It is not an easy question what kind of labels should be sticked to the lab door. Since smoking is forbidden in all FU buildings it seemes not to be meaningfull to repeat this prohibition at every lab door.
Very important is a hint, that unauthorized persons may not enter the lab. In a legal sense then all harzardous chemicals are protected, because nobody may grab them without violating this prohibition.
You may download this example for a lab labelling.
Adjust it to your needs. If you use it as a template this will have the advantage that all labellings of the lab doors have the same layout.