There’s a big problem with chemical suit selection. Right now, many safety managers involved in choosing a chemical suit to protect workers against a specific workplace chemical hazard use a process that is at best deeply flawed and at worst completely misunderstood. In many cases the result can be that users believe they are safe when they may not be. They just haven’t realised it yet…
The Problem with Chemicals
Chemicals present a different type of problem for Safety Professionals. The consequences of most workplace hazards are immediate; it would be difficult to not be immediately aware that a brick has fallen on your head (hard hat or not), or that a cutting tool has just removed part of your index finger. Whilst some chemicals, such as acids, do have immediate effects, many have slow effects (such as skin irritation), and many more chronic effects; health consequences that only become apparent months or even years later.
And those health consequences can be catastrophic. Life-changing if not life-ending. If you have seen the movie “Dark Waters” you will be aware of this. It deals with a real-life situation that occurred in Parkersburg, West Virginia in the 60’s and 70’s when perfluorooctanoic acid – used in the manufacture of Teflon – was released into the environment. The health and legal ramifications continue to this day. The list of health effects of this single chemical is sobering. Various cancers, liver disease, kidney disease, thyroid disease, birth deformities… the list goes on. And that is just one chemical! The Directory of Chemical Producers estimate that over 21,500 chemicals are produced globally. How many of those will cause serious health consequences? And does anyone really believe we know everything there is to know about the long-term effects of every one?
This unique nature of chemicals – the combination of possible un-noticed contamination with catastrophic long-term consequences makes the flawed nature of chemical suit selection even more dangerous.
The Limitations of The Chemical Permeation Resistance Test
As a manufacturer of chemical suits the first question we are generally asked is “What is the permeation test breakthrough against… [let’s say] “methyl ethyl killyatodeath”?
This test (Test standard EN 6529 and US test ASTM 739) measures resistance of a chemical suit fabric against permeation of the chemical. Permeation being the molecular level process by which a chemical will inevitably pass through the solid barrier of a chemical suit fabric. Permeation will happen. The questions are “when?” and “how quickly?”. Chemical suit fabrics are designed to delay and slow the process. They cannot stop it indefinately.
The test result is termed the “breakthrough” and is given in minutes. So, if that breakthrough for methyl Ethyl Killyatodeath is >480 minutes, most users interpret this as “safe for 480 minutes”, and that it is safe to use the suit. But there are a number of flaws with this assumption: –
- Permeation through the fabric is only part of the story. In many cases a much greater risk is ingress of the chemical into the suit through construction elements such as the zipper, or through the joins between the suit and other PPE such as mask and gloves. This is especially the case with chemicals that vapourise readily at low temperatures.
- Being generous, the accuracy of a permeation test is questionable. Send the same fabric sample to five different test houses and you will probably get five different results!
- The test ignores temperature. Permeation rate increases with temperature. As a general rule a 10C rise will result in a doubling of the rate of permeation. All permeation tests are done at 23C ( to allow comparison – the intention of the test), so the result may simply be wrong when performing a task in the real world.
- It is widely misunderstood. “Breakthrough” in the test is more correctly termed “Normalised Breakthrough” and relates not to when the chemical “breaks through” the fabric, but to when the rate of permeation (i.e., the speed at which the chemical is breaking through the fabric) reaches a specific level. This means that at the breakthrough time the chemical has already been permeating through the fabric and may have contaminated the wearers skin. It must have because it must take some time to reach that speed. Combine that with the often un-noticed, long-term consequences of many chemical hazards and the potential problem is obvious; users can easily can think they are not coming into contact with the chemical, when they might be… And what did we say about chemicals sometimes being harmful in very small quantities?
So, the permeation resistance test, whilst useful (and intended) for comparison of fabric performance is all but useless in terms of indicating how long you are safe – or even whether you are safe for any time at all!
Most manufacturers of chemical suits know this. Look closely at the small print that invariably accompanies permeation test data and you will find it – or something very like it – confirmed.
Which is all very well, but that still leaves open the questions of how to select the right chemical suit and “How Long am I safe?”.
