Which method should the pipe sizing calculations follow?

PAHO's Honduran terms of reference use the latest NFPA 99, and HTM 02-01 (2026) bases the overall pipeline design on a 5% pressure drop from the source of supply to the terminal unit outlet at the specified test flows.

Is the design file finished at handover?

No. HTM 02-01 asks for the technical file to be updated whenever modifications or extensions are made, and ACSS asks for the final drawings to be updated as work is done.

What should a medical gas network design report contain?

Q: What should the design report of a medical gas network contain, from assumptions and calculations to drawings and start-up instructions?

PAHO's terms of reference for oxygen network extensions in Honduras ask for a design report with assumptions, calculations, start-up instructions, instructions to maintain the design conditions, printed, .dwg and .pdf drawings and a bill of materials. HTM 02-01 (2026) asks for a technical file with design details, material certificates and pressure test validation.

What should the design report of a medical gas network contain, from assumptions and calculations to drawings and start-up instructions?

The design report in PAHO's terms of reference

The terms of reference that PAHO/WHO published for designing and installing oxygen networks in prioritised hospitals, in a project run with the Honduran Ministry of Health (undated; PDF file created June 2022), ask each design to include:

a project report with the assumptions, the calculations, start-up instructions and instructions for maintaining the design conditions
all the information needed to operate the network, evaluate its performance and use it
the drawings needed to build it, verify its performance and maintain it, with a list of materials and quantities
the drawings in print and in digital form as .dwg and .pdf files
a design based on the latest version of NFPA 99, which is also the basis for accepting the finished work

For the installation stage, the same document asks for test results that state the measurement method, the equipment used, the results and the acceptance or rejection criteria. Bidders were asked to include pipe diameter calculations and diagrams of the network elements and their location in their offers.

What HTM 02-01 (2026) expects

Technical file: details of the design, the components used, their material certificates and pressure test validation, updated whenever modifications or extensions are made (Part A, para 2.14).
Evidence: before a project starts, the Authorised Person (MGPS) or Authorising Engineer (MGPS) completes a risk assessment of all current sources of supply, considering expected gas usage and historical site data, and the evidence-based design is signed off by the Medical Gas Safety Group (paras 2.16 and 2.17).
Pressure drop: the overall pipeline design is based on a 5% pressure drop from the source of supply to the terminal unit outlet at the specified test flows (para 4.7), and Part B uses the flow rates on the isometric drawings for the pressure-drop calculations.
Record drawings: as-fitted plans overlaid on architectural layouts, showing distribution pipework with pipe sizes and accurate to within 0.5 m, and schematic drawings showing each gas separately from plant to terminal units (Part B, para 6.57).

Portugal: ACSS ET 03/2006 (v.2024)

Following ISO 7396-1, Portugal's ACSS recommends final drawings and diagrams of the whole medical gas project that locate the pipework, valves, second-stage reduction sets, tanks, vaporisers and other components, updated as work is done on the hospital installations. ISO 7396-1:2016 itself covers the documentation of pipeline systems along with their design, testing and commissioning.