The premises mentioned in article R. 4227-22 as well as those in which substances or preparations classified as highly flammable or materials in such a physical state that they are likely to catch fire instantly on contact with a flame or spark and to spread the fire rapidly, are used in such a way that :
1° No normal workstation is more than 10 metres from an exit to the outside or to a room which itself opens to the outside;
2° The doors of these rooms open to the outside;
3° If the windows of these rooms are fitted with grilles or screens, these can be opened very easily from the inside.