Factory Follow-Up on Personal Flotation Devices (PFDs)

The required Seal Seam test method is not the most effective method of testing the weld strength on an inflatable chamber. In all tests following the specified methods, the fabric fails not the weld. The requirement to test specific cut parts does not test the complete weld on the chamber. Testing cut samples is not a realistic test of the actual reaction of the chamber and fabric in an overpressure situation. As a better alternative, inflating a chamber until it bursts, tests the full weld and also the performance of the fabric. This clearly identifies the highest stress areas, gives a consistent point of failure and a measurable pressure. It is also a much simpler, quicker inline production test. I am not aware of the background of the Seal Seam Strength test - it is not a requirement in the ISO standard, so would appreciate any input, if people feel it is still a relevant test. Devices featuring a Rescue Harness under Supplement SG within UL 1123 have a higher strength requirement for the Shoulder Strength test which is not reflected in UL 9595 currently. This testing is required under the UL 1123 initial product evaluation and is currently required and expected for follow-up testing. The load/duration table for Inherently buoyant devices in Clause A7.1 establishes the duration for the Vertical Load Test as 5 minutes. UL 1123 Table 24.1 and UL 1177 Clause 43.9 both have the load for the vertical and shoulder strength test as 2 minutes.