For any nitriding potential (Kn) set point value, the average Kn value shall be maintained within limits shown in Table 2 after stabilization of the atmosphere. Stabilization for each stage of the cycle shall be reached such that at least 60% of the stage time shall be conducted under stable conditions for short-duration processes (up to 6 hours) and at least 85% of the stage time shall be conducted under stable conditions for longer processes. Sample readings shall be taken from the outgoing atmosphere. The frequency of readings shall be not less than once every 30 seconds.