The sanitary quality of buildings, and in particular the quality of indoor air, is a relatively recent concern but it has become a central issue since the global pandemic. The facts are clear for all to see: we spend 80% of our time inside a building of one sort or another, where the air is on average eight times more polluted that outdoors!
Engineering in support of user comfort and health
From the earliest phases of building design, Egis tackles the issue of indoor air quality by considering the sources of outdoor pollution, the construction materials used and the interior fittings. Means of natural ventilation and mechanical ventilation solutions are designed by placing the comfort and health of users at the centre of our practices. As a result, Egis prioritises the use of low-emission materials, and designs ventilation systems tailored to meet air exchange needs, while also pursuing best outcomes in terms of the building’s energy performance.
Air quality is studied in our projects from the outline design phase, working in liaison with the architect on the plans, facades, location of air inlets and outlets, conditions of use and natural ventilation. We conduct dynamic simulations to assess the pollution level of the building on its delivery and in its nominal use and operating conditions. These simulations are combined with other considerations (energy in particular) so that we can offer the best systems in a logic of comfort and total cost.
The case of Albert Le Grand gymnasium in Strasbourg
The Albert Le Grand gymnasium, located in Strasbourg, was refurbished and renovated in a project that comprised the upgrading of the existing gymnasium and its conversion into a hall designed specifically for gymnastics, the construction of a second hall for rhythmic gymnastics and school sport (basketball and badminton), with additional toilets and two changing rooms with showers together with the related technical facilities, and the energy renovation of the existing shell and the improvement of the gymnasium hall to “BBC rénovation” energy performance standards.
Environmental and climate issues
The Albert Le Grand refurbishment and extension falls within a sustainability approach pursued by the local authority Eurométropole de Strasbourg, whose aim is to minimise the operation’s impact on the environment in the widest sense.
The aim is to propose high-quality technical solutions to strike a compromise between energy performance (E3 performance on the E+C label scale for the new build part, and BBC renovation for the refurbished part), user comfort and sanitary guarantees. The latter aspect is of particular importance for a building where sporting activities are taking place.
Choosing the right materials
Sanitary quality is a key issue in the construction of the Albert Le Grand gymnasium in Strasbourg, which is dedicated to intensive sports activities. How can you guarantee the air quality in these large volumes? We addressed the subject through the use of indoor construction materials and fittings (floor coverings, wall coverings, ceilings) offering the lowest possible emissions. Selected from very low-emission ranges, they contribute to limiting the sources of indoor pollution.
Ventilation and air treatment
The ventilation systems were designed with the greatest of care, whether in terms of the ranges of air handling units (AHUs), the choice of filters or the sizing of air exchange flows.
The programming of the AHUs was studied in fine detail, factoring in the conditions of use and operation of the gymnasium. Thus, our simulations in preliminary design phase showed that managing airflows in the right way would help avoid pollution peaks, without excessive consumption or cost.
The chart below illustrates the levels of indoor VOC (volatile organic compound) pollution before the optimisation of AHU operation:
We can observe that the guideline values are constantly exceeded.
By occasionally increasing the ventilation airflows and by programming the AHUs to switch on three hours before occupants arrive, we were able to show that the air quality standards could be met in full.
This is shown by the chart below.
