How should chemical-liquid compatibility be specified for industrial heating elements?

Specify chemical-liquid heaters by medium, concentration, working temperature and flow, then set sheath material and watt density before fixing power, tube diameter and flange or threaded mounting, allowing enough cold length and wiring space. One stainless grade rarely suits two media, so require compatibility data from the supplier, and for aggressive duties run coupon or live-liquid tests. Define the IP rating, thermal control interlock and over-temperature cut-off logic, and set acceptance limits for leakage and insulation. Record material heat, dimensions and cold resistance on the drawing for incoming inspection of dimensions, cold resistance and insulation resistance, and after start-up verify that sheath temperature and flow stay within design.