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Abstract
Introduction: Safe and efficient access to potable water in buildings requires rigorous
design grounded in fluid mechanics, applied hydraulics, and technical regulations.
The direct potable water supply system—which utilizes public network pressure
without requiring intermediate storage—is notable for its operational efficiency and
reduced risk of biological contamination; however, its implementation necessitates
the evaluation of pressure variations, head losses, and material selection. The
objective of this research was to develop a comprehensive technical, regulatory,
and methodological framework for the design, sizing, evaluation, and execution of
direct supply systems, addressing how integrating hydraulic analysis with national
standards (Standard IS.010 and the NTP series) and international standards (IPC and
EN 806) optimizes design, material selection, and technical parameters. Methodology:
The research adopted a technical-regulatory and descriptive-analytical approach,
structured into six chapters. A systematic and comparative review was conducted,
contrasting Peruvian regulations (National Building Code IS.010 and Peruvian
Technical Standards for polymeric materials such as PVC-U, CPVC, PP-R, and PE-X)
with international standards from the International Plumbing Code (IPC) and the
European EN 806 series. Concurrently, fundamental hydraulic equations (Hazen-
Williams and Darcy-Weisbach) were applied alongside Hunter’s fixture unit method
to determine head losses, simultaneous flow rates, and residual pressures at the
network's most critical point. Results: A comprehensive design methodology was
systematized, directly linking analytical theory with regulatory practice. Critical
hydraulic variables were identified to prevent phenomena such as under-pressure or
water hammer, and precise criteria were established for the mechanical and thermal
characterization of plastic pipes and fittings under the NTP series. Additionally, a
comparative matrix was developed aligning the IS.010 standard, the IPC, and EN 806
regarding criteria for backflow protection, accessibility, and inspection of interior
piping networks; this was complemented by a step-by-step procedure for calculating
pipe diameters and ensuring compliance with standard flow velocity limits. Discussion:
Integrating rigorous hydraulic calculations, material specifications for polymers, and
alignment with international standards transforms the design of direct plumbing
systems from an empirical practice into a precise applied engineering discipline. It is
concluded that integrating these three pillars ensures a continuous, safe, and
sustainable potable water supply, free from the excess costs associated with
oversizing. Designers are advised to always verify public network pressures before
selecting a system; contractors should ensure the presence of NTP certification
markings and conduct tightness inspections in accordance with IPC/EN 806; and
regulatory bodies should promote the continuous updating of local standards by
incorporating digital calculation tools and advanced water efficiency criteria.
Keywords: Plumbing systems, direct system, potable water, applied hydraulics, IS.010
Standard, Peruvian Technical Standards (NTP), IPC, EN 806, hydraulic calculation.