While researching for my post on Disaster kits part one and two I noticed there seems to be general confusion on on the topic of PPE and what kind you need for different purposes. What really hit the nail on the head and promted me to write this post on PPE was when i read a guide on redcross.org that basically equated a surgical mask and an N95 mask. These two types of masks are not intended for the same purpose at all, but more on that later.
To simplify things i usually divide the threats into 3 main groups:
- Infectious agents
- Radiation (or rather radioactive particles)
- Chemicals and gasses
Some of the groups require the same basic PPE. The easiest to provide protection against are by far particle borne threats such as infectious agents, toxic dust and radioactive particles.
When trying to protect against infectious agents knowledge of the specific pathogen is useful, however in most cases fairly cheap single use PPE and some procedures for putting it on and taking it off, will go a long way to protect the wearer from infection. If you want the gear with the best protection available you can easily spend thousands of dollars on positive pressure suits and a self contained air supply, and even then, all it might take to still be infected is a small tear in the suit. The downside of such suits, apart from the pricetag, is limited mobility making a tear fairly likely to occur. Instead i recommend getting the following:
- plastic apron (outer layer)
- category 3 and 4 chemical suit (outer layer, taped seams and with double liquid tight closing mechanism)
- hood that, when combined with a half mask and goggles or a full mask, covers any exposed skin of the face
- half mask and face shield for non airborne diseases and full mask for airborne diseases (there is a theoretical infection route through the eyes when dealing with an airborne disease) FFP3 or N95 filtering masks are a minimum protection level. A reusable mask fitted with a P3 filter will eliminate 99.95% of all particles.
- absorbent inner layer (surgical clothing or similar)
- nitrile gloves (inner layer)
- long sleeve chemical gloves (outer layer, must provide some mechanical strength as well as act as a barrier)
- liquid tight footwear (rubber boots)
- chemical tape for sealing up the openings where gloves or boots meet the suit
- large garden spray bottle and diluted bleach (used before taking off the PPE and possibly as a decontamination shower after taking off the suit)
The procedure for putting on and taking off the gear is as important as the gear itself, I will cover this in a later post.
There are many types of radiation, some harmless and some harmfull to the human organism. It is however beyond the scope of this blogpost to delve into the specific types of radiation. For those intrested, wikipedia has a fairly easy to understand article on radiation
In movies you often see actors wearing radiation suits to protect against ionizing radiation. The truth is, that the suits are not designed to protect against radiation itself, as this would require a lead lined suit so heavy that even the Hulk would have a hard time walking around in it. The intended purpose of most radiation suits is to protect against ingesting, inhaling or otherwise bringing back radioactive particles from a contaminated area.
Why are a few specks of radioactive dust so problematic you ask? well radiation follows the inverse-square law meaning if you half the distance to a radiation source, you quadrouple the radiation dose (simply put, the closer the source of the radiation is to your body the more damage is done). Furthermore radioactive materials can have a very long half-life and thus emit radiation for a very long time increasing the damage done over time.
When trying to protect yourself from radioactive particles the same equipment used to protect against infectious agents can be used (see list above). The only difference is that dousing yourself in bleach is not necessary, instead a thorough decontamination shower before and after taking off the suit is highly recommended.
Chemicals and gasses:
This is the point when choosing the right PPE becomes either complicated, expensive or both. The problem when dealing with chemicals or gasses is that is that you have to know what chemical or gas you want to protect yourself from and the specific concentration of the chemical or gas in the surrounding environment. As an example a standard run of the mill natural rubber glove will offer excellent protection from acid, but very poor protection from organic solvents (ethanol / alcohol will penetrate in a matter of minutes).
I other words this is a preppers nightmare. If worried about an unknown chemical or gaseous threat the only safe bet is basically an airtight heavy duty chemical suit with its own air supply and those are quite expensive. Even with the best gear expect a limited time before the chemical might breach the suit. If you know the specific threat (gas or chemical) you can probably get by with much less as filters and chemical suits are available for a wide range of applications.
A note on filtering masks (respirators):
When dealing with particle contaminants (infectious agents and radioactive or toxic particles) filtering masks are often used. I have seen a lot of suggestions for using a surgical mask for this purpose probably because they are cheap. However surgical masks are intended to protect patients from saliva droplets from the wearer and as such the mask offers little or no protection for the wearer. FFP3 masks and N95 masks are designed to make a tight seal to the wearer’s face and filter out particles from the incoming air. If you want to step up that protection a half or full mask fitted with a P3 filter will, if fitted to the wearer, do better than the single use masks. Keep in mind though that no filter is 100% effective.
A wide range of filters are available for half or full masks that enables you to filter out harmful things such as organic solvents, mercury or inorganic gasses etc. 3M has a good guide for selecting the appropriate filter for a specific purpose.
For any PPE to be effective you have to know the threat. Sure you can the top of the line gear if you have enough money, but in most cases you will be cumbered to an unnecessary degree by heavy gear. Even the very best PPE will only protect you for a limited amount of time and will not be effective against all threats (radiation for example). When dealing with infectious agents or threats where even small exposures pose a substantial health risk, the proper procedure for putting on and taking off the gear is as important as the gear itself.