Safety matters - Lorry transport at Deichmann

Safety matters

Chemicals in shoes?

According to measurements, up to 20 percent of all freight containers are polluted with harmful substances. This can endanger the people who open them, which is why Deichmann, Germany’s biggest shoe retailer, takes measurements of all containers before declaring them safe to open.

Text Frank Grünberg     Photos Patrick Ohligschläger

Safety matters - Bottrop distribution centre

Containers filled with shoes and bags arrive daily from overseas at the Bottrop distribution centre in North Rhine-Westphalia.

Whether pumps, boots, or sneakers, Deichmann displays its range of footwear in its stores in spectacular style. In one flagship store in Essen’s city center, the company showcases on three floors how it connects the analogue and digital worlds to create a real shopping experience. There is plenty of room between the shelves to try on the shoes for size. Flat screens known as “digital signage” provide entertainment, information, and other shopping incentives. One innovation, however, remains invisible, even though it offers employees and customers a greater degree of safety: Measurements are taken of all shoes to check that they are no longer emitting any harmful substances.

A tradition of safety

Deichmann SE, based in Essen, was established in 1913, and is now owned by the third generation of the family that founded the company. Last year, more than 40,000 employees sold around 183 million pairs of shoes in several thousand stores as well as more than 40 online stores in 30 different countries, making it the market leader in Germany. The guiding principle is as follows: “The company must serve the people.” Not the other way round. This principle is embraced on various levels on a day-to-day basis, including at the company’s distribution center in the neighboring city of Bottrop, just a few kilometers from Essen. Shoes and bags from overseas primarily end up here in containers shipped via the Port of Hamburg. Several dozen employees then check the goods, sort them, and make sure they are delivered to the Deichmann stores in the company’s own trucks. One thing is particularly striking: Unlike the setup at other logistics companies, not a single robot picks the shoeboxes from the high shelves. Instead, forklift trucks are driven solely by real people.

“Robots don’t buy shoes,” says site manager Dirk Nakowitsch. “We have to ensure that the people have enough work.”

Dirk Nakowitsch, site manager

This attitude is also reflected in the approach to occupational health and safety at Deichmann. No logistics worker is allowed to open a container until it has been tested and declared safe. After all, each of the steel containers, which brings up to 8,000 shoeboxes to Bottrop when fully loaded, has spent around six weeks traveling from Asia to Germany. “A mixture of gases can build up inside the container during this time,” says Dirk Nakowitsch. “We must prevent our employees from coming into contact with this.”

Safety matters - Logistics employees taking clearance measurements

Exercising caution: The logistics employees are not allowed to open a container until the test result declares it is safe to do so.

Around 300 volatile organic compounds

Measuring canals, shafts, and tanks to declare them safe has long been part of the daily routine in many industrial settings, including refineries, chemical plants, and waste disposal facilities. It became clear to the managers at Deichmann about ten years ago that the shoe trade should also take an interest in the matter. Back then, the customs officials at the Port of Hamburg reported that inspectors were becoming unwell by inhaling toxic gases when opening a container. The managers at the company’s headquarters in Essen concluded that this could happen at any time to their own employees with its own deliveries. The biggest risk to people is posed by volatile organic compounds (VOCs). They can be emitted by adhesives or artificial leather. In higher concentrations they can cause headaches, irritate eyes and airways, and damage vital organs in the long term. Around 300 different VOCs are currently known to experts, but not all are toxic. Real safety is established when a potential VOC cocktail can be reliably measured for its constituent parts. However, there is no way of forecasting when the concentration of individual organic compounds will reach a critical level in a sealed container. It all depends on the chemicals that were used to manufacture the shoes. The same applies to the weather conditions during transportation: The higher the temperature, the more substances outgas. There are no problems at all in winter, but a real gas cocktail can be concocted in summer. Deichmann was testing for VOCs in containers back in 2009, but the device it used had a flaw: It was only able to determine the overall concentration rather than the concentration of the individual substances. In view of the lack of alternatives, it couldn’t be done in any other way. This changed in 2018, however, when Marcel Cornelissen, who works in the quality assurance department at Deichmann, heard about Dräger’s new X-pid 9500 gas measurement device. He immediately wrote to Dräger and a little later the two companies were doing business.

Safety matters - Gas measurement with the Dräger X-pid 9500

The X-pid 9500 from Dräger simplifies the monitoring and documentation process; it is operated using this intrinsically safe smartphone.

Safety matters - Deichmann in Bottrop

Man not machine: Not a single robot picks the shoeboxes from the high shelves at Deichmann in Bottrop.

