A line of positive pressure low intensity infrared tube heaters has been introduced by Space-Ray with a patent-pending Innovative Tube Integrity Safety System (TISS) that provides additional safety for building owners. The TISS system is unique to Space-Ray. Available in both natural and propane gas, the new PTS/PTU Series Tube Heaters from Space-Ray use positive pressure to push products of combustion through the heavy-duty calorized aluminized or alumatherm steel combustion chamber.