Face shields are personal protective equipment (PPE) devices used across various industries to protect the facial area and associated mucous membranes (eyes, nose, mouth) from hazards such as splashes, sprays, and spatter of body fluids. While face shields are generally not used alone, but in conjunction with other protective equipment and are therefore classified as adjunctive personal protective equipment. They offer several advantages and disadvantages compared to other forms of face/eye protection. This article explores the different types of plastic face shields, their uses, selection criteria, and relevant safety standards.
Introduction
The face is the body part most commonly contaminated by splashes, sprays, and spatter of body fluids, highlighting the importance of facial protection. Face shields provide a barrier against these hazards, serving as a critical tool in maintaining safety across diverse professions. Millions of potential users of face shields include healthcare workers, dental providers, veterinary care personnel, laboratory workers, pre-hospital emergency medical providers, police, firefighters, and custodial staff dealing with spills and contaminated waste.
Eye protection in the medical field dates back to a 1903 patent granted to Ellen Dempsey for a transparent “sanitary face shield for protection from inhaling disease producing germs.” Subsequent innovations included a surgical hood with a suction system to remove exhaled breath (1974) and a cap with an incorporated face shield for non-surgical medical personnel (1989).
Increased attention to face/eye protection has resulted from the introduction of the Occupational Safety and Health Administration's (OSHA) Bloodborne Pathogens Standard 1910.1-030, as well as recent outbreaks of serious airborne infectious diseases (e.g., Severe Acute Respiratory Syndrome [SARS], Avian Influenza, etc.) and severe infectious agents associated with the potential for body fluid exposures (e.g., Ebola virus), have resulted in increased attention to face/eye protection.
Types of Face Shields
Face shields vary in design, materials, and features to meet the specific needs of different work environments.
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1. Components
A face shield typically consists of three main components:
a) Visor
Visors, also referred to as lenses or windows, are manufactured from any of several types of materials that include polycarbonate, propionate, acetate, polyvinyl chloride, and polyethylene terephthalate glycol (PETG) and come in disposable, reusable, and replaceable models. Acetate provides the best clarity and PETG tends to be the most economical, but polycarbonate is one of the most widely used. Polycarbonate and propionate offer better, although still somewhat imperfect, optical quality that aids in reducing eye strain associated with face shield wear. Visors can be treated with advanced coatings to impart anti-glare, anti-static, and anti-fogging properties, ultraviolet light (UV) protection, and scratch resistance features to extend the life of the visor. Some models come with built-in goggles that are incorporated into the visor.
Visors are available in different lengths that include half facepiece length extending to the mid-face, full facepiece length that extends to the bottom of the chin, and a face/neck length that also covers the anterior neck area. Most visors curve around the face and come in different widths; wider visors offer more peripheral protection. Some one-piece face shields have visors that conform to the wearer's face upon donning. Recommendations from the Centers for Disease Control and Prevention (CDC) are for visors that are of sufficient width to reach at least the point of the ear, as this will lessen the chances of the likelihood that a splash could go around the edge of the face shield and reach the eyes. In addition, visors should have crown and chin protection for improved infection control purposes. Some models of disposable medical/surgical face masks are available with an integral, thin plastic visor fitted to the top of the mask with an anti-fogging device.
b) Frame
Face shield frames used in healthcare are generally made of lightweight plastic. There are a variety of frame styles, including adjustable and nonadjustable frames that fully or partially encircle the circumference of the skull or those with eyeglass-type temple bars that are worn like standard eyewear. There are also metal clip-on frames available that are designed to attach face shield visors to prescription eyewear, and some frames allow for the visor to be flipped up when not in use. A number of manufacturers offer detachable frames for easy change-out of the face shield visor. Some models also incorporate a brow cap into the frame that affords additional splash protection in the forehead region, as well as allowing for more visor distance from the face that better accommodates the wearing of additional PPE (e.g., goggles, loupes, prescription eyewear, respirators).
c) Suspension Systems
There are a variety of face shield suspension systems on the market that offer either fully or partially circumferential attachment features. Fully circumferential suspension systems include plastic headbands that are adjustable for comfort by a ratchet mechanism, pin-lock systems, or Velcro®; nonadjustable systems employ elastic straps. Some models utilize eyeglass-type temple bars for suspension with or without eyewear-like nose pads and bridge assemblies to assist in maintaining face shield position and stability on the face.
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2. Material Types
- PET (Polyethylene Terephthalate): Lightweight and economical, PET shields are suitable for brief, low-risk tasks.
