| 1. |
Line temperature fluctuations and the resulting axial pipe movements |
| 2. |
Environment of exposure to chemicals, solvents, UV radiation, etc. |
| 3. |
Availability of cleaning and heating equipment |
| 4. |
Ambient conditions at time of construction (cold, hot, dry, damp, etc.) |
| 5. |
Mainline coating (type and thickness) |
| 6. |
Terrain (rocky, sandy, clay, etc.) |
| 7. |
Pipe diameter and weld protrusions |
| 8. |
Skills of the work crew available |
| 9. |
Buried, under ground or offshore |
| 10. |
Line service temperature |
| 11. |
Insulated line |
| 1. |
Service temperature and ambient conditions largely determine the sleeve temperature rating. |
| 2. |
Coating thickness, weld bead protrusion, pipe diameter, and terrain will determine the sleeve thickness. |
| 3. |
Compatibility with coating plays a role in determining adhesive type. |
| 4. |
Axial pipe movements, type of terrain (soil stress) and type of pipe coating
will affect the mastic or hot melt selection. If the pipe coating has a mastic type
of adhesive, then the sleeve should utilize a mastic adhesive. In all other cases,
if there is significant pipe movements due to temperature fluctuations and heavy
soil stress (dry-wet clay), then a sleeve with hot melt adhesive will be used. In
the majority of the pipelines with relatively constant temperatures and low soil stress,
a sleeve with mastic is suitable. |
| 5. |
Since hot melt adhesives require great
care in application due to their sensitivity
to installation conditions, a well trained
work crew is required. |
| 6. |
Hot melts require greater surface preparation,
usually SSPC-SP6 (SA2) or better, and
high preheat temperatures, minimum 90°C
at the time of installation. |
| 7. |
For the best protection available, the use
of a "3-layer" sleeve with epoxy
primer should be considered. This still requires
high degree of surface cleanliness and also
factors such as epoxy pot life and shelf life,
dust contamination and cure temperature range
primer must be taken into account. |
| |
1st letter: Sleeve Type |
| |
2nd letter: Backing Type Thickness |
| |
3rd letter: Adhesive Type |
