To Lexan will keep their properties is however proper treatment. The material is sensitive to different types of error treatment which has been known a long time. There are therefore several possible causes for yesterday's event.
It seems like this could point to a fundamental problem with Lexan masks.
They may well be more durable and protective than metal mesh under normal conditions (I have no reason to believe otherwise). But, if they can develop flaws under certain abnormal and unusual conditions, and if there's no test which diagnoses those flaws once they occur, you have a significant potential risk.
It seems like this could point to a fundamental problem with Lexan masks.
They may well be more durable and protective than metal mesh under normal conditions (I have no reason to believe otherwise). But, if they can develop flaws under certain abnormal and unusual conditions, and if there's no test which diagnoses those flaws once they occur, you have a significant potential risk.
QFT!
Asking fencers to remember to do something as simple as making sure the screws in the frame are tight is sometimes a nightmare. Given how a lot of fencers "care" for their gear, any special care needs are an unnecessary risk.
Sure...masks rust over time, but at least you can SEE that flaw.
Asking fencers to remember to do something as simple as making sure the screws in the frame are tight is sometimes a nightmare. Given how a lot of fencers "care" for their gear, any special care needs are an unnecessary risk.
Sure...masks rust over time, but at least you can SEE that flaw.
agreed.
how would people feel if Ford or GM produced a line of cars in which 1 in every 10,000 had random complete brake failures, and the failures were undetectable by inspection?
What is the thickness of the lexan on these masks? Is the problem that the lexan isn't thick enough or was there a manufacturing defect?
Minimum 3mm thickness.
A major issue with the lexans is they're MUCH more susceptible to damage caused by improper handling...you need to keep them in a special bag, not mark the plate with a marker (which weakens the plate), be much more careful in handling them, etc.
What is the thickness of the lexan on these masks? Is the problem that the lexan isn't thick enough or was there a manufacturing defect?
There may be no flaw. It may be that the hit merely exceeded material spec.
Whereas a steel mask taking the same hit (one that exceeded material spec) may have dented terribly, (possibly causing the mask to fail subsequent testing), I guess the polycarbonate shield shattered.
It's an interesting thought. When a steel mask gets a hit that's harder than it's designed to take, it still offers a modicum of protection. Not so, perhaps with the lexan mask?
Do steel masks fail more safely than polycarb masks?
If it becomes believed that Lexan masks are more dangerous when they fail than steel masks are when they fail, perhaps Lexan masks should be held to a much higher spec.
Perhaps Fiat Slug is right when he questions if the Lexan wasn't thick enough.
Also, there is no punch test equivalent for polycarb lenses, correct? No way to pressure test them prior to a major tourney? For that matter, how ARE they tested?
There may be no flaw. It may be that the hit merely exceeded material spec.
Whereas a steel mask taking the same hit (one that exceeded material spec) may have dented terribly, (possibly causing the mask to fail subsequent testing), I guess the polycarbonate shield shattered.
It's an interesting thought. When a steel mask gets a hit that's harder than it's designed to take, it still offers a modicum of protection. Not so, perhaps with the lexan mask?
Do steel masks fail more safely than polycarb masks?
If it becomes believed that Lexan masks are more dangerous when they fail than steel masks are when they fail, perhaps Lexan masks should be held to a much higher spec.
Perhaps Fiat Slug is right when he questions if the Lexan wasn't thick enough.
Also, there is no punch test equivalent for polycarb lenses, correct? No way to pressure test them prior to a major tourney? For that matter, how ARE they tested?
It's a drop-test similar to fabric testing for 800N fabric...see the rules Appendix A, section 2.1.2 ...but basically it's 3-5kg weight hitting the lexan at 5-6 meters per second. 2 drops on the same point (center of the mask on the line crossing the center of the visor). 1st drop equals 80 joules of energy....2nd drop at 90 joules.
However, this is testing for homologation purposes....I don't know of any additional testing of the shield, save for the periodic retests of random samples....but that's not the same as a punch test to the metal mesh.
And yeah...a failure on a metal mesh leaves a good possibility the remaining mesh will have some grip on the blade....not so much with plastic, especially if you have a big hole.
