Posted By Son of SkyWalker What about allergic reactions? They can appear to be colds but are not.

Posted By Sharon You also need to look at natural ventilation does the air con circulate fresh air from outside or is the air recirculated? Is the air con unit serviced regular?

Posted By Konstanty Budkiewicz To aid your understanding about Colds in general, please try the following link. http://www.commoncold.org/prevent1.htm For my part, when colds are rampant in the work place, I urge collegues not bite their nails, or put their fingers, or, pens in their mouths, and to wash their hands before eating or drinking. If your staff are not using disposable cups for drinking, I would advise them to wash cups and mugs before re-charge (they can harbour germs in a sneeze zones. These measures appear adequate in reducing the cross contamination risk. Re air con - Our office air con has approx 2 changes per hour with fresh air top-up and I have no evidence of this accelerating cross contamination amongst staff. Some staff have had infections since October, and others have remained cold free this Winter. Also, there is a hidden HR issue, ideally staff should stay off work when infected (see web site). Contract workers, in my experience will stay at work no matter how ill they feel (and cross-infect others). You may need to advise when attendance is not acceptable. Secondly, I note that those with school-age children are most at risk. This would indicate that the infection risk is largely at home and not at work Regards Kon

Posted By CFT Alice Sadly fresh air is not quite what one perceives it to be in these units and for the sake of argument I am assuming either, VRV/VRF with ceiling cassettes, wall units or a packaging unit. The former usually units have only around a 10% fresh air intake anyway so even with the recirculating mode on permanently you are not going have huge problems. Any method of propelling air around an area is bound to circulate germs; any worse than as identified earlier vis, a sneeze, touching, coughing and so on? I doubt it very much. I am no cold expert, so I can't tell you how long the germs need to survive to re infect an individual, they also have a way to travel, through the fan coil, around it/ across the filters and out again; with a packaging unit (identifiable usually by ceiling blades) these also would only be able to spread germs through propelled air, much the same as a sneeze but without the force. I suspect your people are off because they work in close proximity of one another and someone kicked it off; that sneeze, the kissy thing that seems now to be the norm (first the left cheek then the right, what is that all about???)the touch, outside of work, sharing glasses and so on. And no, I don't believe AC is remotely capable of causing a cold all on its own;-) CFT