Ventilation requirements to be PAS2035 compliant

Ventilation requirements overview

 

All installation work completed under the Great British Insulation Scheme (GBIS – Formerly known as ECO+) must be lodged in the TrustMark Data Warehouse and be PAS2035 compliant – More information is available here TrustMark and PAS2035. PAS2035 compliance  includes meeting the requirements of Building Regulations - Part F for ventilation.

 

In Summary:

 

Wet rooms (Kitchens, Bathrooms, Utility Rooms, and WCs) require a minimum of;

 

  • Intermittent or Continuous Extract Ventilation systems - mechanical extractor vents which expel the humid air from a specific room, or space, externally.
  • Kitchen – Minimum 60l/s rated vent
  • Utility rooms – Minimum 60l/s rated vent
  • Bathroom, Shower rooms - Minimum 30/ls rated vent
  • WC – Minimum 30l/s rated vent if no openable window is present

 

Habitable rooms (Living rooms, dining rooms, bedrooms, etc including kitchens and utility rooms) require a minimum of;

 

  • 6,500mm2 of background ventilation
  • A typical window trickle vent would provide 4,000mm2
  • A 150mmx225mm wall vent would provide 10,200 mm2
  • Internal doors between habitable rooms require door undercuts

If <10mm: an undercut is required

If >10mm: compliant with building regulations

  

Combustion Ventilation (CV)

 

Combustion Appliances such as open fire places, log burners and gas fires require a dedicated ventilation source, many appliances have this built in and this can be established by checking the rating plate on the device. Additional combustion vents (CV) may need to be installed where ratings cannot be established, or combustion vents are absent. For example;

 

  • Log burner – CV Required
  • Gas fire – Rated at 6.9 KW and above CV required
  • Open fire – CV Required
  • Electric fire – No combustion ventilation required

 

DFE (Decorative Flue Effect) Gas Fire;

 

  • Must have non closable combustion vents if rated over 6.9kW.

 

Combustion vents can be fitted into floor or on wall adjacent to the combustion device. If no rating is available building regulations require that it is assumed the device is rated over 6.9kW

 

Below DPC (damp proof course) Ventilation

 

A minimum of 500mm2 ventilation per m2 of suspended floor area, or per meter of external perimeter if larger) is required to meet PAS2035 standards. Underfloor, or ‘below DPC ventilation’ is typically achieved the air bricks located around a property.

 

Different types (Clay, Metal, louvred, plastic) of air bricks offer different amounts of open ventilation area. A calculation on the available ventilation area will be made and some air bricks may need to be replaced, or new ones installed.

 

  • Air Bricks must be kept clear at all times
  • Blocking air bricks can lead to a build up of moisture in the floor / void
  • Cross Flow Ventilation, where air bricks are located on opposing sides of a building, is necessary for compliance