Choosing the Best Escape Respirator for Your Emergency Response Plan

Hãy nhớ rằng, nhiều thảm họa công nghiệp trong quá khứ là kết quả của cảm giác an toàn sai lầm trong các SOP và két an toàn.

Keep in mind, many industrial disasters of the past have resulted from a false sense of security in SOPs and fail-safes.With any process involving hazardous materials, the ultimate goal is to prevent the release of the substance. However, there also should be a means of protecting workers in the event those controls fail or do not function as designed.
The Three-Legged Stool of Hazardous Material Risk Management
According to OSHA's 29 CFR 1910.110 Appendix C (Compliance Guidelines and Recommendations for Process Safety Management), personnel working with any hazardous process should be protected by at least three lines of defense. These lines of defense must operate in unison to provide an effective hazard control plan. You can think of this approach as the "three-legged stool" of hazardous material risk management, which includes the following three lines of defense or legs:
1. Containment: Standard operating procedures (SOPs) and engineering controls are designed to control all hazardous substances. (For example, keep it contained by using approved devices, piping, values, and process design specifications.)
2. Back-up controls: Control or mitigate exposure to workers and the environment in the event the first line of defense is compromised or fails. (For example, control the substance with relief valves, scrubbers, flares, surge/overflow tanks, fire suppression systems, etc.)
3. Emergency response plan: Protect plant and human assets by providing a means of escape/ response in the event legs 1 and 2 fail. Depending on the risk and hazard, this can range from a simple evacuation plan to a complex emergency response scenario including escape respirators, escape refuge chambers/safe zones, hazmat (or fire) control teams, and search-and-rescue procedures.
If these three elements are not operating together, then the likelihood of a disaster or fatality is exponentially higher. Most often, it is the third leg of this stool that is neglected. Escape respirators are sometimes seen as a necessary evil or redundant compliance requirement because an escape respirator will not prevent a disaster from occurring. In other words, an organization with good SOPs and fail-safe plans may feel it can prevent an incident from occurring. In other words, an organization with good SOPs and fail-safe plans may feel it can prevent an incident from occurring, so it does not need to invest in good escape respirators. However, many industrial disasters of the past have resulted from a false sense of security in SOPs and fail-safes. In many of those cases, loss of life could have been prevented by a strong emergency response program.

Acquiring the correct type and quantity of escape respirators is just as much a part of risk management as trying to prevent the release of the hazard in the first place.
This article focuses on the third leg of hazardous material risk management. Specifically, it covers the types of escape respirators that are available, identifies the best applications for each, and evaluates the pros and cons of each technology.
Performing a Process Hazard Analysis
If you're interested in strengthening the third leg of your organization's hazardous material risk management plan, the first step is to perform a process hazard analysis (PHA) to make sure you understand the risks in the workplace and the consequences that will result if your SOPs and fail-safes malfunction.
While there are many industrial hazards and risks, this article focuses on the three common types of industrial hazards that present a high risk to the human respiratory system:
Risk of fire. Fire is a risk in virtually every industrial setting, but the highest risk occurs when personnel are exposed to accumulating smoke. Most fire-related deaths are due to carbon monoxide poisoning, not burns. Any industry using high heat processes or flammable materials should be well prepared for fire hazards.
Release of toxins. This includes the release of a chemical, vapor, or gas from a process or vessel at high concentration. The toxins are typically known because they are identified by the PHA. For example, hydrogen sulfide could be released from an oil drilling rig or a toxin such as chlorine, phosgene, or ammonia can be released from a chemical process.
Environmental volatility. The third most-common risk to the human respiratory system is an atmosphere that is likely to change or become dangerous, such as confined spaces where conditions can change quickly. Here, toxins can accumulate or an oxygen deficiency can occur, causing asphyxiation.

Once the type of risk has been identified, the next step is to understand the degree of severity that would accompany an emergency situation in a given environment. This information is important when it comes to selecting the appropriate escape respirator. For the purpose of this article, the degree of severity is classified according to the definitions of High, Specific, and Low established by NIOSH in its document "Concept for CBRN Air-Purifying Escape Respirator Standard":
High: any scenario involving a release or existence of unknown toxic substances in high or unknown concentrations, as well as oxygen-deficient atmospheres (less than 19.5 percent volume)
Specific: any scenario involving the release or existence of known toxic substances in high concentrations (environments with "Specific" hazards always have sufficient oxygen)
Low: any scenario involving the release or existence of known toxic substances in low concentrations (environments with "Low" hazards always have sufficient oxygen)
Understanding the type and degree of a risk will serve as a good foundation for selecting the respirators that are qualified for your applications. However, just because a respirator will work doesn't mean it's the best choice. You also must consider the pros and cons of all qualified respirators to ensure you are maximizing safety and reducing cost of ownership. For example, even though a compressed air type of respirator may work for an application, there may be many good reasons to use a smaller, more portable, and less expensive escape device. Ultimately, you can save money and make a workplace safer by evaluating all of the available options.
Identifying the Best Escape Respirator for the Application
Once you have identified the risk, the next step is to identify the correct escape respirator for the application. This is essentially a two-step process: First, narrow down the options to the escape respirators that will provide effective protection. Second, consider the pros and cons of different respirator types to identify the best option. There are a number of widely accepted escape respirator technologies on the market, including:

