When renovating a building intended for the provision of medical services, it is crucial to create a facility that complies with current requirements and standards, as well as the latest trends in modern medical and preventive institutions and equip it with advanced medical and engineering equipment in accordance with the tasks to be performed.
Our company participated in the construction of the MARS Multifunctional Medical Centre (MMC “MARS Clinic”) with an area of more than 9,000 m2, which was built as part of a complete reconstruction. We were involved as developers of the “Ventilation and Air Conditioning” section, technical consultants and developers of HVAC system components.
Working on the design of engineering systems for medical and preventive care facilities is always quite complex due to the many features of the regulatory framework and the different specifics and diversity of medical and technological requirements for the facility itself.
When working on multifunctional medical centres, where a single building combines departments with completely different specialisations, the work becomes even more complicated, as each department requires its own unique engineering solutions, taking into account its specific characteristics and architectural and planning features.
From the point of view of proper air treatment in healthcare facilities, the word “reconstruction” is key, as it imposes a number of restrictions and additional complications due to several critical factors:
- Available energy resources,
- Availablespace for engineering systems,
- Space for the location of the engineering equipmentitself.
The operating theatre requires special attention, as it is the most energy-intensive due to the large concentration of rooms with assigned cleanliness classes A and B, and particularly operating rooms, which require not only high air exchange, but also year-round maintenance of temperature and relative humidity parameters.
Despite the renovation, the medical and technological specifications required us to provide a laminar flow area of at least 9 m2. We had to solve the problem of supplying at least 8,000 m3/h to each of the five operating rooms with very significant space and energy constraints .
The problem was solved primarily through architectural and planning solutions. In our project, the operating theatre and intensive care unit were located on the top floor of the building, allowing the implementation of the most energy-efficient system by using recirculated air, i.e. organising proper recirculation, where all reused air is reprocessed in a central air handling unit.
This solution does not require long ventilation ducts running through the entire building with the necessary cross-section for 100% outdoor air supply, nor does it require occupying valuable space inside the operating room itself to accommodate recirculation modules (recirculation columns). Moreover, it is sufficient to cite the example of a humidification system operating in winter based on the diagram presented above: the power of each of the three steam generators serving the operating rooms is reduced from 65 to 40 kW of electrical consumption. Add to this the air conditioning and dehumidification system operating in the summer, and we get another reduction of 4 kW from each refrigeration machine. This means that under conditions of extremely limited energy resources, the savings in operating rooms alone amounted to more than 90 kW.
Of course, energy saving is not limited to design solutions; engineering solutions are also very important. In our case, we equipped all ventilation units with the latest generation of IE4 and IE5 class fans, which reduced the energy consumption of the fan group by at least 20%, translating into year-round savings regardless of the operating mode.
In addition, this configuration of ventilation units will enable the entire ventilation system to operate in so-called “night modes”, when the system’s performance is reduced by almost 50% while maintaining the pressure differential cascade in critical rooms and the flexibility of the system for rooms with variable occupancy, such as the entrance area and conference rooms, where air exchange varies depending on CO₂ sensor readings, which will be of great importance for energy savings throughout the entire period of operation of the MMC.
Moreover, we have developed not only the most energy-efficient air conditioning units, but also the most compact ones. It is particularly important that all systems without exception, meet the high requirements of R NP AVOK 7.8–2022 for the hygienic design of central air conditioners, namely:
- smoothinternal surfaces to reduce the accumulation of harmful substances and facilitate cleaning and disinfection
- resistance of equipmentconstruction materials to the effects of disinfectants
- use of fans with smoothadjustment and operation in specified air volume flow modes at any degree of contamination of the preliminary and final filter elements;
- use of filters with final filter elements of a cleaning class notlower than F9 according to GOST R EN 779;
- availability of devices for monitoring the clogging of filter elements;
- the presence of a fan operation monitoring device;
- the air velocitypassing through the surface area of the heat exchangers must not exceed 2.5 m/s to prevent the transfer of water droplets from the coolers to the supply air unit components;
- heatexchanger fins with a distance between plates of at least 2.5 mm for easY cleaning and disinfection;
- noiselevel not exceeding 45 dB at the whirlpool;
- maximum surface temperature of electricheaters limited to 100 °C—120 °C.
- presence of airtight air valves;
- presence of inspection windows with lighting in the servicedsections of the units;
- airtight joints in the unit design;
- use of silicone-free substances for sealing;
- easy dismantling of allinternal functional elements;
- use of curvedstainless steel trays for condensate collection.
In practice, the equipment, design and configuration of ventilation units and various air conditioning units have a crucial impact on the proper functioning of the entire ventilation system. To maintain the required balance of air flow and pressure differences in rooms with assigned cleanliness classes A and B, where HEPA filters are the final element of the system, air conditioning units and supply and exhaust units that serve them are equipped with mini-controllers that automatically compensate for the pressure difference across the HEPA filters, as the difference between the initial and final resistance of HEPA filters can reach 300-500 Pa. If this important aspect is overlooked, the absence of timely compensation can cause imbalances in the ventilation system and uncontrolled air flows, which is particularly hazardous for septic rooms.
For the proper operation of septic rooms, such as isolation wards in various departments, certain laboratories and sterilisation rooms, we have developed highly compact ceiling-mounted absolute purification modules, with “disinfectors” installed within the serviced rooms. This solution is particularly important for ensuring the operation, functioning and airtightness of the air duct system serving septic rooms in accordance with the requirements of RNNP “AVOK” 7.8.1 – 2020.
