Personal Protective Equipment for Chemical, Biological, and Radiological Hazards

Design, Evaluation, and Selection

Eva F. Gudgin Dickson

• Publisher: Wiley
• Year: 2012
• Print ISBN: 9780470165584
• eBook ISBN: 9781118422915
• Edition: 1
• Topic: Technology & Engineering
• Subtopic: Industrial Health & Safety
• Index: Technology & Engineering

Personal protective equipment (PPE) is critical for those dealing with toxic, infectious, and radioactive materials. An easily accessible guide for professionals and researchers in all PPE fields, this book takes a fresh look at how PPE is designed, selected, and used in today's emergency response environment where users may need to be protected against deliberately used chemical, biological, or radiological agents in terrorism or warfare scenarios as well as more traditional hazards. Covering the physics, chemistry, and physiology of these hazards, the book explains how PPE protects from various forms of hazards as well as how to use this information to select PPE against these highly hazardous substances for first responder or military users. The design of PPE and components plus relevant performance and evaluation standards are also discussed.

1 Introduction to CBRN Protection

In this chapter we familiarize the reader with the general concepts that are most important to CBRN protection and personal protective equipment, acting as an introduction to later chapters, where we deal with these topics in more depth.

1.1 WHAT IS CBRN PPE AND WHY IS IT USED?

Personal protective equipment (PPE) is equipment worn to protect the wearer from some external hazard: in this case, chemical, biological, radiological, or nuclear hazards, all of which can be considered to be toxic. The term CBRN, an acronym for “chemical, biological, radiological, and nuclear,” is used here to describe the particular combination of the hazard environment and the intent of use. The book is focused primarily on protection against deliberate use of CBRN agents in a terrorism or combat environment. The same PPE may be useful in a workplace setting in which CBRN agents are handled; however, as we discuss later, this results in some potentially important distinctions in the concept of use of the equipment.

CBRN PPE almost always has protective or operational requirements in addition to its CBRN protective functions. In most cases, however, the CBRN protection is deemed a primary requirement, with the other requirements superimposed once CBRN protection is provided. CBRN protective equipment may be designed to be worn by:

• Those responding to the use of CBRN agents (e.g., first or later responders)
• Those who are expected to perform their normal functions despite the fact that CBRN agents have been used (e.g., the military)
• Those who are being provided with emergency protection for escape purposes (e.g., civilians located in the vicinity)

In addition, CBRN protective equipment may be worn by those who are performing activities such as remediation, demilitarization, or laboratory investigation, where the environment is more controlled but the possibility of exposure to CBRN agents still exists. Protection against toxic materials has often been treated, conceptually, as an “all or nothing” idea—a person is either protected totally or is not protected at all. As we shall see, this approach is both overly simplistic and counterproductive. The degree of protection required is dependent on many factors, and protection need not be “total” to be effective; however, the protection requirements and expected performance must be well understood, and limitations and use of the equipment must be well defined.

A number of issues need to be considered to understand protection requirements. The first is the nature of the hazard for which protection must be provided.

1.2 WHAT ARE CBRN AGENTS?

CBRN agents consist of any chemical, biological, or radiological/nuclear substance that can be deliberately employed to cause harm to unprotected persons [1,2]. Chemicals may cause damage as a result of specific chemical reactions that happen when the body is exposed to them, disrupting bodily functions. Biological agents are living microorganisms that cause disease. Radiological agents (which may either result from a nuclear explosion or themselves be used) will damage living systems as a result of high-energy radiation interactions. CBRN agents may range from military agents, which have been designed or chosen to be particularly effective when used in a deliberate attack, to toxic industrial chemicals, which may be available more readily or in larger quantity.

