Suspension trauma
Also called Harness suspension trauma, Orthostatic intolerance while suspended
Suspension trauma is the recognised hazard of a person being left hanging motionless in a harness after a fall has been arrested. It is the reason a fall arrest system is only half a system without a rescue plan: arresting the fall is the part the equipment does, and everything after that depends on how quickly somebody can reach the casualty and bring them down.
In practice
The honest version of this term is shorter than most pages selling something make it. A person hanging in a harness who cannot help themselves needs to be brought down quickly, and how quickly is not a figure to be looked up — it is a commitment your rescue plan makes and can demonstrate. Anyone offering a number for how long suspension is survivable is quoting a contested study or repeating something they read, and the two are worth treating identically. What is not contested is the shape of the problem: the casualty cannot move, the people nearest are often the ones who also have to keep working, and every minute of the response was decided long before the fall — by where the anchor went, by whether anything can get underneath, and by whether the rescue kit is on the floor below or still in a van. Plan the time. Do not tolerate it.
Where this comes from: UK work at height practice, and a deliberate limit. This page states why rescue from suspension is planned and timed. It gives no first aid, describes no physiology, and states no period for which a suspended person may safely be left — that figure is contested in the published literature, being wrong about it in either direction is dangerous, and no commercial page has any business asserting one. Ask an occupational health professional, not a supplier.
Where it matters on site
The same logic reaches netting without the harness. Someone caught in a net who cannot climb out is dependent on a method chosen in advance, and that method has to work at the real floor-to-floor height with the real obstructions in place, not on the version drawn at tender stage. It is worth being blunt about the difference between the two cases: a person suspended in a harness and a person lying in a net are different rescues needing different equipment, and a plan that covers one does not cover the other. Our own product addresses the net case — it was built after a fatality on a site where colleagues were doing everything right, which is the reason this page will not tell you how long you have.