1) The document examines the behavior of rope constituents (sheath and core) under various risk factors that exist in work environments. 2) Laboratory tests were conducted on samples of static and dynamic ropes exposed to standard conditions, water, acidic and basic solutions, and heat to determine the amount of sheath slippage relative to the core. 3) The results showed that most ropes had sheath slippage lower than specified limits, with one dynamic rope exceeding the limit. Exposure to moisture, acids, bases, and heat increased sheath slippage in static ropes compared to standard test conditions.

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International Journal of Advanced Research in Engineering and Technology
(IJARET)
Volume 7, Issue 3, May–June 2016, pp. 77–86, Article ID: IJARET_07_03_007
Available online at
http://www.iaeme.com/IJARET/issues.asp?JType=IJARET&VType=7&IType=3
ISSN Print: 0976-6480 and ISSN Online: 0976-6499
© IAEME Publication
BEHAVIOUR OF THE ROPES
CONSTITUENTS UNDER THE ACTION OF
RISK FACTORS THAT EXIST IN THE
WORK ENVIRONMENT
Nicoleta Crăciun
Head of PPE Certification: Certification Body
The National Research and Development Institute of Occupational Safety (INCDPM)
"Alexandru Darabont", Bucharest, Romania
ABSTRACT
The ropes used as primary elements of the various components of
individual systems for protection against falls from height, have an important
role in maintaining the safety of workers. Even if they are used in systems
limitation, positioning, rope access, fall arrest or rescue, maintaining the
characteristics of their protection throughout the period of use is mandatory.
Knowing that workplace hazards not only act on the worker but also on
personal protective equipment, through this study I intended to find out the
sliding behavior of the sheath from the core (the main charge carrier) under
the action of the possibly risk factors that exist for the workstation.
Key words: Working at Height, Danger, Ropes, Sliding Sheath
Cite this article: Nicoleta Crăciun, Behaviour of the Ropes Constituents
under the Action of Risk Factors that Exist in the Work Environment.
International Journal of Advanced Research in Engineering and Technology,
7(3), 2016, pp 77–86.
http://www.iaeme.com/IJARET/issues.asp?JType=IJARET&VType=7&IType=3
1. INTRODUCTION
Present in the most workplaces, activities at height requires ensuring the adequate
protection for workers. Depending on your workplace, the personal protective
equipments against falls from height may be selected and mounted differently, so
making various systems whose function is to limit the movement, for prevention of
falls from height, for rope access, to stop the pit fall or as a rescue goal. Depending on
the specific activities carried out at height, workers are not only in danger due to
falling from height but also to the actions of other physical hazards, mechanical and
chemical present in the environment.

2. Nicoleta Crăciun
http://www.iaeme.com/IJARET/index.asp 78 editor@iaeme.com
The presence of hazards in the work environment has a negative impact not only
on the worker but also to personal protective equipment against falls from height
(abbreviated as PPE for working at heights). Designed to link an anchor and the
holding device of body, the ropes used in individual systems of protection against
falls from height, must be made such that under the action of other hazards (physical,
chemical, etc.) existing in the working environment, to maintain the protection
features throughout the entire period of use.
The harm action of dangerous factors to the string behavior it cannot be estimated
by a single characteristic, for example following the appearance or change in mass,
but it must be considered how they may influence the defining characteristic of that
type of protection. If not considered the action of physical or chemical dangers [1] to
the components of PPE made of rope it is possible that over time they lose the
protection features and does not perform its function when the leading factor exercise
its action, which can lead to accidents at work or serious occupational disease [2].
Because of the large number of accidents at work [3] registered each year as a
result of breaking the ropes especially in the access activities through a rope, and the
fact that at the national and international level there are not addressed such problems,
the study conducted analyze the risk factors of chemical action of the movement
towards the core mantle to support decision makers in selecting appropriate ropes
used in personal protection systems against falls from height.
2. STUDY AND RESULTS
Since in the last few decades in manufacturing technology ropes have not been
fundamental changes in the market prevails one material used to make ropes -
polyamide. Other materials such as polyester, aramid coated polyamide or polyester,
steel may be used in special circumstances but only with special protection because of
their lack of elasticity, premature failure or reduced capacity to absorb the energy
produced when fall.
In general, the manufacturers carry out two different types of ropes: with a low
coefficient of elongation (hereinafter referred to as static) and dynamic. The static
ropes do not stretch to absorb the impact energy. Used in most industrial sectors in
rope access systems, as well as for positioning systems and limiting movement in the
workplace, the static ropes (4) are used for rappel and lifting, but never to climb.
Dynamic ropes stretch enough to absorb impacts in a fall, and are manufactured
specifically for climbing.
Structurally the ropes are made of two independent components:
 The SHEATH (the outer shell) is the component that serves both to keep strands core
close in the established contexture and to protect against damage caused by the action
of various factors. This protective sleeve is an elastic yarn braided grouped into
strands
 The CORE - the main charge carrier - made of many parallel elements (strands). The
strands are formed from yarn braided and twisted together in the same direction.

