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The API 936 exam has 85 questions and runs 3 hours 15 minutes.
These 10 free API 936 questions are organized by exam domain, so you can see how each part of the Refractory Personnel Certification (API 936) blueprint is tested. Reveal the answer and explanation under each question.
A contractor used more mixing water than the approved maximum. The daily report accurately records the addition and bears the inspector's signature in a box labeled 'Witnessed by.' No deviation approval was issued. The contractor argues that the signature authorizes the extra water. What does the signature establish?
Correct answer: B - The operation was witnessed; the signature does not itself approve the departure.
Two refractory specimens undergo comparable ASTM C704 abrasion tests. Specimen A loses 14.4 g and has a bulk density of 2.4 g/cm³; specimen B loses 18.0 g and has a bulk density of 3.6 g/cm³. Volume loss equals mass loss divided by bulk density. Which assessment of abrasion resistance is supported?
Correct answer: A - B is better: it loses 5.0 cm³, compared with A's 6.0 cm³.
Refractory specimens were fired at 1000°C, cooled, and then loaded to failure in three-point bending at 25°C. The supplier's report labels the result 'modulus of rupture at 1000°C.' Which description matches the test actually performed?
Correct answer: B - Cold modulus of rupture after the material was fired at 1000°C.
A gunning crew has been producing acceptable panels. The operator increases conveying-air pressure without changing the material, predampening, nozzle water, hose arrangement or nozzle position. Rebound rises sharply, and the next panel has lower installed density. Where should troubleshooting begin?
Correct answer: C - Restore the air-pressure setting used before the change.
A furnace has a dense hot-face lining operating at 1400°C, with Superwool Plus blanket behind it as backup insulation. The verified thermal design limits the blanket itself to 900°C under all specified operating conditions. The blanket data sheet lists a 1200°C classification temperature and a 1050°C continuous-use temperature. Which temperature assessment is correct?
Correct answer: A - The blanket meets the stated temperature duty at its actual location.
Before casting a lining, a contractor proposes removing the specified plastic caps from metallic anchor tips to improve contact with the castable. What essential function would be lost?
Correct answer: D - Leaving clearance for differential expansion of the metal and refractory.
A shotcrete installation instruction specifies liquid activator at 2.0% of dry refractory mass. For a 200 kg dry batch, a calibrated meter delivers 3.20 L of activator with a density of 1.25 kg/L. All other mixing requirements are met. The dose should be:
Correct answer: C - Accepted: the 3.20 L delivery contains the required 4.00 kg.
Removal of a loose area from a newly installed gunned lining exposes a thin, powdery plane between two otherwise coherent layers. Installation records show that rebound accumulated before the upper layer was applied. The defect is best identified as:
Correct answer: D - Lamination at an inadequately bonded deposition interface.
During the initial dryout of a cement-bonded castable, several penetrations begin emitting forceful steam jets while the lining temperature is rising. The adopted procedure is Plibrico Dryout Schedule C. With personnel clear of the affected area, how should heating be managed immediately?
Correct answer: C - Suspend the temperature rise and hold until jetting subsides.
An overhead gunning job has closely spaced anchors. The project requires qualification representative of field placement. The contractor submits passing strength and abrasion results from a cast panel made with the specified material. Which additional demonstration addresses the principal qualification gap?
Correct answer: B - Gun an overhead mockup using the production operator, equipment and anchor layout.
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