Blowdown stacks may either be ignited (like a flare) or un-ignited (a ‘cold’ vent). The height of the blowdown stack must be tall enough to ensure the safe dispersal of vapour.
Blowdown stacks may be initiated (similar to a flare) or left un-initiated (a 'cold' vent). The stack's height should be adequate to ensure the safe release of vapour.