The only way to ensure that the Northern Line Extension isn't detrimental to our communities in the long term is to lobby to make them work towards decent maximum sound level inside our properties.
The World Health Organization has demonstrated that 32dB Lamax sound levels in a bedroom disturbs sleep and a 35dB sound wakes us up. More here.
This is why the standards we should be asking for are:
Lamax = 32 dB (this is the actual maximum sound when one trains passes)
This is achievable and is the national standard in Norway (more here). It is also not as strict as the level that the Northern Line Extension is proposing to use in their Environmental assesment for other uses such as places of worship and theatres that have a maximum of Lamax = 25 dB.