Air-purifying respirators (APRs), including escape mouth-bits, full face gas masks, APR escape hoods
Self-contained emergency escape breathing apparatus (EEBA)
Pressure demand supplied air respirator (SAR) with escape cylinder
Self-contained breathing apparatus (SCBA)
Many of these respirators can be used in multiple types of applications.
Pros and Cons of Respirator Types
Each type of respirator has specific pros and cons. Understanding the benefits and drawbacks will help you make informed decisions that will increase safety and reduce your cost of ownership.
Escape Mouth-Bit
Pros:
Very small, lightweight, and portable
Inexpensive
Provides effective protection against lower concentrations of specific toxins (such as organic vapors or acid gases)
Easy to don
Cons:
Does not protect the eyes or head
Prohibits verbal communication
Cannot be used in oxygen-deficient atmospheres
Does not protect against multiple hazards simultaneously
Single use only
Shorter shelf life
Designated as an "Escape Only" respirator
Full Face Gas Mask
Pros:
Provides protection against higher concentrations of specific hazards
Provides tight-fitting elastomeric sealing surface
Enables verbal communication
Provides eye protection
Reusable -- interchangeable canisters
Long service life
Can be used for more applications than "Escape Only"
Cons:
Difficult to carry, store, and access in emergency
Difficult to don quickly
Cannot be used in oxygen-deficient atmospheres
APR Chemical/Smoke Escape Hood
Pros:
Provides protection against higher concentrations of specific hazards
Can protect against multiple hazards simultaneously
Cost effective alternative to EEBAs in certain applications
Protects eyes, face, and head
Is highly visible and flame retardant
Enables verbal communication
Easy to don
Portable (belt-worn), lightweight, low maintenance, and easy to store
Long shelf life
Cons:
Cannot be used in oxygen-deficient atmospheres
Single use only
Designated as an "Escape Only" respirator
SAR with Escape Cylinder
Pros:
Allows workers to seamlessly switch from supplied air to escape mode without exposure to hazard
Utilizes positive pressure full-face mask to provide maximum protection from IDLH conditions for 5-15 minutes
Can be utilized for more applications than "Escape Only"
Acceptable for use in oxygen-deficient atmospheres
Reusable
Cons:
Practical only for applications that require the constant use of SARs
Apparatus and air supply systems are higher priced and more complex
Requires consistent maintenance
EEBA
Pros:
Acceptable for use in oxygen-deficient atmospheres
Continuous flow from the air source provides 5-15 minutes of protection against any harmful gas, vapor, or chemical
Enables verbal communication
Easy to don and operate
Reusable
Cons:
Heavy and difficult to carry (cannot be belt-worn)
Designated as an “Escape Only” respirator
Requires periodic maintenance
Higher-priced escape device
Hood material is not highly visible or flame retardant
SCBA
Pros:
Maximum protection from all hazards for longer durations
Enables verbal communication
Can be utilized for more applications than "Escape Only" (including operations and search-and-rescue)
Reusable
Cons:
Heavy and impractical to carry (unless being used as an SAR)
Difficult to don quickly in a emergency situation (especially when not often practiced or used)
Requires periodic maintenance
Very high-priced escape device
Long shelf life
Training: Final Step to Creating an Effective Emergency Preparedness Program
Once you have chosen the best respirator for your application, there is one final step that is necessary to turn a good emergency preparedness program into a great one: training! You can have the best respirator in the world, but it is useless if the users do not know how to put it on. While most people hope they will never have to use an escape respirator, anyone who could potentially need to use one should be trained -– regularly and frequently -- on how to don the device quickly and effectively.
It is important to realize that panic easily can take over in an emergency. Donning and using the equipment need to be automatic because even a few seconds of exposure to some toxins can be catastrophic.
It is also essential to train personnel about the reasons why the escape respirator is necessary in the first place. A healthy respect for the consequences of exposure to a hazard will increase the likelihood that workers actually will use an escape respirator in an emergency.

Source: OH&S