MAN advice on safe operating of air-conditioning systems during pandemic

MAN advice on safe operating of air-conditioning systems during pandemicMAN has provided advice to operators on best practice for air-conditioning in buses and coaches in the wake of Covid-19.

Alongside general rules for hygiene and distancing already in effect, the focus is increasingly turning to how best to use air-conditioning systems, according to Heinz Kiess, head of product marketing bus, at MAN Truck & Bus.

“Drivers and operators should take various measures to reduce the possibility of the virus spreading throughout the passenger area in the bus’ air-conditioning system,” says Kiess. Firstly, the air-conditioning system should only be used in fresh-air mode – where possible – and without recirculation. Also, the system should not be manually deactivated using the switch, as this only shuts off the refrigerant compressor and not the blower. 

“To avoid reducing the amount of fresh air in the passenger area, the blower speed should also not be manually decreased. For buses with service sets, we recommend closing these before the start of a trip. This can help to put passengers more at ease, as they will no longer be hit by a direct flow of air. Instead, the air will only come from the vents in the roof duct. To increase air purity, the interior air filters in the roof-mounted air-conditioning system and the front box should also be replaced at regular, short intervals.”

Kiess advises that the temperature is regulated using heating elements in the passenger area: these are situated both under the seats and on the side walls. The front box and roof-mounted air-conditioning systems also help to maintain the set temperature. 

“The air is filtered through interior air filters installed as standard and, to some extent, with activated carbon filters. Further on, the used air is discharged through separate ducts. With active ventilation, the used air is permanently purged from the vehicle interior through these ducts, which guarantees seamless air circulation.

“In theory, we cannot entirely rule out the possibility of coronavirus infection due to the bus air-conditioning system. However, we estimate that the risk is very low. Other factors – mainly a failure to observe the general hygiene and distancing rules in effect – pose a much higher risk of infection.”