I have an opportunity to install a large observation hive in a commercial building as part of a food market kiosk.. A major concern is the length of the tube. Due to the locaton in a busy urban area we wanted to go straight up from the hive and out the roof (flat roof) to keep the bees away from the public sidewalks . After perusing the web I found some reference to straight up access being a problem. How long is too long? The ceiling height is over 15 ft. Does anyone have some experience with large indoor installations and plumbing them to the outside world? -- Visit www.honeybeeworld.com/bee-l for rules, FAQ and other info ---