Tristarsteve wrote:madpropsyo wrote:I mean it's not just going to be cold feet, right? Those rows in the cabin over and near the RCT will be very cold in general if there's an icebox on the floor. So either the passengers in those rows will be very cold or the rest of the cabin will have to be overly hot to compensate. That is a pretty significant lose/lose comfort issue to work out and it's no wonder the airlines with orders are unhappy.FluidFlow wrote:So the design of the tank is actually safe but it is not comfortable, except for one risk that is an external fire:
Lol, yeah it's totally safe... except for the fire.
Why should there be an icebox on the floor.?
The fuel in that tank is inside the pressure hull. It is loaded at around 5 degC or more, and is then warmed up by the cabin air flowing around it. Depends how they vent it , but current tanks are pressurised with cabin air, not vented to ambient
Any gap in insulation blankets beyond an inch or two will make the cabin cold. This is why it is cold around exit doors. Cold air doesn’t get inside through a plug door, but there is area around the door surround that doesn’t have insulation due to the door mechanisms. A huge chunk of floor with no insulation, other than a fuel tank between the floor and outer skin, is going to be uncomfortably cold.
Beyond the coldness factor, the insulation blankets are for fire prevention. They have requirements to withstand a fuel fire for 4 minutes to allow the passengers to escape before the fuselage is penetrated by flames. No insulation blankets between the tank and cabin creates a risk that a fuel fire could quickly go through the floor and enter the cabin before people can evacuate.