Pass the API ICP Programs API-936 Questions and answers with ExamsMirror

To minimize rebound during gunning, API TR 980 clearly instructs to:

“Begin at the lowest level of the installation and build up gradually to full thickness in a small area of approximately 10 ft² (1 m²), avoiding sweeping motions.”

— API TR 980, Section 4.3.4​

This method prevents rebound contamination and cold joints that could occur if a larger area is covered too quickly or in an uncontrolled pattern.

Therefore, Option C is correct, and Options A, B, and D are incorrect according to best practices outlined in API TR 980.

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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.

Pigment in curing compounds serves a visual function to verify that the applied coating has achieved full and even coverage across the refractory surface. This aids inspectors in confirming compliance with curing requirements.

When the owner does not provide explicit temperature criteria for mixing and placement, the refractory manufacturer’s instructions prevail:

“If not specified by the owner, the refractory manufacturer’s published recommendations shall be followed for temperature limits of both material and mixing water.”

— API TR 980, Section 4.5.2​

Thus, Option B is correct.

According to API Standard 936, water used in the preparation of refractory mixes is subject to quality limitations, especially when stainless steel anchors are embedded in or come into contact with the refractory that is installed on a carbon steel surface. High chloride concentrations in the mixing water may promote corrosion in stainless steel anchoring systems.

API 936 explicitly states:

“When water is used for refractory installed on a carbon steel surface with a stainless steel anchorage, the chloride content of the potable water shall not exceed 50 ppm.”

— API Std 936, Section 5.1.2​

This clause is intended to protect the integrity of stainless steel anchors from chloride-induced stress corrosion cracking or pitting, which can compromise the mechanical support of the refractory lining.

Therefore, Option A (50 ppm) is the only correct and code-compliant answer.

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For linings intended for erosive service, API 936 requires testing that includes specimens that experience real service wear simulation:

“For erosive service, bulk density shall be determined using the abrasion resistance test specimens and the linear change specimens.”

— API Std 936, Section 6.4.3​

Thus, both abrasion plates and linear change bars are used to evaluate density in erosion-sensitive applications.

When qualifying materials and personnel for gunning applications, the standard test panel orientation is:

“The gunned panels shall be prepared on steel plate forms inclined at 45° to the horizontal.”

— API Std 936, Section 6.5.1, Gunning Test Panels​

This standardized angle helps evaluate rebound and build-up in conditions that simulate typical applications.

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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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According to API 936, thecontractoris responsible for submitting adetailed dryout procedure. This procedure must be reviewed and approved by the owner or the owner’s representative. While manufacturers may provide guidance, the contractor is accountable for ensuring the procedure aligns with project specifications, material requirements, and environmental conditions.

According to API 936, duringapplicator qualification testing, the equipment used must beidentical to the equipment that will be used in the actual installation. This ensures that all conditions (air pressure, nozzles, mixers, vibration tools, etc.) accurately reflect field performance and allow for a true demonstration of the applicator’s ability to meet the project’s quality requirements.

This rule eliminates discrepancies between mock-up performance and production work, which might otherwise compromise the quality of the installed refractory. Testing with alternative or idealized equipment does not represent real installation challenges.