High-visibility safety apparel (HVSA) is a critical component to keeping workers safe, especially when they work near moving vehicles and heavy equipment.

The idea behind it is simple: if workers can't see each other (or others nearby can't see them), they'll have a more difficult time avoiding accidents. Hi-vis gear is a very simple but effective way to ensure that workers are visible and conspicuous while they're carrying out their work.

Selecting the right hi-vis equipment makes all the difference. An orange safety vest and bright yellow coveralls are worlds apart in terms of visibility, but how do you know which one is right for your workplace or job site? In this article, we'll go over how HVSA works and some of the things you need to consider when selecting hi-vis garments for your workers (learn more about Safety Vests: The Best Choice for Your Job).

The History of Hi-Vis Gear

HVSA is one of the most common personal protective safety controls applied across industries. Few of the workers who don their hi-vis vests and jackets day after day know, however, that they're wearing something with a military background.

The military was one of the first organizations to use high-visibility uniforms and brightly colored apparel. British field infantry, for instance, wore red coats to make themselves identifiable to field commanders (not to hide blood, as an urban legend has it). Different units might also wear different colors so they were easily spotted and distinguished in the heat of battle.

These days, military personnel in combat environments overwhelmingly wear camouflage. It would seem like a strange choice to outfit infantry units in bright orange before deploying them into a combat zone. But hi-vis apparel is still commonly used in the military. Flight deck crew members, for example, must make themselves highly visible and conspicuous on aircraft carriers.

When we think of hi-vis, we no longer think military. Instead, we think of construction workers, road crews, and so on. And although the setting has changed, the hi-vis clothing serves the exact same purpose it did back on the battlefields of yore: making the wearer easy to spot.

The Science Behind HVSA

When we talk about hi-vis clothing, we're talking about highly visible, bright, and even luminescing, fluorescent, and reflective/retrorefelective materials. And this is more than just reflective stripes. Consider Highway Patrol jackets, which are often made entirely of highly reflective material in white or yellow, along with some reflective strips. Road construction flagging workers are often equipped with whole-body HVSA, such as white or yellow coveralls with reflective gloves. Some fire departments even have reflective material on the boots of their turn-out gear.

What makes all of these different types of hi-vis apparel work? The answer has to do with how our vision works, especially how it processes contrast, how light and brightness affects visual recognition, and how some parts of the eye see things more quickly than others.

Green is the color the human eyes most easily, so why are hi-vis garments not all made with green material? The reason has to do with contrast. Imagine a tiny black dot on a large sheet of white paper. It's very hard, if not impossible, to see. Now think of a white dot of the same size on an equally large sheet of black paper. That one's easy to spot, like a single star shining in the night sky. That's because something bright will show up better in our vision than something dark, especially when it's set against a darker background to create a contrast.

HVSA functions on the same idea: it is apparel made to contrast with a background in order to draw the eye (and our attention) to it. In fact, the National Safety Council, Accident Prevention Manual for Business and Industry (13th Edition) adds to this by calling HVSA enhanced visibility clothing for workers made through the use of fluorescent and retroreflective materials.

What makes contrasts so powerful? It has to do with the way our eyes work. The eyes essentially have two pathways for vision: the magnocellular pathway and the parvocellular pathway. The parvocellular pathway transmits information about color contrast and spatial patterns, while the magnocellular pathway transmits information about brightness, contrast, and motion. This contrast-detecting magnocellular pathway also happens to be the strongest of the two: it uses more of the eye (cones, primarily) and has bigger and thicker nerve connections that allow it to transmit information more quickly. And that is why HVSA is designed the way it is. It doesn't just use bright colors to call attention to the wearer, it also takes advantage of contrasts with the background to make them immediately noticeable, because every fraction of a second counts.

HVSA Types and Classes

Now that we know how hi-vis apparel works, let's have a look at how to select the right type.

HVSA is used in various kinds of hazardous work, including:

  • Road construction, surveyors
  • Maintenance
  • Utilities
  • Railways, trucking industry drivers, swampers
  • Crossing guards
  • Emergency services (including police officers, fire fighters, and emergency medical technicians)
  • Hoisting and rigging, crane work, signaling
  • Traffic control
  • Airport ground operations, including baggage handling, plane movement, and fueling
  • Maritime shipping (loading/unloading) operations, and ship operations

The types of HVSA workers in these types of occupation will wear depends on the type and class of garment that are appropriate for their job. Here is how the ANSI/ISEA 107-2015 hi-vis classification breaks down:

  • Type O Garments: For off-road workers who don't work near roadway traffic
  • Type R Garments: For workers exposed to roadway traffic
  • Type P Garments: For first responders and emergency personnel

Type O garments require only Class 1 HVSA, which is the class with the least amount of background material and reflective materials. Types R and P both require either Class 2 or Class 3 (for related reading, see Your Options for Hi-Vis Apparel in Daylight and Low Light Visibility).

Hi-Vis Risk Assessment

As part of your risk assessment and hazard analysis, consider the following to help you nail down your hi-vis needs:

  • The background contrast between the worker and the job site or equipment
  • Whether workers require HVSA that not only enhances their visibility, but also helps identify them by sight as a person, in contrast to the objects around them
  • The weather conditions in which the work will be carried out (rain, fog, snow, dust, mist, etc.)
  • Sight lines, work around heavy equipment, moving equipment, and traffic at low and high speeds
  • The time of day (reflective materials are ideal for work in darker conditions)

These are critical considerations as they provide the cues we need to determine the type of HSVA that best suits the work situation. Consider a normal, simple reflective vest, worn over dark work clothes, in a foggy, near dark situation on a highway work site with vehicle traffic above 50 mph. It hardly seems adequate. Whole body HVSA, incorporating bright yellow reflective material, would be much better at getting the attention of oncoming drivers.

Now consider high line power work in mountainous, wet, misty, terrain in the summer twilight or early evening, where the background is almost entirely dark with shades of green and grey. In this situation, luminescent white with yellow reflective strips might be best.

Choosing the Right Garments

When choosing hi-vis apparel, look for the following:

  • HSVA that is very wearable, comfortable, breathable, and of the correct size
  • Garments that are appropriate for the weather (warm jackets are good for the fall but may be too heavy for the summer)
  • Hi-vis material that will not freeze or crack and that is fire-resistant (find out How to Layer Your FR Clothing)
  • Hi-vis that won't create a new hazard when paired with other PPE (such as creating a snagging hazard or donning issue when combined with a fall protection harness)
  • The garments must be able to withstand the realities of the job, such as repeated contact with abrasive surfaces or exposure to chemical products

One of the best ways to ensure that you select the right clothing is to get the workers involved. Bring several samples to the job site and do a trial run or field test to help you determine which type of HVSA is best suited for your surroundings.

Final Thoughts

Selecting the right hi-vis safety apparel is just the first step to ensuring the safety of your workers. Most people assume that using hi-vis gear is a no-brainer – just put it on and get to work. But it's not that simple. Workers need to understand why they're wearing it and how it's working to keep them safe. They also need to know how to take care of their garments and be aware of the countless little, ordinary things they can do that could compromise the effectiveness of their hi-vis gear. That's why education and training are a must before sending your employees out on the field decked out in orange and yellow.

Oh, and one last thing. Don't forget the headgear! It can be the best HVSA choice you make.