| Term |
Definition |
|
| Data logger |
(Also field data logger.) Keyboard-type device used to electronically record inspection data. |
| Data reviewers |
Personnel from other departments who will review the recorded inspection information for use in future repair planing or during the auditing process. |
| Dead man |
A fixed anchor point used in advancing a saddle or cradle type boring machine. |
| Debris |
Accumulation of material consisting of organic (human waste, food wastes, etc.), (sand, gravel, wood, etc.), grease or roots. |
| Deck assembly |
Drive train assembly for a split design boring machine. |
| Deformed and reshaped |
See modified sliplining. |
| Department contact |
Assigned person responsible to represent the owning department for decision making and necessary notifications. |
| Dereliction |
The gradual decay of a sewer network accelerated by the negligence of effective maintenance. |
| Dewater |
Any method used to lower the water table in the vicinity. |
| Diameter of reamer (d2) |
Largest diameter of reamer. |
| Diameter of standard bit (d1) |
Maximum outside diameter of standard bit. |
| Dimple |
A term used in tight fitting pipeline reconstruction, where the new plastic pipe forms an external departure or a point of expansion slightly beyond the underlying pipe wall where unsupported at side connections. The dimples are used for location and |
| DIP |
Ductile Iron Pipe |
| Directional drilling |
A steerable system for the installation of pipes, conduits and cables in a shallow arc using a surface launched drilling rig. Traditionally the term applies to large scale crossings in which a fluid-filled pilot bore is drilled using a fluid-driven m |
| Discharge point |
The point where the flows in a sewer are discharged to |
| Discount |
A reduction in the calculated price. |
| Discrete sliplining |
See sliplining or lining with discrete pipes. |
| Diurnal |
To vary during the day. |
| Diverting |
Modifying the normal wastewater flow to allow access to some specific sewer structure; often includes bypass pumping. |
| Dog plate |
See thrust block. |
| Dogs |
Moveable protrusions in the thrust block that engage holes or blocks in the track. |
| Double ring brick sewer |
A brick sewer which consists of two layers of bricks. |
| Drainage fixture unit |
A drainage fixture unit, often referred to as a fixture unit or FU, is a unit of measure of the waste water flow generated by an appliance, such as a sink or toilet. For example, the typical full bath has a value of 9 FUs. See Availability Fee for co |
| Drill bit |
A tool which cuts the ground at the head of a Drill String, usually by mechanical means but may include Fluid Jet Cutting. |
| Drill string |
1) The total length of drill rods/pipe, bit, swivel joint etc. in a drill bore-hole. 2) System of rods used with cutting bit or compaction bit attached to the drive chuck. |
| Drilling fluid/mud |
A mixture of water and usually bentonite and/or polymer continuously pumped to the Cutting Head to facilitate cutting, reduce required torque, facilitate the removal of cuttings, stabilize the borehole, cool the head and lubricate the installation of |
| Dripper |
Applied to infiltration to quantify water dripping into a sewer in a non-continuous way through a defect or faulty joint. |
| Drive chuck |
The female hex connector located within the casing pusher. |
| Drive shaft |
See Jacking Shaft. |
| Drive/entry shaft/pit |
Excavation from which trenchless technology equipment is launched for the installation of a pipeline, conduit or cable. It may incorporate a thrust wall to spread reaction loads to the soil. |
| Drop connection manhole |
A manhole in which the influent pipe enters from above the effluent invert depth. If the drop occurs in the manhole itself, it is called an "internal" drop manhole. If the drop occurs a few feet upstream of the manhole, it is referred to as a "extern |
| Drop manhole |
If the upstream pipe is at a greater elevation than the manhole invert then two inlet connections to the manhole are made. One is through the wall at the same grade as the upstream pipe, the other is at the invert so to direct flows through the chann |
| Dry bore |
Any drilling or Rod Pushing system not employing drilling fluid in the process. Usually associated with guided Impact Moling, but also some rotary methods. |
| Duct |
(1) In many instances, a term interchangeable with pipe. (2) In the boring industry, it is usually used for small plastic or steel pipes that enclose wires or cables for electrical or communication usage. (3) Conduit inside which a utility service is |
| DWF |
Dry Weather Flow; is the base flow in a sewer prior to rain induced flows. |
| DWI |
Dry Weather Inflow; is the result of flow entering the collection system from connected sources which are not caused by rainfall. Typically, this could include water from fire fighting, hydrant abuse, street washing, sump pumps etc. |
