It’s a Blessing and a Curse

Over and over in my head I hear myself mumbling TV Detective Adrian Monk’s catch phase “It’s a blessing and a curse, it’s a blessing and a curse, it’s a blessing and a curse…”

Thankfully, I am not quite as neurotic as Adrian (although I know a few contractors who might argue the point.) I truly understand the gift and burdens of “seeing” all the details and the impact they have on my performance. So for a few minutes (or perhaps a series of blogs) you are welcome to join me in the inner depths of my mind, looking at an array of dizzying details….

Take for instance the role of marking seam destructive samples. I never have held the belief that the 1 sample per 500 lineal feet of seam should mean that you wheel off every 500 lineal feet of seam and place a destruct there—that just never made sense to me. My role as a CQA inspector is to assure the liner system installation meets the intent of the design through following the specifications.

Most specifications are written to allow me to take more samples if I feel there are suspect areas that warrant extra samples—but at some point, this could get way out of hand. So, my preferred method has always been to try to incorporate the suspect areas in with the 1 per 500 requirement, using the 500 feet of seaming not as a chosen location for my sample but as boundary for my sample. I look at every 500-foot increment (500, 1000, 1500, and so forth) as I need one destructive sample in that area, whenever possible. (Some firms require that I place them at set intervals throughout the seaming process).

While attending Geosynthetics 2013, I was fortunate enough to be in a presentation where the 1 per 500 was discussed, and it was confirmed that the intent of the wording was indeed to look at the 500 feet as an interval, not a set, pre-determined location on a seam. So, while it was a blessing to get this confirmation after 23 years in the field, it often feels like a curse when “witch-hunt” accusations come from the distraught installer.

When I mark destructs, I take into account everything else that has transpired with that particular machine and operator. My CQA crew is trained to tell me if they observed any suspect areas (as well as the seam number and the station of the suspect area) during the welding process—such as a lack of cleaning, dirt or moisture present in the seam, the operator not paying attention to overlap, pushing or pulling on the machine, welding through tape, and so on.

I watch if the installer is testing end coupons and I inspect them if given the opportunity—if not given the opportunity, I watch for reactions of the operator, foreman, and QC people which are key indicators in keeping them honest. Subtle indications include making machine adjustments or more intense machine cleaning than normal, as well as taking a machine out of use. Obvious indicators include the crew marking an area of the seam for repair, or cutting additional coupons further back in the seam.

A direct approach also can work or at a minimum help you gather necessary clues: ask to see the coupons (you should have a right to see them), or take a look the next time you pass by the tensiometer. I frequently make special trips past the tensiometer if I am curious about end-coupons; I observe discarded coupons for peel separation.

Does the last value on the tensiometer meet peel strength requirements? Even if end coupons are only being tested using a hand clamp test for peel separation, you can still gather important data by looking at the coupons or watching if they break without much effort.

There is nothing more unsettling to a conscientious CQA inspector than finding coupons laying on the liner that have peeled, have no idea where they came from, and no installer ownership of where they came from. If the coupon was hand cut, at least you may be able to use your “Monk” skills and match the size and shape of the coupon to determine where it was cut from.

I typically walk every foot of seam in looking for places to choose destructs—and I try to do it in the best and most favorable lighting conditions. In order to be afforded this luxury, I need to be caught up on everything else going on, sometimes coming in early, working on destructs at lunch, or staying after the crew is gone.

Things catch my eye: differences in wheel depth impressions, lack of wheel track, uneven wheel pressures between tracks, wheel spins, the machine drifting in and nearly out of the seam, overlap, wrinkles, burnouts, and many other oddities that potentially indicate something may be wrong with the seam—and this is just for fusion! I notate the locations of suspect areas, and try to figure out if it is only noticeable on one machine, or across the board, etc.

I also take into consideration historical patterns from a culmination of my experience—areas that have a historically higher probability of failing, as well as trends on the current project when there are failures. For instance, crews working 6 or 7 long shifts in a row may hurry near the end of that last shift before their day off and the destruct failure rate can go up on samples taken near the end of that shift, especially on extrusion welds.

I then go back and mark my samples within the 500-foot intervals, based on machine/operator combinations. I try to get representative samples of anything I have a concern about, but I don’t go overboard and mark every one—but I do have the right to revisit those areas should similar samples fail. And, I try to weigh all of this with the goal of minimizing holes in the geomembrane, but keeping the contractor honest. It can feel like the weight of the whole world is on your shoulders! And, when a sample fails, I go back to the foreman and I either tell them or we figure out the “here’s what happened” so it can be avoided in the future.

I always give the installer the right to repair an area I have marked for a destructive sample. If we find something indicative of a failure, then we try to fix it immediately, as well as simply patching other areas that look similar, to avoid cutting more holes in the liner—sometimes, if there is an excessive amount, we try to cut coupons and test in the tensiometer to narrow down the bad so we are not putting unnecessary patches on the liner.

Unfortunately for the installer, destruct failure rates are usually higher on my projects than what they are used to—it still may be within acceptable limits, but instead of having zero failures, perhaps they have one or two. I have seen even the best installation crews struggle—sometimes to the point of where they may get kicked off the job if the failure rate continues.

My normally unpopular presence takes even more of a hit at times like these. And if it is a competent installer that is undoubtedly trying their best to do a good job, I feel bad for them—I don’t want to see someone get kicked off a job site just because they ran into someone who has a detective-like skill at piecing clues together which lead to the apprehension of a failing destruct. That being said, it doesn’t change who I am, or how I look at future seams. I just go on doing my job, regardless of whether we see it as a blessing or a curse.