Table of Contents

Testing & Acceptance Standards

Rigorous Verification Protocols for Pipeline System Integrity

Acceptance Procedures

Pre-Testing Requirements

  • All indoor gas pipelines must undergo strength and tightness tests after installation

  • Test plans and safety measures must be approved by technical and supervision managers

  • All piping in test scope must be completely installed per design specifications

  • Pipelines must be properly reinforced for testing

  • Isolation from non-test systems with clear identification and records

Testing Medium & Equipment

  • Test medium: Compressed air (water strictly prohibited)

  • Pressure gauges must be within calibration validity period

  • Gauge range: 1.5-2 times maximum test pressure

  • Spring pressure gauge accuracy: 0.4 class

  • U-tube manometer graduation: ≤1mm

Testing Responsibility

  • Conducted by construction contractor

  • Participation required from: Gas operation enterprise, engineering supervision unit, construction unit

  • Final acceptance organized by construction unit according to project nature

Special Requirements

  • Buried pipelines must be tested before concealment

  • Bubble test solution chloride ion content: ≤25×10⁻⁶ for stainless steel systems

Strength Test Specifications

Test Scope Definition

  • Residential: From inlet pipe valve to gas meter inlet valve (including valves)

  • Industrial/Commercial: From inlet pipe valve to appliance front valve (including valves)

  • Pre-valve piping tested together with buried pipelines

Preparation & Pressure Requirements

  • Pipelines must be purged clean before testing (air or nitrogen only)

  • Test pressure: 1.5 × design pressure, minimum 0.1MPa

Test Duration & Acceptance Criteria

  • Design pressure ≥10kPa: Maintain pressure ≥30 minutes, bubble test all joints, no leakage

  • Alternative: Maintain pressure 60 minutes, no pressure drop

  • Design pressure <10kPa: Maintain pressure ≥30 minutes, bubble test, no leakage or pressure drop

  • 0.4MPa tests (industrial/commercial): Stop at 1/2 pressure for 15 minutes, bubble check, then continue to full pressure for 60 minutes, no pressure drop

Tightness Test Specifications

Test Scope & Sequence

  • Scope: All piping from inlet valve to appliance front valve

  • Additional check required for piping between appliance valve and appliance before commissioning

  • Must be conducted after strength testing

Medium Pressure Pipelines

  • Test pressure: Design pressure (minimum 0.1MPa)

  • Duration: ≥2 hours

  • Acceptance: Bubble test all connections, no leakage, no pressure drop

Low Pressure Pipelines

  • Test pressure: Design pressure (minimum 5kPa)

  • Duration:

  • Residential: ≥15 minutes

  • Commercial/Industrial: ≥30 minutes

  • Systems with stainless bellows/plastic-coated pipes: ≥1 hour

  • Measurement: U-tube manometer required

  • Additional check for plastic-coated pipe end seepage

Critical Safety Requirements

  • Water strictly prohibited as test medium

  • Safety relief devices must be removed or isolated during strength testing

  • Proper isolation of non-test systems mandatory

  • Bubble solution must be promptly cleaned after testing

  • Low chloride content bubble solution required for stainless steel