| Term |
Definition |
|
| Obstruction |
Any object or feature that lies completely or partially within the cross section of the microtunnel and prevents continued forward progress. |
| Ogee |
A joint with an elongated "S" profile within the thickness of a sewer pipe wall. |
| Oiler |
Changes amount of lubricating oil injected in supply air. |
| OPC |
Ordinary Portland Cement; customarily used for making concrete, mortar and grout in non-aggressive conditions. |
| Open cut |
The method by which access is gained to the required level underground for the installation, maintenance or inspection of a pipe, conduit or cable. The excavation is then backfilled and the surface restored. See conventional trenching. |
| Open face shield |
Shield in which manual excavation is carried out from within a steel tube at the front of a pipe jack. |
| Operator presence control |
A control or mechanism designed so that operator presence is necessary to activate a specific function. |
| Orangeburg |
Orangeburg is a bituminized fiber pipe. Manufactured as an alternative to metal pipe in response to a metal shortage due to World War II. The life expectancy from experience is about 25 years. This type of pipe has been known to collapse often necess |
| Organic debris |
Production waste and other material that accumulates in sewers or manholes. |
| OSHA |
Occupational Safety and Health Administration. |
| Other sewer structures |
Other portions of the industrial sewer pipelines and manholes, including trap tanks, sumps, and any other structure not specifically identified. |
| Outfall |
An outlet to a sewer system. |
| Ovality |
There are two options: a) the difference between the maximum and mean diameter divided by the mean diameter, and b) the difference of the mean and minimum divided by the mean, at any one cross section of a pipe, generally expressed as a percentage. |
| Overcut |
The annular space between the excavated hole and the outside diameter of the jacking pipe. |
| Overflow |
(1) The excess water that flows over the ordinary limits of a sewer, manhole, or containment structure. (2) An outlet, pipe, or receptacle for the excess water. |
| Owner |
A public body of authority, corporation as partnership, or individual for whom the work in to be performed. |
| Oxidation |
Loss of electrons, as when a metal goes from the metallic state to the corroded state. |
