Promoted Ignition

Promoted ignition testing is similar to Adiabatic Compression except an ignition pill is inserted upstream of the component to guarantee ignition. The objective of this test phase is to determine if a medical regulator can tolerate an upstream ignition event and whether it will result in sustained combustion and burnout of the regulator.

Fault tolerance is evaluated by subjecting the regulator to the forced application of a positive ignition source at the regulator inlet to simulate cylinder valve seat ignition and particle impact events. The ignition source is representative of severe, but realistic, service conditions.

This testing is to be performed on five test articles in a mid-flow or normal delivery condition at a minimum test pressure of 2200 psig or the maximum normal service pressure, whichever is greater. If the ignition pill ignites, only a single pressure cycle is required for this testing. The criteria for a valid test is either, (1) failure of the test article, which is defined as the breach of the pressurized component (burnout) and ejection of molten or burning metal or any internal parts from the regulator, or (2) if the test article does not fail, consumption of at least 90% of the ignition pill, as determined by visual inspection or mass determination. Momentary (less than 1 second) ejection of flame through normal vent paths, with sparks that look similar to those from metal applied to a grinding wheel, is acceptable and does not constitute a failure.

For more information on the background of this standard's development, see WHA's paper that won first place in the ASTM Advantage Award 2008 competition.

Fast Turn-around

Most of our standard testing can be performed in 2-3 weeks and we also offer expedited testing services, if required.

Failure Analysis Support

Should the unfortunate event of a test article failure occur, WHA offers failure analysis support to help with redesigns using proven design and material selection concepts and to help with successfully meeting the test requirements during re-testing.

Oxygen Component Test System Cell

If ignition is not contained within the component, the fire will propagate through the component. For this reason, the test article is located in a secure test cell. See the spectacular video of a medical regulator failing this test.

(a) (b)
(c) (d)
Single frames taken from high speed video of an ASTM G175 Phase 2 Promoted Ignition Test. Each frame was taken after the first frame to exhibit flame corresponding to the following milliseconds time periods from this point; (a) 4 ms, (b) 15 ms, (c) 26 ms and; (d) 65 ms

Other Promoted Ignition Type Standards Tests

Promoted Ignition Testing of Metallic Filters in High-Pressure Oxygen

Abstract

Currently, no test standard exists for the evaluation of ignition tolerance and fault tolerance of metallic filters in high-pressure oxygen. Filters are a critical component in oxygen systems to ensure system cleanliness and mitigate ignitions by particle impact and contamination.  However, filters are at risk to these same ignition mechanisms and fires have occurred in service. A new test method was developed by WHA using ASTM Standard G175 Phase 2 as a basis. The test subjects a pre-contaminated filter to a forced ignition event using an ignition pill while the filter is maintained at elevated pressure. Prior to testing, contaminant was applied to the filter element and was also placed at the filter inlet.  The placement of this additional contaminant was based on the fact that, over time, contaminant could potentially accumulate in a filter.   This contaminant consisted of aluminum powder, iron particles and a perfluorinated lubricant.  An ignition pill, consistent with ASTM Standard G175 Phase 2, was located on the upstream side of the filter. A back pressure was applied downstream of the ignition pill to ensure that the filter was pressurized during the ignition and burning of the pill.  Testing was performed on brass and stainless steel filters of the same design using an oxygen shock to ignite the ignition pill at a test pressure greater than the back pressure applied to the filter.  The brass filters safely contained the ignition event without breaching through the body of the filter.  For the stainless steel filters, the ignition event kindled the filter element and burned through the filter body.  This testing showed that the ignition fault tolerance of the brass filters was far superior to that of the stainless steel filters, which was consistent with the relative flammability of these metallic materials, and therefore helped verify the test methodology.