Each coupling will allow for a setting angularity as follows:
| COUPLING SIZE | ANGLE | INCLINATION |
|---|---|---|
| ≤ 457mm OD | ± 6 ° | 1 in 10 |
| > 457mm up to & including 610mm OD | ± 5 ° | 1 in 12 |
| >610mm up to & including 762mm OD | ± 4 ° | 1 in 15 |
| > 762mm up to & including 1219mm OD | ± 3 ° | 1 in 20 |
| > 1219mm up to & including 1829mm OD | ± 2 ° | 1 in 30 |
| > 1829mm OD | ± 1 ° | 1 in 60 |
Flange adaptors will allow for a setting angularity of half the above figures.
The above schedules should only be used when the pipes will not move in service. For other conditions we recommend working to half these figures to allow for inservice flexibility.
The ability of a coupling to accommodate angular deflection on installation and in service enables it to be used in the following valuable ways:
Take up minor misalignment in straight pipes e.g. at closing lengths.
Lay pipes to long radius curves without special bends.
Absorb large amounts of expansion movement at right angles to the pipelines.
Accommodate ground settlement.
