Public health engineering — specifying appurtenances for water supply: When preparing a schedule of items for a building’s internal water-supply work, for which of the following fittings must you specify size (nominal bore), capacity/pressure rating, and material (e.g., brass, gun-metal, PVC/CPVC)? Select the most comprehensive choice.

Difficulty: Easy

Correct Answer: All the above

Explanation:


Introduction / Context:
In quantity surveying and public health engineering, item descriptions must fully define what is to be supplied and installed. For valves and small fittings, three descriptors avoid ambiguity: size (nominal bore), capacity or pressure rating, and material of construction. This ensures correct procurement, price comparability, and code compliance.


Given Data / Assumptions:

  • The listed items are bib-cocks, stop-cocks, ferrules, and ball valves.
  • Standard practice follows IS codes and departmental SORs where fittings are identified by size, duty/pressure class, and material.
  • Domestic water networks require compatibility among pipe material and fittings.


Concept / Approach:

Each fitting controls or conveys water and must mate with a specific pipe size. Pressure rating (e.g., PN class) guards against failure, and material choice affects corrosion resistance, potability, durability, and cost. Hence, all three attributes are routinely specified for these fixtures.


Step-by-Step Solution:

1) Bib-cocks: need size (e.g., 15 mm), material (brass/CP), and pressure class for reliability.2) Stop-cocks: isolation valves; size and PN rating crucial; material dictates longevity.3) Ferrules: pipe-main tapping fittings; bore and material (gun-metal/brass) must suit main’s pressure.4) Ball valves: require bore, pressure rating, seat/ball material, and body material.


Verification / Alternative check:

Any SOR/BOQ template lists size, material, and rating for these items to avoid site disputes and substitutions.


Why Other Options Are Wrong:

  • (a)–(d) list individual fittings but ignore the others; all of them need these specifications.


Common Pitfalls:

  • Quoting “as directed by Engineer” without size/PN/material leads to claims and delays.
  • Mixing incompatible materials (e.g., brass into PPR) without adapters.


Final Answer:

All the above.

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