You know, I’ve been hearing a lot about respirators and respiratory protection. Are these really useful for protecting me from radioactive and other materials that are in the air?
Yes they are. A respirator is one important method of protecting workers from airborne hazards, whether chemical, physical, biological, or radiological.
From what I know, they sound like simple solutions to me, and that everyone should have one.
Unfortunately, respirator selection and usage is not as simple as it sounds. Let me walk you through the process so you can see what I mean.
First of all, a respirator should only be used by persons who have been trained in their proper usage, and who understand the limitations of the equipment they are using. It is important that the person be able to recognize changing conditions in the work place, and his or her body’s response to wearing such a device. If ambient conditions change significantly, or if the concentrations of hazardous materials in the air increases by quite a bit, the protective properties of the respirator might be overwhelmed. More importantly, however, is the fact that respirators should be the “last line of defense” against the airborne hazard. Those responsible for health and safety in the work place should make every effort to contain the contaminant before it becomes airborne or provide ventilation systems like fans and exhaust ducts to remove it from the breathing zone of the employee, before respirator usage is even considered.
Well, that makes sense. But what if the work area requires the use of a respirator? What happens then?
First you need to know the physical form of the airborne hazardous material so that you can select the proper equipment.
You mean there is more than one type?
Yes indeed. There are two functional types of respirators to choose from, air purifying and supplied air respirators. For airborne solids, for example, an air purifying respirator is very capable and can provide quite a bit of protection. For vapors and gases, the air purifying respirator has some significant limitations, thus it is used sparingly. Some gases can travel straight through a respirator cartridge and be inhaled by the user almost immediately. Other gases and vapors are absorbed or adsorbed easily as long as the cartridge has available capacity. So you can see you need to know what form the material is in, how much is there, and what type of work is going to be performed.
I thought a respirator was a respirator. How much of a difference can there be between an air supplied respirator and an air purifying respirator?
There are big differences! Both respirators are designed to protect your lungs from airborne hazardous materials, but they provide that protection in different ways. Let’s start first with their names. Can you pick up on the means of protection from their names?
Well, I would guess that an air supplied respirator supplies air, right?
You’re correct. The best examples are fire fighters. They use air supplied respirators because they are routinely exposed to hazardous concentrations of toxic gases, vapors and smoke in areas where there are no available engineering controls to reduce the hazard. Those tanks that you see them wearing contain a supply of air that is stored under high pressure. But when the bottle is empty, there is no more air available.
How long does a bottle last?
Well, it depends upon whether the delivery system of the respirator is a “demand” or “pressure demand” mode . Generally speaking, however, a single bottle should hold a 30-minute supply of air for a person who is in good physical condition and who conserves their air by breathing at a steady pace.
What if that person isn’t in such good condition?
That same 30 minute supply may only last 10 minutes for a person who “gulps” their air quickly or is working very hard . . . like trying to carry an injured victim out of a burning building. Unless the air supply is replaced, there will be no more good air available for the user.
Well then, how do they replace the air in the bottles?
Generally speaking, the bottle is exchanged outside of the burning building. Once the exchange is made for a full bottle, the fireman goes back in.
It seems to me, then, that any work using air supplied respirators can only last 30 minutes or less, and that users spend more time traveling in and out of the work area than they do getting the work done.
Well, for some people, that might be the case. However, in certain conditions, these same respirators can be connected to an air hose or pressurized line to a larger air supply.
That sounds easy enough.
It is, but the hoses must be protected from the hazards inside the building. They can’t be pinched or punctured, and the user has to be careful they aren’t melted in a fire. Because of these potential problems, sometimes the only thing that will work is a self contained breathing apparatus with that 30-minute limit.
You mentioned that the other basic type of respirator is an air purifying respirator. How does it purify the air?
An air purifying respirator is much simpler than an air supplied respirator. In this case, the hazardous components in the work place are filtered or adsorbed before the air gets to your lungs. And while the air supplied respirator is easily recognizable by the bottles attached to the wearer’s back, air purifying respirators are recognized by the cartridges that are firmly attached to the base of the respirator face piece.
A face piece . . . isn’t that the respirator?
Well, it’s part of the entire system. A face piece is used to create a seal around your nose and mouth, if it is a “half-face respirator”. If a seal around the entire face is necessary, the device is called a “full-face respirator”. Creative names, huh?
Sorry. Let’s press on. In both cases, the face piece prevents the contaminated outside air from leaking around its seal, and getting in where it can be breathed by the user. You can see that anything interfering with the seal prevents the respirator from doing its job correctly.
What do you mean?
Well, here’s a good example. If you wear glasses, the bows holding the lens on your face will create a gap in the seal. So no glasses are permitted when respirators are used.
But what about those of us that need glasses to see clearly?
There’s a solution to that. For these folks, a set of prescription glasses are attached to the face piece. No bows necessary to hang on their ears.
Okay. But what about my beard. How does the face piece seal around my beard?
