Policy Summary
This policy outlines our procedure for strength testing, tightness testing, and purging of natural gas pipework. It aligns with IGE/UP/1A Edition 2 and IGEM Communication 1701, and applies to both new and existing low-pressure installations.
Applicable Standards
- IGE/UP/1A Ed.2 (2005): For systems ≤ 1 m³ and ≤ 40 mbar OP
- IGE/UP/1 Ed.2 (2005): For larger/higher-pressure pipework
- IGEM Communication 1701: Defines correct testing and purging methods
Definition of “Small” Installations
Installations are considered “small” when the pipework volume is ≤ 1 m³ and operating pressure is ≤ 40 mbar. This is based on gas volume, not building size or pipe length alone.
Scope of Testing
New or modified systems require both strength and tightness testing. For existing systems, tightness testing alone may be sufficient depending on recent alterations, asset condition, and compliance status.
Test Comparison Table
| Feature |
Strength Testing |
Tightness Testing |
| Purpose |
Verify mechanical integrity of new or altered pipework |
Detect and confirm absence of gas leakage |
| When Required |
Before tightness testing on new or modified systems |
All systems before re-commissioning or certification |
| Test Medium |
Air or nitrogen |
Natural gas |
| Test Pressure |
1.1 × Maximum Incidental Pressure (MIP) |
Operating Pressure (OP) |
| Acceptable Drop |
None — test must hold pressure |
Refer to Table 5 of IGE/UP/1A |
Purging Process
Purging is undertaken after successful testing to either safely remove air (purge-in) or remove gas (purge-out). This must follow defined safety procedures under IGE/UP/1A Ed.2 Section 7.
Certification and Logbook Recording
All test data, including purging actions, are captured via the Logbook Portal. Certification is issued upon completion to confirm safety, traceability, and full compliance.
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