interesting output from this study of fit-testing done in France (slides 20-22, easy to understand even if not at ease with French language) with different types of respirators.
Conclusion is for a clearly better chance of fitness with soft-type like "duckbill" and "flexwing" types as compared to semi-rigid models like "half-cup".
As this has practical consequences for procurement and effectiveness of staff protection I wanted to share this experience and wondered :
1. if some of you have the same experience, even if not as rigorously evaluated. Regional differences are likely to be observed as various face shapes exist and can fit better with some models : if members from SE Asia, India/Sri Lanka, various part of Africa, without mentioning countries with huge ethnic diversity like Russia or USA could share on their experience in this regards it"d be extremely useful
2. what are your field practice in terms of procurement : are various models ordered ? If single model is it always the "cup" or "half-sphere" one ? Do you know what drive this choice ?