In O&G EPCI projects, both Dia-Inch & Inch-Meter are generally considered as units for measurement of the piping job loads (mainly for Welding/ Installation/ Hydro Test measurements). The former being denoted by the DI of (phi) ” or ” and Inch-metre by IM respectively; can be understood as below:
Consider a 10″ NB pipe of length says 30 metres. If there are 5 joints of this pipe to be welded, the quantum of this welding job is calculated as:
DI = *Pipe Dia (in inches ~ 10) x No. of joints (~5) = 50 Dia-Inch
*Notes: The joint included of Flanges, Branchs, Fittings (the Pipe Dia in Formular will be changed as per actual Dia on each item respectively)
In terms of IM, we say the quantum of the job as:
IM = Pipe Dia (in inches~10) x No. of Metres (~30) = 300 Inch-metre
Once again, DI is generally taken as a unit of measurement (of quantum of the job) for Welding, Radiography (RT), DPI, MT, PAUT, TOFD, TFM, AUT tests and are used as units for payment purposes with NDT agency.
IM is considered normal to define the quantum of Piping Erection job, Insulation (besides Metre cube) and its payment purpose with Construction Main/Sub-Constructors.