Anyone who has read NFPA 70E and plans on using the Hazard/Risk Category (HRC) classifications will understand that face protection is an integral part of a worker’s personal protective equipment (PPE). Face shields are also one of the most common pieces of PPE that workers complain about. We often hear, “The shield is too dark”. “I can’t distinguish colors easily!” And, “Why can’t I wear a clear shield?” To better understand arc rated face shields and why they are the way they are today, you need to look at the advancement of face shields over the past 10 years.
Originally the options for face shields were very limited and, in fact, were not specifically designed for the arc flash hazard. Many workers simply used a welders shade 5 shield designed for welding or cutting applications with a very low visible light transmission or a clear shield that was designed for impact protection. While these shields worked well in the environment they were designed for, they did little to protect the worker in the case of an arc flash incident. For instance clear face shields, while performing well as “impact protection shields,” will transmit the arc flash energy and allow second degree burning of the user if exposed to as little as 1.7 cal/cm². This is hard to imagine but has been proven time after time. Additional problems with the clear shields being used in those days included the face shields igniting and contributing to the injury of the user.
As technology and awareness increased, so did the performance of shields specifically designed for arc flash protection. The race was on to provide face shields that could meet the requirements of HRC 2, 3, and 4. The original arc flash shields were designed and introduced to the industry approximately five years ago. While these shields met the requirements of the NFPA 70 E HRC categories, they did not solve the issue of clarity and wire color recognition. A clearer face shield was needed and the users demanded improvements.
Manufacturers such as Salisbury, now offer face shields that not only meet the requirements of HRC 2(8cal/cm²), HRC 3(25cal/cm²), and HRC 4(40cal/cm²), but also with high visible light transmission and improved color recognition to satisfy the needs of those in the field.
When discussing the clarity of face shields, there has to be an understanding of Visual Light Transmission or VLT. VLT is a measurement of the amount of light that is allowed to pass through a surface such as face shields. The higher the percentage of VLT the clearer the face shield will be. Because there is a natural deflection or refraction of light through any surface, there is no true 100% VLT rated shield. For instance, a clear welder’s shield designed for splash protection will most likely have a VLT rating around 85%. In contrast a shade 5 welder’s face shield will have a VLT rating around 2%. Salisbury’s new 10cal/cm² hard hat mounted face shield for HRC 2 has a VLT rating of 70%. The new Salisbury 50cal/cm² face shield for HRC 3 and 4 has a VLT rating of 50%. As little as a year ago the HRC 2 face shield had a VLT rating of 60% and the HRC 3 and 4 face shield had a VLT rating of 38%.
These new face shields have a distinct tinting that allows for much easier color identification. They also allow the worker to perform tasks in areas that may not be in well lit areas. Keep in mind though that NFPA 70E states specifically, “Employees shall not enter spaces containing live parts unless illumination is provided that enables the employees to perform the work safely” (130.6 (C) (1)). In other words, in areas where even the new clearer face shields fail to provide enough light to work safely, then auxiliary lighting is required.
All arc rated face shields must meet the ASTM F2178-02 standard. This standard 
specifically references the ANSI Z87.1 standard which is the standard for occupational and educational eye and face protection. Arc rated face shields must meet the Z87.1 standard to eliminate the potential of shrapnel from the shield causing additional injury to the worker. The NFPA 70E protective clothing and personal protective equipment matrix 130.7(C)(10) requires that safety glasses or goggles be worn along with and underneath an arc rated face shield. OSHA recognizes eye protection and face protection as two separate issues. Because of this, even though the arc rated face shield meets the Z87.1 standard, it is not specifically designed for eye protection but is to be worn as face protection only. Therefore safety glasses or goggles specifically designed for eye protection must be worn in addition to an arc rated face shield.
Another aspect that must be taken into account when selecting proper face protection for a task is the requirement of HRC 2*. This sub category of HRC 2 states “…a double layer switch hood and hearing protection are required for this task in addition to the other HRC 2 requirements of table 130.7(C)(10).” Be sure to select a double layer switching hood that offers the clearest shield available while still meeting the requirements for this category.
One of the most difficult parts of implementing a successful electrical arc safety program is to ensure that the worker will wear the proper PPE in the environment they must work in. The surest way to achieve this is to make the PPE as non-intrusive as possible. These workers are already faced with a very difficult job. A successful safety program should allow for this and provide PPE that is both easy and safe to wear. Today’s technology allows us to provide the worker with not only the proper face shield for the HRC their task falls in, but also provide the worker with a face shield that is easier to wear due to the clarity of the shield and allowance for easier color recognition.