3. Behaviour of the Ropes Constituents under the Action of Risk Factors that Exist in the
Work Environment
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Strands Yarn
The Sheath The Core
Figure 1 The components of the rope
Different technologies to achieve the two components of the rope, lead those two
elements to have various elongations. For this reason, when ropes are used with
different specific devices friction forces arise which causes additional movement of
the sheath from the core. As the lengthening string is higher, the possibility of
slipping the sheath from the core increases.
If, during work, there is a large shift of the sheath to the core may experience the
following situations:
 There may be areas where the rope contains only sheath and user's weight is
supported only by this element, which does not have sufficient mechanical strength to
ensure the necessary protection (core is component-carrying)
 There may be portions of the sheath is crowded, which can have an adverse impact on
the functioning of other devices, blocking them.
As a result the previous studies have been established by standards (SR EN 1891:
2003 and SR EN 892: 2005) [4], [5] limits considered by specialists as admissible on
the slip value for sheath against the core in a positive or negative test under
standardized conditions. However, depending on the type of string, these values
differ. Thus, the relative movement of the sheath from the core to:
 The static ropes type A with the diameter less than 12 mm should not exceed the
value obtained by applying the formula: 20 mm + 10x (D-9) mm, where D is the
diameter of the rope to try expressed in millimeters;
 The static ropes type B should not exceed 15 mm;
 The dynamic ropes must not exceed 20 mm.
However, many producers claim in briefing documents that their products for
sheath elongation have a value virtually zero.
The length measurement for sheath displacement from the core is performed
according to the test method given in section. 5.5 of SR EN 1891: 2003, respectively
5.4 of SR EN 892: 2005 and consists of:
 Exposing at least 24 hours in an atmosphere with a temperature of (50 ± 5) ° C and a
relative humidity of less than 10%, followed by cooling them for 2 hours in an
atmosphere having a temperature of (20 ± 2) ° C and a relative humidity of not more
than 65%
 The exposure of at least 72 hours in an atmosphere having a temperature of (20 ± 2) °
C and a relative humidity of (65 ± 2) %.

4. Nicoleta Crăciun
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Figure 2 shows the equipment used and the principle of the test method.
Figure 2 The Presentation of the Equipment used and Test Principle
Most often, however, working conditions differ from those in the laboratory, not
only in terms of temperature, but also the presence of certain factors such as water
(rain, immersion), the presence of acidic and basic solutions, as well as repeated
exposure to the caloric radiation. All these factors can strongly influence the sliding
feature of the sheath. Knowing the influence of risk factors present in the work
environment on different types of ropes can be an important factor in selecting the
type of chord. To obtain more comprehensive information the choice of ropes needed
to the study was based on the variety and the configuration of jobs and the wide range
of diameters posed by the ropes.
Thus the series of tests were performed on samples of rope made from polyamide,
both dynamic (simple with 10.5 mm diameter and double with 9.5 mm diameter used
primarily mountaineering) and static (type A and B, with diameters between 10 mm
and 11 mm). Samples of ropes acquired to carry out series of tests are shown in Table
1.

5. Behaviour of the Ropes Constituents under the Action of Risk Factors that Exist in the
Work Environment
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Table 1 Acquired string samples
Rope
number
The Rope Type
Diameter,
mm
Structure Encoding
1.
Dynamic - Single Rope
10.5
 the sheath structure has colored
yarn woven in 48 (12 threads
orange and 36 black yarn)
 the core is made up of 13 strands
twisted with the diameter 1.9 mm
A
2.
Dynamic - Single Rope
10.5
 the braided sheath structure has 48
colored wires (4 wire red, green 4-
wire, 4-wire blue 12 yellow and 24
black yarn threads)
 the core consists of 162 twisted
strands with a diameter of 0.46 mm
B
3.
Dynamics - Half Rope
9.5
 the sheath structure has colored
yarn woven in 48 (30 red yarn, 4
wires green, 10 blue yarn, 4 yellow
yarn)
 the core it consists of 10 twisted
strands with a diameter of 1.96 mm
C
4.
Static Rope Type B
10
 the sheath structure has 32 colored
wires twisted (2 red, 2 blue, 28
white)
 the core is made up of 11 strands
twisted diameter of 2.08 mm
D
5.
Static Rope Type A
10.5
 the sheath structure has 16 colored
wires twisted (2 wires blue, one red
wire, one wire yellow, gray 12
threads)
 the core is made up of 40 strands
twisted diameter of 0.63 mm
E
6.
Static Rope Type A
10.5
 the sheath structure has 64 wires
twisted black
 the core is made up of 16 strands
twisted with a diameter of 2.03 mm
F

