Exterior 100mm wall grill for kitchen fan

[Possom]

I'm choosing a grill to place on an external wall as a vent from a kitchen extractor fan.

I noticed the one below, though possibly it doesn't have the protruding circle on the back for the tubing to be connected to.

If that's the case, I presume it's one with a protruding circle on the back I would need? That is, unless there's some way of connecting up the tubing.

 

[noseall]

There is no need to connect the duct hose as long as you terminate the hose robustly, to the outermost part of the masonry, using sealant etc. It will discharge through the grill just the same.

A lot will depend upon how neat the hole is. We often sleeve ours through the wall with a short length of 110mm drain pipe and then make good the masonry against the rigid pipe. If your hole has been neatly core drilled then there is no reason why the softer hose can't be made good with cartridge type sealants.

 

[John D v2.0]

Nose all has answered you but as an additional, We actually used the next size up of grille 150mm round, but the pipe coming through the wall is 125mm. This is to make things quieter as the grille has quite a lot of pressure drop. Actually if you can, the bigger the duct the better to keep the noise down at the fan unit. Noise is the reason many people hate cooker extractors.

 

[Possom]

We actually used the next size up of grille 150mm round, but the pipe coming through the wall is 125mm. This is to make things quieter as the grille has quite a lot of pressure drop. Actually if you can, the bigger the duct the better to keep the noise down at the fan unit. Noise is the reason many people hate cooker extractors.

Is the diameter of the tubing is dictated by what is required by the cooker fan?

What would be the standard diameter for cooker fan tubing (small kitchen)?

Do you prefer to use a gravity/flap grill as opposed to the one pictured above which is permanently open?

 

[John D v2.0]

Is the diameter of the tubing is dictated by what is required by the cooker fan?

What would be the standard diameter for cooker fan tubing (small kitchen)?

Do you prefer to use a gravity/flap grill as opposed to the one pictured above which is permanently open?

Yes the diameter for any half decent fan should be at least 125mm, ideally 150mm. Check the instructions for a minimum standard.
Flaps on the grille can be very noisy on windy days, if you get a cooker hood with an internal flap, and an open grille it shouldn't be so bad.
If you omit the flap completely it can get cold and draughty inside.

 

[Possom]

Flaps on the grille can be very noisy on windy days

I did notice that external flap grills come in plastic or metal.

Plastic grills can look a bit "cheap", though I suppose are quieter, the metal flap grills (below) look a bit classier. If choosing a flap grill I might possibly choose a plastic one just for quietness.

 

[John D v2.0]

Plastic won't be quiet. The only way to have quiet during wind is to put the flap on the ducting internally.

 

[John D v2.0]

Anything along these lines

https://www.airflow.com/Products/pg_BDF/Backdraught-Flaps

 

[Possom]

Anything along these lines

https://www.airflow.com/Products/pg_BDF/Backdraught-Flaps

Very nice, I wasn't aware of these.

So does one of these go at the external grill end of the ducting (internally), or at the cooker fan end of the ducting (ducting might be 2 metres in length)?

 

[noseall]

All of the cooker hood extractors I have seen are 125mm and above.

 

[John D v2.0]

So does one of these go at the external grill end of the ducting (internally), or at the cooker fan end of the ducting (ducting might be 2 metres in length)?

I'd probably go for the cooker hood end, but it doesn't make a big difference. As long as the wind can't catch the edges and slam it open and shut.