Safety breakthrough

All chemicals will eventually permeate protective clothing. Breakthrough, or permeation, resistance is related to the concentration and temperature of the challenge chemical, environmental temperature and thickness of the barrier material. Therefore, higher temperatures can result in faster breakthrough. Similarly, lower temperatures can lead to longer breakthrough for certain chemical/material combinations.
ASTM F739 is the standard test for permeation. It measures the resistance of protective clothing materials to permeation by liquid or gaseous chemicals under the condition of continuous contact. The test determines both the breakthrough time and steady-state permeation rate of chemicals through a sample of the protective barrier.

The ABCs of chemical hazards

PPE should be selected based on the specific hazards present in a given situation. EPA identifies four levels of chemical protective ensembles for responding to chemical spills:

Level A protection is used when contaminants are present that require the highest possible degree of both respiratory and skin protection. This ensemble includes the use of an atmosphere supplying respirator such as a self-contained breathing apparatus (SCBA) and a totally encapsulating chemical protective (TECP) suit.

Level B is used when contaminants are present that require the same degree of respiratory protection as Level A, but a lesser degree of skin protection such as a splash suit that is not totally encapsulating or gas tight.

Level C involves the same degree of skin protection as Level B, but a lesser degree of respiratory protection, which includes air purifying respirators.

Level D provides protection against only normal workplace hazards and is not designed to protect against chemical hazards. Equipment may include safety glasses, hard hats, steel-toe boots and leather work gloves.

Tailor made for safety

For application involving the handling hazardous substances, an important piece of PPE is Chemical Protective Clothing (CPC). CPC is protective gear designed to prevent chemicals from coming into direct contact with human skin. Some workplace chemicals may present hazards simply upon dermal contact, others present dangers if they're ingested or inhaled.

Chemical Protective Clothing includes all clothing that can provide a barrier between hazardous substances and skin. Not all materials can effectively prevent chemical contact; depending on the chemical, some materials may breakdown in a matter of seconds, allowing almost instant contact with the skin. Chemical Protective Clothing materials are evaluated in terms of breakthrough time, or how long it takes a chemical (under continuous contact conditions) to break through the fabric of the clothing.

Some chemical protective clothing is made of specially developed materials to withstand the strongest chemicals. Ranging in thickness from 15 to 30 mm, CPCs are tested against as many as 260 chemicals to determine breakthrough time. Many full-body suits are brightly colored, as well, to increase visibility in poor lighting.

Though many CPCs are designed for protection against gaseous chemicals as well as liquids and solids, in many dangerous situations, more protective gear is synonymous with reduced risk. There are fully encapsulated, Level A suits available for protection beyond your protection. Some such suits are constructed from aluminized fiberglass, and include attached gloves and sock boots.

Full body protection

It may sound like the latest techno-geek gadget, but PPE is the bureaucrat's way of saying Personal Protective Equipment. PPEs are a kind of working wardrobe designed to safeguard the health and physical well-being of working guys and gals on the job. There is PPE to cover your body from head to toe: Helmets, hard hats, safety eyewear, respiratory masks, chemical and Tyvek suits, gloves, footwear, and more. Which PPEs your workers wear to the jobsite will depend on the potential hazards of the particular job.

Putting protective clothing to the test

The ASTM method establishes the time to breakthrough under conditions of continuous liquid or gaseous contact. The default breakthrough time is 480 minutes (eight hours). A lot of companies choose clothing materials that offer the eight hours of breakthrough time - which represents a worst-case scenario - when the exposure situation may only require, say, four hours. By properly assessing the resistance of protective clothing materials to permeation, employers can effectively downgrade and still get optimum protection.

The right protection for the job

The best way to take the guesswork out of chemical suit selection is to do a risk analysis. Go through your site and identify the substances (particulates, liquids and gases) present in the work site as well as the hazards associated with these substances (i.e., dermal toxicity, reactivity, etc.). Make a list of physical or environmental hazards, such as sharp instruments, rough surfaces or machinery. If you work at night, you might want to consider a reflective safety vest and hard hats with built-in flashlights. Also, note who will be wearing the clothing, the work that person will do, and what equipment will be used. In general, the nature of the hazard will guide you to the appropriate clothing.