If the tip wasn't broken, I wonder how bad was the injury. Was the lexan shards a factor in the cuts?
Perhaps, but not necessarily. I have had an unbroken foil punch through my glove and into my hand -- an intact foil at an unlucky angle can provide sufficient damage for "profuse bleeding".
And yeah...a failure on a metal mesh leaves a good possibility the remaining mesh will have some grip on the blade....not so much with plastic, especially if you have a big hole.
The only mask failure that I am familiar with resulted in a puncture wound where the tip of the epee penetrated the skin just below the cheek bone and exited below the ear. The hole in the mask was the same size as the epee point, therefore no 'grip on the blade', which I am assuming you mean that the mesh of the mask will deform, fail, and then close back up around the blade.
So, at the risk of opening a flame war "Was this an FIE mask? What, if any, safety check was done prior to allowing it to be used? Should there have been a safety check (other than checking the date, OBTW, which format was it in? MM/YY or YY/MM?) been done?
Remember those who put their lives in danger for your sake.
The only mask failure that I am familiar with resulted in a puncture wound where the tip of the epee penetrated the skin just below the cheek bone and exited below the ear. The hole in the mask was the same size as the epee point, therefore no 'grip on the blade', which I am assuming you mean that the mesh of the mask will deform, fail, and then close back up around the blade.
Once the blade has penetrated the mesh I don't think a mesh mask is any better than a lexan screen. But, the mesh mask gives some warning, you can see deformed wires, you can test at a dent or rusty spot. If the lexan is weakened in an invisible way, that's a problem.
So, at the risk of opening a flame war "Was this an FIE mask? What, if any, safety check was done prior to allowing it to be used? Should there have been a safety check (other than checking the date, OBTW, which format was it in? MM/YY or YY/MM?) been done?
I'd like to know too, and I don't see why this would start a flame war.
These things aren't that expensive, it would be interesting to, for example, test a mesh mask to failure with an epee point at 90 degrees to the mesh, and at 45 degrees to the mesh, with a measured striking force applied, then do the same to the lexan. If the mesh consistantly is visibly deformed before it gives, that's good, that means you could look at it, say "Hey, there's a big dent here!" and not fence with it anymore*.
If the lexan breaks with no visible damage beforehand, that's bad. Indeed, if the lexan can be shown to break with no visible damage beforehand that's beyond bad, for me it's a deal breaker, even if the average lifespan of the lexan is very high. Undiscoverable damage is a bad, bad thing.
K O'N
* I know, there are cases of mesh not having visible damage and the mask failing. The problem with that is that we didn't actually look at the mask before it failed. There may have been a dent or spread wire no one noticed.
So, at the risk of opening a flame war "Was this an FIE mask?
Does anyone even make a non-FIE visor mask?
edit: Never mind - apparently Zivkovic sells one - although the shell is from PBT so I have to wonder if it's not just an FIE shell and visor to which they're adding their own bib
What, if any, safety check was done prior to allowing it to be used? Should there have been a safety check (other than checking the date, OBTW, which format was it in? MM/YY or YY/MM?) been done?
I can't speak for the Danish NGB however the DFB (Germanany's NGB) has an armoring manual on their web site which includes the following instructions regarding inspection and testing of masks (I've underlined the portions specific to visor masks)*:
Mask Testing
The mask must have a safety strap on the back. The two ends must be firmly fixed to both sides of the mask.
No obvious holes by individual broken wires
The mask bib is firmly connected with the mask mesh
Firm seat rivets; particularly regarding the bib and mesh on the underside
No holes in the bib
All edge seams of the bib are firm; no loose, individual fabric plies
The bib/edge of fabric is firmly connected with the mesh on all sides and the bib height is 12 cm;
Should be rubber/edge of fabric be loose in some places, these may be repaired with glue; in emergency and if it only a few places are involved then repairs with a firm fabric tape are permitted;
Spacing of the mask mesh is even (1.9 to 2.1 mm);
The lacquer finish should not exhibit damage; if the lacquer finish is damaged or if the mask mesh oxidized then this can be an indication for the fact that the mesh is in itself no longer firm and/or not made of high-grade steel; here it is to be particularly examined whether in some places the spacing of the mask mesh changed; in such places the mesh wires can exhibit also breaks, which permit a breakthrough. If the uneven spacing should be to large the firmness is to be examined carefully with a mash punch test; this examination is to be performed only by technical personnel; otherwise the danger exists that the mask mesh will be irreparably damaged!!!
