Feature article: HVAC and Cleanroom Design – thoughtful planning is of the essence

While cleanroom technology used to be a special field of building services engineering, it has recently become part of process engineering. In the pharmaceutical industry, cleanrooms are indispensable for providing process environments with a low bacterial and particle count.

When it comes to planning and developing production facilities for the pharmaceutical and biotech industries, not only the high quality and safety standards of the facility itself are key, but also the demands on building services engineering are rigorous. This is particularly true for the design, construction and operation of cleanrooms. The disciplines of process engineering, cleanroom technology and building services engineering must pool their knowledge and effectively manage the interfaces between the contractors involved to ensure result-oriented design of the production environment based on process requirements. The pharmaceutical industry focuses mainly on Good Manufacturing Practice (GMP) guidelines with end-to-end documentation.

The paramount objective of cleanrooms in the biopharmaceutical industry is to provide a process environment with a low bacterial count. A shell principle is used in designing the cleanroom to make sure this goal is achieved, with the process-critical zone always designed to be the cleanest.

Air locks, filters and pressure zones are important safety elements of a cleanroom. They place specific demands on the HVAC system. Besides controlling the temperature and humidity of cleanrooms, the ventilation systems also have to ensure the level of particle cleanliness that is required by the respective cleanroom class. Air speed and air change rates are key design criteria, and there are corresponding guidelines for each cleanroom class. High cleanroom classes in the pharmaceutical industry, for example, require 40 to 60 air changes an hour, while only 0.5 to 4 hourly air changes are sufficient to ensure proper ventilation for an average living room or office.

ZETA offers comprehensive expertise from one source: HVAC and cleanroom experts have now joined the team of mathematicians, biotechnologists, automation experts, process engineers, welders, fitters and electricians. In its cooperation with selected long-term trusted partners, ZETA can draw on the combined know-how of 45 top engineers who cover the full range of building services engineering issues, including the Building Management System (BMS) and the Environmental Monitoring Systems (EMS).

HVAC team cooperates closely with the project engineering

The BMS deals with HVAC systems and manages parameters such as cleanroom temperature, relative humidity and differential pressure. The EMS is a qualified system for monitoring the critical parameters such as the particle count.At ZETA, the HVAC team cooperates closely with the project engineering and project management teams and also with the automation experts, each one of them making vitally important contributions to each project phase.

In the course of the feasibility study, ideas are scrutinized for technical feasibility, while all the economic issues and objectives are evaluated and risks and opportunities analyzed. ZETA’s HVAC team provides expertise for all project aspects: from changing the equipment and modifying the building services up to and including the construction of new production facilities in the framework of green field projects. The result of this feasibility check analysis is a precise project plan for the next steps in the project.

Concept design

Concept design then adds structure to the ideas. A flow diagram for the production process is drawn up, and the required space is defined in layout plans and 3D model studies, which also include personnel and material flows. The layout freeze (i.e. the definition of the process architecture) is the moment where supporting systems, including media supply and HVAC, and consequently the building itself, must be defined. In the course of concept design, the HVAC engineers check the reserves or limits of the current systems or provide efficient integration of suitable HVAC technology in new plant concepts.

Project planning phase (basic design)

All the requirements to be met by contractors and cleanroom systems are defined in the project planning phase (basic design). Sound space management needs to be ensured, from a very early stage, because the space in suspended ceilings and shafts is usually limited.

Design of fine details (detail design)

The process engineers then continue with the design of fine details before construction can begin. After the project planning phase, the HVAC team hands over the design plan to an execution partner and coordinates the plant and assembly planning, and later the implementation in the further stages of the project.