1. Did you know that when a Depth is given to you by a locator the depth will always be to the center of the electro magnetic field which is the center of the pipe not the Top or bottom of the pipe.This may not matter in smaller pipe but in larger pipe it can be a significant amount of distance.
2.All Line locating equipment only picks up horizontal Conductors (Pipelines,cables and wires).For vertical (Piles.Pins and well casings) you must use Pin finders.
3.Line Locating guns are not Metal Detectors, locating equipment induces an electro magnetic field around the conductor which can be received by our guns and followed.
4.Insulated pipe on hard packed gravel leases can sometimes be very hard to locate versus uninsulated pipe.
5.Locating cannot be done safely in the rain or very wet conditions due to high conductivity and or electric shock or damage to locating equipment.
6.When putting pipe or cable depths on lathe we only do straight sections as bends and corners can be out as much as 30%.
7.Working near barb wire or metal fences causes locating transmitter to induce signal to fence wire (path of least resistance) when you get to close.1m on either side of a fence is the closest.The fence must be removed to properly blind sweep.
8.Hard packed gravel or pit run can be very difficult for locator's as signals have trouble making it back to the receiver and depths can be very inaccurate.
9.As with survey equipment locating equipment can be disrupted by solar bursts from the sun.
10.When direct connecting to a pipe the insulating kit on the flange must not be bypassed. If it is our signal will continue on to all other conductors until it stops.This goes for non-insulated unions,sleepers with no rubber insulators,jumper cathodic cables etc..Making it very difficult in most cases to isolate one pipe from another.
11.Overhead power lines and transformers can distort signal and cause false locates,when working close proximity.
12.You must never locate during Lightning storms as our equipment is one large grounding rod.
13.When locating pipes in common trench or paralleling each other it is not always possible to separate the signal into 2 separate Peaks,but it is possible (not always) to use the Null method to separate.This is why Hydrovacing to confirm is a must!
14.When following and staking out P/L on ROW always walk and stay on pipe.(Second locator follows with quad/lathe).Common practice is to stake every 20-30m,many people drive up 30m locate pipe and then put lathe in.We do not.You could miss an expansion loop,which is critical if a company is going to parallel your Pipeline or you are paralleling theirs.
15.When locating cables always confirm each cable separately. Do Not Assume that it is a common cable trench,this mistake happens more than you think.
16.Always make sure your locator's have completed a circle search around the wellhead as sometimes old drains lines are present.
MYTHS AND fACTS ABOUT LOCATING
17.Did you know that locating transmitters can effect a persons Pacemaker if they have one.Always discuss this at safety meetings or make sure all people working close by are aware before you turn your transmitter on.
18.Winter locating can cause problems when inductive locating if deep snow is not plowed or removed signals can air couple and not penetrate ground and back to receiver,making it difficult to properly Blind sweep (Inductive ).
19.When you request or require a Second Locate(HIGHLY RECOMMENDED ON CONGESTED SITES)
it is highly recommended that the companies doing the sweeps are using different brands of equipment.
20.When doing double locates on any project it is advisable that each Locating Company complete there locates at different times.Reason is locators signals will interfere with each other,unless each pipeline and or line,flange,union etc has a working isulating kit (in my experience I have seen maybe a handful of sites that this is true.Conductively this will not work.Blind Sweeping can be accomplished at the same time as long as there proper proximities between both parties.
21.Most locators are not surveryers and the same
said for surveryors.Why,Locators look for the unknown conductors with special locating techniques 4way scans,circle scans,box scans,RF scans,50/60hz and grid pattern scanning plus the use of many different Frequencies and techniques.
22.Plastic,fiberspar pipe can be located,but not without great incovienance.SONDE OR TRACKING PIG can be used but requires slow flow or depressurring of pipeline.Common methods used by experienced and trained locators are witching in APPROX location and using hydrovac to expose.
23.When scheduling a locate make sure the work area is clear of service rigs,tanks,cats ect..that you want scanned.
24.PLEASE remember locating equipment has never been a 100% we are following a electro magnetic signal which can be distorted very easily .Always listen to the concerns or issues he or she is having and follow through with what they recommend (hydrovacing larger or longer slots,a second locate or maybe even a third,old drawings etc.