Hydrostatic design basis can be defined as the normalized long-term strength or calculated hoop strength of the material at 100,000 hours obtained by long-term hydrostatic testing of pipe samples from which the probable safe life of the pipe at various stress levels (working pressures) and at various temperatures can be predicted.
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) which enter the wastewater collection system through various sources including, among others, pipe defects, defective service connections, manhole covers, roof leaders, and foundation drains./Inflow; this is the sum of all the extraneous contributions to the collection system.
Internal Condition GradeThe elevations shown on plans and/or survey grade stakes for the installation of the carrier pipe. It is occasionally to give elevations for casing. In most cases, it is given to the flow line but can also be given to the top of the pipe or casing.; numeric criteria applied to visual images of sewers to develop a priority rating based on defects observed.
Lost time when the MTBM is not in operation; not including make-up time or downtime.
Information Guidance Notes; an international reference source for some lining materials.