For drainage pipes in buildings the test applied before putting them to use, is

ANS:B - smoke test

For drainage pipes in buildings, various tests are commonly conducted before putting them to use to ensure that they are installed correctly and function properly. Among these tests, the following are particularly common:

1. Water Test: A water test, also known as a hydraulic pressure test or hydrostatic test, is a standard procedure used to check for leaks or defects in drainage pipes. During a water test, the drainage system is filled with water to a specified pressure and allowed to remain pressurized for a set period. Any leaks or abnormalities in the system are identified by observing changes in water level or pressure. This test helps ensure that the drainage pipes are watertight and capable of withstanding normal operating conditions without leakage.
2. Smoke Test: A smoke test involves introducing non-toxic smoke into the drainage system to identify any points of leakage or improper connections. The smoke is forced through the pipes, and any leaks or openings in the system allow the smoke to escape, indicating potential issues that need to be addressed. Smoke testing is particularly effective for identifying leaks in sewer lines, vent stacks, and other parts of the drainage system that may be difficult to access visually. It helps detect leaks, blockages, or improper connections that could compromise the performance of the drainage system.
3. Straightness Test: A straightness test is conducted to ensure that drainage pipes are installed correctly and are free from deformities or obstructions that could impede flow. During a straightness test, a surveyor or inspector uses specialized equipment to measure the alignment and straightness of the pipes. This test helps verify that the pipes are installed according to the specified design and alignment requirements, ensuring smooth flow and proper drainage within the system.

• All the above: Water test, smoke test, and straightness test are commonly applied before putting drainage pipes in buildings to use. Each test serves a specific purpose in ensuring the integrity, functionality, and proper installation of the drainage system.