The mask mesh should bow up; pay special attention to any dents, ensuring that the blade will glide over the dent; if not, the dent is by careful pressed with the hammer to remove or the mask cannot become certified; otherwise there is a substantial risk of injury to the fencer by a hard impact!!!
The front and side mask mesh must be firmly connected; cracked welding seams can be detected by lightly squeezing the mask together and listening; the possibility exists for the fencer to injured by the loose mesh parts or a breakthrough in the side;
For masks with transparent visor it is to be verified that the framework securely fits all-sides of the visor;
All screws/rivets of the framework are firm - the visor may not have holes, very deep scratches or breaks
Month and year of the production must etched or engraved into the visor. It may not be older than two years;
The tang is firmly connected with the lattice;
With saber and foil masks the resistance shall be measured using an analog ohmmeter or similar measuring instrument (max. 5 ohms permissible)
*apologies to Herr Vennemann of the DFB for any mistranslations - my German is more than a little bit rusty
Last edited by SJCFU#2; 11-03-2009 at 02:18 PM.
Reason: addressed one of my own comments
Part of the problem with the visor masks is that the material, when it does fail, the failure is much more likely to fail suddenly and catastrophically than a mesh mask.
There are only a few non-destructive tests available to check the material, for example polarization stress:
Unfortunately, just re-shaping the mask a little, or the presence of the screw holes will probably give strong stress patterns and it may prove impossible to use as a reliable predictor. Any NDT experts out there?
The picture shows two samples, one with a crack. It is easy to make one, just get a polarizing filter or cheap polarized sunglasses or even 3D movie glasses in reverse, and use your LCD computer monitor as a polarized light source. I would post a visor mask if I had one...
Last edited by the ancient one; 11-03-2009 at 04:58 PM.
"a braggart, a rogue, a villaine that fights by the book of arithmatick. Why the dev'l came you betweene us?.."
The only mask failure that I am familiar with resulted in a puncture wound where the tip of the epee penetrated the skin just below the cheek bone and exited below the ear. The hole in the mask was the same size as the epee point, therefore no 'grip on the blade', which I am assuming you mean that the mesh of the mask will deform, fail, and then close back up around the blade.
That was basically what I meant...slim though the chance is.
So, at the risk of opening a flame war "Was this an FIE mask? What, if any, safety check was done prior to allowing it to be used? Should there have been a safety check (other than checking the date, OBTW, which format was it in? MM/YY or YY/MM?) been done?
Given that this was in Europe, I would guess that it WAS an FIE mask (since they're tougher about FIE gear overseas than in the US)...but I'd also guess the only thing done at control was a visual/tactile test and not the punch...which wouldn't have helped in THIS case, since the failure was in that area we can't put the probe on anyway.
When a steel mask gets a hit that's harder than it's designed to take, it still offers a modicum of protection.
I was thinking that initial failure on steel mask results in a dent. The higher over spec the hit, the deeper the dent.
It would be one mother of a hit to punch through with an unbroken epee. I don't think I could do that if I tried as hard as I could multiple times on the same mask.
But, if that were to happen, I'd guess that the denting process could possibly disipate some of the force prior to penetration?
In any case, with mesh, the harder over spec the hit- the deeper the dent until breach...whereas the visor has no dent forgiveness prior to a complete matl breach.
---
So, checking a visor mask at a tourney is no more than a visual check then.
We don't even punch test the mask area beneath the visor in front of the mouth? Well. That seems... counterintuitive.
Last edited by foibles; 11-03-2009 at 04:46 PM.