Sorry, the beard has to go too. No hair or other things on our faces, such as side burns and long hair, that might interfere with the seal. In fact, some people with facial scars or other facial irregularities cannot wear a respirator at all just because they can’t maintain a good fit.
Gee. I had no idea that fitting the face piece was so important.
It is so important that you must actually test for a good seal and measure the ability of the respirator to protect you and your face from the conditions that are outside the mask. Without this type of testing, you just can’t be sure the respirator is doing you any good.
Air purifying respirators sound much simpler to use than air supplied respirators. Are there any other choices to make when selecting an air purifying respirator?
Of course. There are many different types of air purifying respirators. In addition to the half-face and full-face respirators I mentioned a bit ago, there are also mouth bit emergency respirators and powered air purifying respirators. Each of these are best suited under some well-specified conditions, with the biggest difference being the amount of protection provided.
Wow. So once I select the proper face piece, am I done?
No. It doesn’t stop there. You also have to match the respirator face piece with a disposable cartridge that is “approved” for the airborne chemical to which you are about to be exposed. In addition, the face piece has a capacity rating, as does the cartridge.
Gosh. How do I know if I have made the right selection?
Well, it is not as arbitrary as you might think. Respirators and cartridges are tested in the United States by the National Institute for Occupational Safety and Health (NIOSH). Respirators that pass the NIOSH test criteria are “approved” for certain uses and durations. The listing can be found in Title 42, Code of Federal Regulations, Part 84, “Approval of Respiratory Protective Devices”.
What about OSHA? Doesn’t it have any requirements for respiratory protection?
Yes. That agency’s rules are found in Title 29, Code of Federal Regulations, Part 1910.134, “Respiratory Protection”. This law, called the “Respirator Standard”, requires that each employer establish written procedures for the correct use of respirators, evaluate the workplace for airborne hazards, provide medical evaluations for the employees that wear respirators, select the correct respirator system for the hazard that is going to be encountered, provide fit testing to measure the capacity of the face piece for each individual, provide for cleaning and inspection of all equipment, and ensuring respirators and ancillary equipment are stored properly. In addition, the standard requires that people be trained in the limitations of the respirators they are authorized to use, and in how to recognize that a problem might exist.
Whew. I thought you could just put one on your face and you were good to go. Obviously not.
You are absolutely correct. Inappropriate selection and use of respiratory protection equipment, at best, gives you a false sense of security. At worst, it can be downright dangerous.
Lately I have been hearing quite a bit about biological agents, like anthrax. When I see people testing and decontaminating areas on the television, I always see them wearing respirators. Why is that?
A properly-fitting air purifying respirator equipped with a high efficiency particulate air filter is a good tool for protection against a particulate, like the anthrax spore. But remember, the respirator will only protect your lungs. What you may not see on the television are the procedures people follow to minimize the spread of contamination on clothing and work surfaces, the removal and decontamination procedures for the equipment, the skin protection methods, and a host of others. In these cases, a respirator by itself is not a complete solution.
What if I wanted to learn more about respiratory protection and respirator usage. Is there somewhere I could look on the internet?
Absolutely. OSHA (www.osha.gov) has a lot of technical information about the correct use and selection of respirators. And almost all of the equipment manufacturers provide information not only about their products but recommended criteria for selection and evaluation. You might start with MSA, Inc. (www.msanet.com) or Survivair (www.survivair.com), as just a couple of examples. However, I’m not giving you any recommendations here, as there are many manufacturers of approved respirators for many applications.
What about in an emergency? You know, there has been all this terrorist fear lately. Is my only protection to airborne hazards, whether radiological or biological, dependent upon having a stockpile of a variety of respirators and cartridges?
Actually, that would be a bit inefficient, and quite expensive. However, you already have some supplies in your house that can be very effective for short duration respiratory protection.
Really? Like what?
A wetted, cotton handkerchief placed around your nose and mouth provides some pretty good protection from airborne particulates. A damp bath towel is pretty effective as well. And don’t forget that water is a great tool for removing particulates from surfaces, including your body, and from keeping them out of the air.
You mean a shower?
Exactly. Even a shower can be helpful in reducing inhalation exposures.
But what about the fit aspect you talked about?
You’re learning fast. Yes, one of the biggest problems with household remedies is maintaining a good seal around your nose and mouth.
Yes. You might consider using bandanas, stocking type ski masks or even “female hosiery” to hold the towel or handkerchief over your nose and mouth.
What a good idea! Any last words for me on this topic?
I think there are two important things to keep in mind when it comes to respirators. The first is that respiratory protection alone does not assure complete protection from airborne radioactivity or other particulates. And the second is that even when respirators are used as one part of a comprehensive protection program, they must be selected properly, tested for a good fit, and cleaned, stored, and maintained appropriately. Ignoring either of these two can be detrimental . . . in more ways than one.
So if I want to use respiratory protection, I really should speak with a professional in this area rather than marching off on my own, right?
That would be a wise decision. A health physicist or an industrial hygienist would be an excellent place to start. And don’t forget to “Ask a CHP” if you still have questions.