At each time we visit a lab, people are confident in the equipment they use for ambient air management while these equipments are not able to respect the basic rules/standards required for cotton testing. In fact, there are missing technical information describing what is and should be any laboratory system able to regulate both temperature and relative humidity in the air in the worldwide agreed tolerances. This system is very complex while some traders can argue that they are able to make it easily, and at the final step, the laboratory is challenged for its results. To counter this, we wish to make a full description of the system with all its components including the regulations rules so that anyone will know what is necessary in his lab and know what to ask when a tender is launched for installing / improving a laboratory.