Development and evaluation of intermediate-scale testing for oxygen reduction systems

Compact automated warehouse solutions are a challenge for conventional fire protection systems, such as sprinklers. As an option to sprinkler systems some warehouses employ an Oxygen Reduction System (ORS). When designing an ORS, the most important parameter is the limiting oxygen concentration (LOC). The level of protection attained is directly proportional to the oxygen level applied, which is a result of the LOC, as it affects both ignition and flame propagation. Today there are some published experimental results of LOCs for a variety of materials. Some of these results come from bench-scale tests applying an external heat flux to account for geometry and other parameters that cannot be replicated by a smaller sample. However, due to uncertainties in scaling, a large-scale method was created to try and take real world conditions into account. One issue with this large-scale test, is that it is costly to run both in terms of sample material and nitrogen flow need. Therefore, there is a need to investigate the possibility to create an intermediate-scale test that is capable of testing variable geometries and other real-world conditions by using less sample material and nitrogen than the large-scale test. In this paper a first attempt for such an intermediate-scale setup is examined. Preliminary tests using HDPE, wood and cardboard are discussed in order to understand the performance of the test setup in relation to the existing data on LOC. • Testing of ORS in intermediate-scale to compliment bench- and large-scale testing. • Use of species calorimetry for energy calculations in oxygen reduced environments. • Design considerations for experimental setup when oxygen concentration is important