Part F and Trickle Vents (Calculation)

peter_dublin

Hi.

Does anyone know when calculating the ventilation provided by a trickle vent which figure do you use, I am looking at having Ventair Simpress fitted to new windows so I can close up old wall vent which given the site are wind tunnels.

http://www.brevis.com.pl/en_pressure-ventilators.html


Is it the closed value, the open value or an average.

Thanks

BryanF

http://www.environ.ie/en/Publications/DevelopmentandHousing/BuildingStandards/FileDownLoad,1647,en.pdf

fatty pang

IMHO trickle vents in windows are not fit for purpose.
If they are big enough to provide useful ventilation then they will also be drafty and closed by the average occupant on the first windy day… and subsequently forgotten about.
If they are in the head of the window (the best place for weather protection and minimising drafts) they are often hard to reach and as a result…. left closed again.
If they are in the jambs of windows they are highly susceptible to leaking water in exposed locations and/or will be drafty to occupants sitting in close proximity… and again closed and forgotten about.

If you start adding some of the fashionable third-party products similar to that described then you will simply reduce the airflow even further. Great for drafts but not so good for indoor air quality.
The figures supplied for airflow and acoustics are pretty meaningless as the vent should be tested on the actual window it will be fitted to rather than a generic window.
The volume of background ventilation specified by Part F varies with the design air permeability of the building. If your architect is planning to use the Equivalent Area volumes then by rights you should have test data for the vent on the specific window as the rate of airflow will vary with the path the air takes. If the choice is to use the Free Area volume then you will have to have the geometric area 25% larger the area shown in TGD- F Table 1. That volume will have to be increased by a further 40% if your design air permeability is less than 5m³/h/m² - which is where you want to be aiming for anyway.
More and bigger holes – great for drafts and noise !

Holes in windows is not the way to sort out the problem of providing good indoor air quality in buildings.

peter_dublin

Hi.

Thanks for the replies, as the building was built in 1990 it has a vent in each bedroom and only an open fireplace with mechanical ventilation in the bathroom and kitchen.

The issue is that we had the cavity pumped and other improvements which means its more air tight and if the extract fan is on in the kitchen it sucks air from the fire pulling smoke into the room if the bedroom doors are closed.

As we are getting new windows we were looking at having vents installed in each window which would supply all rooms with their own source of fresh air to meet the 35000 requirement for the property.

Thanks

sydthebeat

peter_dublin wrote: »

Hi.

Thanks for the replies, as the building was built in 1990 it has a vent in each bedroom and only an open fireplace with mechanical ventilation in the bathroom and kitchen.

The issue is that we had the cavity pumped and other improvements which means its more air tight and if the extract fan is on in the kitchen it sucks air from the fire pulling smoke into the room if the bedroom doors are closed.

As we are getting new windows we were looking at having vents installed in each window which would supply all rooms with their own source of fresh air to meet the 35000 requirement for the property.

Thanks

so no permanent ventilation in the room with the open fire?

can you not just drill a 4" vent hole in the wall?
as has been said previously, trickle vents can be closed and left closed....

peter_dublin

sydthebeat wrote: »

so no permanent ventilation in the room with the open fire?

can you not just drill a 4" vent hole in the wall?
as has been said previously, trickle vents can be closed and left closed....

Not in this case as it's an apartment building and it's not allowed.

Thanks