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PASSIVE SAFE POLES - TRIGLASS® lighting poles successfully tested according to EN 12767/2019

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Lighting poles can become dangerous elements if cars crash into them while travelling on roads or highways. Official data collected by ISTAT (the Italian National Instituite of Statistics) show that the number of road accidents due to collisions with these elements exceeds 5000 cases each year.
For this reason, Top Glass has decided to measure the passive safety of its own poles by analying the parameters described in the EN 12767 European standard in some crash tests at Transpolis S.A.S. 
In July 2022, Top Glass has tested its lighting poles of 11,6 meters and 9 meters of length that have been classified in a specific energy absorption category:

-No energy absorption (NE). After the impact, the pole can break up or detach from the foundation without arresting the vehicle which continues travelling at a lower speed.
-Low energy absorption (LE). After the impact, the pole collapses while the vehicle loses most of its starting speed. 
-High energy absorption (HE). The pole does not collapse, and it stops the vehicle provoking a fatal accident.

PARAMETERS

Besides the energy of absorption category, the EN 12767 standard also analyzes:
  • the speed class of the vehicle, at 35 km/h and at 100 km/h.
  • the occupant safety class, from A (low gravity) to E (high gravity).
  • the collapse mode, that can determine a detachment from the foundations or a simple collapse (SE or NS).
  • the direction class of the vehicle.
  • the penetration of objects into the passenger compartment with the risk of a roof indentation.

TEST SET-UP

Different test sets were prepared at Transpolis S.A.S: the poles were installed on a backfill of sand and gravel to guarantee the optimum degree of compactness (GNT/31.5). To reproduce the worst scenario, a metallic bracket with a luminaire (with the total weigh of 10 kg) was fixed on the top of the poles. 

The vehicle used for the impact (Peugeot 106) weighed 910 kg and contained all the necessary equipment to direct the test, and control and record the speed of acceleration or deceleration. Inside, was collocated a SID to detect further data during the impact such as the effects of the crash on the driver.

According to the standard, the tested speed must be two: a minimum speed of 35 km/h and a maximum speed chosen from 50, 70, and 100 km/h. Among them, Top Glass opted for the highest one.

TEST RESULTS

The results showed that the poles 11,6 meters long are included in the "low energy absorption" category (LE) while those which are from 3 to 9 meters long are part of the "no energy absorption" (NE) because the vehicle output speed was slightly reduced from 100 to 79 km/h. In both cases and despite the strong deformations, the poles were never detached from the foundations. 

The classification of the poles according to their length is related to the geometric properties of the poles themselves and to the percentage of the glass fiber of which they are composed. For longer poles, more glass fiber is used: this affects the weight of the pole and, consequently, the results. 

Another important parameter is the safety class of drivers that corresponds to level C for both pole lengths tested. The safety class is analyzed on the basis of the injuries on the driver inside the car that can go from A (very low severity) to E (very high severity). Top Glass result is a very positive one.
    Futher information about EN 12767/2019 standard


Passive safety of support structures for road equipment - Requirements and test methods

The EN 12767 European standard specifies the requirements and test methods to assess the Passive Safety of supporting structures for Road equipment.
Passive Safety is intended to reduce the severity of injury to vehicle occupants in case of impact with road equipment.
In this standard, any kind of road equipment can be assessed, but the most common are the sign support, signal support, lighting column, utility pole, cantilever support.
The following description explain the test set-up and procedure, the possible test results and the classification of the poles.
Evaluation by crash-test
The object of this standard is an impact test of a vehicle with specific characteristics against a pole. Whatever the category, the car to be crash-tested is a standard passenger car of 910 kg. The car is equipped with plenty of sensors and data measurements box, so that severity criteria may be measured. The crash-test is filmed with high-speed cameras.
The main criteria which define a pole are:
  • Speed class
  • Energy Absorbing category
  • Occupant safety class
  • Collapse mode behaviour
  • Direction class
  • Risk of roof indentation.
A test is non successful if the severity criteria on occupants are too high or if a part of the pole penetrates inside the vehicle.
 a. Speed class of a pole
The standard defines 3 Speed Class: class 50, class 70, class 100.
It’s upon to the manufacturer to choose the class he wants its pole to be compliant with.
For each class selected, the pole need to be crash-tested at 2 different speeds:
- At the speed of the class ( 50, 70 or 100 km/h)
- At a lower speed: 35km/h.
A speed class of 50 will be preferred for poles to be installed in city, whereas a class of 70 or 100 can be preferred when poles are installed on rural roads, highways, etc.
b. Energy Absorption Category
The Energy Absorption of a pole is a very important parameter which determines a lot of other parameters.
Three categories exist, defined by the exit speed of the car after having impacted the pole:
  • HE = High Energy Absorbing: the car is stopped or almost stopped by the pole.
  • LE = Low Energy Absorbing: the car is slowed by the pole, losing a lot of its speed
  • NE = Non-Energy Absorbing: the car pass through the pole, without losing too much speed.
The following table shows the correspondence between the energy absorption category and the speed class:



c. Occupant Safety Class
The occupant Safety class goes from A (very low severity) to E (most important severity) and is defined by 2 values:
  • THIV: it corresponds to the theoretical impact of the head against any point of the car
  • ASI: it corresponds to the deceleration that the passenger will endure.
THIV and ASI values need to respect specific value in order the pole to be classified into one of the category A,B,C,D,E. If one of the values is too high, the pole cannot be compliant to the EN 12 767 standards.
Generally, A and B are for plastic delineator or similar harmless device; C category generally applies for NE pole; D and E for LE and HE.

d. Collapse Mode
Two collapse modes can be observed:
  • SE = Separation Mode. The pole breaks / separates.
  • NS = No separation Collapse Mode. The pole didn’t break, it mainly deforms and wraps into the car.
NB: for a same pole, we can observe the two different collapse mode: It is often bound to the test speed.

e. Direction class
The poles can be categorized into three Direction Class:
  • SD = single-directional
  • BD= Bi-directional
  • MD=multi-directional
In a general manner, a pole having more than two symmetric axes is considered as a MD: the exact location of the vehicle impact into the pole doesn’t matter, the pole will have its same performance and can be installed in a cross section, in median strip., etc.
A pole that doesn’t have two symmetric axes, will have to be tested successfully at different angle to get the MD classification.

f. Risk of roof indentation
This criterion gives a classification about roof deformation due to the pole falling in the vehicle
Class 0: roof deformation < 102mm
Class 1: roof deformation >102 mm

Notion of Product Family
The standard introduces an important focus on product family. If a pole is manufactured in different sizes, not all the sizes need to be tested:
  • The tests need to be run on the biggest/higher pole.
  • Given result obtained on the higher poles, additional tests need to be done on the smallest pole.
  • According to the result on the smallest pole, additional test may be necessary on intermediate sizes.

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