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

The cure period before initiating the dryout process is a critical phase of installation:

“Newly installed air-setting, hydraulic, and chemically bonded materials shall be allowed to cure for a minimum of 24 hours at 60 °F (16 °C) or above prior to initial heating.”

— API TR 980, Section 6.2.1​

This condition ensures chemical bonding processes are complete before exposure to thermal stress.

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API 936 clearly stipulates that the selection, installation, inspection, and testing of anchors must comply with theproject's drawings and specifications. These documents define anchor spacing, type, material, orientation, and welding requirements, which must be followed during construction and QA processes.

API 936 does not defer this responsibility to external documents like API RP 577 or welding codes unless explicitly referenced in the project specifications. QA/QC departments may oversee adherence, but do not define the criteria themselves.

API 936 clearly states that applicators/installers must be qualified to demonstrate the ability to install refractory linings in accordance with the specified project quality standards. This includes using the correct methods, achieving proper material density, and avoiding defects like voids and laminations.

API Std 936 defines the acceptance criteria for CCS under erosive service in Section 6.4.2:

“Test values for cold crushing strength shall meet or exceed 75% of the manufacturer's minimum published value for each individual specimen.”

— API Std 936, Section 6.4.2​

This criterion ensures that all tested samples meet a critical durability threshold before field acceptance.

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.

The term “overlay” is defined in refractory terminology as:

“Overlay: A layer of refractory material applied over an existing lining, generally to extend service life or repair localized damage.”

— API TR 980, Section 2, Definitions​

The other terms do not carry this specific meaning in the context of refractory maintenance.

Mock-up installations serve as a qualification tool to verify that the installation procedures, personnel, and equipment can consistently meet quality standards. API 936 stipulates that refractory samples cast during the mock-up must becured for a minimum of 24 hoursbefore demolding or further processing. This curing period ensures full initial set and adequate strength development of the castable.

Failure to meet this curing requirement can result in incomplete hydration, premature cracking, or misleading performance test results. The 24-hour period allows for optimal moisture retention and chemical reaction completion in hydraulic-bonded castables.

API TR 980 provides guidance for hot weather installation, recommending:

“Preventive measures include shading material and equipment, cooling of mix water and forms, and in some cases, air conditioning of ambient air. Spraying water on equipment may be used to reduce radiant heat.”

— API TR 980, Section 4.5.2​

However, decreasing mixing time is not advised; it can result in insufficient material wet-out or inconsistent dispersion. Therefore:

A (air conditioning): Acceptable

B (decreasing mixing time): Not acceptable

C (shading): Acceptable

D (spraying water): Acceptable

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As per the testing procedures outlined in API 936:

"All specimens used in ASTM C704 and ASTM C133 tests shall be dried and fired to 1500°F (815°C) prior to testing."

— API Std 936, Section 6.3.1​

Firing to 1500°F ensures proper evaluation of the refractory's behavior under service conditions.

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.