| Term |
Definition |
|
| I/I |
Infiltration/Inflow; this is the sum of all the extraneous contributions to the collection system. |
| ICG |
Internal Condition Grade; numeric criteria applied to visual images of sewers to develop a priority rating based on defects observed. |
| IGN |
Information Guidance Notes; an international reference source for some lining materials. |
| Ignition temperature |
Temperature at which the vapors emitted from a material will ignite either without exposure to a flame (self-ignition) or when a flame is introduced (flash ignition). |
| Impact |
Stress in a structure caused by the force of a vibratory, dropping,, or moving loads. This is generally a percentage of the live load. |
| Impact machines |
A type of machine that pierces the earth (piercing tool) or rams an object to produce a bore (ramming machine). |
| Impact moling |
Method of creating a bore using a pneumatic or hydaulic hammer within a casing, generally of torpedo shape. The term is usually associated with non-steered or limited steering devices without rigid attachment to the launch pit, relying upon the resis |
| Impact ramming |
See pipe ramming. |
| Impact strength |
The ability of a material to withstand shock loading. |
| Impervious |
Impenetrable. Completely resisting entrance of liquids. |
| In line/on line replacement |
The breaking out of an existing pipeline and the installation of a new service on the same line. See replacement. |
| In situ |
Describes work on site; in the original place. For example, in situ concrete would differentiate cast in place concrete from precast concrete. |
| Inadvertent contact |
Contact between a person and a hazard resulting from the person’s unplanned actions during normal operation or servicing of the machine. |
| Inert material |
A material which is not very reactive, such as a noble metal or plastic. |
| Infiltration |
(1) Penetration of freshwater or groundwater into the sewer system through cracks, defective joints in the pipeline, and holes, or through lateral connections, manholes or inspection chambers. (2) All extraneous waters (storm water and ground water) |
| Infiltration/Inflow (II) |
The total quantity of water from both infiltration and inflow without distinguishing the source. |
| Inflow |
Water discharged into a sewer system and service connections from sources on the surface. |
| Inhibitor |
(1) A chemical substance or combination of substances which, when present in the environment, prevents or reduces corrosion without significant reaction with the components of the environment. (2) A substance which sharply reduces corrosion, when add |
| Input parameter for electrical drive |
Maximum continuous rated voltage and amperage. |
| Input parameter for hydraulic or pneumatic drive |
Maximum continuous rated torque and shaft speed. |
| Input parameter for mechanical drive |
Maximum continuous rated torque and shaft speed. |
| Insertion |
See sliplining. |
| Inspection event number |
The unique reference number used to identify a specific inspection of a sewer structure or a group of sewer structures, referred to as an Inspection. |
| Inspector |
The owner's on-site representative responsible for inspection and acceptance, approval, or rejection of work performed as set forth in these specifications. |
| Interaction |
The division of load carrying between pipe and backfill and the relationship of one to the other. |
| Intercepting drain |
A ditch or trench filled with a pervious filter material around a subdrainage pipe. |
| Interceptor sewer |
A sewer that conveys flow from a trunk sanitary sewer or dry weather flow plus a small volume of stormwater from a trunk combined sewer to a wastewater treatment plant. |
| Intergranular Stress Corrosion Cracking (IGSCC) |
Stress corrosion cracking in which the cracking occurs along grain boundaries. |
| Interjack pipes |
Pipes specially designed for use with an Intermediate Jacking Station. |
| Interjack station |
See Intermediate Jacking Station. |
| Intermediate jacking method |
Pipe jacking method to redistribute the jacking force by the use of intermediate jacking stations. |
| Intermediate Jacking Station |
A fabricated steel cylinder fitted with hydraulic jacks that is incorporated into a pipeline between two pipe segments. Its function is to distribute the jacking load over the pipe string on long drives. |
| Internal corrosion |
Corrosion that occurs inside a pipe because of the physical, chemical, or biological interactions between the pipe and the water as opposed to forces acting outside the pipe, such as soil, weather, or stress conditions. |
| Internal erosion |
Abrasion and corrosion on the inside diameter of the pipe or tubing due to the fluid that is being transported. |
| Internal inspection |
Means of ascertaining the condition of pipelines, either by visual inspection for man-entry size or by the use of remote control instrumentation. |
| Internal pipe inspection |
The television inspection of a sewer line section. A CC-TV camera is moved through the line at a slow rate and a continuous picture is transmitted to an above ground monitor (see also PHYSICAL PIPE INSPECTION). |
| Inversion |
The process of turning a fabric tube inside out with water or air pressure as is done at installation of a cured in place pipe. |
| Invert |
(1) The lowest point on the pipe circumference; also the defined channel in the manhole platform that directs flow from inlet pipe to outlet pipe. (2) The inside bottom, lowest elevation, of a sewer pipe. |
| Invert level (elevation) |
The level (elevation) of the lowest portion of a liquid-carrying conduit, such as a sewer, which determines the hydraulic gradient available for moving the contained liquid. |
| Ion |
An electrically charged atom (Na+, Al+3, CL-, S-2) or group of atoms known as "radicals" (NH4+, SO4-2, PO4 3). |
| Ionization |
Dissociation of ions in anaqueous solution (e.g., H2C03 - H+ + HCO3- or H2O - H+ OH). |
