Re: Re: New Part L Revision re Applications lodged after Nov 201

@onq wrote:

MVHR is a cut down version of full air conditioning but with none of the fire prevention measures.
In addition the hazard is higher in the house which has potentially a 100% sleeping occupancy.
.

on this issue i completely agree with you. all my specifications for hrv include smoke protection collars for all ducting when passing through floors / walls. Also, connection to fire detection system is a must to allow for full ‘shut down’ in case of fire.
These were issues brough to the attention of BRAB, but no mention in Part L 2011. We can only hope for main stream provision in an altered Part B…. but regardless we as designers must provide the best spec we can .

@onq wrote:

Ducts containing water and deposits can be a breeding ground for bacteria.
This can create conditions for legionella to grow outside of the hot tub.
http://www.cmse.ie/blog/legionella-in-ireland/

I don’t think we’ve thought this all through for Irish conditions.

in this i dont agree. again, care needs to be taken with the specification ie never flexible ducting!! and always locate the system within the heated insulation envelope.
The exhaust air never actually mixes with the incoming air, therefore there is no influx of contaminated air back into the house… if anything the hrv system works as an efficient exhaust vent system. the temps required to allow legionella wont be reached in the exhaust system as long as common sense prevails with condensation issues.