Recording the number of storeys above ground as a range can be used to reflect either the surveyor’s lack of certainty for a single building, or when height ranges are used in regional surveys.
HBET:a,b
where a=upper bound and b= lower bound for the range
Example: HBET:3,1 (height range from 1 to 3 storeys)
Height of buildings within this block in Lisbon, Portugal ranges from 4 to 5 storeys (S. Brzev)