A flexible protection system is not finished on the day it is installed. Acceptance inspection, periodic and post-event inspection, corrosion assessment, spare parts and renewal of old lines; everything is entered on the line’s tag, and the next inspection date is read from there.
The problem
Flexible protection systems absorb energy by deforming. After catching a block, a braking element may have opened, a support rope may have stretched and the net may have shifted; from outside, the line still looks as if it is standing. The same applies to an avalanche line that has taken snow pressure, a debris flow barrier that has filled up, or an anchored mesh whose rock face underneath has loosened. Whether the system can still do its job is found out by measuring, not by looking.
The second problem is records. The crew that installed the line leaves, people at the owner change; five years later there is often no answer to "which system, which class, when was the last inspection". Maintenance should therefore be tied to need, not to the calendar, and the need should be read from the record. That is why we leave a QR-coded tag on every line we install and enter inspections and events in its log.
Service levels
| Level | When | What is done | What goes on the tag |
|---|---|---|---|
| Acceptance inspection | When installation is finished | The manufacturer's final checklist item by item: rope ends and number of clips, clip torque, anchor heads and plates, braking elements, net-to-rope and net-to-net connections; anchor pull-out test where the specification requires it | "Installation" record, date of the acceptance report, next inspection date |
| Periodic inspection | At the interval on the tag; default 12 months, for avalanche lines before winter and after the snow | Visual and measured: residual height, rope sag, braking element elongation, material accumulated in the net, erosion around anchors, coating condition, vegetation | "Inspection" record; the next date is recalculated from the log |
| Post-event inspection | Impact, full net, flood, landslide, earthquake or sensor notification | Emptying of accumulated material; replacement of deformed braking elements, ropes and net panels; assessment of the remaining capacity | "Event" and "Repair" records |
| Corrosion assessment | At the survey and at intervals over the service life of the line | Microclimate and atmospheric corrosivity category of the site (EN ISO 9223), effect of soil and slope water, condition of coating and ropes; manufacturer laboratory analysis if needed | Inspection note and estimate of remaining life |
| Renewal and upgrading | Old lines, systems whose supplier no longer exists | Matching spare parts, completing missing components, upgrading the energy class, adding monitoring sensors | New tag |
What is checked in an inspection
Rockfall barrier. Anchor heads and base plates; post inclination and base hinge; number and torque of clips and sag on support, retaining and tensioning ropes; elongation and signs of opening on braking elements; tears in the net and secondary mesh, opened rings in ring net; material accumulated in the net and residual height; coating and corrosion; erosion and vegetation around anchors; that the tag plate is in place and legible.
Anchored mesh and drapery. Seating of the plates on the surface and nut torque; mesh tension and joints; new loosening or voids under the mesh; material and drainage at the toe; the upper edge rope and its anchors.
Avalanche line. Before winter: post inclination, pressure plate seating, closure of the net surface, rope tension; after snowmelt: signs of snow gliding, displaced posts or plates, broken connections.
Debris flow barrier. Filling ratio, emptying of the material accumulated behind the net, scour at the edge anchors, erosion on the side slopes.
Decisions by measurement
| Observation | Criterion | Decision |
|---|---|---|
| Braking element elongated | Manufacturer's elongation limit exceeded | Braking element replaced; entered on the tag with an event record |
| Material accumulated in the net | Residual height has dropped below the design height | Net emptied; if accumulation is continuous, the class or position of the line is reassessed |
| Number or torque of clips insufficient | Below the value in the manufacturer's manual | Completed on site; entered in the acceptance report |
| White rust or red rust on the coating | Corrosivity higher than expected | Interval shortened, affected component replaced, life estimate updated |
| Sensor reported an event | Impact or tilt-change threshold exceeded | Post-event inspection planned; result written in the log |
Together with remote monitoring
On lines that are hard to reach or closed in winter, sensors attached to the support rope report impacts and tilt changes; the notification tells when a site visit is needed, it does not replace the visit. For details, see the early warning and monitoring (Turkish) page.
Reporting
The output of each inspection is a photographic list of findings, the condition component by component, the recommended work and the order of urgency. The report goes to the owner; its summary is published on the tag page in a form everyone can see. Project name, client and coordinates are not published on the tag. Print the inspection form from your tag: the component list for the line type is filled in on site and the result is entered on the tag (sample tag form (Turkish)).
Training
We give hands-on training at the line to the owner's or the contractor's own maintenance team: what to look at, what to measure, when to call us. The aim is not to call us for every inspection, but to call us at the right time.
How it starts
For an existing line the first step is the tag and a "zero point" inspection: the system is identified, its current condition measured, the maintenance interval set and the first entry made in the log. On newly installed lines this step is combined with the acceptance inspection. To apply, use the contact page; sharing the location of the line and any old project documents is enough.