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7.
Static Rope Type A
10
 the sheath structure has 40 colored
wires twisted (4 wires black and
blue wires 36)
 the core is made up of 16 twisted
strands of 1.86 mm diameter
G
8.
Static Rope Type A
11
 the sheath structure has twisted 48
colored wires (6 wires black and
blue wires 42)
 the core is made up of 16 twisted
strands of 1.68 mm diameter
H
9.
Static Rope Type A
10.5
 the sheath structure has 54 colored
wires interlaced (6 wires khaki and
48 black wire)
 the core is made up of 16 strands of
1.82 mm diameter twisted
I
In order to have a clear picture of the behavior of the sheath slippage relative to
the core to the different types of chord, attempts were made both in standard
conditions and in conditions simulating actual use, when the ropes may come into
contact with water with acidic or basic chemical substances or they can be exposed to
sources of radiant heat. The results obtained after performing the series of tests the
sliding core to the sheath, under standard conditions, are shown in Table 2 and plotted
in Figure 3.
Table 2 The sheath slippage relative to the core under conditions imposed by standards
method
No.
The code of
the test
sample
Rope Type Diameter, mm
The sheath
slippage
relative to the
core, mm
The sheath
slippage, Ss,
%
1. A Dynamic Single Rope 10.5 3 -
2. B Dynamic Single Rope 10.5 25 -
3. C Dynamic Half Rope 9.5 0 -
4. D Static Rope Type B 10 0 0
5 G Static Rope Type A 10 1 0.052
6. E Static Rope Type A 10.5 0 0
7 F Static Rope Type A 10.5 0 0
8. I Static Rope Type A 10.5 1 0.052
9 H Static Rope Type A 11 0 0

7. Behaviour of the Ropes Constituents under the Action of Risk Factors that Exist in the
Work Environment
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The sheath slippage, Ss, % is calculated using the formula:
1930
100Vx
Ss 
(1)
Where:
- V is the sheath slippage relative to the core, in mm;
- 1930 is length tested.
Figure 3 Sliding Core from Sheath under Standardized Conditions
Analyzing the distribution of values for slipping of sheath to core obtained for
different types of ropes it is noted that all the ropes are tested in relation to the
movement of the sheath to the core, significantly lower than the maximum levels
specified in the reference standards, with one exception (rope encoded B). Comparing
the results we can say that the relative value of sliding for sheath is not influenced by
the type of rope or diameter.
Comparative analysis of the first two ropes dynamic (A and B), having the same
diameter and which were made different amounts of displacement of the mantle, it
can be said that discrepancies are due to both the structural characteristics of the
sheath and the core. This conclusion was determined after analyzing the embodiment
of the components of both types of chord, in which it is found that, the encoded string:
 A – The sheath has a structure of 48 colored wires twisted and the core consists of 13
twisted strands, each strand with diameter of 1.9 mm;
 B - The sheath has a woven structure of 48 colored threads and the core is formed by
162 twisted strands, each strand having a diameter of 0.46 mm.
Since the sheath is made by weaving the same number of strands, and has a
structure similar in both cases, the conclusion would be that the sheath slippage
relative to the core is influenced in this case only the core structure, this is the greater
as the number of strands increases or decreases the diameter of each strand.
In addition to static ropes, ropes with low coefficient of elongation, it is found that
the relative value for lengthening the sheath from the core vary slightly depending on
the diameter of the rope.

