BLOG 4: What is the elasticity of a bandage? What are the differences between extensibility and elongation?

BLOG 4: What is the elasticity of a bandage? What are the differences between extensibility and elongation?

In previous posts we have discussed the different characteristics of a bandage, among which is elasticity. Speaking generally, elasticity is: “the ability of a material or substance to return to its original shape, size and condition after it has been stretched.”

How is the elasticity of a bandage calculated?

Elasticity is the property of a bandage to stretch and return to its original position after the force that stretched it has ceased to act. The elasticity of a bandage gives it the ability to deform to form a bandage in an area that is uneven in shape, such as the elbow or knee. In this way, a bandage, thanks to its elasticity, can modify its length at different points of the area where it is being applied.

If a bandage were made of an inelastic fabric, there are regions where there would be folds, since in areas of complex shapes it would not adapt itself correctly. In contrast, an elastic fabric can change its length and adapt itself depending on the needs of the shape.

Figure 4.1 Prepared by Carlos Izquierda S.L.: Initial position; stretched long-stretch; stretched short-stretch

The way to calculate the elasticity of a bandage in Europe is given by EN 14704-1:2005 which is calculated by the following formula:

Figura 4.2 British Standard BS EN 14704-1-2005 Determination of the elasticity of fabrics (BSi)

Figure 4.2 British Standard BS EN 14704-1-2005 Determination of the elasticity of fabrics (BSi)

S (%): Elasticity of the bandage in %.
E (mm): Maximum length in mm after stretching it to its maximum extension 5 times
L (mm): Initial length of bandage in mm without being stretched

From here we see that the elasticity is measured in percentage (%).  For example, using a bandage of 5 meters initially and without stretching, if after the five cycles of maximum stretching it has a length of 10 meters, the elasticity of the bandage would be 100%.

 

What is elongation?

When we talk about the elongation of a bandage, it is exactly the same as elasticity. Analyzing the European standard DIN 53504, this is confirmed. In fact the formula for the calculation of elongation is the same as for elasticity.

So when we talk about the elongation of a bandage or the elasticity of a bandage, we are referring to the same thing.

 

Extensibility of a bandage

Technically speaking, the extensibility is the property of the bandage to stretch to the point of rupture, hence its extensibility will be given by the point before that rupture occurs. But we must be careful since there is a clear difference between this and elasticity. While elasticity means the stretching and the return of the bandage to its usual position if there are no forces that stretch it, extensibility is not the same thing and only involves the maximum stretching capacity.

This is due to the fact that from the point of maximum elasticity to the point of maximum extensibility the bandage deforms and does not return to its original position even if there are no forces applied to it. If the maximum elasticity is exceeded by 10%, this is not recovered and the bandage without forces applied will have 10% more length. In other words, once the maximum point of elasticity is exceeded, extensibility begins, and it does not recover its original shape. The extensibility is measured until the fibers break.

In any case, these are technical and theoretical definitions; in everyday life, it is common to refer to elasticity, elongation and extensibility as synonyms.

No mention has been made of how to classify bandages according to their elasticity. As a simplification, since there is no consensus on the matter, a possible classification would be as follows:

  • Inelastic bandages: elasticity < 10%
  • Elastic bandages: elasticity >10%. Within this category we would also have:
    • Short-stretch bandages: elasticity between 10% and 100%
    • Long-stretch bandages: elasticity greater than 100%

However, as we have just mentioned, this is only an approximation based on the categorization made in the European standard DIN 61632 “Verbandmittel” (1985).

Figura 4.3: DIN 61632 Verbandmittel. Idealbinden

Figure 4.3. DIN 61632 Verbandmittel. Idealbinden

To conclude, it is worth mentioning that no reference has been made at any time to the compression of the bandage. This is because the elasticity of the bandage and the compression it exerts depend on other factors, as we will see in future posts on compression.

 

Prepared by the technical department of Calvo Izquierdo S.L.

with the collaboration of Carmen Alba Moratilla

Bibliography:

  • https://www.collinsdictionary.com/dictionary/english/elasticity
  • British Standard BS EN 14704-1-2005 Determination of the elasticity of fabrics (BSi)
  • http://oa.upm.es/38763/1/Manual_%20textiles2021.pdf
  • https://www.sciencedirect.com/topics/engineering/stretch-bandage
  • EN 29073-3 look for this standard. It is the test methods for textiles and you will find useful information.
  • DIN 61632 Verbandmittel. Idealbinden. Berlin, Wien, Zu ̈ rich: Beuth Verlag; 19
  • Partsch H, Clark M, Mosti G, Steinlechner E, Schuren J, Abel M, et al. Classification of compression bandages: practical aspects. Dermatologic Surgery 2008;34(5):600-9. [PUBMED: 18261106]
    Calvo Izquierdo participate ANECORM 14

    Calvo Izquierdo participate ANECORM 14

     From October 27th to 29th, CALVO IZQUIERDO SL attended as an exhibitor to the 14 CONGRESS OF NURSING COORDINATION OF MATERIAL RESOURCES (ANECORM) in the city of Santiago de Compostela (A Coruña).