Reason: clarity
K O'N
* I know, there are cases of mesh not having visible damage and the mask failing. The problem with that is that we didn't actually look at the mask before it failed. There may have been a dent or spread wire no one noticed.
Many years ago at a local event in LA there was a mask failure with a Negrenii (sp?) Non FIE mask the mask passed punch test, I did the test, and the failure was with in an inch of one of the areas I checked. No obvious rust or dents. Blade went thru intact and caused a small cut below the bottom lip. Fortunately the fencer had his mouth closed.
Go to the well until the well is dry. When the well is dry find a new well.
Not firsthand, but the translation from Google Translator - there is some interesting info in here:
----
Now that the heavy lifting is done, let me improve upon Google translator:
------------- Yesterday, a Lexan mask visor was pierced during the mens jr foil competition at the European junior fencing championships in Odense. The fencer got no life threatening injuries, but the incident is assessed as very serious. The Medical Commission of the European fencing federation now has "proposed by facts that do not use the mask during the continuation of these championships championships."
The reason that a hole in the visor could be created will now be investigated, but it will take time, and probably it may be difficult to find a unambiguous explanation. Lexan is very strong and in all durability tests masks with visors have been stronger than the masks of the traditional type. To assess the risk, it is important to remember that masks with transparent visors recently been used in hundreds of thousands, perhaps millions, of training and competition matches.
Reportedly, there were no unusual circumstances during the fencing when the accident occurred. It was not a case of a broken blade. One fencer did a normal lunge which hit the visor. The hit created a hole in the visor, about 2 centimeters in diameter, and the attack hit above the corner of the mouth which caused a substantially bleeding wound.
This season, visor masks have had a wide breakthrough within foil also at the junior level, because new rules have been introduced so that the maskbib has become a valid area. Many fencers have since opted for masks with transparent visors, because this model is mandatory at world championships and in the latter stages of World Cup competitions.
It is unclear what the consequences will be of the recommendation from the EFC's medical board. All participants with visor masks continued the men´s foil competition yesterday as if nothing had happened.
All in all, over a hundred foil fencers arrived in Odense with visor masks. Still to go is the ladies´individual competition, and both team competitions. Even if the fencers would want to switch, there is in all likelyhood onlya very limited number of new foil masks without visors in Odense.
This mask model is also in use since several years in saber, but in that case this risk must be considered significantly less. In epee few fencers have chosen to switch to visor masks.
In order for Lexan to keep its properties, correct treatment is necessary. The material is sensitive to different types of faulty treatment, which has been known a long time. There are therefore several possible causes for yesterday's event.
•Improper installation of visors: The Lexan visor becomes scratched after a while, and needs to be replaced periodically. Those replacements are often made by the fencers themselves. When the visor is mounted, it is very important that one does not use any "violence" to get it into place, as Lexan may become fragile because of stresses.
•Too old visor: According to the regulations, no visor may be older than two years, since the properties of the Lexan deteriorate with age. It seems, however, that the manufacturers mark the visor with a date only in connection with the sale, and not when it is produced, which creates an uncertainty about the actual age of the visors.
•Chemicals: Lexan is sensitive to contact with various chemicals (for example acetone).
•Cold: It is known that the material will get inferior properties at very low temperatures. Since the temperature in aircraft bagage comparments can be very low, it is recommended that mask owners should never keep their masks in the checked baggage, but instead carry it in the hand luggage. It is known that not all follow this recommendation.
Currently, there is no testing method which shows whether a mask visor still retains its original properties, or if it for some reason has lost these, partly or wholly. The leadership of the International Fencing Association and the SEMI Commission now face a difficult task in how to decide how to act.
An earlier accident with a mask visor is known from Venezuela. However, there it quickly turned out, that it was a case of an obviously mistreated mask which was in a very poor condition. In the current event, there were no apparent defects on the used mask.
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Thus ends my refinement upon the Google translation. In order so that you can inspect my handiwork, the original text follows below:
Originally Posted by Pierre Thullberg
Allvarligt tillbud med nya masken i Odense
Igår genomborrades plexiglasvisiret i en fäktmask under herrfloretttävlingen vid europamamästerskapen för juniorer i Odense. Fäktaren fick inga livshotande skador men incidenten bedöms som mycket allvarlig. Europeiska Fäktkonfederationens medicinska kommission har nu "föreslagit fäktarna att inte använda masken under fortsättningen av dessa mästerskap".