Two-stage measuring process

The X-pid has been developed for applications where VOCs are frequently and, above all else, selectively measured in low concentrations. Selective means that the device not only detects the overall concentration, but also the individual substances. The abbreviation “pid” stands for photoionization detector. This exposes the collected ambient air to the UV light of a gas discharge lamp in a measuring chamber. This intensive light can ionize gas molecules so that electrons are released from the molecules, creating a measurement current, which is analyzed by the detector as a measurement signal.

In the first measurement stage (“Seeker” mode), the total concentration is read and displayed. In the second stage (“Analysis” mode), gas chromatography measures selected target compounds. The analysis breaks down the broad overview provided by the seeker into single concentrations (substance by substance). Deichmann has incorporated both the measurement device and the process in a company directive for quality control. “Before any container is opened, a measurement must be taken to provide a guide value of the level of harmful substances inside,” states the directive. “The Dräger X-pid 9500 gas measurement device must be used for this purpose.”

From the data gathered in the testing laboratories, Deichmann knew that it was dealing with 16 relevant substances that can be harmful to human health. Most prominent among these are benzene and toluene. When it came to setting the threshold limits, the company played it safe. By its own account, compared to other players in the industry, the limits were set low. In simplified terms, depending on the threshold value, the following has applied ever since: A container can be unloaded if the total concentration is less than ten parts per million (ppm). Experience shows that there is no need to take action here. With concentrations of up to 50 ppm, a second measurement is mandatory. In such cases, it is to be expected that the concentration of individual VOCs exceeds the critical level. The container may not be opened if the figure is higher than 50 ppm. Instead, it must be ventilated together with its load until the concentration has dropped to a safe level. If this doesn’t work, the consignment is sent back. “Critical thresholds are exceeded here once or twice a month,” says quality assurance manager Marcel Cornelissen. “The problem can usually be solved with fresh air.”

Safety matters - Testing whether the shoes contain chemicals

Chemicals in shoes? Gases can be emitted from adhesives and cause headaches and irritate airways in higher concentrations. 

Safety matters - Shipping containers carrying up to 8,000 shoeboxes

Packed to the rafters: Up to 8,000 shoeboxes fit in a single container.

Nine-month test phase

The X-pid 9500 was tested for nine months before Deichmann adopted it for the regular measurement of containers. During this period, comparisons with laboratory analyses revealed that the portable device delivers very fast and reliable results. In addition, it is easy to operate and can wirelessly send the test results to a digital network – including important supplementary data such as GPS coordinates and the container ID. This simplifies monitoring and documentation, allowing the quality management team to remotely view and evaluate in real time all the data recorded by the goods receiving department at the distribution centre.

The commitment of the Dräger employees also convinced Deichmann’s quality management team. Step by step, they adapted the device, which had originally been developed for measuring the levels of harmful substances in cramped containers in the oil and gas industry, to the special requirements of the shoe containers. For instance, they replaced the plastic tip on the measurement probe with a thinner steel tip so as not to damage the rubber seal on the container door. They also expanded the measurement range of the probe by feeding in fresh air in a controlled manner so that the device – unlike the standard version – can also analyze concentrations above 65 ppm.

Finally, they enhanced the range of detectable VOCs and integrated the new features in the X-pid 9500 via a software update. “We can now select eight of the 16 substances relevant to us,” says Marcel Cornelissen, describing the current state of affairs. “As such, we have the best solution currently available.”

Hot mixture

Freight containers spend up to eight weeks traveling from Asia to Europe by ship. Various harmful substances can build up inside the containers during this time. There is no way of forecasting when their concentration will reach a critical level. The weather conditions during the journey also play a role. There are no problems at all in winter, but a real gas cocktail can be concocted in summer. This can be recorded in detail by measuring the concentrations.

Standardised testing methods?

On April 1, 2020, Deichmann completed the delivery of the X-pid 9500 to its nine distribution centers. Five of these are located in Germany, the others in the Netherlands, Slovakia, Poland, and Switzerland. The devices are regularly maintained as part of a service contract. The employees in Germany were trained centrally in Bottrop, while those in other countries were trained at their own respective locations. Furthermore, Marcel Cornelissen recommended the X-pid 9500 to the VOC working group of the “Cooperation for assuring defined standards for shoe and leather goods production” (cads). One of the remits of the 83 member companies is to secure the quality of footwear and leather goods. Why is it in Deichmann’s interest to ensure its competitors also use the X-pid 9500? “It would be good if the entire industry could agree on a standard measurement method for VOC concentrations,” says Cornelissen. “Then we could increase the pressure on the manufacturers to adhere to our specifications.”

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