Some of the most important items of PPE are used to protect the head, as David McKeown and John-Mark Edmundson explain.
Protection of an employee’s head, eyesight, hearing and respiratory tract is crucial for workers in many types of environment and industrial processes. Injuries to the head, eyes and hearing are among the most serious that workers can suffer, with some of the most severe consequences including permanent loss of hearing or sight, traumatic brain injury and even death. Inhalation of toxic gases can also lead to equally serious health problems. Wearing personal protective equipment (PPE) is one way of isolating workers from hazards present in the workplace, and the selection of the most suitable types of PPE is critical to employees’ health and safety.
Selecting the correct type of protection for the application is vital to ensure that identified risks are reduced, if not annulled. There are types of PPE that can provide an all-in-one combination, thus offering simultaneous protection to the head, eyesight, hearing and respiratory tract, although this may not be the most ergonomically appropriate in a working environment. It is vital that the selection of any PPE is based on a robust and thorough risk assessment carried out by qualified personnel.
“injuries to the head, eyes and hearing are among the most serious”
Before being placed on the market in the United Kingdom or the European Union, Category 2 and Category 3 PPE must be subjected to testing and a type-examination before a UKCA or CE mark can be applied. Most protective eyewear and all helmets are at least category 2, whilst RPE and hearing protection are always category 3. Markings on the product or in the user information will give guidance in what levels of protection each item of PPE can offer. These include the standard to which it has been tested, as well as other notations for specific tests. Understanding these markings is fundamental to the PPE selection process.
There are several options when it comes to head protection in an industrial setting. Depending on the application and the risks identified in the working environment, the examples below are common standards for helmets.
- Bump caps conforming to EN 812:2012
- Helmets conforming to EN 397:2012+A1:2012
- High-performance industrial helmets – EN 14052:2012+A1:2012.
Many helmets in conformity with EN 397:2012+A1:2012 and EN 14052:2012+A1:2012 will also offer protection against electrical hazards (low voltage) according to EN 50365:2002.
Bump caps offer the least protection in terms of shock absorption and impact from penetrative objects. They are intended for use where ceilings are low or when working in and among shelving but, importantly, where there is zero risk of a dropped object falling onto the head. The testing includes impact shock absorption tests and resistance to penetration tests. All bump caps are subjected to temperature, water immersion and ultraviolet (UV) conditioning before testing in order to ensure, as far as possible, that the testing covers use in a wide range of temperature environments – for example, from -5°C to +50°C, when wet and after a period of ageing.
In addition to the mandatory tests, some other optional tests for manufacturers include impact and penetration testing at sub-zero temperatures (-20°C or -30°C), resistance to flame and protection against electrical hazards for additionally hazardous environments.
Industrial safety helmets
Industrial safety helmets (‘hard hats’) offer an increased level of protection, and these are covered by EN 397:2012+A1:2012. These helmets are subjected to similar conditioning treatments and tests to bump caps. The main exception is that the impact energies used for the shock absorption and the penetration tests are much higher, meaning that these helmets give more protection against objects dropped (see Table 1). These helmets are also subject to resistance to flame testing as mandatory, to provide extra reassurance.
High-performance industrial helmets
Helmets meeting the requirements of EN 14052:2012+A1:2012 offer a higher level of protection as assessed by the basic impact and penetration tests. As indicated in Table 2, this standard includes a wider range of performance requirements than EN 397 or EN 812. A range of optional tests may be applied to all three helmet types. If the testing is successful, the helmets may be marked with an appropriate code.
Testing of chin strap anchorages only applies if these are fitted to EN 812 and EN 397 helmets, and tests for release of the retention system only apply to EN 14052 helmets fitted with a retention system.
For some two decades, the main standard for occupational eye and face protectors in the UK and the EU has been EN 166:2001. Dependent on the application, there are various different standards in use for testing and certification of the same age or older.
“under EN ISO 16321-1:2022, six sizes of headform are now specified”
From a standardisation perspective, these standards have now been superseded by the EN ISO 16321:2022 series, plus related test methods in the EN ISO 18526 series of standards. From a legislative point of view, the current situation is that in both the EU and UK, EN 166:2001 and related standards (such as EN 175:1997 and EN 1731:2006) are still used for testing and certification. Eye and face protectors meeting the EN ISO 16321 series of standards will, however, ultimately become the norm for testing, certification and placing on the market in the UK and the EU.
In the meantime, welding protectors are covered by EN 175, while mesh protectors are covered by EN 1731:2006. Filtering aspects of lenses and visors are covered by EN 169:2002, EN 170:2002, EN 171:2002 and EN 172:1994.
Changes to testing of eye/face protection
The new eye and face protector standards differ significantly from EN 166 in many areas, for instance i) the headforms used for the testing and ii) the marking of protectors.
Previously, two standard sizes of headforms, namely ‘medium’ and ‘small’, were the only options and, of these, well over 99 per cent of testing used the medium-sized version. Under EN ISO 16321-1:2022 and related standards, six sizes of headform are now specified. These are designated ‘1S’, ‘1M’, ‘1L’, ‘2S’, ‘2M’ and ‘2L’. The new headforms were developed as a result of major international research projects which involved the scanning of hundreds of test subjects’ heads. When selecting eye/face protection, the headform used for testing will be specified in the user information to enable better selection. However, many manufacturers may still choose the 1M (‘medium’) headform, and it is expected that this will remain the default size.
Marking of protection
While some marking codes remain the same, there are a number of changes to the way eye protection will be marked, which is highlighted in EN ISO 16321. Some similarities are shown in Table 3, along with a number of key changes.
