Full-Scale PES Testing: Assessing a Protective Structure at the Client’s Site
Material documentation describes the properties of the netting. Engineering calculations establish the basis for the design. Once installation is complete, however, the client still has a practical question: how will the structure perform under load?
Full-scale testing helps answer that question. For protective enclosing structures (PES), this means assessing the installed netting, fixings, cable system and supporting frame together, in the configuration in which they will be used.
This article presents a test of a protective structure designed by SD PROSPECT and installed at the client’s site. A pre-weighed load was dropped onto a section of the netting. The net took the impact, deflected and retained the load within the protected span.
These tests are carried out by prior, separate agreement with the client. The conditions are determined for the individual project and site.
Full-scale testing helps answer that question. For protective enclosing structures (PES), this means assessing the installed netting, fixings, cable system and supporting frame together, in the configuration in which they will be used.
This article presents a test of a protective structure designed by SD PROSPECT and installed at the client’s site. A pre-weighed load was dropped onto a section of the netting. The net took the impact, deflected and retained the load within the protected span.
These tests are carried out by prior, separate agreement with the client. The conditions are determined for the individual project and site.
Why test the whole structure, not just the netting?
Discussions of passive UAV protection often focus on the material: its strength, elongation and mesh size. These properties matter, but an installed system consists of more than a sheet of netting.
The net is attached to load-bearing members through cables, connections and fixings. All these components work together under load. The netting’s product data sheet alone is therefore not enough to assess the installed PES.
SD PROSPECT uses Darwin anti-drone netting in its designs. Selecting the netting goes hand in hand with designing the supporting structure and its connections. The material has to be considered as part of a specific design, not in isolation.
An on-site test provides an opportunity to check how these elements work together after installation. The client can see how the netting responds to the load, how it deflects and whether it continues to hold the test weight. The design engineer can compare this behaviour with the structural model, while the subsequent inspection helps assess the condition of individual components.
Calculations and tests serve different purposes. Calculations substantiate the design before it is built. Testing shows how the assembled system behaves under a specified load. Neither should be treated as a substitute for the other.
The net is attached to load-bearing members through cables, connections and fixings. All these components work together under load. The netting’s product data sheet alone is therefore not enough to assess the installed PES.
SD PROSPECT uses Darwin anti-drone netting in its designs. Selecting the netting goes hand in hand with designing the supporting structure and its connections. The material has to be considered as part of a specific design, not in isolation.
An on-site test provides an opportunity to check how these elements work together after installation. The client can see how the netting responds to the load, how it deflects and whether it continues to hold the test weight. The design engineer can compare this behaviour with the structural model, while the subsequent inspection helps assess the condition of individual components.
Calculations and tests serve different purposes. Calculations substantiate the design before it is built. Testing shows how the assembled system behaves under a specified load. Neither should be treated as a substitute for the other.
The on-site test: a 168 kg load
A bag filled with ballast served as the test weight. Before lifting, it was weighed using a crane scale; the video records a reading of 168 kg. A mobile crane then raised the bag above the net canopy and released it from the lifting rig.
The load was dropped onto the installed PES, into a span between members of the supporting frame. The test involved a section of the assembled structure, not a separate material sample.
On impact, the netting deflected. The bag settled into the pocket formed by the net and remained there after the movement subsided. It neither passed through the mesh nor slipped over the edge. A post-test photograph shows that the load was still held in place.
This is the result that matters to the client: the structure not only arrested the fall but continued to retain the load after the initial impact. The test used the system as installed, with its supporting frame, fixings and actual net tension.
The condition of each connection must nevertheless be checked by inspection, rather than inferred from a wide-angle video. Whether any components need adjustment or replacement can only be determined after that check.
The load was dropped onto the installed PES, into a span between members of the supporting frame. The test involved a section of the assembled structure, not a separate material sample.
On impact, the netting deflected. The bag settled into the pocket formed by the net and remained there after the movement subsided. It neither passed through the mesh nor slipped over the edge. A post-test photograph shows that the load was still held in place.
This is the result that matters to the client: the structure not only arrested the fall but continued to retain the load after the initial impact. The test used the system as installed, with its supporting frame, fixings and actual net tension.
The condition of each connection must nevertheless be checked by inspection, rather than inferred from a wide-angle video. Whether any components need adjustment or replacement can only be determined after that check.
What does "the net held the load" tell us?
Mass is a clear, readily understood figure, but it is not enough to characterise a dynamic impact. Drop height, the shape of the test weight, the point of contact and the way the system is secured also matter. The result therefore applies to a particular structure under particular test conditions.
Dropping ballast tests how a PES performs under load; it does not reproduce every possible collision with a drone. On its own, the result cannot demonstrate protection against every type of UAV or establish that a warhead will not detonate. Those are separate questions requiring appropriate input data and assessment methods.
This distinction does not diminish the value of the test. The client receives a result that can be checked: a measured load mass, a recording of the drop, evidence that the load was retained and information on the structure’s condition after loading.
The deflection of the netting deserves particular attention. It is not enough to arrest a falling object; its final position relative to the building or equipment below also needs to be assessed. This takes the evaluation back to the design: the position of the netting, the clearance beneath it and the behaviour of the connections must be considered together.
