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Submission to the Department of Environment from EASCA (Environmental and Sustainable Construction Association) regarding Proposals to Amend Part F

October 2008 

General Comments:

Ideally there should be a distinction between infiltration (drafts in a building due to insufficient airtightness) and deliberate ventilation.  Infiltration should not be considered as ventilation and should be limited to a certain air change rate per hour.  There also should be a further distinction between designed ventilation and ventilation that is not designed (hole in the wall), with the former being recommended.

There should be increased regulation of installers and suppliers. Solar thermal installers certainly learnt from making mistakes, MHRV installers cannot be given that luxury. SEI's role is to promote renewables but not to regulate. Part F regulations should set minimum standards for ventilation installation.

Specific Notes: 

• 1.1.1.9 Concern that this item stops dangerously short of good guidance (refers to Parts J + B). Specifically Part F should highlight that where ducts pass through fire rated construction that they should be firestoped to Part B (3.4.5(b) - Protection of Openings and Fire Stopping)
  
  In the event of a fire the HRV should be relayed to the smoke detector or fire alarm system to immediately stop the HRV operating- to prevent smoke from being pushed around the building
  
  

Particularly any additional action a HRV system can take in affording occupants of a dwelling, or non-dwelling, maximum possibility of escape and protection in case of fire. With the HRV system working it exacerbates the problems associated with fire by adding the spread of flame and smoke, while with the system shut down it actually aids in (1) the restriction of movement of smoke and fire through the building (2) affords greater protection for occupants regarding time to escape.

Therefore, particularly in dwelling situation, there should be a co-relation between the automatic fire detection and the mechanical ventilation system which enacts when a fire is detected.

A HRV system could be used to
1. Help de-oxygenate a room to aid in the control of fire
2. Exhaust smoke from a room or escape route

• Part F should refer to Appendix Q. Strictly speaking it is a Part L concern i.e. Part F compliance, in isolation, could be achieved by an energy hungry HRV unit - but the two parts (F+L) should tie together. 

• 1.1.8 An emphasis could be placed on ease of access to filters.  What is
  visible and easy to access will be more likely to be remembered, used,
  changed.

• 1.1.11 A large proportion of noise in ductwork can be down to the shape of
  the ductwork, narrower ducts and lengths of ducts with a large number
  of twists will be noisier.  Designers of the building (i.e. architects) therefore need to think about accommodating duct runs at an early stage

• 1.2.1.3 '...not less than 400mm from ceiling level'. Should this read 'not
  more than'?  Could there be an ideal range: i.e. 'between 200 and
  500mm of ceiling' for instance?

• 1.2.1.5 - The 'suggest' dimensions in diagram 3 should be made an actual minimum requirement for new builds, and a differentiation be made between new and existing buildings. Relaxations should be afforded to existing builds when being converted or renovated.

• 1.2.2.7. Ensure proper sealing/fitting of grill to avoid 'bypass' leakage when grill is closed.

• 1.2.2.8 This appears contrary to an airtight strategy.  We should be encouraging the use of dampers on all flues that aren't direct fed to an appliance.  A flue should not be seen as part of a ventilation strategy: this is contrary to a low energy approach and is haphazard
  at best.

• 1.2.2.10 The distance between the two background ventilators for single sided ventilation is a product of the depth of the room.  One metre may not be acceptable in a majority of cases.   The diagram should also be changed to reflect that the distance need not relate to a window.  There could for instance need to be a low level vent (often behind a
  radiator) and a high level vent in the window.

• 1.2.2.12. All new installed open fireplaces should have a control damper to guard against heat loss by draught/excessive exfiltration
  
  
• 1.2.3.2 refers - using crude adjustment factors for permeability, makes no sense when actual test results (if we are paying attention to Part L) should be available - or at least we should have a design target for permeability.  Adjusting for permeability by a fixed factor does not make sense when actual permeabilities can and indeed must be attained under Part L

• 1.2.3.6 Could refer here to the necessity of providing dedicated air supply direct to fire places in airtight houses with MHRV so as not to negatively pressurise the house/room. Reference should also be made again to the ease of changing the filter.

• 1.3.2.1 Supply air rates indicated are low - 4l/s per person, should be 10l/s as indicated for offices at 1.3.1.6

• 1.3.3.1 Many carparks work in mixed mode: that is they need some assistance in ventilation 'black spots' but otherwise can rely on natural ventilation.
  
  
• 2.1 What are 'normal conditions'? There is no reason why a highly insulated roof can't also be condensation free if vapour permeability of materials and ventilation is understood.

• 2.4 A comment may be made that the roof Vapour Control Layer (VCL) is typically an integral element of an airtight installation and needs to be considered in light of airtightness detailing at eaves and top of wall in any case.

• 2.9 Needs to refer to the new Irish 'Acceptable Construction Details', not UK details