There are many certifications around the world for motorcycle helmets, as you can see by the chart.
I only have experience and information on the US and European helmet certifications, so DOT and ECE22.05 and independent safety standards, Sharp and Snell.
Hopefully you will continue to seek more information and this little page will inspire you to look further into certifications as there is so much information to be found.
ECE 22.05 Helmet Standard: All the exact information on UNECE (United Nations Economic Commission for Europe) website ECE 22.05
ECE stands for “Economic Commission for Europe,” which was created under a United Nations agreement in 1958. The 22.05 part refers to the specific regulation that the standards for testing are described in.
The ECE standard, which is accepted in 47 countries, is similar to the DOT standard in several ways, for example: like the DOT standard, peripheral vision through an arc of 105° from the helmet midline is required. Also, environmental conditioning of helmets to be tested is required similar to the DOT standard and certain labeling requirements apply, as well.
Impact absorption testing is performed in a manner very similar to the DOT standard, involving a drop test from a fixed height on a steel anvil with a headform fitted inside to measure the energy transmitted. Peak acceleration energy at the headform allowed to pass the test is 275 G. Impact absorption and rotational forces are also tested at points where any surfaces or parts project from the shell of the helmet.
The retention system is tested with a free-fall drop test of a 10 kg (22.0 lb) weight from a height of .75m (29.5 in.) attached to the fastened chin strap. No more than 35mm (1.37 in.) displacement of the attachment point is allowed.
The chin strap buckle system is also tested for slippage under load, and the strap material itself is tested for abrasion resistance and tension failure load (which cannot be less than 3kN or 674.4 lb.). There are also tests for ease of release and durability of quick-release buckle systems.
There are some areas where the DOT and ECE standards differ, for example: For ECE the surface of the helmet is tested for abrasion resistance—but in this test the performance standard requires that the helmet surface either shear away or allow the test surface to slip past the helmet. This is to minimize the amount of twisting force the helmet would transmit to the wearer’s head and neck. Projections from the helmet (snaps, rivets, etc.) may not exceed 2 mm.
Another ECE test assesses the rigidity of the shell of the helmet by measuring the deformation of the helmet shell when progressively more load is applied up to 630 Newtons (141.6 lb.).
In addition to these areas, ECE 22.05 includes performance for the visor on a helmet, if it is an integral part of the helmet. DOT provides standards for visors and other eye-protection gear in a separate standard referred to as VESC 8 (Vehicle Equipment Safety Commission).
The ECE standard includes requirements for retro-reflective materials that may apply in specific member countries.
One of the biggest differences in testing, between ECE and DOT is that the DOT system does not subject their products to third-party testing prior to sale.
ECE requires batch sampling when production begins where the third-party laboratory choose a batch at random and test the batch of up to 50 helmets. The laboratory works for the government that uses the ECE standards and has nothing to do with the manufacturer. Also continuous testing is done throughout the production run.
Many ECE helmets can pass DOT certification but not as easily the other way around.
Sharp certification is a more stringent certification than ECE see the certification process here. SHARP SAFETY TESTS. SHARP testing requires that they buy each helmet from a retailer and then perform testing. Which is great because there is no outside interference.
The idea of SHARP testing is very helpful in choosing a helmet is really great. If we could just go on their website and see all helmets that are on the market now, that would be great but...
The biggest problem with SHARP testing is the amount of time it takes them to test helmets. Most big helmet brands come out with 1-3 new shells a year not to mention all the new brands starting up. If they are testing an avg of one per month I don't see how it would be possible to keep up with what's out there.
In January of 2018 the Sharp website said they had "published a safety rating for a total of 432 helmets and in April 30th they said they had published a total of 436 helmets. Many of the helmets listed are not even produced any longer and some are not even brands any more. Needless to say the SHARP testing is VERY slow to test all the helmets out there.
DOT is a helmet certification in the USA. The test itself comprises three elements.
First what’s called the impact attenuation test – which means the helmet is subject to impacts against a rounded and flat anvil after the test helmets have been ‘conditioned’ to reflect four different operating environments. That includes low/med/high temperatures and water immersed – all of which aims to ensure the helmet will still perform in different extremes of riding conditions.
Next is a penetration test where a 6lb 10oz pointed striker is dropped from 118 inches onto various parts all round the helmet – again against helmets that have been pre-conditioned to reflect four different operating conditions.
And finally, the retention strap is tested under 50 and 300lbs loads to ensure it doesn’t elongate more than an inch after load.
One big problem that many have with DOT is that the testing is not done by an uninvolved third party. The US government sets out the parameters of the test and the helmet manufacturers are told they need to do it. So this system works on the honor system. The government doesn't test the helmets BEFORE they are for sale. The government then does random checks, not of EVERY helmet on the market but a random sampling, of which information is very hard to come by. So for DOT it seems, the testing is a bit of a lottery as some helmets will never be tested by the government.
You can see more complete info on the testing here LABORATORY TEST PROCEDURE
Below is an interesting and informative video about the DOT helmet standards.
The Snell Memorial Foundation is a private not-for-profit organization that sets voluntary standards for motorcycle helmets, bicycle helmets and auto racing helmets, as well as other kinds of protective headgear.
SNELL tests helmets in the USA. This test is paid for by the helmet brand or manufacturer and is seen by many as a way for the helmet brands to raise prices for their helmet. It often said that the SNELL sticker or name on a helmet can raise the price by $40-60
DOT and SNELL believe a helmet shell should be quite stiff and resilient. While ECE and SHARP believe that the helmet should absorb the impact. This is an ongoing debate but there was an extensive study called COST 327 study done that has agreed with ECE and SHARP, which isn't very helpful if you are in an area that requires DOT... of course there are many helmets on the market that have both certifications, maybe that's the best choice. If it interests you, there is a lot of information available online. Happy researching.