The video shows what happened. The engineering assessment explains what that result means for the installed system.
Dropping ballast tests how a PES performs under load; it does not reproduce every possible collision with a drone. On its own, the result cannot demonstrate protection against every type of UAV or establish that a warhead will not detonate. Those are separate questions requiring appropriate input data and assessment methods.
This distinction does not diminish the value of the test. The client receives a result that can be checked: a measured load mass, a recording of the drop, evidence that the load was retained and information on the structure’s condition after loading.
The deflection of the netting deserves particular attention. It is not enough to arrest a falling object; its final position relative to the building or equipment below also needs to be assessed. This takes the evaluation back to the design: the position of the netting, the clearance beneath it and the behaviour of the connections must be considered together.
The video shows what happened. The engineering assessment explains what that result means for the installed system.
Site conditions are part of the design from the outset
A protective structure cannot be considered separately from the facility it covers. People and equipment continue to operate beneath it, utility lines pass through the area, and maintenance routes must remain accessible.
When designing UAV protection for industrial facilities, the site’s purpose, layout and operational constraints all have to be taken into account. At an operating plant, the protective structure must not introduce new obstacles to production or equipment maintenance.
PES for vertical steel tanks (VST) and oil depots have their own design requirements: tank geometry, spacing between structures and the layout of process infrastructure. A design for a standalone tank cannot simply be transferred to a tank farm without checking its suitability.
For UAV protection at energy facilities, the characteristics of the electrical equipment and access for maintenance require separate consideration. Site requirements influence both material selection and the positioning of load-bearing members.
The conditions for an on-site test are therefore set for each project. Testing one section provides useful information about its behaviour, but it does not replace calculations or checks for the rest of the design.
When designing UAV protection for industrial facilities, the site’s purpose, layout and operational constraints all have to be taken into account. At an operating plant, the protective structure must not introduce new obstacles to production or equipment maintenance.
PES for vertical steel tanks (VST) and oil depots have their own design requirements: tank geometry, spacing between structures and the layout of process infrastructure. A design for a standalone tank cannot simply be transferred to a tank farm without checking its suitability.
For UAV protection at energy facilities, the characteristics of the electrical equipment and access for maintenance require separate consideration. Site requirements influence both material selection and the positioning of load-bearing members.
The conditions for an on-site test are therefore set for each project. Testing one section provides useful information about its behaviour, but it does not replace calculations or checks for the rest of the design.
Arranging a test after installation
A drop test at an operating facility requires preparation. It cannot be treated as an impromptu demonstration of net strength: buildings, equipment and people are nearby.
The feasibility, scope and conditions of testing are agreed separately with the client in advance. The test concerns a PES installed to a design prepared by SD PROSPECT. It is not automatically included in every design commission.
Before testing, the parties need to define the load case to be assessed and the criteria for evaluating the outcome. Site access, the use of equipment, a safe testing area and arrangements for the post-test inspection must also be agreed.
The client should receive more than a video. Test parameters and inspection findings should be recorded in a report identifying the tested section, the load mass and drop height, and the condition of the netting, fixings and supporting members. The documents and records to be handed over are agreed when the work is arranged.
This keeps the discussion specific. The question is not whether "the net held" in general, but what load the particular system took, how its components responded and what needs to be done afterwards.
The feasibility, scope and conditions of testing are agreed separately with the client in advance. The test concerns a PES installed to a design prepared by SD PROSPECT. It is not automatically included in every design commission.
Before testing, the parties need to define the load case to be assessed and the criteria for evaluating the outcome. Site access, the use of equipment, a safe testing area and arrangements for the post-test inspection must also be agreed.
The client should receive more than a video. Test parameters and inspection findings should be recorded in a report identifying the tested section, the load mass and drop height, and the condition of the netting, fixings and supporting members. The documents and records to be handed over are agreed when the work is arranged.
This keeps the discussion specific. The question is not whether "the net held" in general, but what load the particular system took, how its components responded and what needs to be done afterwards.
What the client gains from testing
The main value of a full-scale test is the opportunity to see the design perform once it has been built. Installation comes between the drawing and the finished structure, and the client needs to understand how the assembled system behaves under load.
In the test shown here, the PES designed by SD PROSPECT arrested and retained the dropped load. The video and photographs record that result. Inspection of the components after loading adds the information needed to draw conclusions within the limits of the test.
SD PROSPECT designs protective enclosing structures. Its work includes reviewing input data, planning support locations, calculating loads and protective performance parameters, and preparing project documentation and detailed design documentation for construction. Examples for different types of facilities are available in the Completed Projects section.
To discuss PES design and the possibility of an on-site test after installation, contact our specialists. Test arrangements are agreed in advance for your site and the design developed for it.
In the test shown here, the PES designed by SD PROSPECT arrested and retained the dropped load. The video and photographs record that result. Inspection of the components after loading adds the information needed to draw conclusions within the limits of the test.
SD PROSPECT designs protective enclosing structures. Its work includes reviewing input data, planning support locations, calculating loads and protective performance parameters, and preparing project documentation and detailed design documentation for construction. Examples for different types of facilities are available in the Completed Projects section.
To discuss PES design and the possibility of an on-site test after installation, contact our specialists. Test arrangements are agreed in advance for your site and the design developed for it.
October 22