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Development and verification of a protection concept by accomplishment of large scale fire tests

The AutoStore system

AutoStore is an automated warehouse system that stores goods in plastics boxes. These boxes are stacked inside an aluminum grid structure and are picked up and delivered to picking stations by robots.

The system is usually 16 boxes in height (i.e. 5.4 m) while the number of total boxes is in theory unlimited. The average installation consists of 30,000 to 40,000 boxes, with the largest installation so far having 180,000 boxes.

Customer demands

When the AutoStore development started we had little to no experience concerning fire safety. Initially, we thought it impossible for a fire to start inside the system and therefore considered fire safety to be part of the general building regulations.

After winning our first customer in Germany (pre-sales meetings started in 2007) they demanded a VdS approval for the system. At this point, we were still convinced that it was enough to explain the system and show how small the chance of a fire actually was.

However, we soon realized that it was to be more complicated than this. Many different entities were involved in the approval process, and we had to figure out the best way to satisfy all demands.

Challenges and implementation

During our meetings with the customer and our safety advisors it became obvious that VdS was the key to a feasible solution.

During our meetings with representatives from VdS we came to the conclusion that the best solution for this specific scenario was an extinguishing system using light foam.

Together with Norconsult in Norway we conducted small scale tests in order to ensure that foam indeed extinguished a fire and that there was not enough oxygen inside a box to fuel a fire further.

This test proved not to be enough to satisfy VdS’ demands, but we at this point lacked the knowledge concerning fire safety, and nobody was able to come up with a clear direction in which to take further tests.

Together with Norconsult we discussed how we could take the process further in order to receive product approval.

Large scale testing with light foam

We had multiple challenges that had to be addressed and we needed support from someone who had experience with similar systems. We therefore contacted the “Technical Research Institute of Sweden” (SP) and created a list of top priority questions:

  • Which method was most effective for extinguishing the plastic boxes used in AutoStore
  • How fast could a fire spread inside AutoStore
  • What was the best system to detect a fire
  • Which method would work best in a compact system such as AutoStore

As you can see, there were many questions to be answered in order to receive VdS approval.

At the same time the process was moved from the local VdS representative to the headquarters.

As a manufacturer we had two main goals:

  • We wanted to satisfy VdS’ demands and receive an official approval of the system that was acceptable for the customer
  • We did not want to change the overall design of the system

One of the biggest challenges for VdS and us was to decide how to test AutoStore. Since it was a newly developed system it was not covered by any existing standards. It became obvious that a fire test was necessary, but it was not at all clear how this could be done.

This was the beginning of a long project that started in 2009 and is still in progress (because AutoStore is continuously being developed further).

Together with VdS and SP we agreed on a test plan and beginning in 2009 we started with full scale fire tests with light foam. During these tests we also looked at other variables such as fire detection and foam distribution inside the AutoStore system.

In early 2010 we received approval for the customer for a solution based on light foam, and we could move on to the next project.

Large scale sprinkler test

During the tests we had acquired knowledge that shed some new light on the whole issue of fire safety. We discussed the insights with VdS and SP and boiled them down to three main points:

  • Fire expansion is slow
  • Water could be used as a fire-extinguishing agent
  • No pool fires at the bottom of the system

Based on this we decided to look for alternative methods of extinguishing fires inside AutoStore. Our main focus was to find out whether it was possible to stop a fire with conventional sprinkler systems.

We decided to ask SP for a new fire test that could show what a sprinkler system could achieve. This test was conducted in 2010 with promising results. Afterwards, we approached VdS in order to discuss the possibility of receiving an approval for the whole system and not just for a customer installation.

Once again there were many questions that needed to be discussed, especially what and how should be tested.

It was agreed upon that full scale tests were necessary, but these proved to be too large and couldn’t be done on-site at SP.

The solution was Underwriters Laboratories Inc. (UL) in the US who could do tests at their laboratory in Chicago.

Again we had to discuss test plans and criteria, but by this time we had worked with VdS and SP for many years and it didn’t take long to agree upon a common plan of action.

The project was a cooperation between VdS, SP, and UL and the test was performed in 2012 with good results. The one remaining issue was concerning large AutoStore installations where VdS wished to prevent the fire from spreading inside the system.

The solution was to implement steel firewalls that would prevent the fire from spreading. These firewalls had not been a part of the original test at UL and we therefore needed to conduct a new large scale test at SP in order to prove the solution’s efficiency.

These new tests were done in 2013 and we finally received a general product approval from VdS based on a sprinkler system.

This was a major milestone for AutoStore because it allows customers to implement an approved fire protection system and to receive a VdS approval based on this system.

Experiences and results

Experiences

This is the short version of long and ongoing story. All reports and test results are publically available, and I’m not going to discuss them in detail. I will rather focus on our experiences and the consequences these results have for us.

Taking our knowledge back in 2007 as a starting point I think it’s safe to say that during this whole process both VdS and us have gained some valuable insight; considering that this kind of system had not been widely known before.

Our biggest challenge has been to establish a constructive dialogue with the right people at VdS, sine we have been a relatively unknown player with a new product in a field where we had little prior knowledge.

In the early stages of the process VdS pointed us to existing rules and regulations that set strict limits for height and footprint of the system, which made it impossible for us to comply. Had these restrictions not been removed, we would today not be able to deliver AutoStore to very many customers.

The crucial point is to communicate the unique specifications of the system to the fire safety professionals on our partners’ side and help them to understand what sort of solution will work for AutoStore and what most likely is not going to work.

It takes time to build up trust, but to cooperate closely and trustfully is all important in processes where the main goal is to find good common solutions. It is therefore important that all parts dare to look beyond existing rules and regulations in order to find the best approach to new challenges.

For us as a “customer” this means that we have to consider the economic consequences of such a process.

Our experiences with VdS show an organization that is a positive and constructive partner with a tendency to scrutinize proposed solutions.

The lesson to learn is that our world moves forward constantly and there will always come new products that will not fit existing specifications and regulations.

Products that are already established in the market today have to follow fewer or no regulations while new products have to follow a comparatively large set of rules. This demands an open and creative cooperation between customers on one side and VdS and other players who are responsible for this kind of approval on the other.

Results

For AutoStore the VdS approval is essential. It allows us to sell our product with the certainty that it can be protected in an effective way. This allows us to cut short the planning period with customers where fire safety is often an important issue.

We also experience that authorities in other countries recognize the approval that was done in cooperation with VdS, SP, and UL. This makes our sales process easier even if VdS approval is not a specific requirement from the customer side.

Today we sell AutoStore in over 27 countries, something that would not have been possible without the experience, tests, and approvals that we have worked for over the last years.

What started as a simple meeting between a customer, VdS, and us in 2007 has been a costly process, both financially but also in resources. Because we could walk all this way together with VdS we are where we are today.

 

Article written by Ivar Fjeldheim, Product Manager for AutoStore

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