Balancing the risk…

Roy Jones, Technical Director at Gilberts Blackpool, offers advice on how to balance keeping pupils and staff COVID-safe and warm.

As we head into the cooler weather, there is one question on every school estates management team’s mind: how to ensure adequate ventilation to minimise COVID risk, maintain a comfortably warm internal environment- without spending even more of limited budgets on ensuring no further waste of energy?
The question is further complicated in that COVID guidance is still frequently changing, and often varies depending on your geographical location. Fortunately, at least where schools and ventilation is concerned, there seems to be a united approach from the devolved Governments: follow the guidance issued by the Health & Safety Executive (1). I would further advise to cross-reference with the latest advice from the Chartered Institute of Building Services Engineers CIBSE(2).
Whichever guidance you choose to use, the priority is to ensure there is adequate ventilation within the spaces: there is greater risk of catching any illness in a poorly ventilated room. It is further stressed that there needs to be a balance between ensuring occupants have a reasonable level of thermal comfort without a significant increase in energy demand.

Inevitably, one has to balance the advice alongside the ventilation system in place. Few schools can afford the cost and disruption of completely replacing the ventilation system. The Government is currently consulting on Building Regulations Approved Document F (ventilation), Approved Document L (conservation of fuel and power). It is also consulting on its approach to choosing schools for the School Rebuilding Programme. Indeed it is assessing every school in England to review the need and type of refurbishment. One thing I am certain about is the new need to review ventilation systems in line with current COVID guidance, which will impact on the decisions taken, with the need to balance energy efficiency, health & wellbeing.
Currently, the key elements for any ventilation strategy are to avoid overheating, provide exemplary indoor air quality including addressing pollutants, and meet energy efficiency and environmental standards. Department of Education preference (Building Bulletin 101) is for ventilation strategies that are sustainable; natural ventilation has for years been the strategy of choice, and the recommendation of the DfE, but there is a growth in popularity in alternatives such as hybrid/ mixing box systems, ground or air heat source.
Our climate is actually well suited to natural ventilation, with low extremes of temperature. It delivers benefits for everyone. For the architect and M&E consultants it is comparatively easy to design in when committed to the scheme; for the contractor it is usually simple to install. For the school it costs literally nothing to run and there are very low associated maintenance costs. For the occupants it gives improved air quality eliminating ‘sick building syndrome’- indeed, it is proven to aid student concentration and performance. Assuming appropriate performance targets are met in the system design, it should also deliver the air quality and air changes required to be COVID- compliant.
However, the simplicity of hybrid systems has led to their becoming the alternative of choice within school buildings, with their taking the best of natural ventilation but minimising energy wastage. Computer modelling of hybrid systems has shown in a typical primary school, all the ventilation performance criteria are met, and an improvement in the Target Emission Rate (TER)  against alternative strategies: 12% achieved, compared with a typical MVHR system, which yielded only 8.5%.
Ventilation hybrid systems (such as Gilberts’ MFS {Mistrale Fusion}) are stand-alone, with one (or two) units serving each classroom. The unit ensures an even distribution of airflow, with control over temperature and CO2 levels within, and maintains a comfortable internal environment for occupants, with energy costs as low as £5/classroom/year (based on current energy costs for running the fan). COVID-compliant ventilation is achieved either by increasing flow rate to reduce CO2 levels, or by utilising LPHW coils.
In these COVID times, it is possible to adjust the system to run on 100% fresh air, using the heat coil to temper the incoming air temperature (COVID mode). This keeps a cleaner and safer environment whilst ensuring indoor temperatures are not compromised at all, thereby avoiding cold draughts without the need to boost heating systems to maintain internal comfort levels.
We’d advise the best way forward is to work with experts, such as Gilberts, who have the knowledge to guide you and ensure the systems you install are not just energy efficient, but compliant and COVID-safe.

(1) https://www.hse.gov.uk/coronavirus/equipment-and-machinery/air-conditioning-and-ventilation/assesssment-of-fresh-air.htm
(2) https://www.cibse.org/knowledge/knowledge-items/detail?id=a0q3Y00000HsaFtQAJ

www. gilbertsblackpool.com