Building drainage pipe commissioning — pre-use checks: Before putting drainage pipes in buildings to service, which of the following tests are applied?

Introduction / Context:
Plumbing and building drainage systems must be leak-tight, correctly aligned, and free from obstructions. Several standard tests are employed before commissioning to verify workmanship and system integrity.

Given Data / Assumptions:

• Pipes, joints, and fittings have been installed as per layout.
• Tests are conducted prior to covering or backfilling wherever applicable.
• Building codes typically mandate more than one test.

Concept / Approach:

• Water test: Confirms watertightness under hydrostatic head.
• Smoke test: Detects leaks and improper traps by observing smoke escape.
• Straightness test: Ensures alignment to minimize blockages and maintain gradient.

Combining these tests provides confidence in performance during actual use.

Step-by-Step Solution:
Identify the standard set of tests from codes and practice.All three tests are commonly required or recommended.Therefore, the correct response is “All the above.”

Verification / Alternative check:
Many municipal and national plumbing codes include water and smoke tests explicitly; straightness/alignment checks are standard site QA/QC procedures.

Why Other Options Are Wrong:
Selecting only one omits other equally necessary tests.“None of these” contradicts accepted practice.

Common Pitfalls:

• Skipping smoke tests in favor of only water testing.
• Ignoring alignment, which can lead to frequent choking.

Final Answer:
All the above