Man-hours calculation — Piping welding: Welding efficiency.
Piping Works — Man Hour Calculation for Pipe Welding
Calculation of the number of inches diameter of welding.
First of all, we will divide the welding of pipes into two large groups:
1 - Piping where the final quality control is performed by hydrostatic testing.
2 - Piping where, in addition to the hydrostatic test, the quality control is carried out with non-destructive tests (e.g. RT or UT).
ENGINEER - CONSTRUCTION - ESTIMATING PIPE WELDING MAN HOURS - PIPE WELDING TIME CALCULATOR
At present, for piping works, the contractors do the engineering, for example: by isometric drawing, pipe model that allows a fast construction in the workshop and an easy assembly on site.
We divide each isometric line into sections called spools for fabrication in the shop.
Once the spools are manufactured, we transport them to the construction site for their adjustment, positioning and the execution of the adjustment welds.
In general, with good engineering, the number of welds performed in the prefabrication phase is between 70 and 90% of the total to be performed.
This not only reduces costs and man-hours.
It also improves the possibilities of meeting the construction deadlines by reducing the incidence of weather conditions in the process of work execution.
It has been proven that welds made in the workshop are faster and with better quality control than those made in the field.
We must also understand that welding times vary depending on the material we are working with.
For the moment we will refer to carbon steel pipes.
It is also necessary to understand that the welding time varies according to the thickness of the pipe (the thicker the pipe, the more time we have to prepare the bevel and the more welding work we have to do because we have to fill more).
It should also be noted that the larger the diameter of the pipe, the more difficult it is to handle.
Finally, we give here the standard times (we emphasize that speaking of standard times means that the operators have no economic incentive to make an effort to achieve a higher performance).
For the first type of welding (where the quality is controlled only by the hydrostatic test) and for a standard 4-inch carbon steel pipe, the crew time for one inch of welding is
0.70 MAN HOURS * inch, for field welding, and 0.40 MAN HOURS * inch, for prefabricated welding.
The crew consists of a helper, a journeyman and a welder).
If the crew works 10 hours per day, each group will produce approximately 42 field and 75 shop inches per day.
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For the second type of welding (here the quality is controlled with non-destructive test, besides the hydrostatic test) and for the same diameters, the times for inch of welding in the field, will be of 2 MAN HOURS * inch, welding and 1 MAN HOURS * inch, welding in prefabricated.
The production for 10 hours of work is for each group of 15 and 30 inches per day.
Read more in Calculate man hours
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Note:
The time includes:
Piping welding
It does not include:
Complicated handling of piping.
Painting.
Insulation.
Supports.
Clamps.
Scaffolding for piping.
