Scottish Government DMEV Research

Anderson Bell + Christie were commissioned by Scottish Government Building Standards Division as part of a team led by MEARU to research Decentralised Mechanical Extract Ventilation.

This research established if new build dwellings fitted with dMEVs in moisture producing rooms, coupled with a reduced area of trickle ventilation in apartments of 2,500 mm2, can maintain satisfactory IAQ throughout the habitable rooms of dwellings.

The findings would suggest that whilst there are some situations where a dMEV system can assist with the ventilation provision of modern airtight homes, the ability to act as a whole house system is limited, particularly in larger more complex layouts, and where ventilation loads are high.

Issues to consider therefore include:

• Better design of ventilation strategies using dMEV as a component of the system and accounting for other key components.

• A need for pass vents between rooms, fire protected where required, ideally at higher levels.

• Better standards for commissioning and testing in use.

• Improved standards for noise for as-installed systems.

• Better design of occupant interfaces of mechanical systems, in particular boost modes and occupant control elements.

• Better advice and information for occupants about the ventilation system, its optimal use, and requirements for maintenance.

• Fall-back strategies for ventilation, where mechanical systems may fail or become sub-optimal over time.

• Direct extract ventilation for non-flued gas appliances.

• The development of performance standards for ventilation rates that can be compared with in-use data, and that provide an alternative means of compliance.

The full report from this research is published here: https://drive.google.com/file/d/1nUmRghwSOC8J3eblGLcvM0Oasr5sS-6D/view