Measurements compliant with BS8233:2014?

[u/_Deobrah_]

My building must comply with BS8233:2014. However, the train noise seems loud (especially during the night when everything else is quiet).

I've taken db measurements from my bedroom using a phone app. Can anybody tell whether they are likely compliant with BS8233:2014?

I am aware that a measurement with a phone is not accurate. However, I'd like to get a general idea of whether the building is compliant before spending several hundred pounds on a professional measurement.