What constitutes the acceptance/rejection criteria for qualifications testing according to API 936?

The acceptance/rejection criteria for qualifications testing according to API 936 emphasize that physical properties must meet established criteria fully. This means that each tested sample’s physical characteristics, such as compressive strength, thermal shock resistance, and density, must adhere to the predetermined standards specified in the relevant API guidelines. Meeting these criteria demonstrates that the refractory materials perform as expected under operational conditions.

Testing is critical in ensuring that the materials used in construction can withstand the intended service environment. If a material fails to meet the specified physical properties, it cannot guarantee the integrity and durability necessary for industrial applications. Therefore, the criteria are designed to ensure that only those materials that perform to the required standards are accepted and used.

Although other options may involve relevant aspects of testing or approval processes, they do not capture the essence of the complete and unconditional requirement represented in the correct answer. For instance, average properties meeting minimum standards could allow some materials that do not perform adequately to be accepted. Similarly, the notion that all samples must be tested before application, while generally good practice, does not encapsulate the essence of the acceptance criteria fully. Moreover, automatic rejection for any failure implies a lack of nuance in assessing degrees of failure or alternative remedial actions that might be considered based on the nature