This is a deminer in Angola wearing a prototype AVS Mask visor - the result of an experiment to see whether it was possible to make a well vented mask visor using the same material and manufacture methods as the old visor.
1) All parts use a natural curve forming method (catenary) so do not need expensive moulds.
2) The weight can be 10-15% less than that of the standard full face visor (it is narrower and trimmed creatively).
3) It is not possible to steam it up.
4) Peripheral vision is as good as with a full-face visor, possibly better because the eyepiece is closer to my eyes, reducing possible distortion and inner reflections.
5) A revised head-frame to visor attachment reduces possible "wobble".
6) Other people can see when I am trying to talk to them - and the sound of speech vents from the visor well.
7) The material used is 5mm untreated polycarbonate - the same as the normal full-face visor - which is much less expensive that the ROFI mask laminate.
8) It is possible to lengthen or shorten the whole visor face to prevent the bottom hitting the chest of short people. Thoughtful overlaps make it impossible to open the "vents" wide enough to inadvertently introduce a blast-entry gap.
9) There is more material and more work involved than in making a conventional visor - and there is some waste material - so the cost over a conventional visor would go up. But not by much.
10) The slight inner curve at the bottom makes throat and lower face protection better - and hits the face if the visor is raised, so preventing it being raised (I hope). (An either 'on or off' visor is preferred because of the high percentage of accidents in which a visor is raised and supervisors failed to notice.)
I published this on a demining forums and asked if anyone could optimise a design and make them, suggesting that ROFI might like to. In May 2008 I was told that a UK university was making a version in Cambodia, but I heard no more of that.
So in November 2009 I made a finished polycarbonate mask myself. The picture shows a female deminer wearing an AVS polycarbonate mask in Sri Lanka while demining using the REDS system.
The ROFI mask has featured in some recorded AP blast mine accidents - both raised (sitting on top of the head) and down. In one accident in which all witnesses say that the mask was being used properly, the deminer's face was sprayed with environmental fragmentation which somehow got under the mask. This could only have happened if the mask was lifted up by the first fragments to reach it. I asked ROFI for an explanation and it transpired that they had never blast tested the mask. They apoligised for the oversight and had the ROFI mask blast-tested at CTRO in Croatia. It passed, but the test did not include evaluating whether the mask could be lifted.
I think the ROFI mask is unsafe in several ways - and believe that the material is a real constraint on improving the design.
However, with the exception of the Norwegians (some of whom seem to feel obliged to use the mask because it was designed in Norway) most demining groups seem happy enough with a polycarbonate visor or goggles. They seem to have come to the same conclusions as I did.
Today, the ROFI mask is still being sold and, as far as I know, no one is actually making my AVS polycarbonate mask. I use one every time I use my chainsaw but I take a standard visor into the minefield.