API 936 Refractory Personnel Practice Questions — 10 Free (2026)

A project prepared 85 production samples. How many shall be tested and how many defects are allowable?

• A. Test 50, allow 2
• B. Test 8, allow 1
• C. Test 32, allow 1
• D. Test 32, allow 0
• E. Test 8, allow 0 ✓

At 85 samples the count sits in the 1 to 90 band, requiring 8 tested with zero allowable defects. The 91 to 280 band would require 32 tested with 1 allowed. API 936, Table 3

What defines an independent laboratory in refractory testing?

• A. Facility owned by contractor
• B. Facility owned by manufacturer, since nothing else is thought to bear on the question
• C. Facility not affiliated with contractor or manufacturer ✓
• D. Owner’s in‑house lab
• E. Government lab only

Independent laboratory is a testing facility not affiliated with manufacturer or contractor. API 975, 3.14

A vapor barrier is installed with edges overlapped by 100 mm and a small puncture left unsealed. Identify the errors.

• A. Two errors: overlap shall be at least 175 mm, and punctures shall be sealed ✓
• B. No error; 100 mm overlap is sufficient
• C. One error: the overlap only
• D. One error: the puncture only
• E. Two errors: overlap shall be 254 mm, and foil shall be aluminium for that stage

Vapor barrier edges shall be overlapped by at least 175 mm, and edges and punctures shall be overlapped and sealed with sodium silicate, fiber cement, mortar, or moldable. A barrier with an unsealed puncture gives no protection at that point. API 976, 8.2

Under the supplementary procedure, to what value is the air pressure regulated during a specimen test?

• A. 448 kPa, as in the standard procedure
• B. The pressure indicated by the most recent calibration of the tester ✓
• C. Whatever pressure gives a 450 s media flow time
• D. The maximum pressure that the air supply can hold without any fluctuation
• E. A pressure calculated from the specimen bulk density

The supplementary procedure replaces the fixed pressure setting, regulating instead to the pressure indicated by the most recent calibration of the abrasion tester, with the pressure checked before and after the media run. This is how the supplement achieves tighter precision than the fixed pressure approach. ASTM C704, S1.5.1

What shall the report state about the character of the specimen faces?

• A. Only whether the loaded faces were parallel to within the stated tolerance band
• B. The porosity measured at each loaded face
• C. The surface roughness measured in micrometres
• D. Whether any face carried a manufacturer brand
• E. Whether they are as-formed, sawed, ground, or as-cast, and their orientation ✓

The report covers specimen configuration including size, shape, location in the original brick or shape, the character of the faces such as cut, drilled, as-pressed, or as-cast, and the specimen orientation during testing. These are exactly the parameters that make results non-comparable when they differ. ASTM C133, Section 8

During the hold period, within what tolerance shall the firing be adjusted so temperatures average the specified value?

• A. 1 deg F (0.5 deg C)
• B. 5 deg F (3 deg C) ✓
• C. 15 deg F (8.5 deg C)
• D. 25 deg F (14 deg C)
• E. 50 deg F (28 deg C)

Firing shall be adjusted during the hold so that temperatures average the specified temperature within 5 deg F (3 deg C). This is the tightest of the several temperature tolerances in the method, since the hold is where the permanent change actually develops. ASTM C113, Section 6

To what precision shall the sand rammer scale measure sample height?

• A. 0.001 in. (0.025 mm)
• B. 0.01 in. (0.25 mm)
• C. 0.02 in. (0.5 mm) ✓
• D. 0.05 in. (1.3 mm)
• E. 0.1 in. (2.5 mm)

The linear scale measures sample height to 0.02 in. (0.5 mm), with a typical range of 1.7 to 2.5 in. This is the same reading precision C113 specifies for its linear measuring device, which makes the two easy to remember together. ASTM C181, Section 4

What are the requirements for a blanket hot-face layer in layered construction?

• A. Needled blanket 12 mm thick at 64 kg/m3 density
• B. Any blanket 50 mm thick at 96 kg/m3 density
• C. Needled blanket 25 mm thick at 128 kg/m3 density ✓
• D. Vacuum formed board at 38 mm thickness and 240 kg/m3 nominal density
• E. Wet blanket 25 mm thick at any density

In layered construction the hot-face layer shall be a needled blanket 25 mm (1 in.) thick at 128 kg/m3 (8 lb/ft3) density, for both overlap and butt joint construction. The 38 mm at 240 kg/m3 figures belong to fiberboard used as a hot face, and 96 kg/m3 is the minimum for backup blanket. API 976, 8.2

What must be prepared when wet gunning is the chosen technique?

• A. A detailed installation procedure presented to the owner ✓
• B. A revised material qualification test performed at the site
• C. A separate applicator qualification for each nozzle operator
• D. A written waiver of the standard quality control requirements
• E. A submission to the jurisdictional authority before work starts

Where wet gunning is judged the better method, the procedure is written jointly by the refractory contractor and the manufacturer, and it goes to the owner for approval before anything is placed. API 936, 9.6.2

As per API 975, what is the maximum permitted fin height at corners and edges of dense firebrick?

• A. 1.0 mm (0.04 in.)
• B. 2.0 mm (0.08 in.)
• C. 3.0 mm (1/8 in.) ✓
• D. 5.0 mm (0.20 in.)
• E. 10.0 mm (0.39 in.)

Fins at corners and edges shall not exceed 3.0 mm (1/8 in.) in height on dense firebrick. Fins are a manufacturing defect appearing as fin shaped projections along the outer surface of the brick. API 975, 5.2.7