When working around moving vehicles and equipment, being able to visually stand out from the environment is critical to safety.
Wearing bright colors makes a worker more conspicuous, but it's not enough to simply request that workers dress colorfully. Deliberate effort has been made to define what qualifies as high-visibility safety apparel (HVSA), and what properties it has to have.
This is not a frivolous endeavor. If you take a look at OSHA’s list of incidents since 2015, 41 out of 47 entries involving a "Flagger" describe a worker being struck and often killed by a moving vehicle. Being hit, backed over, or run over by a vehicle is highly likely to result in a serious injury or death. In certain lines of work this is a major hazard that can’t be overlooked.
Certain kinds of incidents can be prevented completely if workers wear the appropriate safety equipment. But hard hats or pads are not going to be of much help if a worker is hit by a car. Instead, the best strategy is to use use PPE that will increase the worker's visibility and prevent accidental contact and collision in the first place.
Standards for high-visibility safety apparel (HVSA) focuses primarily on the amount and configuration of background material and retro-reflective material, and when to use it. Different scenarios may invoke additional standards, but let's start with the big one.
1. ANSI/ISEA 107-2015
ANSI/ISEA 107-2015 is the standard for general high-visibility safety apparel. The bulk of the standard is concerned with sorting HVSA into both a class and a type according to the category of work for which it is designed and the visibility needs of those tasks. Class and type are taken together to define their appropriate gear for a given application.
Classes 1-3 rank the conspicuousness of the clothing in high and low lighting by laying out design guidelines for retro-reflective material and background material.
Background material is not reflective, but is subject to florescent color criteria so that it is highly visible in normal light.
Retro-reflective material is defined by its ability to reflect light (such as from a headlight) back in the direction of origin.
With the combination of both, a worker should be plainly visible and easier to spot at a distance in anything from very bright to very dim light, as well as easier to spot at a distance. This is important because of the potential high speed of approaching vehicles in different scenarios – particularly for those working on an active roadway. Drivers being able to see the worker at a distance gives them a better chance to avoid a catastrophic collision.
Type O: Occupational Off-Road Use
Type O hi-vis gear is for use in environments where powered mobile equipment may be operating, but this excludes public access highways and exposure to vehicle traffic. This type is also not designed for use in roadways under construction and temporary traffic control zones.
Type R: Roadway Use
This is probably the type that most people are familiar with, since it is designed for use on public roadways and roadway construction temporary traffic control (TTC) zones.
Type P: Public Safety
This type is used by law enforcement and emergency responders. It has many characteristics in common with roadway HVSA, with exceptions and consideration of other hazards that may be characteristic of emergency response work.
2. CSA Z96-15
The Canadian Standard Association's (CSA) adapted standard for use in Canadian industry offers guidelines on HVSA design in fine detail. Amount and color of florescent background material is detailed to granular level, even giving specific, allowable shades such as “international orange” or “safety orange.” The exact placement and pattern of retro-reflective materials is fully laid out and the intended usage specified.
CSA Z96-15 really does dive deep into the specifics, with chromaticity and luminance factors for either “bright” or “background” colors, photometric performance of retro-reflective materials and well-defined design criteria. This standard is somewhat more technical than the American National Standard Institute (ANSI) version, and would be more relevant to those designing HVSA products than it is to an average safety manager selecting work wear for a site.
Much like in the ANSI standard, there are three classes of garment defined by their relative background material, color, and retro-reflective material requirements.
3. ASTM F1506-19 and NFPA 2112
As with other personal protective apparel, certain circumstances and roles may require both visibility and fire resistance.
The ANSI 107 standard notes that if a garment is to be marketed as both high visibility and fire resistant, it must meet an accepted fire resistance testing standard. In this case, ANSI 107 standard defers to the specifications found in the American Society for Testing and Materials (ASTM) standard F1506 or the National Fire Protection Association (NFPA) 2112 standard.
Those standards outline additional performance criteria that fire resistant HVSA has to satisfy. Using established and standardized test methods, the materials are assessed for their Energy Breakopen Threshold (EBT) or Arc Thermal Performance Value (APTV) – two related but slightly different metrics that describe how well a material resists heat energy.
4. ASTM F1891-19 and F2733-17
Some environments require light and dark visibility, fire protection, and water resistance all in one. It’s no use to have individual garments serving each purpose, because layering them means they can’t all perform their protective function.
If a material serves multiple purposes, it may be subject to several of the above standards. Understanding how those standards interact and what they lay out is crucial for selecting the right gear. A rigorous hazard assessment is the first key step in understanding which and how many of these standards will apply.