In brief
Choosing safety glasses starts with the hazard: impact and flying particles, chemical splashes and dust, and optical radiation each require different eye protection. The mechanical strength letter (F, B, A) and field of use number (3, 4, 5, 8, 9) in the TS EN 166 markings are the key to this choice; if the frame and lens markings differ, the lower one applies. For employees who wear prescription glasses, there are prescription safety glasses, over-glasses protectors or face shields, and the cost is not passed on to the employee.
Choosing safety glasses starts with the hazard
The workshop rule "everyone wears glasses" is right but not enough. Framed glasses that are adequate against chips on a lathe do not stop splashes coming from the side when transferring acid; a face shield without a welding filter gives no protection against arc radiation. Choosing safety glasses therefore starts not from a product catalogue but from the hazard identified in the risk assessment.
The Regulation on the Use of PPE requires the employer to determine which personal protective equipment is needed for which job based on the results of the risk assessment (Art. 7). The equipment is provided free of charge by the employer (Art. 6/1-e) and bears the CE mark and Turkish instructions for use. For the general selection method, see our article on PPE selection; this article focuses on eye and face protection.
There are four hazard groups for the eyes:
- Mechanical: Chips, grinding particles, broken bits, wire ends, impact.
- Chemical and dust: Liquid splashes and droplets, fine dust, gas and vapour.
- Thermal: Molten metal splashes, hot solid particles.
- Optical radiation: Welding arcs, gas welding and cutting flames, infrared radiation from melting furnaces, lasers.
How to read TS EN 166 markings
The basic standard for eye protectors is TS EN 166. Markings appear on both the frame and the lens (ocular). The two groups of markings most useful in selection are the mechanical strength letter and the field of use number.
| Marking | Meaning | Where is it found? |
|---|---|---|
| S | Increased robustness | Spectacles, goggles |
| F | Low energy impact (45 m/s) | Spectacles, goggles, face shields |
| B | Medium energy impact (120 m/s) | Goggles, face shields |
| A | High energy impact (190 m/s) | Face shields |
| T | Impact resistance also at extreme temperatures (next to F, B or A) | All types |
| 3 | Liquid droplets or splashes | Goggles (droplets), face shields (splashes) |
| 4 | Large dust particles | Goggles |
| 5 | Gas and fine dust | Goggles |
| 8 | Short-circuit electric arc | Face shields |
| 9 | Molten metal and hot solids (with F, B or A) | Goggles, face shields |
| K, N | Resistance to surface scratching, resistance to fogging | Ocular |
| 1, 2, 3 (optical class) | 1 continuous use, 2 intermittent, 3 occasional use | Ocular |
When reading, watch for two rules. First, if the mechanical strength markings of the frame and the lens differ, the lower one applies: fitting a B-marked lens into an F-marked frame does not give you B protection. Second, field of use numbers (3, 4, 5) are found only on goggles and face shields. However wide the side shields of framed spectacles may be, they do not carry a "3" marking against chemical splashes.
Grinding goggles and face shields: mechanical risks
For mechanical risks, selection is based on the speed and energy of the particle:
- Machining and assembly: F-marked framed spectacles with side shields are sufficient for most jobs. On lathes and milling machines, the direction from which chips come and the condition of the machine guard are assessed together; details are in our article on safety at lathes and milling machines.
- Grinding and cutting: With angle grinders, particle speed and the risk of the wheel breaking are high. Here, B-marked goggles or a face shield with spectacles are used as grinding goggles. A face shield may not fully stop particles coming from below and the sides; this is why in grinding a face shield is not used alone but with spectacles or goggles worn underneath.
- High-energy particles: When working with dies that may break, wire that may snap or high-speed discs, an A-marked face shield is considered.
If a face shield is to be fitted to a helmet, the manufacturer's instructions must state that the helmet and shield can be used together. That equipment worn together must not reduce each other's protection is a requirement of Art. 6/1-b of the Regulation on the Use of PPE.