    It was our first time as exhibitors at the congress and we find the experience very satisfied. Thank you for the entire congress organizing committee for their help and all the participants for coming to meet us, for dedicating their time and their comments. We hope to be able to participate in future editions since the feedback received has been very helpful.

    In addition to our line of Vendari bandages, we were able to show other distributions that Calvo Izquierdo has, such as the WOODCAST brand of wooden splints and the MILLIKEN compression kits, which were very well received by the attendees.

    MEDICA 2021
    See you next year!
    Calvo Izquierdo returns to MEDICA 2021.

    Calvo Izquierdo returns to MEDICA 2021.

    MEDICA is the leading trade fair for the global medical sector.

    Its high level of international influence and its reputation as a leading source of information in the field of medicine make it the meeting place for the international medical industry. The world’s largest event for the medical sector has been firmly established in the calendar of all experts for more than 40 years.

    There are many reasons why MEDICA is so unique. Firstly, the event is the world’s largest medical trade fair: it attracts several thousand exhibitors from more than 50 countries in the pavilions. In addition, every year, leading individuals from the fields of business, research and politics participate in this top-level event, along with tens of thousands of national and international experts and decision-makers from the industry. MEDICA includes an extensive exhibition and an ambitious framework program, which together present the entire spectrum of innovations for ambulatory and clinical care.

    And how could it be otherwise Calvo Izquierdo S.L. participated in this edition.

    MEDICA 2021
    In the past days November 15,16,17,18 we have been at our stand, four days of full power, knowledge transfer and networking in the face-to-face format.
     
    We are very happy with the results obtained. We hope that the next MEDICA 2022 will be as successful as this one has been.
     
    See you next year!
    BLOG 3: Latex and latex-free bandages

    BLOG 3: Latex and latex-free bandages

    Latex in bandages has been a common compound for many years, but over the last few decades its use has been declining. The main problem with latex is that it provokes an allergic reaction in some people, causing serious harm that may even produce asphyxia in some rare cases.

    Bandages with latex

    Latex is a derivative of natural rubber that contains certain enzymes that can be allergic to a certain percentage of the population. In the last two decades, latex allergy has become a health problem of worldwide relevance. It has been estimated that between 0.3 and 1% of the general population is allergic to this substance. In most cases, this allergy generates a very mild reaction with itching or reddening of the skin, but in a small percentage of cases the patient may suffer an anaphylactic reaction that may even result in death.

    In other countries there are specific products with latex, but in Spain, as well as in the rest of Europe, the authorities are trying to phase it out. What latex provides are certain properties that are very desirable in the manufacturing of some bandages:

    • Elasticity: latex is found in some natural yarns such as rubber and these yarns have good elasticity.
    • Cohesiveness: latex has the property that it adheres to itself but not to skin or tissues, allowing a more stable, durable and consistent hold and support, while permitting the removal of the bandage to be easy and painless.
    • Compactness: in some bandages such as plaster casts, latex is used to provide consistency and allow for a more rigid bandage.

    Latex is still used in the veterinary field, which does not impose a specific “latex-free” rule, unlike the healthcare sector.

    Latex-free bandages

    To avoid using elastic yarns containing natural rubber and latex, the Dupont company developed a very thin but highly elastic yarn: elastane or spandex. This yarn is the latex-free version of the rubber yarns used years ago. To learn more about the yarns most commonly used in the manufacture of bandages, visit our post: What types of yarns are used in bandages?

    Regarding the manufacture of cohesive bandages, the transition has also been progressive but steady. Currently, to replace latex, several latex-free components are being used, such as polyisoprene, which, although it endows the bandages with the same cohesive properties, being synthetic it does not contain latex.

    As we have been able to appreciate in this post, the use of latex is being phased out, especially in the medical sector and for bandages for humans. In the next post we will discuss different types of bandages, noting the presence or absence of this component, as it has become a very important characteristic to consider.

    Prepared by the technical department of Calvo Izquierdo S.L.

    with the collaboration of Carmen Alba Moratilla

    Bibliography

      WE EXPAND THE PRODUCTION CAPACITY AT CALVO IZQUIERDO, SL

      WE EXPAND THE PRODUCTION CAPACITY AT CALVO IZQUIERDO, SL

      CALVO IZQUIERDO SL has been expanding its production capacity for months. This allows us to provide a better service to all our customers around the world.

      Our objective has always been the same, to provide our clients with a high quality product at a competitive price.

      For this expansion in the CALVO IZQUIERDO, S.L. through the line “Aid for investments to improve the competitiveness and sustainability of industrial SMEs in the sectors of the Comunitat Valenciana, within the third phase of implementation of the Strategic Plan of the Valencian industry for the year 2020″, convened by the CONSELLERIA DE CONOMINA SOSTENIBLE, SECTORS PRODUCTS, TRADE AND LABOUR” has received a grant of 40. 40,952.73 for the execution of the project “Expansion of the production capacity of the company Calvo Izquierdo, S.L.”.