The only way you can stop foes from running away from Burn is either having Ice Patch from Ice Melee set(as a tanker) or teaming with a dominator with an AoE immob/hold as a Brute.
As it currently is Burn is useful only for the immobilization resistance it gives, to avoid a team mate being meleed and to scatter mobs if you are surrounded, it's no more a damage power..
Hand clap would be the worst choice anyway as it knocks foes back radially from you.
You may try with Footstomp but it's nothing like Ice Patch even if it has a 100% knockup chance..
deleting my brute... please wait
damn I hate fire since i4 was released 
im like yeah gather em all up... Mwhahaha burn £$!%! dont run away :/
I guess Midnight Grasp would stop one running away............. then there's a hold in the stone................ um sorry
"Well, they found my diary today.
They were appropriately appalled
at the discovery of the eight victims
They're now putting it all together.
Women wrapped in silk
with one leg missing
Eight legs, one body, silk,
spider, brilliant!"
For brutes seeing as Ice Malee isn't an option with Ice Patch to stop them running away from burn patches the only options really are Super Strenght with footstomp or Stone with Seismic Smash and Tremor.
Stone having two knockdown/dissorient powers to cycle is possibly the better option but I prefer Super Strenght. Footstomp 'em then the damage you can cause with Rage, Fury and Knockout Blow etc is just far more satisfying. 
[ QUOTE ]
deleting my brute... please wait
damn I hate fire since i4 was released
im like yeah gather em all up... Mwhahaha burn £$!%! dont run away :/
[/ QUOTE ]
But you're making a Brute now, not a Tanker.
I found Fire/Fire to be a very good combination - it's certainly the best PBAE damage combination of any brute. I can decimate an entire spawn with Fire Sword Circle & Blazing Aura boosted with Fiery Embrace + Build-Up + full Fury (& maybe Forge and Fulcrum Shift if you're lucky) - the team only has to focus on injured bosses and lieuts because the minions are all dead or dying.
Of course without Fire primary, and with Burn unaffected by buffs/Fury, I can see how you'd get dispirited at your AE damage (I didn't take Burn - it looked crap on paper and nobody had a good word to say about it). But don't write off the whole Fiery Armour set just because of Burn - it's a great set, despite having one duff power.
I keep hearing on the forums that /Fire is a weak armour set and it's complete rubbish - my Brute is not at all fragile by comparison with the other secondaries. Providing you take CJ/Acrobatics to fill in the status resist holes (and you need Acrobatics for /Dark too) it's a perfectly good set - just a bit behind /Dark on all-round resists (but way ahead of Invul & EA, and just ahead of pre-Granite /Stone) - /Fire costs less End than /Dark too, so you can afford to run Tough for better S/L resists than anything short of Invul (with Tough - though Invul is crap for non-S/L resists) or Stone (post-Granite).
I love Fire/Fire as you can probably tell, although I'm playing SS/Dark now until I7.
You could allways get teleport foe, from the power pool set, a handy little power anyway.
Just a quick question about hand clap... I want to know how often it disorients I want something that will stop the foes running away
I plan to do ??/Fire brute I have a fire / fire tanker on CoH but really sick of the mobs running away when I put burn down. I plan to do all of my missions so I will be soloing a lot.
I know that a dark prim set has a fear but I know with fear if you attack someone once they are feared they can react for x amount of time then they go back feard.