The preliminary design was entered in 2019 with the idea of using only the ground floor and the 2nd floor. On the ground floor of the building, a laboratory for “quick response”, “Kill Tank” room, electrical and server rooms, rooms for storage of process equipment, office, kitchen and toilets were planned, while on the second floor, on the so-called technical level, HVAC systems with duct distribution, filter units, compressor station, mechanical and electrical installations were planned.

With the beginning of the pandemic that year and the accelerated needs for research work in the field of vaccination, a decision was made by investors to form 4 new laboratories on the first floor of the building for the possibility of studying, manipulating and storing “live” viruses. Something like this was very convenient from the aspect of the existing investment in the original BSL class 3 laboratory. The preliminary design only needed to be scaled and supplemented to the full capacity of the building.

When we talk about the redundancy of the system and “fail-safe” design, and above all the requirement that the pressure in the space must be preserved in every situation, we would like to mention the following technical solutions:

· redundancy of main air chamber capacity and effort,

· redundancy of main suction chamber capacity and effort,

· high-class non-return valves on the discharge line towards the BSL-3 room,

· constant flow regulators (CAV) of high sealing class on the pressure branch of BSL-3 rooms

· variable flow regulators (VAV) of the highest sealing class on the exhaust branch of BSL-3 rooms.

The water part of the installation followed completely high requirements in design and construction, where the company Instalater from Belgrade participated as a partner – subcontractor. For the production of cold water, three air-cooled chillers were planned with a designed capacity so that two of the three always meet the needs of the nominal flow of the installation, thus achieving redundancy. Cold water was distributed by means of a working and backup pump through pipelines to all consumers in the building. The primary distribution brought to the facility from the local heating plant was used as a source of hot water, while Termovent designed a substation for summer and winter operation as well as distribution to consumers. Sanitary and technical water systems were supplied from the city water connection. Independent tanks with their own “booster” pumps were designed to maintain the pressure of sufficient capacity to support the simultaneous operation of all showers required when leaving the BSL zone. Hot water heating in separate tanks was solved by means of a spiral pipe steam-water exchanger.

Unclassified general purpose spaces were air-conditioned by duct fan-converters connected to the control system. The supply of fresh air in the rooms where the users stay was designed from a dedicated air chamber with the rotary recovery of waste air energy. The server room was air-conditioned with a classic split system, while the cold room in which the temperature regime is maintained at 2-8oC was made with an external compressor-condensing unit and an internal evaporator.
The validation of the system was done according to the GMP standard with the partner laboratory LabProva from Belgrade accredited by ATS. Validation was performed with proven parameters of temperature, humidity, pressure cascade and number of particles in space.

A special challenge on this project was the period of the beginning and the logistical organization of the installation on the facility, which took place in parallel with the beginning of the COVID-19 epidemic in Serbia. In the most uncertain period and suspension of all trips throughout Europe, Termovent managed to export and deliver dozens of trucks of its own equipment and materials, send a team of fitters and engineers to the Netherlands and thus meet the requirements and needs of the client in emergency situations. With a systematic approach to the project, plan, organization and technical support of all colleagues, the project was successfully completed, and the client received an outstanding facility capable of meeting even the most stringent requirements in terms of biosafety standards, reliability and system management.