API API-936 - API 936 - Refractory Personnel

API 936 specifies that:

“The owner shall provide acceptance criteria for hammer testing, visible cracking, and surface voids.”

— API Std 936, Section 8.3.1​

This ensures that acceptance standards align with the owner’s operational and design tolerances. Option A is correct.

The curing of newly installed refractory linings must adhere strictly to manufacturer guidelines to ensure integrity and performance:

“Forms shall not be stripped until the lining has cured per the manufacturer’s recommendation.”

— API Std 936, Section 5.4.2.1​

The manufacturer's recommendations ensure that the product reaches sufficient strength before demolding.

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mixing time

mix water levels

installation procedures

According to API Std 936 and supporting guidance from TR 980, cast sample mock-ups are used during pre-installation trials to ensure the suitability and repeatability of installation variables such as mixing procedures and water content. These mock-ups are critical to confirm that the material can be properly installed under anticipated field conditions.

From API 936:

“Mock-up cast sample trials shall be used to demonstrate the adequacy of the mixing time, water addition (mix water levels), and installation procedures prior to production installation.”

— API Std 936, Section 6.3.2​

This ensures that full-scale application performance is achievable using the approved methods and materials. However:

The “quality of the inspection equipment” and

“fabricator of the mock-up”

are not part of the qualification objectives defined for cast sample testing.

Correct selections:

mixing time

mix water levels

installation procedures

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 TR 980 – Monolithic Refractories: Installation and Dryout, when multiple heat sources are used during refractory dryout, the final approval must come from the Owner:

“If more than one heat source is used, the contractor shall obtain written approval from the Owner for the dryout procedure.”

— API TR 980, Section 6.2.2​

While the contractor may propose or execute the dryout, the responsibility for ensuring its validity and safety—especially when multiple heat sources are involved—rests with the Owner.