The contractor on a field vibration casting job is preparing for a continuous pour that...

API TR 980 explicitly defines the minimum temperature requirements for castable installation:

“Installation should not proceed if the ambient temperature, substrate temperature, or material temperature is below 50°F (10°C). The material and substrate must be maintained at or above this temperature throughout the placement and curing process.”

— TR 980, Section 4.5.1 Cold Weather Installation​

Therefore:

Option D is correct as it meets the standard.

Option A is partially correct but does not include the shell or ambient temperature.

Option B is incorrect—work should not start if temperature cannot be maintained.

Option C is incorrect and contradicts API guidance.

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