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Just wondering if anyone has suggestions for as-built surveys of pipelines. I'm currently on a project that contains 3 pipelines (16", 12", 6" pipes) for a stretch of about 15 miles. The ditch trench is 10ft deep (about 16 ft wide), and we are not allowed within the ditch due to safety concerns. Previously, we used an R10 attached to a 10ft pogo, and reaching above the pipes with a 14ft painters rod, holding said rod on edge of the trench. This method was extremely difficult and could only be done by someone tall and very strong. When the project starts up again within the week, we have been told by our company to NOT use the r10 as this method was very unsafe. I am going to be trying a reflector less total station, but I have also heard that Trimble recommends using a distometer. Has anyone used these techniques recently and could suggest or advise me? We are using the Trimble TSC3, with their pipeline module. 

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  • I had a project similar to this with beams to be as -builted over a 50' wide trench and 15' deep.

    Because the contractor would not allow us in the trench he paided for a bucket truck to traverse the top ofeither slope while the rodman could extend the boom over the trench and take a shot by lowering his staff.

    The contractor had no problem paying for this apparatus because he made money in increased production. He couln't keep up with us.

  • Alyssa,

    Safety should be your priority

    .

    Canada should have some type of safety requirements for excavation, such as shoring and/or trench slopes, which would permit someone to enter the work area safely.

    If not, my suggestion is to have the pipe welder carry a mini prism with them and record the weld, with a Total Station, when each weld  completed..

    • Yes, there is safety protocols, which I understand to be 2 ladders every 8-10 m for multiple exits. Again, this is not practical when they are lowering in 300-500m of each pipe at a time. Welds are done above ground (except for tie-ins and connection welds, in which we can access the pipe from in the trench).

      Its all a big learning curve for me! Thanks for the suggestion and advice!

  • Well tell your boss you're not working in a trench. In the USA OSHA (federal safety Aholes) define a trench as being deeper than it is wide. So climb on down there and walk the center pipe. Just present it in a polite logical way.
  • Hi,  If you used GPS and Total station you will be working in grid and then converting to ground at some point when surveying the welds. What about your combined scale factor? Good luck.

    Maurice Heter

    Underhill Geomatics Ltd.

  • Hi Alyssa,

    As someone that has been there and done exactly that, I'll say a few things...

    1) Yup - heavy construction surveying work and certainly pipeline survey work IS hard and dangerous..

    2) Wimpy people need not apply for this type of work....

    3) Your company is in an "unsafe" business to start with, so they need to check their business model, maybe shift to mortgage surveys...

    4) The method you described - I have used it myself - is just about the only way to do this.  Sorry, but whoever suggested a drone does not understand this type of work.

    5) Seriously, have an on-site safety meeting with this person from your office.  Have they seen the conditions?  The needs?  Or are they simply concerned about the the R10 being damaged?

    I was on pipeline for several years and you just have to adapt to the situation and "Git er Dun" as they say.  But never do somethings risky or unsafe.  No shot is worth a serious injury.

    Good Luck,

    Kevin

    P.S. - Do not take any of this as a disparaging to women in the surveying field - I've fired more than one young "man" who just could not keep up and do the job.  

    • Yes, I understand that there is no real "safe" way to do this. Safety meetings happen all the time amongst our company and the client, but nothing was ever done about it since my chief was doing such a good job so efficiently, and no one except the two of us understood what type of work we are doing. That and our project manager is completely useless.Moving on... Now with my chief gone, its not just the safety concern, but we managed to wreck our 2 R10 receivers that were rentals, due to the long painters rod and suspended weight. 

      Its unfortunate that there isn't some sort of middle ground on this project. My old chief worked on hundreds of miles of pipeline down in the states, and this was the first time he faced any issues, as we are working in Canada. 

      I'm also just asking for suggestion since this is the first time I will be in charge of anything since I finished university and want things to go kinda smoothly on my own. Thanks for the advice though, everything helps :)

  • Just use reflectorless mode. More accurate than your previous method I would say.
  • What about a man on each side of the trench, each holding an end of a light-weight rope with a 360 prism secured to the center of the rope. Another rope, or small fierglass rod could be suspended from the rope/prism to the pipe so distance to the pipe could be measured accurately. Simply walk down the sides atop of the trench stopping to take shots where necessary.  

  • If you are going to use a Trimble for the reflectorless i would recommend using the tracking mode rather then the standard measurement mode as i have found it to be more accurate with the S6 that i use. Although the tracking is a single observation you can move the cross hairs around to see what distance range you are measuring to surrounding objects like trench wall, floor and the pipes and ensure that you are measuring what you want to measure and not an object behind. I found that the standard mode would seem to do some sort of averaging at times between the objects that were within the footprint of the reflector less beam and you would end up with short building walls that were out of square by 100+mm. Its just easier to see the raw distances as you go.

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