Hi,

Is there any regulations that state where a thumb turn lock is needed. A riser cupboard at my work place is large enough to walk into it & if any work is being done in there it can be locked  and if someone was in there they would have no way of getting out. As I do the maintenance around the building I have raised this query with my manager but nothing as been done.

I would advise your employer to carry out a risk assessment for this issue.  If it is felt that there exists a risk of a person being trapped inside then the lock should be changed to provide for keyless egress.