Belfast·SPG004 Residential Extensions and Alterations·Page 37·4.3.9
Use of obscure glass and high-level windows
Obscure glass, Velux windows and high-level windows can minimise overlooking problems, but should not be used for windows serving main rooms such as bedrooms, living rooms, dining rooms or kitchens.
The use of obscure glass, velux windows and high-level windows in appropriate circumstances can often minimise this potential. However, this is not considered acceptable for windows serving main rooms such as bedrooms, living rooms, dining rooms or kitchens.
Source — /Users/richardhill/Documents/planning-arch-project/data/documents/belfast/SPG004 Residential Extensions and Alterations.pdf