HTM 02-01 (2026):
Why Isometric Drawings Are Now Essential for Medical Gas Pipeline Compliance
New requirements place accurate isometric drawings at the heart of medical gas system safety, verification and asset management.
The publication of the 2026 edition of HTM 02-01 (Medical Gas Pipeline Systems) introduces a significant shift in how NHS healthcare organisations, designers, Authorised Persons and estates teams manage medical gas infrastructure.
While many of the underlying engineering principles remain unchanged, the updated standard moves decisively away from largely prescriptive design approaches and towards an Informed Design Process (IDP), supported by robust lifecycle asset management and auditable technical documentation.
One of the most notable developments is the elevation of isometric drawings from a useful design tool to a fundamental compliance requirement.
What Does HTM 02-01 Require?
Under HTM 02-01 Part B (Operational Management), record documentation must include fully detailed, distinct isometric drawings that support the safe operation, maintenance and verification of Medical Gas Pipeline Systems (MGPS).
The standard requires isometrics to clearly identify:
- Gas service types using recognised industry symbols
- All terminal units and the direction of flow
- Pipe sizes throughout the network
- Valve numbering and identification
- Full listings of Valves, LVAs and AVSUs
- The exact clinical areas served by each Area Valve Service Unit (AVSU)
- Representative plant information
- Accumulative design flow rates throughout individual pipe runs
These drawings are intended to provide a complete visual representation of the system, enabling healthcare organisations to safely manage alterations, shutdown procedures, backfeeding arrangements, re-verification activities and ongoing operational maintenance.
Why Are Isometric Drawings Now Critical?
1. Supporting Pressure Drop and Flow Calculations
The 2026 standard places a much greater emphasis on evidenced design decisions.
Designers are now expected to demonstrate and document how pipeline sizing has been determined and justified. HTM 02-01 specifically requires recorded flow rates within isometric drawings to be used when carrying out pressure drop calculations across departments, operating theatres and the most remote points within the system.
Without accurate isometric data, demonstrating compliance becomes increasingly difficult.
2. Providing the Foundation for the Technical File
A major addition to the latest edition is the requirement for a comprehensive Technical File.
This file must contain accurate and verifiable information relating to the installed system before it can be accepted for clinical use.
Detailed isometric drawings form a key part of this documentation package, providing authorised stakeholders and independent Authorised Examiners (AEs) with the information necessary to verify:
- System configuration
- Pipework routing
- Valve arrangements
- Design intent
- Operational functionality
Incomplete or inaccurate documentation may delay verification and impact project handover.
Beyond Compliance: Improving Safety and Lifecycle Management
The updated guidance recognises that healthcare estates teams require more than basic schematic diagrams to safely manage increasingly complex medical gas networks.
Detailed isometrics deliver benefits throughout the asset lifecycle, including:
- Faster fault identification
- Safer shutdown planning
- Improved emergency response
- More efficient future modifications
- Clearer verification and re-validation processes
- Stronger asset management records
As healthcare organisations prepare for the implementation of HTM 02-01 (2026), ensuring accurate and compliant isometric documentation should be considered a priority rather than an afterthought.
Organisations that invest in high-quality MGPS documentation today will be better positioned to demonstrate compliance, support patient safety and manage their infrastructure effectively throughout its operational life.
