Your Feb. 4 article "How To Keep Those Home Fires Burning Safely" by Lois Gibson was informative and well researched with the exception of Gibson's suggestion of using one chimney to accommodate more than one fireplace or barbecue. Although such an arrangement may be convenient, it would not be in compliance with building codes and may be hazardous.
Each solid-fuel burning appliance should be connected to its separate flue. Certain gas-fueled appliances may be common-vented with certain other gas appliances if both appliances are within the same room or zone. Common venting of multiple appliances located on different floors requires specialized techniques. The most common technique is to locate all the appliances outside of, and isolated from, habitable spaces.
In most circumstances, the above code-based requirements would prevent the use of a single chimney for venting more than one fireplace. Obtaining a permit from the building authority should ensure a safe and legal fireplace installation.