Multi-story Office Ventilation

BEM Services have completed many projects that require ventilation installation and one recent project required fresh air to be supplied and extracted across three floors of an office block in Nottingham. The office building was to hold over 600 people in an open-plan format with associated management offices, meeting rooms, canteen and toilet facilities.


The outline design supplied by the client stated that each floor was to have its own Heat Recovery Ventilation Unit so that floors could be isolated and switched off if not in use. Heat Recovery (in this case a thermal wheel) is an excellent method of extracting the heat of rejected air and adding it to the supply air thus increasing its temperature. This transfer of energy is very efficient and helps reduce the amount of energy need to warm the incoming air. Recent changes to the European Regulations on state that:

In ventilation units with two directions of airflow, the minimum thermal efficiency of all heat recovery systems at balanced airflow (except run-around liquid systems) shall be the following:

  • As from 1 January 2016: Minimum 67%
  • As from 1 January 2018: Minimum 73%

This has led to newer equipment being larger and heavier than previously expected due to the additional requirements. We had to deal with this within this office block project and had to liaise with the client and architect to ensure our proposed equipment was suitable for the available space. We also had to maximise the efficiencies within the air distribution system to ensure that every bit of the power used in the fans was used effectively. This included the careful selection of fire dampers, sound attenuators and grilles to ensure that the air flow was not disrupted unnecessarily.


A separate system was sized and designed for the WC and shower extract. This is required due to the additional smell and moisture found in these areas, as well as being a key requirement of Building Regulations. As with the main ventilation system careful coordination with fire barriers, on/off/timer controls and maintenance access must be completed.


We also had to deal with a late change of layout by the client where the reflected ceiling plans were changed and new locations for grilles had to be agreed. At this late stage careful liaison with the electrical engineers was required to ensure there were no clashes with lighting, fire alarms, sprinklers and security systems.


Through process led design procedures and thorough internal checking BEM Services completed the works on time and installation is expected to start soon. If this sounds like a service that would be of interest to you then contact us by calling 0115 7788227 or email info@bem-services.co.uk