The following is an example of full marking with the old and new standards. This example is for a UV filter with protection against high-speed particles at extremes of temperature and with anti-fogging lenses:
EN 166:2001 2C-1.2 X 1 FT N
EN ISO 16321-1:2022 X UL 1.2 CT N
It is also important to appreciate other differences between EN 166 and EN ISO 16321. For instance, although the increased robustness test from EN 166 and the basic impact test in EN ISO 16321-1 appear similar, the test in EN ISO 16321 uses a larger and heavier steel ball than in EN 166. This results in a higher impact energy and, therefore, a more severe test.
“following the COVID-19 pandemic, the use of face masks is much more familiar”
New performance requirements have been introduced for resistance to impact from a high mass impactor, protection against streams of liquids, protection against radiant heat and chemical resistance. However, it should be noted that most of the requirements listed in Table 3 are optional, since they would only be tested if specific claims of protection were made by the manufacturer.
Following the COVID-19 pandemic, the use of face masks is much more widespread. Hence, many more people have heard of technical terms such as ‘FFP2’, but may not understand what it refers to. Wide varieties of respiratory protection are available on the market, with an even wider range of hazard protection. For example, dust and particle filters are essential for woodworkers and decorators, while gas filtering masks or breathing apparatus are available for more gaseous environments.
Types of protectors
There are many different standards that cover different components and uses of respiratory protective devices, for example:
- EN 143:2000+A1:2006 is for particle filters as individual components
- EN 14387:2004+A1:2008 covers gas filters as individual components
- EN 140:1999 covers small masks to which the filters attach
- EN 136:1998 covers full face masks (that also cover the eyes)
- EN 149:2001+A1:2009 is for masks that do not have separate filters
- Multiple standards for masks with supplied air (such as EN 12491:1998)
- Multiple standards for devices, including suits for specific cases (for example, EN 1146:2005)
In many of these standards, three classes are specified. Class 3 provides the most protection, while Class 1 provides the least protection. The equipment can be deemed disposable and used once. Another option is multi-use products, which may include a case for storage. If they are designed to be re-used, there will be a limit on their period of use once opened.
Different markings are used for each type of product to help with identification when selecting a suitable product. See Table 4 for examples of codes. It is worth noting that not all tests are mandatory. The different protective claims have various additional test requirements to fulfil. Using this table, we can determine that the FFP2 marking is used for masks that have a filtration system integral to the mask and have achieved a Class 2 rating with respect to particle filtration.
“a key test in filtering products is often performed using human subjects”
It may be surprising to learn that a key test in filtering products is often performed using human subjects. Innocuous challenge chemicals are continuously delivered into the air within the test chamber, and probes are placed in the gap between the mask and the test subject’s face to detect inward leakage. This is carried out during a thorough ergonomic assessment which involves a treadmill. However, there are also a number of tests completed in a laboratory environment including the following:
- Filter effectiveness (for particle filters – assessing the proportion of the challenge aerosol that passes through the filter)
- Penetration tests (for gas filters – given a specific set of conditions, how long it takes for a challenge gas to ‘break through’ into the mask)
- Inhalation and exhalation resistance (using a ‘breathing machine’); this can be optionally carried out in a ‘dusty’ environment
- Carbon dioxide retention
- Strength of any valves
In the UK, the ‘Control of Noise at Work Regulations’ provide minimum health and safety requirements for noise levels within the workplace. Where limiting these noise sources is not possible, hearing protection is essential to reduce the exposure. While there are many types of hearing protection, the most notable are earplugs and earmuffs, which can be either ‘passive’ or ‘active’. In addition, they can be standalone or as part of other items of PPE – such as safety helmets. The EN 352:2020 series of standards is made up of ten parts, each of which covers the general requirements of a specific type of hearing protection (see Table 5 for a basic breakdown). This series was updated in 2020, with changes to some of the methodology of the calculations and the requirements are expressed differently. However, in most cases, this will not affect the selection of protectors from a safety standpoint.
All types of hearing protection are required to undertake what is called ‘subjective attenuation’ testing. This is the level of noise reduction noted by the wearer and is assessed using human subjects within a hemi-anechoic chamber. This test measures the ‘threshold of hearing’ – the lowest sound pressure level perceivable by the ear – of 16 human test subjects, with and without the hearing protection worn. The performance of the model is calculated when comparing these values.
The aim is to reduce harmful noises to a safe exposure level while still permitting necessary communication. Three sets of numbers are provided to help chose products with the right compromise. In Tables 6, 7 and 8, a fictional example shows attenuation data that will be provided to assist with hearing PPE selection.
The main values to note are ‘APVf84’ – assumed protection level and ‘Sf’ – standard deviation.
Table 6 shows data for each octave band which can be used directly where the risk assessment conducted specifies a harmful noise level in an octave band. In our example, the earmuffs have very inconsistent performance at 1,000 Hz, as there is a high Sf. However, the APV value at 4,000 Hz could be highly effective in an environment that identified this range as the only issue.
The ‘high, medium, low’ (HML) numbers shown in Table 7 are simplified attenuation provided for high, medium and low frequency noises.
Finally, the ‘single number rating’ (SNR) is the simplest representation of the attenuation. For our example product, it will often be a good approximation to say that it reduces the sound level by 23 dB when fitted well. However, it loses all the detail the other data presentations provide.
“the requirement that the product should be chemically innocuous is vitally important”
As well as the PPE containing no dangerous or sharp elements, the requirement that the product should be chemically innocuous is vitally important. In addition, a number of other physical tests are required across the range of hearing protective devices, dependent on their application. These include:
- Sizing, cup rotation, headband force and cushion pressure assessments
- Insertion loss testing
- Resistance to damage, and a flexing and water immersion pre-treatment
- Ignitability assessment.