A Holistic Chemical Suit Selection Approach
There is no simple answer. No single test or assessment provides all the information needed. Users need to take a holistic approach to a risk assessment and the selection process to ensure all the factors that might affect the outcome are considered. Some of those issues are outlined below: –
Understand the chemical.
What hazard does methyl ethyl killyatodeath present? How does it enter the body (through the skin? Inhalation?). How serious are the consequences and are they long term or short? Will a wearer be aware of contamination? How easily does it vaporise? What is its toxicology (how much of it will cause harm?). At what point will the consequences be permanent?
Whilst a permeation test result may indicate a breakthrough on a standard coverall fabric of >480 minutes, if methyl ethyl killyatodeath is highly toxic, can absorb through the skin and easily vapourises, then a full gas-tight suit might be the safest choice.
Use garments certified to EN standards for Type 3 and 4 (EN 14605)
Certification to these standards requires whole suit testing in which a liquid is sprayed at the garment ensemble in a controlled test to determine how effectively it resists ingress. It tests the full suit – not just the fabric. The Type 3 test especially presents a challenge to garments, spraying strong jets of liquid at potential weak areas, so is a good test of the suit’s effectiveness. Using non-certified PPE of any type might mean it has not been tested at all, so you have no idea whether it will protect or not.
But beware! The test is normally conducted with joins between hood and mask, and sleeves and gloves, and sometimes even the zipper flap securely sealed with strong adhesive tape. So to match the test performance users in the field also need to tape up the garment securely.
Go beyond basic Permeation Test Data
It may be possible to gain additional information from permeation test reports – such as “first breakthrough” and permeation rate that can help in assessing how much of a chemical might permeate over time and whether it might be harmful.
Consider garment design and features.
Poor design and fit of a chemical suit affect comfort and durability, which in turn impacts work rates, productivity and finally, the bottom line. Meanwhile specific features can enhance protection and help ensure garments are worn as they should be.
Lakeland ChemMax® chemical protective clothing features the “Super-B” design – a unique combination of three key elements that result in a more ergonomic, better fitting garment that enhances comfort, freedom of movement, and durability. Standard features include a double-zip and storm flap front fastening to ensure protection to the front, stitched and taped seams, and cushioned knee-pads, enhancing comfort and protection where workers must kneel or crawl.
Establish written and effective donning and doffing procedures
A suit not worn properly will not protect properly. Chemical suits are inevitably not comfortable to wear and the danger of “risk tolerance” means workers have greater tendency to take risks (such as pulling down the zip to allow a little air in). An appropriate donning and doffing procedure along with regular training and review will help mitigate this risk.
Read chemical suit User Instructions carefully
The detailed User Information supplied with CE certified PPE can provide useful information and importantly, should outline any limitations of use. An example is where the detail indicates Type 3 protection is achieved in the test only with the zipper flap securely taped. If you have not read this, you might assume Type 3 protection is achieved without taping, which means in the real world you will not get the protection you expect.
The point is, for effective chemical suit selection and management, too much focus on any single data such as permeation test breakthrough – especially when it is such a flawed and misunderstood test – can be dangerous and may risk omission of important factors. Tests like this can make a useful contribution but are lab-based, and not, in isolation, the answer to real world challenges. A holistic approach, considering all the factors that might play a role, is the only way to be as sure as you can be.
Finally, the world is changing. Increasingly, technology is applied to enhancing protection of workers. A good example has evolved from the increasing recognition of heat exhaustion as a serious hazard. “Bodytrak” is a non-invasive tool for real-time monitoring of key health and wellbeing indicators – a valuable addition to the task of keeping workers safe and with huge potential benefits in many situations where workers are under stress, strain or extreme discomfort.
So, seek out new technology that helps ensure protection. In terms of chemical hazards, Lakeland will shortly launch the latest version of Permasure®. This free-to download smartphone app works with Lakeland ChemMax® suits and uses molecular modelling to calculate Safe-Wear Times, solving many of the problems associated with permeation test data detailed here. The new version also incorporates whole suit assessment through the use of suit Protection Factors derived from inward leakage testing, along with known toxicological data on over 2,400 chemicals.
Permasure® V4 represents the first comprehensive, science and data-based whole suit assessment of Safe-Wear Times for chemical suits.