There are a number of additional distinctions between C, B, and R/N agents: in terms of how they act on the body, their relative toxicity (Figure 10.1), and how they may be delivered, which is discussed in Chapter 2; nevertheless, it is apparent that they can all be described in general terms as materials that may be hazardous when the body is exposed to them, and there are a number of generic ways in which these hazards can be described, regardless of the class of agent. The most important aspect of these materials in the context of CBRN protection is the idea of deliberate use. Deliberate use implies the features outlined in Table 10.1 compared with those of an accidental release.

FIGURE 10.1 Approximate relative toxicity (related to mass of agent required to cause effect) of a variety of agents by various routes of entry.

Table 10.1 Differences Between an Accidental or Workplace Exposure to, and Deliberate Use of, a Toxic Material

Ultimately, the worst-case deliberate event is as bad as any accidental event that can be conceived. This does not mean that PPE designed for a deliberate event will then necessarily provide appropriate protection for an accidental event; many factors must be considered, and potentially traded off, to permit the optimum response to the spectrum of events that could occur.

1.3 CONTEXT OF USE AS IT RELATES TO DESIGN, SELECTION, AND PERFORMANCE

To design, select, and use the most appropriate PPE for a job, the context of use must be understood. For each potential toxic substance, user, or exposure scenario, the following questions are important:

• What might the toxic substance be?
  • How toxic is it?
  • Where and how does it enter the body?
• Who may be exposed to the substance?
  • What level of effects resulting from exposure is acceptable for this population?
  • What operations and activities will be performed by them during exposure?
• What might the conditions of exposure be?
  • How long?
  • How often?
  • How large is the potential exposure dose?
  • What is the range of possible environmental conditions?

The three main questions above can be answered once the context of use of the protective equipment is analyzed and understood. The answers to all of these questions together determine the level of protection that is required. Additional questions may affect other important design and selection considerations.

• What other external hazards may exist?
  • Does the wearer, or the equipment, need to be protected against these hazards?
• Under what conditions might the equipment be stored or worn both before and during use?
  • What type of shelf life may be desirable?
  • What type of use life may be desirable?
  • What are its requirements for durability and survivability?
• What other activities must the wearer be able to perform?
• What other requirements may affect use of the equipment?
  • How does it need to integrate with other equipment?

The answers to the questions above may be very different depending on the user; the military, for example, may require that PPE be wearable for several weeks while continuing to protect after multiple exposures or launderings, whereas a first responder may expect to wear equipment once for only an hour or two in a hazardous environment. The military or police may potentially accept a higher level of risk to the wearer to reduce risk from equally potentially lethal hazards compared with an emergency medical worker who may be exposed to more limited or different hazards. These very different contexts of use can have a significant impact on the appropriate design of equipment.

Examples of standards that follow the process as we outline it here are two CBRN PPE standards: Canadian standards for civilian responders [3] and the NATO clothing standards for military users [4], and much of the information given here is consistent with those documents.

1.4 ACQUIRING EQUIPMENT

To actually begin the acquisition of PPE, there is a significant onus on the user to perform a number of activities. Outlined in this section in brief, and throughout the book in more detail, is an approach to acquiring CBRN PPE that significantly increases the likelihood that the equipment that is procured will suit the user's requirements.

1.4.1 How Not to Do It

This is a true story—repeated hundreds, if not thousands, of times over the past decade.

You work for an organization that has been in existence for some time, or even a newly minted user group, and you've just been told that your group must be able to support CBRN operations. You've been given a budget and a requirement to develop an operational capability as quickly as possible to satisfy your superiors, governments, and t...

Table of contents

• Cover
• Title Page
• Copyright
• Acknowledgments
• Chapter 1: Introduction to CBRN Protection
• Chapter 2: Hazardous Substances
• Chapter 3: Setting High-Level Requirements
• Chapter 4: Designing for Appropriate Protection and Performance
• Chapter 5: Protective Equipment: Concepts, Components, and Systems
• Chapter 6: Performance Evaluation and Standard Test Methods
• Chapter 7: Selection and Use of PPE
• References
• Index