Seam length and welding time calculator
Converts a lined area into metres of wedge seam, machine hours at your actual welding speed, and the days that represents on site.
Estimate
Why seam length matters more than area
Area tells you how much material to buy. Seam length tells you how much work the job contains, and those two numbers move independently.
A long narrow canal and a square reservoir of identical area contain very different amounts of welding, because seam count depends on how many panel widths fit across the structure. Quote a lining job on area alone and the geometry will eventually catch you out.
Seam length also determines how much testing there is. Every metre of wedge seam gets air pressure tested, and every detail weld gets vacuum boxed. On a project with heavy detail, testing can take longer than the welding.
Using this to size a machine
Once you know the seam length and the days available, the required welding speed follows, and that tells you whether one machine is enough. If the figure demands more than a single machine can produce inside the programme, the answer is a second wedge welder rather than a faster one, because production speed is capped by the liner and the conditions rather than by the machine.
Carrying a second machine also removes the single point of failure. A crew with one welder and a failed heating element stops entirely, which is the argument for keeping spare elements on site.
Frequently asked questions
How do I calculate geomembrane seam length?
Divide the width of the lined area by the effective panel width, which is the roll width minus the overlap. That gives the number of panels. The number of seams is one less than the number of panels, and total seam length is that figure multiplied by the panel run length. A 7 m roll with a 100 mm overlap gives an effective width of 6.9 m, so a 30 m wide area needs five panels and contains four seams.
What welding speed should I assume?
Not the machine's maximum. Production speed is set by the liner thickness and the conditions, and it is lower than the figure on the specification plate. For planning, 2.5 to 3.5 m/min is realistic on 1.00 mm sheet, 1.5 to 2.5 m/min on 1.50 mm, and 1.0 to 2.0 m/min on 2.00 mm. Starting parameters by gauge are in the settings guide.
Why is the real programme longer than the calculated welding time?
Because welding is a minority of the work. The machine time calculated here excludes deploying and positioning panels, which on a windy site is slow and needs a crew. It excludes trial welds and coupon testing at the start of each shift, non-destructive testing of every seam, extrusion detailing at penetrations, repairs to anything the CQA engineer finds, and weather stoppages. On a typical project the welding machine runs for a small fraction of the hours the crew is on site.
How much extrusion detail work should I allow?
The default here is ten percent of wedge seam length, which suits a simple basin with few penetrations. A tank farm bund with dense pipework can run far higher, sometimes exceeding the wedge seam length entirely, because the geometry is nearly all detail. Set the percentage to match the structure rather than accepting the default. Every metre of it needs a hand extruder and matched welding rod.
Does panel orientation change the seam length?
Yes, significantly. Running panels along the long axis of a rectangular basin produces fewer, longer seams than running them across it. Fewer seams generally means less welding and less testing, so the long axis is usually preferred. Other factors can override it, particularly on slopes, where panels normally run down the batter rather than across it so that seams are not loaded in shear by material sliding down the face.
The rest of the range is on our main equipment and liner page.
Size the plant to the programme
Send the seam length and the days you have. We will tell you how many machines the programme needs and quote them delivered.