Chemical goggles: splashes, dust and vapour
For chemical risks, the first document to look at is the product's safety data sheet. Section 8 of the sheet states what is recommended for eye and face protection; for how to read it, see our article on how to read a safety data sheet.
| Task | Recommended protection | Marking to check |
|---|---|---|
| Transferring acids, alkalis or solvents | Closed chemical goggles | 3 |
| Pressure washing, high-volume transfer | Face shield together with goggles | 3 on goggles, 3 on shield |
| Fine dust (cement, pigment) | Closed goggles | 4, or 5 for fine dust |
| Irritant vapours and gases | Gas-tight goggles or full-face mask | 5 |
| Electroplating and coating baths | Goggles and face shield | 3 |
Indirectly vented goggles reduce fogging but do not protect against gas and vapour. For work with a vapour risk, either unvented goggles or a full-face mask designed together with respiratory protection is chosen. Respiratory protection and goggles often push against each other; trial both together with the employee.
Optical radiation: welding, furnaces and lasers
For optical radiation, the protective ocular is a filter that filters light to a certain degree of darkness (shade number). The standards are divided as follows:
- Welding filters (TS EN 169) and welding protectors (TS EN 175): The shade number is chosen from the filter manufacturer's table according to the welding process and current. Auto-darkening filters comply with TS EN 379.
- Ultraviolet (TS EN 170) and infrared (TS EN 171) filters: For melting furnaces, glass and foundry work, a protector with an infrared filter is considered.
- Laser (TS EN 207): Laser safety glasses are chosen according to the laser's wavelength and power; glasses supplied for another laser may not provide protection. For conditions in laser cutting, see our article on laser cutting machines.
The helper, grinder and forklift operator working next to a welder are also affected by arc radiation. Welding screens take priority in protecting these people; a helper working close to the weld is also given eye protection with a suitable filter. For other welder-specific risks, see our article on welders' occupational safety risks.
Prescription safety glasses and other solutions
For an employee who wears prescription glasses, ordinary glasses are not protective: the lenses have not been tested against impact and there are no side shields. There are four solutions:
- Prescription safety glasses: Glasses whose frame and lenses are marked to TS EN 166, made to the employee's prescription. This is the most comfortable solution for employees who wear glasses all the time and need eye protection all day. The lenses must be made according to the system specified by the frame manufacturer; if an unmarked lens is fitted to a protective frame, protection is lost.
- Over-glasses safety spectacles: A protector designed to be worn over the employee's own glasses. Suitable for those who need protection occasionally and for visitors.
- Goggles suitable for wearing over glasses: For chemical and dust risks, goggles with enough internal volume to accommodate glasses are chosen.
- Face shield: Can be used over glasses, but for mechanical risk, safety glasses are needed underneath.
Which solution is chosen depends on the exposure time and type of hazard. Prescription safety glasses are also personal protective equipment; they are provided free of charge by the employer, and under Art. 4 of Law No. 6331, the cost of OHS measures cannot be passed on to employees. The situation of an employee with a visual impairment is assessed together with the workplace physician.
The 2026 basic administrative fine for not providing PPE that meets standards and bears the CE mark is 8,980 TL per employee; you can see other amounts in the OHS administrative fines tool. In our OHS specialist service, we enter eye and face protection into the task-based PPE matrix and carry out product trials together with employees. Metalworking businesses can also see our metal and machinery page.
Frequently Asked Questions
Is a face shield alone enough for grinding?
No. A face shield protects the face but may not fully stop particles coming from below and the sides. In grinding, a face shield is used together with safety glasses or goggles worn underneath.
Which marking should I look for on chemical goggles?
For protection against liquid splashes, look for the "3" field of use marking from TS EN 166 on goggles or face shields. For fine dust, 4 or 5 is needed, and for gas and vapour, 5. Section 8 of the product's safety data sheet should also confirm your choice.
Who pays for prescription safety glasses?
The employer. Prescription safety glasses are personal protective equipment; under the Regulation on the Use of PPE they are provided free of charge, and under Art. 4 of Law No. 6331 the cost of OHS measures cannot be passed on to employees.
If the frame and lens markings differ, which one applies?
For mechanical strength, the lower marking applies. If a B-marked lens is fitted to an F-marked frame, the glasses provide F-level protection.
A certified specialist matched to your hazard class: site inspections, approved logbook, training plan, annual plan and report follow-up.
Bursa SİSTEMER OSGB Technical Team — written from the field experience of our OHS specialists and workplace physicians. Legal information is valid as of the publication/update date; contact us for an assessment specific to your business.