I.-Without prejudice to the provisions of articles R. 4227-28 to R. 4227-33, the following fire-fighting measures are taken for fixed installations within the pyrotechnic enclosure:
1° The immediate surroundings of pyrotechnic installations are weeded and cleared of undergrowth. The products used for weeding and clearing are of such a nature that they cannot cause dangerous reactions with the materials used in the pyrotechnic enclosure;
2° Pyrotechnic installations where substances or objects are handled which, due to the operations carried out, present a high risk of ignition which could lead to a fire, are equipped with an automatic extinguishing system compatible with the nature of the products to be extinguished. It must also be possible to operate this system manually from a location that remains accessible and protected in the event of a fire breaking out in the installation concerned;
3° Automatic fire detection systems controlling an instantaneous alarm system are installed in installations where equipment likely to cause fires, such as ovens or driers, are operated without permanent supervision.
II – However, without prejudice to other regulations applicable to fire-fighting, the devices provided for in 2° and 3° of I are not required if the fires envisaged cannot, due to the nature or quantity of the substances concerned:
1° Spread to neighbouring installations ;
2° Nor initiate a pyrotechnic event;
3° cause dangerous projections or the release of dangerous quantities of toxic gases or vapours.