How should support spacing be specified for industrial heating elements?

Support spacing should be set from tube length, maximum sheath temperature, material and diameter together: first estimate the allowable span from surface load and thermal expansion, then choose a value that prevents hot sag without crushing the insulation. High-temperature or large-diameter elements usually need closer spacing, horizontal runs are more critical than vertical, and long horizontal tubes should have a sliding support near mid-span. Ask the supplier for the design basis and calculated span, then verify hot-position deflection and support contact marks after installation, and cross-check wattage, protection rating, temperature control method and mounting dimensions so supports neither restrict expansion nor create cold spots.