[Jet Pack Pyro]

I actually devised a way to do up to a 7-pipe pip jump without dying. First you lay the pipes in 1 spot (duh) near a ledge or ramp. Then you simply jump off the ledge and det about half a second AFTER you jump. The effect is similar to a conc nade. You want to catch the very edge of the explosion. The damage isn't fatal (but kinda almost) and boosts you ridiculously far. Usually a 7-pipe jump is overkill for most maps, so just use 4-5 pipes on most maps. Occasionally, you can make it to enemy battlements with only 3.
Here's a chart with the damage you take from the different jumps:
1 pipe: barely any damage, but hardly any distance.
2 pipes: Not noticable damage, decent jump, but not yard-crossing.
3 pipes: Most people say this will kill you. They're wrong. With right spacing, this is the jump you will use most. Enough health and armor to get the job done with a nice boost.
4 pipes: This is where the pipes start taking a toll on your reserves, but will easily get you through almost every yard in fortress forever.
5 pipes: This is quite taxing, leavin you with 35-50% of your health and armor left, but this jump is an awesome showoff move and WILL get you through every CTF yard in the game.
6 pipes: Yikes, the damage from this one is fatal if you don't space right. Use this on attack and defend maps to get some serious distance on that flag.
7 pipes: The most pipes you can use without dying, and if you don't land on something higher up or near your ground level, the fall damage will render you useless... or dead.
8 pipes: The mother of all pipe jumps. If you can pull this one off without dying from the detonation, you will find yourself with roughly 11hp and no armor, probably kill you form the fall. However, I HAVE lived through this, and you can, too if you land right.