Can't tell the hazards without a scorecard

There are a lot of hazardous chemical compounds in the world. Fortunately, NIOSH the National Institute for Occupational Safety and Health (NIOSH) publishes a Pocket Guide to Chemical Hazards to help workers, employers, and occupational health professionals. recognize and control occupational chemical hazards. The Pocket Guide presents key information and data in abbreviated tabular form for 677 chemicals or substance groupings (e.g., manganese compounds, tellurium compounds, inorganic tin compounds, etc.) that are found in the work environment. The guide also contains substances for which the National Institute for Occupational Safety and Health (NIOSH) has recommended exposure limits (RELs) and those with permissible exposure limits (PELs) as found in the Occupational Safety and Health Administration (OSHA) General Industry Air Contaminants Standard (29 CFR 1910.1000). Should be a part of your working library.

Assessing The Workplace

Assessment of the workplace is beneficial in determining the areas in which people will need to wear protective clothing. This assessment can be done inter-company or carried out by a private safety assessment firm.



The workplace assessment should identify areas where employees are at risk for contamination from industrial hazards, as well as identify what the particular hazard would be. The benefit of this information is it can be used to discover areas where protective clothing should be worn.

Seams right for safety

When it comes to chemical suit, seams are of utmost importance. There are various types of seam construction that provide varying degrees of protection.
Serged seam. Appropriate for low-level exposures, but not suitable for skin-absorbable or skin-toxic chemicals. A serged seam joins two pieces of material with a thread stitch that interlocks. It is typically used on limited-use clothing where dry particulates, non-toxic dirts, dusts and a low concentration of residual contamination are involved.

Bound seam. The next level up, this is a serged seam with material folded over the edge and sewn on for a higher degree of protection against liquids and dry particulates. The seam is chain stitched through all of the layers for a clean finished edge.

Ultra-sonic seam. Offering yet a higher level of protection, this is a seam without thread - no holes are sewn. Used widely in the medical field and to a lesser degree in the industrial arena, this seam can be liquid-proof and is good for higher splash exposure.

Heat-sealed seam. The highest performing and highest cost seam, this seam is sewn and then hermetically sealed with a thermally welded seam tape. The impervious seal provides a liquid-proof seam and should be used when working with a high concentration chemical. Heat-sealed seams are well suited for Level A and B chemical protective clothing.

A Disadvantage of Protective Clothing

One of the major disadvantages of wearing protective clothing is the inability to have data or statistics on the actual level of safety the protective clothing provides.

This is due to fact that protective clothing is tested within laboratories under precise and easily repeated conditions. However, when the protective clothing is worn during the workplace, other factors can affect the level of protection the clothing provides.

Even though this disadvantage exists, this is no incentive to stop wearing protective clothing because the level of protection is decreased compared to the test conditions in the laboratory in which the clothing was subjected to.

Resources Online Selling Protective Clothing

With the increasing popularity of the Internet, there are numerous resources available to find Web sites which sell protective clothing.
If you have never bought protective clothing online before, it is important to spend time familiarizing yourself with the process. After selecting protective clothing to purchase, these items are placed within your electronic shopping cart on the online store's Web site. When you are ready to check out, a credit card will be needed to purchase the protective clothing you selected. Some online stores might even give you the option of fast delivery, and in record time your new items will be shipped to your home or workplace.

Monitoring the Efficacy of Protective Clothing

To increase the effectiveness of protective clothing, the employee should be educated and trained on how to use the protective clothing in the best way. For example, the way to properly wear a construction safety vests, can be discussed.



Beyond this, the statistics on the amount of injuries should be reviewed yearly to determine if the wearing of protective clothing has shown an improvement in a particular area.

Research Opportunities on Skin Exposure

There has only been a small amount of research completed on skin exposure to harmful chemicals while wearing protective clothing. A few studies have been conducted on the high rates of contact dermatitis on farm workers and employees in manufacturing. However, the research was insufficient in discovering exactly why these reactions occur, and ways to prevent these reactions from occurring.

In regards to research on protective clothing, more substantial data needs to be collected not just on the effectiveness of wearing one type of glove over another type of glove, but also what other protective clothing combinations can offer more protection, for example, such as the combination of work gloves and safety glasses.

Future research is aimed at investigating the long-term health problems associated with not wearing protective clothing, and any methods to help decrease or prevent these health problems.

Heat Stress

Some employees working in hot areas, a