- Polycarbonate: This is arguably the most popular choice. Polycarbonate face shields provide superior impact resistance and excellent optical clarity. Polycarbonate excels in impact and high/low temperature resistance. Face shields 0.8 mm (0.031 in) thick made of extrusion polycarbonate sheets can withstand the impact of a 6 mm (0.24 in) nominal diameter steel ball traveling at the speed 120 m/s (390 ft/s) (European standard, protection against high-speed particles - medium energy impact), while injection molding face shields must have at least 1.5 mm (0.059 in) thickness to withstand the same impact. Polycarbonate is as clear as glass and 250 times stronger. A&C Plastics offers enhanced UV-resistant polycarbonate sheet with exceptional weatherability & superior impact strength.
- Acetate: Boasting excellent chemical resistance, acetate shields are perfect for those working with chemicals or solvents.
- Nylon: Nylon, a versatile thermoplastic known for its strength and flexibility, presents unique advantages in certain industrial settings. Nylon also exhibits good thermal stability, allowing it to withstand high temperatures without deformation or degradation. Nylon offers superior heat and chemical resistance
- Tritan: Tritan, a relatively newer player in the transparent plastic arena, combines the benefits of both polycarbonate and nylon while offering unique properties of its own. With excellent impact resistance comparable to polycarbonate and enhanced chemical resistance akin to nylon, Tritan presents a compelling option for versatile face and eye protection in industrial settings. Additionally, Tritan exhibits exceptional clarity and optical quality, ensuring clear vision without distortion or haze. However, it’s essential to note that Tritan may have limitations in extreme conditions, such as ultra-high temperatures or prolonged exposure to highly corrosive chemicals. Tritan provides a balanced blend of both while ensuring optical clarity.
3. Style and Features
- Headgear-Mounted: Reusable and adjustable, headgear-mounted face shields offer enhanced comfort and longevity.
- Disposable: Ideal for short-term use or single-use scenarios, disposable options are lightweight and typically more affordable.
- Full-Length Face Shield: These measure 9-10 inches long and 9-13 inches wide, giving great protection in many healthcare settings.
- Flip-Up Face Shield: The hinged design lets you flip the shield up when not in use, giving both protection and flexibility.
- Clear Face Shield: Clear face shields give you excellent visibility while keeping you protected.
- Extra-Wide Face Shield: These shields measure 20 inches wide and 9.625 inches high, offering more protection than regular shields.
- Reusable Face Shield with Replaceable Visors: Choose Types of Medical Face Shields, reusable options with replaceable visors stand out as a smart long-term investment.
- Face Shield with Integrated Goggles: From my experience, they’re the best choice for risky medical settings. These shields work great for healthcare workers who might get splashed or exposed to airborne particles during their work. The built-in goggles seal tightly around your eyes, giving you better protection than regular face shields.
- Anti-fog: To prevent fogging and maintain clear visibility, some face shields come equipped with anti-fog coatings.
- Tinted: For workers exposed to bright light or glare, tinted face shields can help reduce eye strain and improve visibility.
- Mesh face shields: Mesh face shields are great for cutting tasks where large particles could strike your face.
- Clear plastic/acrylic shields: Clear plastic/acrylic shields are better for tasks where small particles, splattering, or sparks could strike the face.
Applications Across Industries
Face shields are used across a wide array of industries, each with its unique hazards and safety requirements:
1. Healthcare Settings
In hospitals, clinics, and dental offices, face shields are crucial for infection control, offering an additional layer of protection alongside masks and other PPE. Face shields provide a barrier to acutely-expelled aerosols of body fluids and are commonly used as an alternative to goggles as they confer protection to a larger area of the face. Face shields are meant to be used as barrier protection for the facial area and associated mucous membranes from airborne body fluids (blood, saliva, bronchial secretions, vomit, urine, etc.) expelled as a result of various physiological processes (vomiting, coughing, sneezing, etc.) and medical, dental, and veterinary procedures (suctioning the airway, placing nasogastric tubes, obstetrical procedures, surgery, dental procedures, etc.).
2. Manufacturing and Distribution Environments
In manufacturing and distribution settings, face shields protect workers from flying debris, sparks, and other hazards.
3. Construction Sites
On many construction sites many workers use face shields to protect them from debris or sparks. Many tools for cutting and working with metal recommend the use of a face shield. Hazards where face protection, in addition to safety glasses, are found when doing tasks like: Welding, Using a chop saw to cut concrete or rebar, Operating a chainsaw, Pouring, washing, or spraying chemicals or materials, Grinding with hand held or heavy duty table grinder.
4. Educational Institutions and Laboratories
From science labs to workshops, face shields are vital in educational settings to protect students and staff from chemical splashes, debris, and other hazards.
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5. Building Services and Maintenance Tasks
Maintenance workers and building service professionals often face hazards like chemicals, falling objects, and flying debris.
6. Military and Law Enforcement
In military or law enforcement environments, a face shield may be designed for ballistic or non-ballistic protection.
Selection Criteria
Selecting the right face shield involves considering a variety of factors, from the specific hazards at your workplace to the desired comfort and durability.
