The norms are written in the frames and / or on the lens/es of each glasses.
ANSI Z87.1 is an important norm for the eye protection industry in the USA. This standard covers different types of eyewear: spectacles, goggles and face shields as well as prescription and plano lenses. ANSI Z87.1 gives general descriptions and requirements to the eyewear and provides the test methods.
The general requirements to the eyewear include the optical quality, luminous transmittance, refractive powers and haze for clear lenses. The general physical requirements are no sharp edges and no other defects that may cause discomfort or injury. The minimum coverage area is also checked to make sure that eyewear doesn’t restrict the view field of the user. The ”drop ball test” is applicable only in case of no high mass impact and velocity tests are done. The eyewear has to endure also the ignition and corrosion (if there are any metal parts) tests. Eyewear shall provide a good and tight lateral coverage of the eye. The high mass and high velocity tests are passed if no part of the eyewear becomes detached from the inner surface, if there is no fracture, no complete penetration of the projectile through lens or frame, no rupture of the lens.
ANSI Z87.1 lays down also the requirements to the optical radiation protection. Among the common industrial filters like infrared and visible light protection (for welding), the standard lays down the criteria for protection against ultraviolet radiation. While the first two are not needed in the ballistic glasses, the latter is very important. All Swisseye tactical lenses hence offer a complete UV protection up to 400 nm.
The Swisseye models Apache, G‑Tac, Raptor, Maverick, Net, F‑18, Sandstorm, Stingray M/P, SWAT Mask Pro and Nighthawk were successfully tested according to the norm ANSI Z87.1.
DIN EN 166 is an European norm which defines the personal eye protection requirements.
This norm uses the common procedures of EN 167, EN 168 and EN 170.
EN 167 defines the optic requirements for the protective eyewear: spherical, astigmatic and prismatic power. The results of the test of the above mentioned refractive powers are classified into three categories. The optical class 1 is the highest one and allows eyewear to be used permanently. All Swisseye lenses fulfill the requirement of the optical class 1.This test method also checks the light transmission (light filtering) as well as light diffusion and quality of material and surface.
EN 168 determines non-optic tests like the test on increased robustness, stability at elevated temperatures, UV resistance and resistance to ignition, high speed impact, resistance to fogging and protection against gases, dust, and smoke. According to EN 166, glasses may be tested with high speed particles with low energy impact only (marked as F, energy of about 0,87 J) while goggles may have the medium energy impact (B, ca. 6,19 J) and full-face shields are the only ones allowed the test with high energy impact (A, ca. 15,52 J).
The Swisseye tactical model Net for example has marking EN 166 FT. F stays for the safety against high speed particles with low impact energy and T is for protection against the high speed particles at high temperature conditions.
EN 170 tests the protection of the object against ultraviolet radiation. The marking on the lenses like 2C‑1.2 for clear and yellow lenses and 5–3.1 for smoke are defined by the result of this test, where the kind of filter is shown in the part before the hyphen and the shading is the part after the hyphen. All tactical lenses offer the UV protection up to 400 nm.
You will find more details about the marking on the glasses and their explanations in the manual “Information for users” enclosed to the EN 166 tested tactical glasses.
MIL-PRF-31013 is an US military norm that covers the requirements for a special protective eyewear to provide ballistic eye protection. It describes the general requirements to the spectacles like, optical qualities, UV protection, light transmission levels, chemical resistance and temperature stability, ballistic qualities of the spectacle etc.
The ballistic resistance is defined by the test method specified in MIL-STD-662. It uses a 0.15 caliber, 5,8 grain to gain the V0 or V50. V50 is the velocity at which complete and incomplete penetration are equally likely to occur. V0 point is the maximum velocity at which no complete penetration will occur. Our model Raptor showed e.g. no penetration at 660 fps in the test report of this norm. The temperature tests are done at the prolonged conditioning with ‑50 and +70°C where object shall show no distortion or discoloration. Solar radiation and humidity shall not affect the glasses. The glasses shall also absorb 90% of the UV radiation up to 380 nm.
