Moisture vapor transmission rate (MVTR) is the rate at which water vapor transfers through a given substance. MVTR can be tested and evaluated for everything from clothing to building materials.
High MVTR is desirable in spaces or situations likely to get wet. This is because efficient evaporation and breathability ensures adequate drying. Conversely, material with low MVTR (i.e., water vapors do not easily transfer through it) can offer a protective barrier for water-sensitive equipment which reacts negatively to moisture.
For clothing—particularly occupational protective garments—water vapor evaporation is effectively synonymous with sweat evaporation. In this case, MVTR would refer to how quickly sweat dissipates from the skin and thereby achieve a desirable "moisture wicking" effect. Not only can this help a person stay dry, but it can also help a person stay cool, too.
In other words, the MVTR of disposable protective clothing can be an indicator of how comfortable a given article of clothing is for its wearer.
Benefits of MVTR in Protective Clothing
Physical discomfort of protective clothing is consistently found to be the leading cause of PPE non-compliance among occupational and industry research. For this reason, it's plausible to suggest that improved worker comfort improves the chance of compliance to personal protective equipment (PPE) protocols.
Common complaints of protective clothing include garments which feel too hot, too sweaty, too stiff, or otherwise ill-fitting. As a workaround, some employees may simply opt to fail to comply with protocol. For instance, they may not zip up a protective suit all the way up, or they may cut holes into the material to increase breathability. Such judgment calls puts employees at serious risk of injury, illness, or even death.
By providing protective clothing which is comfortable and has a high MVTR, employees will be more likely to consistently wear their gear, allowing sweat to get out and preventing chemicals, biological waste, and other harmful occupational substances from getting in.
In addition to effective moisture wicking ability, a protective garment with good MVTR can also help alleviate heat stress.
Breathable protective wear must allow for generated body heat to evaporate through the material; this prevents employees from getting too hot. This is a critical feature, because heat stress can also lead to potentially dangerous and symptoms including fatigue, confusion, dizziness, headaches, cramping, tachycardia (fast pulse), and loss of consciousness.
Protective clothing which can effectively transmit both moisture and heat is of utmost important for industries such as construction, industrial, healthcare, military, and first responders. This is because employees in these fields often must not only wear PPE, but also exert a considerable amount of physical effort in order to perform routine job tasks.
The Challenges of PPE Non-Compliance
The goal of PPE is to maximize workplace efficiency and safety. These objectives are primarily obtained through protecting employees from injury and contamination—health hazards which in extreme cases can be severe or even fatal. In many settings, such as hospitals and other healthcare facilities, PPE also helps to prevent the spread of infection and protect non-employees, including patients, family members, and in effect the community at large.
Even the best PPE protocol will not be effective if employees choose not to adhere to company policy.
Why does PPE non-compliance occur, especially at what some evidence would suggest is such an alarming rate? As an example, a 2008 survey conducted at the National Safety Council Congress & Expo found that nearly 9 out of 10 safety professionals have observed workers failing to wear PPE as indicated.
The reasons for PPE non-compliance is multifactorial. Research indicates a variety of confounding factors are posing a potential barrier to appropriate PPE use, including:
- Discomfort, consistently found to be the leading reason for non-compliance
- Employee dissatisfaction with look and style of the PPE (employees often find protective wear unattractive—a potentially overlooked yet impactful consideration)
- A company culture which is not conducive to nor stresses the importance of workplace safety (e.g., not enough emphasis placed on employee education and training, lack of a consistent precedent)
- Inconvenience and inaccessibility (e.g., PPE is not readily available nor easily accessible when needed)
- Employee beliefs, including the belief that PPE inhibits their ability to perform their job and communicate effectively with colleagues, clients, and patients, or the belief that the PPE is not truly necessary for a task
- Sociodemographics (including age, race, and ethnicity)
- Perception of risk
- Lack of time (real or perceived)
Selecting the Ideal Material for Protective Clothing
An important consideration to take into account when attempting to address these factors is the quality, comfort, and breathability of the material. This is particularly essential when it comes to protective clothing. That is, employers need to procure protective garments which provide employees with as much comfort as possible without negatively affecting the intended protective function of the garments themselves.
Organizational safety professionals are cautioned against believing that selecting more comfortable protective clothing will be the answer for workplace PPE non-compliance. By researching MVTR and other important design elements of protective garments, these administrators may be able to help curb the problem.
Different industries—indeed, individual companies within different industries—must also take into consideration many factors when deciding which type of material is best for protective clothing for its employees. Aside from adhering to industry standards, employers must also ensure that it is promoting a culture of workplace safety while also addressing employee concerns and potential barriers to PPE.
Industry employers are encouraged to stay up-to-date with advances in textiles, technology, and other issues which may influence how safety protocols are designed and implemented in order to optimize employee safety.