Fire protection: prevention is better than extinguishing

The gigantic warehouse is the first building in the USA to be protected with the active fire prevention system "OxyReduct" from Wagner. However, "warehouses of this size and height pose a particular challenge", as Wagner experts emphasize.

Fire protection for a gigantic deep-freeze high-bay warehouse

Schematic: OxyReduct stick pot production in the operating room. Photo: Wagner

As a fire prevention solution, an OxyReduct Pressure Swing Absorption (PSA) system was installed that was individually adapted to the structural conditions. Its principle is based on lowering the oxygen content by means of a controlled oxygen supply. The specified residual oxygen content was determined on the basis of fire tests and takes into account the ignition limits of the stored goods packed in ready-to-ship cartons and the sub-zero temperatures (-23 degrees Celsius) in the warehouse.

The oxygen content has been reduced to 16% by volume so that a fire can no longer develop or spread. The PSA system uses activated carbon to generate nitrogen directly from the ambient air. This can then be fed directly into the protected area. The oxygen sensors of the OxyControl control system are used to monitor the air ratio in the protected area. These ensure that the nitrogen supply and the oxygen content in the protected area are optimally coordinated and that the oxygen concentration is continuously maintained at the specified level.

Fuel cells for fire prevention and energy supply

The system has reduced the oxygen content to 16 percent by volume, meaning that a fire can no longer develop. Photo: Minimax

Minimax and Fuji N2telligence have successfully implemented the world's first project for simultaneous energy supply and fire prevention with fuel cell technology in a deep-freeze warehouse. It enables the customer Wolf ButterBack to produce energy- and cost-efficiently, avoid fires and, as a side effect, protect the environment. Since 2005, Minimax has been protecting the baked goods deep-freeze warehouse in Plant 2 of Wolf ButterBack KG in Fürth with an Oxeo Prevent fire prevention system.

There, the oxygen content is permanently reduced to 17% by volume through the supply of nitrogen produced on site, so that a fire cannot develop in the first place. Last year, the decision was made to replace the existing fire prevention system, partly for energy cost reasons.

A fuel cell supplies 100 kilowatts of electrical energy continuously and without interruption and can therefore cover part of the basic energy load in production. At the same time, it produces low-oxygen air without interruption, which can be fed into the deep-freeze warehouse as required. Users such as Wolf ButterBack thus benefit from significantly reduced operating costs and can even expect a return on investment in the medium term. This is unique in the fire protection sector. In addition, there is a state subsidy for sustainable electricity and heat production.

Economically positive side effects

In December 2016, a "QuattroGeneration" fuel cell powered by natural gas was installed within just two weeks and integrated into the control and piping system of the existing fire prevention system. Minimax cooperated with Fuji N2telligence on this project. By using the fuel cell, the deep-freeze warehouse is supplied with electricity and protected against fire at the same time. Fuel cells generate electricity and heat simultaneously according to the principle of combined heat and power generation and, as a by-product, clean and nitrogen-rich exhaust air; this can be ideally used to operate an oxygen reduction system for fire prevention.