Orsaken till att ett hål i visiret kunde uppkomma ska nu utredas men det kommer att ta tid och förmodligen kan det bli svårt att hitta en entydig förklaring. Plexiglas. eller Lexan som det ofta kallas, är mycket starkt och i alla hållbarhetstester har masker med visir varit starkare än masker av traditionell typ. För att bedöma risken är det viktigt att komma ihåg att masker med transparent visir under senare tid använts i hundratusentals, kanske miljontals, tränings- och tävlingsmatcher.
Enligt uppgift var det inga ovanliga omständigheter runt fäktningen när olyckan inträffade. Det var inte fråga om en bruten klinga. En fäktare gorde ett "normalt" utfall som träffade på visiret. Stöten skapade ett hål i visiret med cirka 2 centimeters diameter och attacken träffade ovanför mungipan och orsakade ett kraftigt blödande sår.
Denna säsong har mask med transparent visir fått ett brett genombrott inom floretten också på juniorsidan, eftersom nya regler införts så att maskens skägg blivit giltig träffyta. Många har då valt transparent visir på sin nya mask eftersom denna modell är obligatorisk på världsmästerskap och i de senare faserna av världscuptävlingar.
Det är oklart vilka konsekvenser rekommendationen från EFC:s medicinska råd kommer att få. Alla deltagare med transparenta masker fortsatte herrflorettävlingen igår som om ingenting hade hänt.
Sammanlagt rör det sig om över hundra florettfäktare som kommit till Odense med transparenta masker. Fortfarande återstår den individuella damflorettävlingen och lagtävlingarna i både herr- och damflorett. Även om fäktarna skulle vilja byta finns det med all sannolikhet ett mycket begränsat antal nya florettmasker utan visir att uppbringa i Odense.
Maskmodellen används också sedan flera år på sabel men här måste risken bedömas vara betydligt lägre. På värja har få valt att gå över till mask med transparent visir.
För att Lexan ska behålla sina egenskaper krävs dock korrekt behandling. Materialet är känsligt för olika typer av felaktig behandling vilket varit känt länge. Det finns därför flera möjliga orsaker till gårdagens händelse.
•Felaktig montering av visir: Lexanvisiret blir efter en tid repigt och behöver bytas med jämna mellanrum. Detta utbyte görs ofta av fäktarna själva. När visiret monteras är det mycket viktigt att man inte använder något "våld" för att få det på plats eftersom Lexan kan bli bräckligt av spänningar.
•För gammalt visir: Enligt bestämmelserna får inget visir vara äldre än två år då Lexanets egenskaper försämras med ålder. Det förefaller dock som att tillverkarna datummärker visiren först i samband med försäljningen och inte när det tillverkas, vilket skapar en osäkerhet om visirens egentliga ålder.
•Kemikalier: Lexan är känsligt för kontakt med olika kemikalier (till exempel aceton).
•Kyla: Det är känt att materialet får sämre egenskaper vid mycket låga temperaturer. Eftersom temperaturen i flygplansbabagerum kan bli mycket låg rekommenderas maskägare att aldrig förvara sin mask i det incheckade bagaget utan att bära med sig den i handbagaget. Det är känt att inte alla följer denna rekommendation.
I dagsläget saknas en testmetod för att avgöra om ett maskvisir fortfarande har kvar sina ursprungliga egenskaper eller om det av någon anledning, till exempel felatig behandling, förlorat dessa helt eller delvis. Internationella Fäktförbundets ledning och SEMI-kommission står nu inför en svår uppgift för att bestämma hur man ska agera.
En tidigare olycka med maskvisir är känd från Venezuela. Där visade det sig emellertid snabbt att det var fråga om en uppenbart felbehandlad mask i mycket dålig kondition. I det fall som inträffat nu fanns inga synbara felaktigheter på masken som användes.
Originally Posted by misha
