During concrete pouring, the pipe must be maintained at what condition?

When considering the condition of pipe during concrete pouring, maintaining it at operating pressure is essential. This is crucial because during the curing of concrete, the pipe can be subjected to physical stress due to the weight of the concrete and the movement associated with pouring. Keeping the pipe at its operating pressure ensures that it remains in its designed shape and has the necessary structural integrity to withstand any external force.

If the pipe were not maintained at operating pressure, it could deform or buckle under the weight or pressure of the wet concrete. This could lead to potential leaks or failures once the system is in use. Additionally, operating pressure helps ensure that any potential internal stresses are stabilized during the concrete setting process.

In contrast, options related to ambient temperature, water pressure, and test pressure do not provide the same level of immediate structural integrity or address the stresses that the pipe will face during the concrete pouring process. Thus, maintaining the pipe at operating pressure is the most appropriate condition during this critical phase.