8. Nicoleta Crăciun
http://www.iaeme.com/IJARET/index.asp 84 editor@iaeme.com
Since the ropes are made of polymers, there is in principle a risk that under the
action of existing hazards in the workplace, such as chemicals, humidity and heat, to
lose its protective characteristics. Since moving sheath from the core represents one of
the characteristics of protection to be achieved for marketing such a product, in the
study was aimed specifically the influence of excess moisture, basic solutions, acidic
and radiation caloric on this feature. Being used in most industrial areas, the influence
of degradation above was followed on static ropes of different diameters. Thus,
samples taken in the ropes of the encoded G, I, H were immersed for 4 hours in a
solution of sulfuric acid concentration of 30% solution of sodium hydroxide with a
concentration of 10% and water at a temperature of 24 0
C.
The results obtained after carrying out series of tests on sliding sheath from the
core are shown in Figure 4.
Figure 4 Slipping Core from the Sheath in Real Conditions of use for Static Ropes
Analyzing the distribution of values obtained is observed that all this have a
movement of the mantle relative to the core, significantly lower than the maximum
levels specified in the reference standards. However, high values are obtained for all
the ropes when exposed to radiant heat; phenomenon that occurs after stiffening the
mantle relative to the core, the latter slipping as through a channel.
Regarding the distribution of values obtained for the four types of degradation, as
seen in the figure 4 for rope whose diameter is 10 mm (codified G) is an increase.
To understand the phenomenon that emerged after the damages that were exposed
to three types of chord structures were analyzed both components of the chord
(mantle and core).
Thus it has been found that the encoded string:
 G with a diameter of 10 mm, whose mantle has 40 colored wires twisted structure (4
wires black and blue wires 36)  weaving density is 4 threads/unit length;
 I diameter of 10.5 mm, whose mantle has 54 colored wires twisted structure (6 wires
khaki and black yarn 48)  weaving density is approx. 5.2 threads/unit length;
 H with a diameter of 11 mm, whose mantle has 48 colored wires twisted structure (6
wires black and blue wires 42)  weaving density is approx. 4.4 threads/unit lengths.

9. Behaviour of the Ropes Constituents under the Action of Risk Factors that Exist in the
Work Environment
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 Corroborating the results of degradation with the results from the analysis of the
sheath, it can be said that the only factor that increases the sheath from slipping core
is its weaving way. Thus, one can say that if the ropes whose sheathing (outer fabric)
have a low density favors penetration of chemicals or radiation calorific thereby
internal structural changes that can lead to loss of protection features.
3. CONCLUSIONS
Used to obtain various individual systems to protect against falling from height, either
as a means of connection or anchoring support flexible the ropes have an important
role in maintaining the safety of users.
It is neglected that the elements being made of textile, the ropes, are exposed to
action of hazards present in the work environment, being able to lose protection
features. The loss of protection features determines in its turn the obstruction of the
individual protection against falls from height to fulfill its function when the main
factor exercising the action, which often leads to accidents at work or occupational
diseases serious.
The displacement of the sheath from the core being one of the protective
characteristics of the ropes, was studied to see its behavior under the action of
potential hazards existing at various jobs.
Thus, in the study, different types of ropes were exposed to a series of
degradation.
After conducting series of tests it was found that the relative slip of sheath:
 It is not influenced by the diameter when the test is conducted under standardized
conditions
 Depends on the achievement of core (thickness and number of strands); the ropes
with stranded thicker they slip less;
 Is influenced significantly by exposure to radiant heat, in particular in the case of the
ropes of small diameter, which is increase a rise of between 5 and 8 times greater than
that obtained under standard conditions, while the hardening and contracting rope
approx. 4.3%,
 Is influenced by the manner of the sheath (weaving density), and treatments applied
to it,
 Is influenced by the damage caused by chemical agents (sulfuric acid solution with
concentration 30%, respectively hydroxide solution sodium concentration of 10%),
particularly ropes of small diameter.
The study results can be used as a reference in a ropes selection processes used in
various protection systems for working at height, after identifying existing hazards
from risk assessment to workstations.

10. Nicoleta Crăciun
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REFERENCES
[1] ROL.ro, Stirile. Climber died after falling from the fifth floor.
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617028.html%3FPageSpeed%3Dnoscript+&cd=11&hl=en&ct=clnk&gl=ro.
[Interactiv] 8 mai 2010.
[2] Someseanul. http://someseanul.ro/un-alpinist-utilitar-a-murit-la-cluj-dupa-ce-a-
cazut-de-la-etajul-6/. [Interactiv] 8 martie 2013.
[3] Click.ro. http://m.click.ro/news/national/video-un-alpinist-utilitar-murit-dupa-ce-
cazut-de-la-etajul-sase-al-unui-camin. [Interactiv]
[4] EN 1891:1998 Personal protective equipment for the prevention of falls from a
height – Low stretch kernmantel ropes
[5] Saleh Alawi Ahmad, Usama H. Issa, Moataz Awad Farag And Laila M.
Abdelhafez, Evaluation of Risk Factors Affecting Time and Cost of Construction
Projects In Yemen. International Journal of Advanced Research in Engineering
and Technology, 4(5), 2013, pp 168–178.
[6] EN 892:2012 Mountaineering Equipment - Dynamic Mountaineering Ropes -
Safety Requirements and Test Methods