James Harris wrote:
7`
I got some ideas from the official regs but overall found them
confusing so, yes, I think I'll need to ask.

In summary this is for a first floor flat with a concrete floor.
There is a neighbouring flat below and a loft above. An air brick
vents into a kitchen cupboard.

Am concerned about ventilation into the flat rather than that to the
interior of the walls. I gather there are two reasons for such an air
brick: condensation and keeping the air quality acceptable. About
right?
How much airflow is required into the kitchen and other rooms? Does it
depend on whether there are naked-flame fires in those rooms? (The
flat has no gas or open fires. All cooking and power are electric.)

Reason for asking: to limit winter cold air flow to just what's
needed but also to ensure enough is maintained. The flat was built
around 1990 if that gives some idea of the likely airtightness of the
rest of the flat apart from the air brick.

Any guidance appreciated.

James

The airbrick is probably left over from when there may have been gas
appliances in the flat, IE a CH boiler although it's possible someone may
have added it for another reason.
I have a 3 bedroom mid terrace with a condensing boiler upstairs and a
woodburning stove in the living room.
There are no vents anywhere in the house, nor any condensation or damp.
There's enough ventilation coming through the poorly sealed aluminium window
frames and the letterbox, also people opening and closing doors every day.

If the vent in your kitchen is causing a cold draught, you can seal it up,
there are no safety issues as you don't have gas in the place, but it may
have been keeping condenstaion down, so if it were mine, I'd seal it with
tape and cardboard for a year to see if anything happened, if not, seal it
up completely by removing and bricking up and then plaster.

It can't be a cavity vent as the walls will be filled with insulation if it
was built in the 90's, ergo, there's no cavity to ventilate.

I'm not sure what glazing you have but I'd guess DG? - often there are
permavents on such frames, but even without them, there's still enough
ventilation and you'd be surprised where this air comes from - not long ago
I worked on some new build houses and they had a vaccuum test done on each
house to see how much draught etc was getting in, the chap affixed a huge
plastic sheet over the (open) front door and sealed it all around. In the
centre of the sheet was a big fan, about 2ft across which blew the air out
of the house, while he went around with his instruments to measure the
draughts in each room - they were everywhere.
Gale force winds blowing out of the sockets (the air was coming down the
conduit from the loft), wind blowing from under the skirtings (coming from
behind the dry-lining), tiny holes around pipes and cables going through
exterior walls allow a draught as do upstairs light fittings that allow loft
air into the rooms below, and this had only been built in 2012, with unseen
cracks etc that you will undoubtedly have, I wouldn't worry too much about
room ventilation