According to the NFPA 70E  standard, arc flash incidents occur five to ten times a day (in the USA and Canada). The occurrence of an arc flash is the most severe threat in the power system.
The destructive outcome of an arc flash can lead to serious injury to operating staff, costly damage to electrical equipment and prolonged system downtime.
The event energy analysis method is defined by NFPA 70E and IEEE 1584 .
The two main parameters are:
1. Arc discharge energy (incident energy) – the amount of thermal energy at a specified distance from the arc source, represented in units of calories per square centimetre(cal/cm2).
2. Arc flash Boundary – the distance at which the incident energy is 1.2 cal/cm2.
At the value of 1.2 cal/cm2, without PPE, an operator can suffer second-degree burns.
The arc discharge energy and arc flash boundary for each circuit are determined using the equations in the IEEE 1584 standard.
Protective clothing in the form of overalls made of flame retardant materials, leather and electrical insulating gloves protects the electricians against the thermal effects of an arc flash. However,
the most crucial issue is the face protection of the electrician. The principal intent of headgear with
a visor is to protect the face and more sensitive parts such as the eyes and respiratory tract. The face shield production is even more difficult due to the required transparent material and design allowing the user to breathe.
Helmet wearers use various criteria in electing and determining the performance of their helmets.
It depends on the standards and legal regulations in force in the respective country. For example, European Union countries use EN standards [3-7] and Regulation 2016/425 of the European Parliament on personal protective equipment . Countries in the Americas and Australia use the American standards ANSI [9, 10] and ASTM  or the Canadian CSA [12-13] and the NPFA 70E standard for safe work practices intended to protect workers by reducing exposure to electrical hazards and assisting in meeting the requirements of OSHA 1910. (Occupational Safety and Health Administration
– is a government institution that ensures compliance with regulations that protect the safety and health of employees in the US), while GOST standards are in force in Russia and the former countries of the Commonwealth of Independent States .
It is necessary to meet the standards and legal requirements of the country to introduce a new helmet to the market. It is important to note that users commonly require helmets to meet the standards in force in their country and the exact or exceeding parameters established in the criteria of other countries.
The SECRA -2 E40HT helmet is the uppermost achievement in the comprehensive protection of the user’s head, both against arc flash, electric shock, and mechanical hazards. While a high level of mechanical and electrical protection is a common feature of all SECRA helmets, the new SECRA-2 E40HT integrated visor helmet outclasses all other solutions available in the world in terms of arc flash protection. Additionally, it was the first to surpass the threat protection rating of 30 cal/cm2 and set the bar extremely high, seizing 36 cal/cm2 in an official test at Canada’s Kinectrics Inc lab. The photos taken during the tests and the results are shown respectively in Figures 1 and 2.
Fig. 1. Images of the conducted test according to ASTM-2178
Fig. 2. Test result according to ASTM-2178; the lower graph shows the exceedance of the Stoll-Chianty curve.
The helmet meets the less restrictive requirements of European standards regarding resistance
to the effects of an arc flash, the so-called Box Test class 2 [7, 15], with an enormous safety margin,
as shown in fig. 3 and 4.
Image: a few milliseconds after ignition of the arc flash.
Fig. 3. High-speed camera shots during the GS-ET-29 7 kA test.
Fig. 4. Temperature changes determined with the use of calorimeters during the GS-ET-29 class 2 test.
The helmet visor is manufactured in the United States. It utilises the latest achievements
in nanotechnology and material engineering, including the manufacturer’s patented formula
of nanoparticles that absorb blackbody radiation generated during the ignition of an arc flash.
At the same time, nanoparticles allow radiation to penetrate in the visible range. Thus, the helmet
is an example of the balance between the visor’s transparency and its ability to absorb infrared energy in a volume suitable for protecting the user from an arc flash. The new technology used in the visors allowed for excellent colour reproduction. Traditional arc flash visors based their action on colour admixtures which, by blocking thermal radiation, at the same time gave visors a vast, usually green, or yellow tint. It resulted in problematic colour perception for the user. Other advantages of using innovative technologies in the visors of SECRA-2 helmets are increased resistance to ageing caused by UV radiation – nanoparticles do not degrade over time. The scratch resistance of the visor material has also increased.
All tests of the SECRA -2 E40HT helmet were performed by accredited laboratories: Polish – CIOP, German – ECS, PZT, Westenergie and Canadian – Kinectrics.
Helmet with the E40HT face shield test was conducted with additional accessories: a flashlight enabling illumination of the workplace and reflective panels. The principal purpose of the test was to determine the degrees of its protection against thermal hazards caused by the action of an arc flash. Both
in the tests determining the APC (box test) [7,14] and the ATPV – open arc  parameter of the face shield, the flashlight and reflective panels were not ignited, which confirmed the safety of their use with the helmet (Fig. 5).
Fig. 5. SECRA -2 E40HT helmet with an attached flashlight and reflective panels before and after the box test.