26 Dec Real world performance of workwear
For anyone working within the petrochemical and oil and gas industries, the need for flame and heat protection for workers is firmly established – especially against the devastating and ever-present risk of flash fire – thus it is essential to understand how effectively a garment will perform. Lakeland Industries have recently published an ebook which explains what the tests mean for real world performance and how to determine the effectiveness of combined Primary and Secondary FR workwear to safely deliver both chemical protection and protection against flame and heat. There follows a potted version of this informative and accessible publication.
Protection against flames and heat and especially flash fire is a basic requirement in most chemical and petrochemical plants. At the same time, many workers also need to be protected from exposure to toxic products and chemicals that can present multiple hazards. Primary FR workwear certified to EN 11612 : Protective Clothing – to protect against heat and flame – specifies performance requirements for garments made from flexible materials, which are designed to protect the wearer’s body, except the hands, from heat and/ or flame is essential and when heat, flame and chemical protection is required at the same time, the chemical suit should be certified to the Secondary FR workwear standard – EN 14116.
These two standards’ tests are poor at indicating how well a Primary FR garment will perform in the real world. So how effectively will they indicate how well a combination of garments will perform – especially where the Secondary FR garment may be of inferior quality and could adversely affect the performance of the Primary FR garment?
Workers, particularly those in petrochemical environments, require both heat or flame and chemical protection at the same time and in such cases it is common to wear a chemical suit over Primary FR workwear. The chemical suit should be certified to the Secondary FR workwear standard – EN 14116 – as well as to the required chemical protective standard.
There is some misunderstanding of the difference between the purpose of Primary FR (EN 11612) and Secondary FR (EN 14116) workwear and standards. Primary FR workwear is specifically designed to protect against flames and heat. Secondary FR workwear on the other hand, is designed to provide chemical protection over Primary FR workwear without compromising thermal protection. In other words, to allow safe combination of flame and chemical protection. So how might the different performance of Secondary FR workwear affect the performance of Primary FR workwear?
And, most importantly, how do you know your chosen workwear ensemble will protect your employees if the worst happens? Discovering that a Primary and Secondary FR ensemble is not very effective when an accident happens is not the time to find out!
The two main standards for testing and assessing FR workwear (excluding more specialist standards such as EN 61482 for Arc Flash protection and EN 11611 for welding and similar applications :
EN11612 Primary Workwear
Testing in the standard includes:
- • Heat Resistance – to confirm shrinkage in response to heat is minimal (5%)
- • Vertical flammability – to show the fabric does not ignite or hole in contact with a small flame. It applies a small flame to a vertically suspended sample (200mm x 160mm) of the fabric for ten seconds.
But does this test indicate any level of safety in a flash fire? No.
It does not reflect any real-world situation: even if a scenario arose where a small flame is applied to one spot on the garment, is the wearer likely to stay in that one spot and not move for ten seconds? Hardly. The more realistic scenario is flash fire and a burst of flame for a few seconds, from a cracked pipe or a burst valve, in which case there is nowhere for that fabric to escape to, it is engulfed.
VERDICT: The Vertical Flammability Test is a useful basic test to prove minimal requirements but provides little information about how a garment will perform in the real world.
- • Five Heat Energy Resistance Tests (radiant, convective, contact and molten splash of iron and aluminium) to indicate level of resistance against transfer of heat energy (only one must be tested)
While these tests can provide a general indication regarding the level of heat protection based on the classes, matching that to a risk assessment is less straightforward. While heat energy resistance tests can be applied to notional hazard levels (Level 1 = Low Risk; Level 2 = Medium Risk; Level 3 = High Risk) there is no clarity of definition. Without knowing what those terms mean in the real-world, confusion can arise.
VERDICT: The Heat Energy Transfer Test performance levels can be a useful indication that a garment might be suitable for either low, medium, or high-risk applications, and useful in comparing performance of different garments, but has very limited use in terms of answering the question “will it actually protect me?”
FIRE-ALT 3. ISO 13506: ‘The Thermal Mannequin Test’ to predict likely body burn in a flash fire (optional)
Whereas all the other tests in EN 14116 and 11612 are merely tests on fabric samples, ISO13506 is a test on a whole garment. The test equipment consists of a “thermal mannequin” covered in 123 heat sensors, each relating to a specific area of the body, each designed to replicate the rate at which human skin absorbs heat energy, and each connected via cables inside the mannequin to a computer. The mannequin is surrounded by four burners which can apply jets of flame for a set time. A test garment or combination of garments is put on the mannequin and jets of flame applied. The heat sensors record heat energy absorbed during the burn and for usually 30, 60, 90 and 120 seconds after.
Using this data, the computer can calculate (using “stoll curve” analysis) where on the body there would be pain and first, second and third degree burns.
This is the only test which bears a real equivalence to a flash fire situation in the real world in that: A. It tests the whole garment – not just the fabric B. It simulates the garment being engulfed by a flash fire C. It uses well-established principles to determine the level and depth of pain and burn that would have resulted had a person been inside the suit, rather than a mannequin.
VERDICT: This is the only test in either EN 14116 or EN 11612 which provides any real indication that a garment will actually perform and protect in the type of real-world flash-fire scenario.
The official title “Protective Clothing – protection against
flame – limited flame spread materials, material assembly and clothing” is potentially misleading because most garments certified to this standard will NOT provide protection against flames. Rather, they are garments that will not ignite when in contact with flame.
Testing comprises one test:
- Vertical Flammability – to show the fabric does not ignite, burn and drip molten debris in contact with a small flame. Note: this is the same test as used in EN 11612 but with lesser requirements.
If you are not happy in relying on the EN 11612 or 14116 testing to confirm that a garment will actually protect in the real world, it is worth looking for results of a Thermal Mannequin Test to provide greater reassurance. The test, through its provision of predicted body burn maps, provides vital insight into how effectively a Primary FR garment or a combination of Primary FR and Secondary FR garments will protect the wearer in a flash fire scenario.
Manufacturers will be happy to supply the results, or if they are not then it is reasonable to assume that either the test has not been done, or that the results were poor. In either case it’s a good indication your choice of FR workwear is unlikely to provide effective protection. Understanding how effectively a combination of suits will work in the real world; and the potential risk of pain, 1st , 2nd or 3rd degree burns is far more informative for a safety manager than a generic set of EN 11612 or EN 14116 test results.
Go to https://bit.ly/34e888f to dowload your copy of Lakeland Industries invaluable e-book ‘How can you assess the effectiveness of Primary and Secondary FR Clothing?