Free Practice Questions for API API-936 Exam

API Std 936 specifies the drying duration for specimens prior to testing as follows:

“Test specimens shall be dried for not less than 12 hours at 230 °F to 250 °F (110 °C to 120 °C) to constant weight.”

— API Std 936, Section 6.3.1, Drying Procedure​

This ensures the specimens are free of moisture and meet consistent testing conditions.

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When using refractory plastics or ramming mixes, it is critical thattrimming, jointing, and venting be performed before stopping work for the day or shift. API 936 and TR 980 specify that proper surface preparation helps relieve vapor pressure during dryout and prevents cracking. If these steps are postponed, the surface may dry unevenly or set improperly, complicating the subsequent installation and reducing bond quality between layers.

Venting paths are particularly important in thick plastic or ramming layers where moisture may be trapped, and jointing ensures layer-to-layer continuity. Trimming also smooths out inconsistencies and aligns the lining to specifications.

The manufactureris responsible for specifying the exactdimensions, type, concentration, and metallurgical propertiesof metal fiber reinforcement in castable refractories. These fibers are often integral to the formulation and performance of the material and are introduced during manufacturing (not field mixing), with characteristics tailored to improve thermal shock resistance and crack propagation control.

API 936 defers to the manufacturer’s technical data for the design and quality control of any material component, including reinforcement. The contractor is responsible for verifying that materials match the manufacturer’s documented specification.

Theinspector’s responsibilities, as defined in API 936, include visual and mechanical inspection of installed linings.Hammer testingis one such non-destructive method used to detect delamination, voids, and rebound areas by listening for variations in sound. It is a practical method during and after installation.

Other tasks like providing compliance documentation or water testing are typically done by the contractor or laboratory personnel.

According toAPI TR 980, Section 4.4.2, mock-ups are required prior to actual installation for vibration-cast materials to verify theadequacy of equipment, the method of vibration, and vibrator attachment. These mock-ups are not intended to assess the craft skill in form construction.

"Mock-up vibration-casting trials are used to demonstrate the adequacy of the equipment, the means of vibrator attachment, and the method of vibration for the particular installation geometry and refractory type."

—TR 980, Section 4.4.2​

Therefore:

B (equipment)is correct.

C (means of vibrator attachment)is correct.

D (vibration method)is correct.

A (craftsman’s ability to construct the forms)is not the intent of this mock-up and thus not correct.