WHAT IS TESTED IN THE SIEVI LABORATORY?

 

Sievi’s safety and occupational footwear fulfils the requirements of the EN ISO 20345 (safety footwear) or the EN ISO 20347 (occupational footwear) standards. Safety and occupational shoes are also further divided into different safety classes based on the shoe’s properties. All Sievi shoes are tested as a part of the certification process, in which an external testing company makes sure that the shoes fulfil the requirements laid down in the EN ISO standards. Sievi also has its own state-of-the-art test laboratory where different models and components are constantly tested.

WHAT IS TESTED IN THE SIEVI LABORATORY?

 

Sievi’s safety and occupational footwear fulfils the requirements of the EN ISO 20345 (safety footwear) or the EN ISO 20347 (occupational footwear) standards. Safety and occupational shoes are also further divided into different safety classes based on the shoe’s properties. All Sievi shoes are tested as a part of the certification process, in which an external testing company makes sure that the shoes fulfil the requirements laid down in the EN ISO standards. Sievi also has its own state-of-the-art test laboratory where different models and components are constantly tested.

Bending test to check the extent of cracking

The purpose of the bending test is to test the durability of the sole. As part of the test, the sole material is bent 30,000 times in a bending test machine. In the standardised test, a 2 mm-wide cut is made in the sole being tested. Bending the sole may not expand this cut by more than 4 mm, and the sole may not split as a result of bending. The test is carried out to determine how durable the sole is after it has sustained minor damage.

In addition to the standardised test, Sievi also tests soles in sub-zero conditions using the same method to make sure the sole is also durable at sub-zero temperatures. Sievi also tests the hardness of the sole in sub-zero conditions before and after bending. This is done to ensure the sole does not harden too much when the temperature drops below zero. The PU sole mass used in the production of shoes is tested every day at Sievi to make sure the quality of the sole material is uniform. Rubber soles are also tested regularly.

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ESD resistance testing

The majority of shoes manufactured by Sievi are ESD approved, meaning that they dissipate electrostatic charge in a controlled manner. ESD shoes can be worn to prevent damaging sensitive electronic devices or components. Shoes must be antistatic to meet the requirements of safety and occupational footwear standards, but for Sievi, the main objective is to fulfil the ESD requirements. The limit values for ESD properties are stricter than the antistatic limit values. In addition to the Sievi laboratory, ESD properties are examined on the shop floor when the shoes are finished. Moreover, this testing also applies to insoles.

 

Abrasion resistance testing

In standardised tests, the lining of the shoe is tested for abrasion resistance. In the Sievi laboratory, however, the upper and soles are also tested to see how abrasion resistant they are. In the abrasion resistance test, the test machine rubs the material against a dry and wet abrasion surface. When this is done, the material is inspected for any changes. To meet the requirements of the standard, the test must include 51,200 rounds on a dry surface and 25,600 rounds on a wet surface. At Sievi, however, more rounds are often used in the testing to ensure the materials are durable.

GORE-TEX testing

GORE-TEX shoes are regularly tested for waterproofness. In addition to the manufacturer, these tests are also conducted in the Sievi factory. Each week, a random is sample is taken from the GORE-TEX models in production, and the sample specimens are then tested to examine how waterproof they are. All of Sievi’s new GORE-TEX models are also tested at the GORE-TEX test laboratory.

 

Water resistance testing of leather

Water resistance of leather is regularly examined at Sievi. In the test, a piece of leather is soaked in water for an hour in line with the standard's requirements. After this, the material is analysed to see how much water it has absorbed and how much water has penetrated the material. To pass the test, the material may not exceed the limit values set out in the standard.

 

Slip-resistance testing to measure the friction coefficient

The grip provided by the soles in different conditions is tested in slip-resistance tests. In the test, a shoe is placed on a surface treated with a certain liquid or contaminant, such as glycerol. The test machine measures the friction coefficient of the shoe, or the amount of friction generated between the sole and the surface. The entire sole, or just the heel or the ball of the foot can be tested. The friction coefficient should exceed the limit set out in the standard. In the Sievi test laboratory, the friction coefficient of soles is tested on standardised surfaces and also on an icy surface. This is done to ensure the shoes are also suitable for cold and snowy conditions. All new sole materials and updated sole patterns are always tested in the Sievi test laboratory.

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Breathability testing

The breathability of shoe materials can also be tested in the Sievi test laboratory. The conditions inside the test machine can be adjusted to a specific temperature and humidity. The test is carried out to examine two different properties, or how much water vapour can escape through the material and how much moisture the material absorbs.

 

Heat resistance testing

The Sievi laboratory also tests the heat resistant properties of soles. When testing HRO soles, the soles must stay intact (i.e. they may not melt or crack) when exposed to a temperature of 300 °C for one minute.

Puncture resistance testing

Sievi manufactures shoes with two different puncture resistant plate options: textile and steel. The puncture resistance test procedure depends on the material being tested. The goal of the test is to ensure that nails or other sharp objects defined in the standard cannot puncture the puncture resistant plate. By conducting its own tests, Sievi also wants to make sure that the quality of the puncture resistant plates remains uniform and that the plates are safe regardless of the batch or manufacturer.

 

Adhesiveness of sole layers

Some of Sievi’s shoes have a two-layer sole configuration, and the standard requires testing the adhesiveness of the layers in these shoes. In the test, a pulling machine is used to check if the separate layers of the sole remain glued together when the machine pulls the layers apart. Two-layer soles are constantly tested at Sievi, as soles manufactured in every shift are put aside for testing.

Shock absorption testing

Shoes can also be tested for their shock absorbing properties in the Sievi laboratory. Shock absorption is a requirement of the EN ISO 20345 and EN ISO 20347 standards, in which the minimum shock absorption provided by the shoe must be at least 20 J.

 

 

 

Toe cap compression resistance testing

Safety shoes with toe caps must be tested to determine the compression resistance of the toe caps. In the test, a shoe with a toe cap is compressed with a force of 15,000 N. After this, the shoe is measured to see how much space is left inside. To pass the test, the shoe must meet the limit values specified in the standard. Sievi tests toe caps whenever new toe caps are introduced to production or when the toe cap supplier changes.

Toe caps must also undergo impact testing, in which a 20 kg weight is dropped on the toe cap from a height of 1 metre. This test, too, has its own limit values specified by the standard. These values determine how much space there must be left in the shoe box after the test. These tests are carried out to ensure that the shoes can protect the feet from serious damage in case the shoe is compressed or something is dropped on it.

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Other tests

The Sievi laboratory can also carry out other tests not required by the standards. Different products and materials, such as socks and certain upper materials, can be tested in a washing machine. The bending machine for whole shoes can be used to see how different shoe materials work together in practice. The machine emulates walking and it can be used to examine the properties and durability of the sole, upper and other components, such as GORE-TEX lining, at the same time.

 

Testing service for customers

The Sievi test laboratory can also, to a certain degree, test shoes submitted by customers for testing. If you suspect that your GORE-TEX or PU shoes are leaking, you can send them to our laboratory for testing. The shoes remain intact during testing and can be returned to the customer if no leaks are found. We can also test the batteries, insoles, chargers and the entire heating system of Alaska Thermo shoes and replace any faulty components in our laboratory.