Thank you everyone for the great responses! Once again, you nailed it!
There were both safety issues and quality issues present in the photograph of double-sided drainage geocomposite.
I’ll start with the safety issues, which I illustrated as numbers 1 and 2 on the photograph.
- No gloves while working with the sharp edge of the geonet layer of the geocomposite.
- Loose geonet, which wraps behind the technician’s feet is a slip, trip and fall hazard. Anyone remember how fun the days before bonded geocomposite were, trying to install geonet on slopes?
As many of you pointed out, #3 is a safety hazard and a quality issue. I’ve seen numerous holes burned in the geomembrane below the geocomposite when this procedure (propane torch) is used and I definitely prefer a heat gun such as those made by Leister.
Regardless of the heat source, the geocomposite should be lifted up and off of the geomembrane if heat is going to be used. There is also the potential geonet damage as a quality issue. When it comes to safety, on most landfills, methane is going to be in the area, either in a nearby cell or in the cell below a cap project, so there is the fire potential many of you mentioned, not only in gases but in the other geosynthetic materials.
I’ve seen where a flame was used to melt/seal the fusion welded seams in preparation for air pressure testing on a cap and seen fire start at the other end of the seam that hadn’t even been heated!! I’ve also seen geotextile patches performed with this method start on fire several minutes after the technician walked away – luckily in this instance they were the last repairs required before backfill and I was following up on my punchlist so we were able to extinguish them immediately (and then repair the geomembrane and geotextile).
I feel whether or not propane torches are used on a project should be addressed in corporate health and safety plans and/or construction documents and definitely should be a topic of discussion at the preconstruction meeting. Without something to fall back on, many engineers are reluctant to disallow procedures that an installer may argue would speed up the process.
In these blog posts, Do You See What Glen Sees, I will present a photograph or short video related to earthwork or geosynthetics construction and have you identify the significance of what you’re seeing.
It could be things being done correctly or incorrectly. Primarily, these will be things that impact quality.
In addition to my blog, I’ll post this content on X and LinkedIn. You can post your response on one of those two.
I’ll give you my thoughts on each photo or video when I post the next installment.
Do you see what I see? Or did you find something I missed? I’m excited to find out!
