Clay air brick or plastic vent for kitchen extraction?

[johnnyBv8]

I’ve recently fitted a downdraught induction hob in our kitchen. It currently just vents into the crawl space below the floors, as haven’t pipe-connected it to a vent in the exterior wall of the house. I’ve just knocked out a brick for this and was about to use one of those plastic terracotta vents, but it’s pretty orange so I was wondering about getting a clay air brick instead which would look better. It’s a 100 year old red brick house.

This is part of a building warrant, which requires me to have 30l/sec mechanical extraction. Does anyone know if the building inspector will complain if I use a clay air brick instead of a plastic vent?

[Crumpet]

I’d have thought an air brick would be pretty restrictive compared to a proper flappy vent thing. Even the ridges in flexi pipe ruins the flow. Plus if any grease gets past the filter it’s going to build up in the non-removable air brick.

I’m not a pro, but I have just fitted two extractors in our kitchen and do understand where you’re coming from with the aesthetics. For me it’s function over form for this one.

[smokey mow]

Crumpet said:

I’d have thought an air brick would be pretty restrictive compared to a proper flappy vent thing. Even the ridges in flexi pipe ruins the flow. Plus if any grease gets past the filter it’s going to build up in the non-removable air brick.

I’m not a pro, but I have just fitted two extractors in our kitchen and do understand where you’re coming from with the aesthetics. For me it’s function over form for this one.

I agree.

A typical terracotta airbrick has a free area of around 1300mm2 which is about the same as a single 40mm diameter hole.

A plastic air brick is around 6000mm2 but that’s still half the area of the extract ducting.

[johnnyBv8]

These are the 2 options I was looking at - there’s only 1 brick height available (there are 2 brick courses below the floor but above ground level, and I don’t want the vent in line with the ground or what will run through. The induction hob runs through standard filters and acoustic filters and will then be piped under the floor in 220x90 ducting (as per Bosch manufacturer) to the external vent

[Rough101]

I’ve a plastic flappy thing on ours, they come in a kinda terracotta colour, the air bricks are far too restrictive and you need 150 diameter equivalent the whole way if using for building warrant.

[johnnyBv8]

Ok, thanks. I’ll ditch the air brick idea! Plastic one is 6450mm vs 1300mm for brick.

Edited by johnnyBv8 on Sunday 9th February 15:06