1. Hazard Assessment
Before choosing a face shield, it’s essential to identify the specific hazards present in your work environment. This may include flying debris, chemical splashes, bright light sources, or infectious agents. In the process of choosing between polycarbonate, nylon, and Tritan for industrial face and eye protection, it’s important that a thorough assessment of the predominant hazards in your workplace be conducted.
2. Comfort and Durability
While protection should be your top priority, it’s also crucial to consider comfort and durability. Look for adjustable headgear options that offer a snug fit and replaceable visors for long-term use.
3. Fit and Adjustability
A well-fitting face shield is not only more comfortable but also more effective in providing protection.
4. Cost vs. Performance
Although cost is an important consideration, it should never compromise safety or performance. Weigh the price of the face shield against its protective features, durability, and comfort.
Usage and Maintenance
To ensure optimal protection, it’s essential to know how to wear, maintain, and inspect face shields correctly.
1. Correct Wear
Face shields should be used with spectacles and/or goggles. In order to be efficacious, face shields must fit snugly to afford a good seal to the forehead area and also to prevent slippage of the device.
2. Maintenance
Visors manufactured from acetate, propionate, and polycarbonate offer improved visual clarity and optical quality with the potential for less eye strain. Visors that offer protection from UV light would be an important feature for individuals utilizing UV light sources (e.g., dental personnel). Face shields should be selected that have visors treated for anti-glare, anti-static, and anti-fogging properties. For improved protection from infectious agents, face shields should be, at a minimum, full face length with outer edges of the face shield reaching at least to the point of the ear, include chin and forehead protectors, and cover the forehead. Brow caps or forehead cushions should be of sufficient dimensions to ensure that there is adequate space between the wearer's face and the inner surface of the visor to allow for the use of ancillary equipment (medical/surgical mask, respirator, eyewear, etc.). Cost-effective considerations include disposable face shields vs. reusable models and those that offer replaceable parts.
3. Inspection
Employees should never risk danger to their face and eyes even for just a few minutes of welding, cutting, or grinding. The damage can happen quickly and be permanent! Workers should always wear face and eye protection that is designed for safety protection and rated as required by OSHA regulations.
Standards and Regulations
When choosing a face shield, it’s crucial to consider the relevant standards and certifications, as well as your employer’s responsibilities and industry-specific regulations.
1. OSHA Standards
The Occupational Safety and Health Administration (OSHA) requires employers to provide appropriate PPE, including face shields, for employees exposed to hazards.
OSHA Construction Standard 1926.102(a)(1) says that employees shall be provided with eye and face protection equipment when machines or operations present potential eye or face injury from physical, chemical, or radiation agents.
OSHA General Industry Standard 1910.133(a)(1) The employer shall ensure that each affected employee uses appropriate eye or face protection when exposed to eye or face hazards from flying particles, molten metal, liquid chemicals, acids or caustic liquids, chemical gases or vapors, or potentially injurious light radiation.
OSHA Construction Standard 1926.102(a)(6) says that eye and face protection equipment shall provide adequate protection against the particular hazards for which they are designed.
OSHA Construction Standard 1926.102(a)(2) says that eye and face protection equipment required by this Part shall meet the requirements specified in American National Standards Institute, Z87.1-1968, Practice for Occupational and Educational Eye and Face Protection.
OSHA General Industry Standard 1910.133(b)(1) Protective eye and face protection devices must comply with… American National Standards Institute ANSI/ISEA Z87.1-2010, Occupational and Educational Personal Eye and Face Protection Devices.
2. Industry-Specific Regulations
Some industries, such as healthcare and construction, have additional regulations and guidelines regarding the use of face shields.
The Importance of Additional PPE
Face shields provide a barrier to acutely-expelled aerosols of body fluids and are commonly used as an alternative to goggles as they confer protection to a larger area of the face. Appropriately fitted, indirectly vented goggles offer the most reliable practical eye protection from splashes, but face shields are considered an alternative to goggles for prevention of eye contamination with infectious agents. Any additional protection afforded the eyes when protective eyewear (e.g., safety glasses or goggles) is combined with a face shield has not been thoroughly investigated, though the combination of a face shield and goggles has been espoused for use during invasive surgical procedures. The combined use of some forms of protective eyewear with a face shield may impact visual clarity and limit peripheral vison to some extent and these effects must be taken into consideration before use. Goggles have also been reported to fog more than face shields. Also, if a respirator is required in conjunction with face shield use, goggles may not fit properly over the respirator. Use of a face shield alone for eye, face, and mucous membrane protection from contamination by body fluids is likely insufficient and it has been recommended that in those situations where a face shield is used to protect against splash or splatter, a medical/surgical mask would also be indicated. Face shields are not meant to function as primary respiratory protection and should not be used alone because aerosols can flow behind the visor. Safety glasses aren't always enough - sometimes you need both the safety glasses to protect your eyes AND a face shield to protect your face.