| Contents | ISO 15741, Annex C | NACE TM 0185 |
| Coating type | Liquid epoxy as internal coating | Plastic coating |
| Objects | Steel pipes and fittings | Tubular good |
| Media | Non-corrosive gas phase; nitrogen | Corrosive media ( H2S) and /or Chloride solution; hydrocarbon phase |
| DFT | 60~ 100 μm (4.3.3) | Not specified |
| temperature | Not specified | Elevated temperature required |
| Pressurizing system | Ramping 1 bar/min | Continuous monitoring |
| Depressurizing rate | Release pressure rapidly ( no more than 5 min) | Cool to 93oC, and depressurized at a uniform rate to ATM within 15~ 30 mins |
| Testing panel | Type I : 100 mm x 50 mmx 1 mm Type II: 100 mm pipe min. D 80 mm | Area Min. 26 cm2, min 25% area exposed to each phase |
| Pre test | Test after one-month coating application | NA |
| Duration | 10 test cycles up to 100 bar 1 to 4, 6 to 9 cycle; 20 + 4 h 5 and 10 cycles, 68 + 4 h | Sufficient length , no less than 16 h at T and P |
| Pressure cycle test | 10 test cycles up to 100 bar 1 to 4, 6 to 9 cycle; 20 + 4 h 5 and 10 cycles, 68 + 4 h Release pressure rapidly ( no more than 5 min) 4 h in atm for blister Adhesion test at 0 h; appearance check at 0, 24h and 48 h (ANNEX C) | Not specified |
| Decompression blistering test | At MAOP 24 h Release gas quickly < 5min Examine appearance at 0 h, 24h and 48 h Adhesion test at 0 h (ANNEX C) | Not specified |
| Examination | Adhesion test at 0 h; appearance check at 0, 24h and 48 h (ANNEX C) | Appearance check at 0 h for exposure at both phases |
| Exam items | Appearance adhesion | BlisteringSofteningCoating thickness changeAdhesion to metal and intercoatsColor changeMetal attackUnderfilm creepIntracoat foam or porosity |
| Rating | Not specified | appearance No changeSlight changeModerate changeSevere change Adhesion No changeSlight loss of adhesionModerate loss of adhesionSevere loss of adhesionDisbondment |
Reference
- ISO 15741 2016 Paints and varnishes- friction-reduction coating for the interior of on and offshore steel pipelines for non-corrosive gases
- NACE TM0185 2006 Evaluation of internal plastic coatings for corrosion control of tubular goods by autoclave testing
- Kaley Stanczyk , High Temperature, High Pressure, Depressurization Testing of Coating Systems Prior to Large Scale Installation, ktauniversity.com
