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

According to API Standard 936, the correct specimen dimensions for cold crush strength testing are:

“Test specimens for cold crushing strength shall be2 in. (50 mm) cubesamples prepared in accordance with ASTM C133.”

—API Std 936, Section 6.4.2​

This directly invalidates option A, which incorrectly states the specimen size as 4-1/2 inches.

For the other options:

Option B – Density determination:

API 936 states that density shall be measured using the same specimens used for linear change and abrasion resistance:

“Bulk density shall be determined using the same specimens prepared for the linear change and abrasion resistance tests.”

—API Std 936, Section 6.4.3​

“These specimens include cubes, linear change bars, and erosion plates.”

—Appendix A, API Std 936​

Option C – Abrasion resistance specimen size:

“Two 4-1/2 in. × 4-1/2 in. × 1 in. (114 mm × 114 mm × 25 mm) specimens shall be prepared for abrasion resistance testing.”

—API Std 936, Section 6.4.4​

Option D – Permanent linear change specimen size:

“Permanent linear change (PLC) is determined with a bar 2 in. × 2 in. × 9 in. (50 mm × 50 mm × 230 mm) cast in steel molds.”

—API Std 936, Section 6.4.1​

Therefore, Option A is the only false statement.

The API 936 terminology section defines "green refractory" as:

“Green Refractory: A monolithic refractory that has been placed but has not yet been exposed to curing or dryout temperatures.”

— API Std 936, Section 3: Definitions​

Thus, “green refractory” is the technically correct term for the unheated, freshly installed condition.

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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.

According to API TR 980, a form must be able to support its own weight and the pressure from the refractory material:

“Formwork shall be self-supporting and capable of withstanding the static and dynamic loads imposed during installation.”

— API TR 980, Section 4.2.1, Form Requirements​

Transparency and chemical resistance are not required characteristics for refractory formwork in installation.

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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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.

According to API Std 936, cold crushing strength tests for non-erosive service require:

“For non-erosive service, a minimum of two specimens per sample shall be tested for cold crushing strength.”

— API Std 936, Section 6.4.2, Cold Crushing Strength​

This ensures adequate verification of mechanical integrity without the more stringent criteria used for erosive applications. Therefore, Option B is correct.

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Apparent porosityis a measure of the volume of open pores (voids that can absorb water) within a refractory sample, relative to the total volume. It is always expressed as apercentage. Testing is done using standards such as ASTM C20, which API 936 references. This metric is crucial for understanding a material’s permeability, thermal shock resistance, and mechanical integrity.

When installation is interrupted, the partially installed refractory must becut back to the shell between anchorswhile it is still workable. This ensures a clean, rough bonding surface free from weak or partially set material. API 936 requires this method for bothhydraulic bondedandchemically bondedsystems to preserve lining integrity and avoid delamination between old and new material.

According to API Std 936, which incorporates ASTM C181 by reference:

“Each sample tested for workability index in accordance with ASTM C181 shall consist of three specimens.”

— API Std 936, Section 6.4.6 Workability Testing​

Thus, Option C is correct. This testing ensures consistency in the flow characteristics of castable refractories prior to installation.