Importance of the sliding doors
in the control of Vermiculations |
Since
the installation of the Machine Room (Salle des Machines) at the
entrance of the Lascaux cave, it is separated from the Bulls' Room
(Salle des Taureaux) by a wall. This wall carries several openings:
Michel Goldberg- one door giving access to Bulls' Room, - two upper openings allowing the warm air - which accumulates by convection at the vault of the Bulls' Room near its entrance - to leave the cave and penetrate into the Machine Room - two lower openings allowing the cooled air which accumulates by convection at the bottom of the Machine Room to penetrate into the cave. The upper and lower openings thus allow air exchanges by convection between the Machine Room and the Bulls' Room. They are an absolute requirement for a proper control of the temperature and hygrometry of the cave by means of the climatic assistance machine set up in the Machine Room. However, these openings are usefull only during periods of activity of the climatic assistance machine, i.e. about six months per year. This is why they have been equipped with sliding doors aimed at isolating the Bulls' Room from the Machine Room whenever their communication is unnecessary. Closing these openings is highly recommended during periods of very low temperatures so as to prevent air from the Machine Room, exageratly cooled either by cold air coming from outside via the gate or by thermal exchanges with the outside, from rushing into the cave. Keeping the sliding doors open during cold periods results is an important lowering of the cave temperature and quasi instantaneous drying of its walls. During the last meeting of the Scientific Council, Paul-Marie Guyon and Pierre Vidal learnt that, since several years, the sliding doors of the Bulls' Room are out of order, and blocked in the open position. The administration does not consider repairing them, considering that the repair works of the sliding door might have deleterious effects on the balance of the cave. We consider that the blocking of the sliding doors represents an even bigger risk for the cave. Indeed, alternating periods of excessive humidity and dryness, of which we know that they are the main and undisputable cause of vermiculations (see the note by Pierre Vidal on vermiculations) impose a proper closing of the sliding doors to avoid a quick drying of the cave walls during cold periods. Furthermore, blocking open the sliding doors increases the risk of cross contamination between the Machine Room and the Bulls' Room during the periods when an air exchange between these two rooms is unnecessary. We therefore wish to strongly insist on the necessity of setting up a system allowing one to block at will air exchanges between the Machine Room and the Bulls' Room. This could be done either by repairing the sliding doors, or by replacing them with new ones, or by setting up a "light" system made of removable isolating panels. |
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