirculated air can be used.

Adapted to current research

A key aspect in the design of laboratory buildings, including their ventilation systems, is the need to adapt to changing requirements. These changes may arise from a shift in research focus, a change of user or the completion of project-funded research.

To accommodate such changes, a modular and flexible room layout, together with an adaptable ventilation infrastructure and adaptable components, is essential. This applies to both the laboratories themselves and the ancillary spaces. It is highly recommended to consider flexible solutions during the planning phase to allow for quick and efficient implementation of later adjustments, such as modifications to the ventilation solution.

Through the clever combination of air handling components, it is possible to meet the diverse requirements described above: high air volumes combined with comfort, the absorption of high loads and flexibility when requirements change.

One example is the “Lab line System”, a modular solution for wet laboratories with an adjacent documentation zone. This air handling solution consists of:

• Round pipe outlets for fresh air supply with adjustable air deflection rollers

• A silencer in front of it

• Mountable active cooling convectors for rooms with high loads and the option to condition the fresh air afterwards

• An overflow element for supply and exhaust air to the documentation zone

• A pre-installed iris diaphragm to regulate the amount of air flowing coming through
  

Another advantage of the “Lab line” system is that the overflow element eliminates the need for exhaust air infrastructure in the documentation zone, as the air is extracted via the laboratory fume hood.

This solution is installed in some of the most modern research institutes in Europe, as well as in laboratories of leading food manufacturers. The design of these laboratories with innovative air handling solutions is presented in the this reference from Bonn, Germany.

*J A Teixeira da Silva, Room temperature in scientific protocols and experiments should be defined: a reproducibility issue, BioTechniques 70: 307–308 (June 2021)