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

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.

When drying out units withmultiple types of refractories, API 936 and API Technical Report TR 980 emphasize that the most conservative dryout schedule must be followed to avoid premature failure orexplosive spalling. This meanschoosing the refractory material or lining system that requires the longest duration or slowest heating rate.

Different refractory types—gunned, cast, plastic, or fiber—have varying sensitivities to moisture and thermal gradients. Selecting the schedule with the longest duration ensures full water removal, especially from thick sections or materials with high water retention capacity.

According to API 936, ceramic fiber batten strips are used in fiber lining applications to secure joints or protect against gas penetration. The specification sets a strict requirement on their length:

“Ceramic fiber batten strips shall be a maximum length of 3 ft (0.9 m).”

— API Std 936, Section 5.3.2.3​

Other anchoring methods such as lock studs or staples may apply in different contexts or materials, but they are not prescribed for ceramic fiber batten strips per this specific requirement.

Removable back panels in gunning test panels are requiredto allow inspection for internal defects, particularlyvoids, laminations, and rebound pocketsthat are not visible from the surface. These panels are taken off after gunning so that the interface between layers or the entire cross-section can be visually examined.

This approach ensures that the test section is representative of actual field performance and that the gunning technique (angle, nozzle distance, rebound control) is achieving full compaction without defects.

Hydraulic bonded castables, such as those using calcium aluminate cement, cure through ahydration reactionthat requires the presence of water. Premature drying due to wind, sun, or heat can halt the hydration process, weaken the structure, and cause surface cracking. API 936 mandates thatno part of the exposed surface of the castable shall be allowed to dry more than 3 hoursbefore a membrane curing compound is applied.

This statement ensures:

Retention of sufficient surface moisture for ongoing hydration.

Prevention of microcracking, which can later act as stress risers during service.

Uniform strength development across the lining.

The curing compound forms a film that limits evaporation, allowing for continued hydration over the next 24–48 hours.

Hydrationrefers to the chemical reaction between water and cement components in refractory concretes (hydraulic bonded castables), resulting in the formation ofcalcium-aluminate hydrates, which are responsible for initial strength—known asgreen strength. This strength enables the lining to be demolded and eventually dried without mechanical failure.

Hydration is not related to final heat resistance or dryout; those come later during the firing or heat-up stages. It is distinct from setting in air-setting refractories or sintering in ceramic-bonded types.

According to API 936, thecontractoris the entity responsible for overseeing and implementing the quality control system for refractory installation, which includes the documentation of all material and applicatorqualification test results. This responsibility includes maintaining traceability, ensuring compliance with testing protocols, and presenting evidence of conformity for review.

API 936 outlines that proper documentation is part of the contractor's quality assurance program and must be made available to the inspector and owner upon request. This ensures that refractory materials and installation personnel meet the project requirements before work proceeds.

According to API Std 936, responsibilities are clearly defined when it comes to conflicts in documents or drawings:

"Where conflicts exist in documents and/or drawings, resolution shall be by the owner."

— API Std 936, Section 4.2.1 Responsibilities​

Therefore, Option B is correct. Inspectors may report or note discrepancies, but only the owner has the authority to officially resolve such conflicts.

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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.

Cold wall refractory systems are typically backed by steel shells, which are poor at withstanding the thermal stresses that come from reverse heating. API 936 and API TR 980 clearly emphasize thatthe heat-up or dryout process for cold-wall linings must always begin from the hot face— that is, the process-exposed surface.

Heating from thehot faceallows for controlled migration of moisture toward the cold face and eventual venting to the atmosphere. Conversely, heating from the cold face or steel shell side traps moisture between the hot impermeable material and the outer surface, leading to:

Steam buildup

Explosive spalling

Cracks in the material or at the interface with the steel

For these reasons,only the hot facemethod is specified unless the design and dryout plan justify a different method under special engineering review.