Tests for fire suppression systems intended for engine compartments

Purpose

This method assesses the fire suppression performance of fire suppression systems under mock-up operational conditions. For this purpose, several different types of fires are ignited and stabilised inside an enclosure with engine compartment characteristics. Fire suppression systems are then evaluated based on its ability to extinguish the various test fires.

SP Method 4912 tests fire suppression systems intended for engine compartments in a well-defined and objective way. Systems are subjected to realistic fire scenarios that can occur on and around a vehicle or machine, as a means to evaluate their performance. The system tests are based on the geometry, obstructions and air flow typically found in engine compartments. This allows for rapid performance evaluation under reproducible and repeatable conditions.

Method

The fire suppression system may be subjected to the test scenarios listed below. In the end, a system will achieve a ranking based on the number of tests completed and the conditions, e.g. ventilation rates and/or level of openness of the testing rig, under which this was achieved. 

• High Fire Loads evaluate the fire suppression system's ability to suppress large fires. As an example, these large fires may originate from a broken pressurised fuel hose that sprays against hot surfaces, resulting in rapid fire development. It is crucial that fire suppression systems can effectively deal with these fires, as they may even occur if reliable detectors are installed.
• Low Fire Loads are used to judge the system's ability to deal with small fires in an enclosure. These small fires can be difficult to extinguish and require that the distribution of suppressant in the compartment is effective.
• Systems that can extinguish our Class A Fires have proven their ability to deal with deap-seated fires in fibrous materials. Examples of such materials are sound insulation, rubber and/or some plastics, which commonly act as a secondary fuel source.
• Obstructions are often present in engine compartments. This is emphasised in our Hidden Fires test. Here the suppression system shall extinguish a small obstructed fire that is out of reach for direct fire suppression. As such, the total flooding capabilities of a system is evaluated.
• Certain components in engine compartments may still be hot enough to ignite flammable material after a fire has been extinguished. Our Hot Surface Re-Ignition test evaluates the fire suppression system's performance in cooling down those hot surfaces.

The Level of Opennes of our testing rig can be modified to reflect the environment in which the fire suppression system shall be used. This will affect the final rating of the fire suppression system also, with an increasing score for an increasing level of openness. The highest possible openness level is achieved when tests are completed when no floor, ceiling, and walls are considered in the testing rig.

Deliveries

After testing, a test report is delivered with the results which may be the basis for product approval, for example according to SPCR 183 or SPCR 199 (P-mark).