I have used O.C. Pepper Spray 25 + times in the past 14 years as a police officer. The words to look for in reguards to nowing how "Powerful" a Pepper spray is, is in 'Scoville Heat Units'. It should say something like "2 Million Scoville Heat units" on the back of the can. Also, there are options when considering what type Pepper spray to buy. Forget things like 5%, 10%, ect., it's all in 'Scoville Heat units'. If it does'nt say 'Scoville Heat units' forget it.
Next is the type spray volume that comes out of the can. What most call "Stream" or "Spray" is a straight stream that comes out a couple of feet. In my option, if you are trying to use your pepper spray durning a physical altercation, these may not be such a good idea to use. WHY? Well, it's like trying to be Annie Oakley durning a fight. You sure need alot of training to be able to fight with someone with one hand and aim your pepper spray with the other...I've seen alot of problems result from this. Next is what is called, "Cone", this means it comes out in a wide pattern and this type can usually be somewhat accurate due to not having to aim very much. This type can blow back at you in sever conditions. But, you can usually hit the suspect when it counts most...in the face/eyes. There are several other types out there. My option is get yourself some "Bodyguard LE-10" if you are in law enforcement; if not I'd recommend at least getting a brand that has the words "Scoville Heat Units" on back...
Now, that you've bought your spray, here's the hard part. Training with and understanding the effects of your Pepper spray. There are several brands of inert (fake pepper spray that is safe to train with) spray. I'd recommend getting some and training with it. It would be best to get the same type volume (Stream, Cone, foam, ect) as the real pepper spray you have. Then, the only way to truely understand your pepper spray is to have yourself sprayed. I know this will scare many away and get me at least a few responses about this being a crazy idea...but, please hang on. Now, spraying yourself is painful - yet relatively safe, if done with a partner. Don't try this by yourself...at least not the 1st time. Pepper spray is really good for one thing in a fight; blinding your opponent and causing him pain that may interfer with his ability to combat you in any effective manner. Don't count on miracles with pepper spray. If you don't get it in their eyes good, expect continued resistance at least for a few minutes. Now, if you plan to have yourself sprayed...let me give you some advice. Do it in as cool of a area as you can. Make sure its outside. Have plenty of towels, water and at least one bar of Ivory soap (It has no oils and it works great on cutting thru the pepper oil in the pepper spray). Now, once you've been sprayed remember to breath as best you can. You see that water can be your friend and it cools you down. But, the longer you stay on the water, the longer the burning will continue. Here's what you buddy needs to know. They are there to help you. To get you whatever you need; water, soap, a chair to sit in, ect.). The sooner you let your partner scrub your face with the soap, flush your eyes out good and get you away from the water the better off you are. Remember, it's not going to kill you and you are going to make it! I don't recomend spraying yourself while wearing contacts or if you do not have a safe invironment in which to train (I.E.- a good training partner).
I can say I was sprayed lightly 5-6 times durning altercations and I could continue fight easily. After I was really sprayed good durning a training class, I found that I could'nt open my eyes. It took me about 45 minutes before I could see where I was at. My skin did burn and I did have alot of snot running down my throat causing me minor difficulty breathing; sort of like running a mile hard. It also caused me to have a adreniline dump and I was zapped of my strength in a short period of time. Now, after I was "Trained" in the use of my OC Pepper spray I have been directly sprayed 3-4 times and indirectly sprayed about 6-7 times by fellow officers durning altercations; usually while I was already fighting with the suspect. Since my training I was able to easily overcome the effects of pepper spray due to my knowledge of what was happening to me and that knowldge allowed me to continue fighting. I do not believe that could have happened prior to me being sprayed directly durning training.
Durning my 14 years as a police officer I have seen many people sprayed with OC Pepper spray. Some drop like they've been shot. Most walk around in circles and beg for help. Some try to continue to fight, but quickly find themselves unable to do so. I have had a few who could withstand the pain for a few minutes and do things like run a few blocks or fight. But about 95% of everyone it was used against was under control in a matter of seconds. Also, something to remember... If you spray someone, you need to immediately fall back from them (About 10 or more feet) and wait a few seconds before trying to subdue your opponent. This will help with having it blow back into you. Also, remember you just sprayed them. If you get it on your hands, arms, whatever and rub it in your eyes...it will then be in your eyes too. It's very easy for this to occure.
I know some of this information is'nt useful to everyone, but I hope I was able to help at least one person.