This standard test method establishes two recommended methods for measuring the relative carburization resistance of alloys for tubes intended for service in ethylene cracking furnaces, or for assessing the performance of these tubes after service. Application procedures for the two methods are defined in detail. The combustion analysis method is preferred because it is quantitative. The chemical etching method is simpler and less expensive, but is only semi-quantitative. Other methods considered and the reasons they are not recommended are discussed in Appendix A.