102.Natural ventilation: In any establishment where overall ventilation is provided by natural means, it shall be obtained by means of windows, shutters or vents having a ventilation area at least equal to the percentage of floor area indicated in the following table, according to the type of establishment in question:
Type of establishment Percentage of floor area
Laboratories and office buildings 5%
Any other establishment 2%
For the purposes of this section, floor area does not include stairwells and other vertical empty spaces.