MIL-PRF-32432 is a US military norm for glasses and goggles for both prescription and non-prescription wearers. MIL-PRF-32432 lays down that the eyewear kit shall include spare lenses, case, instruction booklet, cleaning cloth and strap depending on the kind of the kit. Goggles must also have a protective sleeve. Spectacles and goggles have to be compatible with the prescription holder, which Swisseye calls RX clip adapter.
Lenses have to be easily detached without using any tools. The eyewear has to be lightweight, durable and compatible with other military equipment like weapons, clothing, helmets etc. The textile has to be resistant to mildew. The eyewear shall show no degradation under the exposure of extreme temperature (from ‑50 to +70°C), solar radiation, humidity, adhesion, wind and dust. The optical requirements include luminous transmittance of the light and the allowed spectral transmittance, chromaticity, a wide field of view and the resistance to optical degradation because of fogging and scratching. The lenses shall absorb the UV radiation from 290 to 380 nm. This norm uses the test methods of ANSI Z87.1 for the following issues: requirements for the prismatic power, high impact protection, flammability and corrosion resistance to salt water as well as temperature and humidity requirements. Ballistic fragmentation protection after MIL-PRF-32432 is done with a projectile of 0.15 caliber and 5.85 grain for spectacles at the velocity of 640–660 fps (195–201 ms). For goggles the hit must be done with a 0.22 caliber, 17 grain at 550–560 fps (167–170 ms). The lens shall not be completely perforated, shattered, cracked or fractured. The frame shall stay attached to the lens during this test.
Our goggle G‑Tac has successfully been tested to the protection against the ballistic fragmentation according to MIL-PRF-32432 and showed no penetration of the projectile at the highest allowed velocity.
MIL-DTL-43511D is an US military norm that covers general and performance requirements for curved polycarbonate flyer’s helmet visors worn by aircrew personnel. The ballistic test is conducted using the caliber 0.22, 17 grain according to T37 FSP (fragment simulating projectiles). The velocity of the projectile is detected by a light beam 34,29 cm (13,5 inches) in front of the test sample. Penetrations are determined by examining of an aluminum foil mounted behind the visor. Sample gets shot on the right and left side.
The test sample is required to withstand 167,6–170,7 m/s (550–560 fps) velocity. Our model Raptor has successfully completed the test withstanding 170,9 m/s (560,6 fps) without any penetration. This value comes up to 16 J.
STANAG 4296 is one of many NATO standardization agreements concerning military procedures and equipment. It states the overall characteristics for the military protective eyewear like lightweight and comfortable fitting, fogging and scratch reduction, not less than 160° clear vision field, compatibility with other protection gear and of course impact protection defined by STANAG 2920.
STANAG 2920 test procedure determines the V‑50 ballistic limit for body protection material, including eyewear. The V‑50 ballistic limit is calculated from an average between the highest partial and the lowest complete penetration velocities on the test object. E.g. figures from STANAG 2920 for the orange lens of 40291 Nighthawk show average partial penetration of 247 m/s and average complete penetration of 258,3 m/s. The V‑50 is the average of both figures and makes 252,7 m/s (829,1 fps). STANAG 2920 test is done with 3,6 mm caliber and 0,325 g bullet mass from 3,8 meters. The sample has a precedent conditioning at the given temperature and humidity. These regulations provide uniform test conditions equal for all test objects.
STANAG 4296 is an important reference point for the military environment as well as for sports and hobby shooters and hunters. In addition, it is also significant for airsoft, as instead of defining the threshold for different protection levels, it shows exactly how much impact energy and velocity each single product withholds. Each airsoft field has own rules concerning maximum energy impact allowed, depending on the art of airsoft gun. However most fields don´t go over 3 J. Guns with even lower impact can heavily damage the eye, which makes the personal protection compulsory. Nighthawk e.g. was tested with V‑50 of 10,4 J.