Hi. Welcome to Just Answer.
Having worked in restaraunts for many years myself I can say that you are absolutly correct. If the building is equipped with ventillation fans, extractors, or hood vents they must be used to eliminate the excess moisture in the building. Moisture is not like hot air. It will not vent itself via convection methods like hot air will (So installing more vents will not do any good). If the building was only a meeting hall it would be different. Meeting halls do not produce steam from boiling foods, high huimidity from the dish washing machines, or grease vapors, and moisture, from cooking foods.
All of the moisture from these things will not vent without the assistance of fans, vent hoods, or other means of mechanical extraction. They will condense on the walls, ceilings, and range hoods.
In the case of range hoods it is mandatory that the hood be on whenever the stoves or grills are. If they are not on the grease will collect and is a very real fire hazard in less than a few weeks of everyday cooking.
Every kitchen I have worked in the very first thing we did after lighting the grills and broilers was turn on all of the fans. The last thing we did after turning off the grills and broilers was turn off the fans.
Extraction fans are used for two main reasons
1) to extract and filter grease laden air away from ignition sources.
2) to prevent excessive moisture in the air that can cause mold development, and to prevent the formation of bacteria in the food preparation and eating areas due to condensed moisture.
Consider the cost of a salmonella outbreak caused by this in the restaraunt. What customers you have will no longer be customers. At least not those that survive. Those that dont, ....Well I think you get the picture.
Please let me know if you have any other immediate concerns.
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