Shock sets in an adult above what percentage of burns, if untreated

the overall effect of changes in burns is to produce a net flow of water, solutes and proteins from the intravascular to the extravascular space. As the burn size approaches 10-15 per cent of total body surface area (TBSA), the loss of intravascular fluid can cause a level of circulatory shock. Above 15 percent of the surface area, the loss of fluid produces shockFuhermore, once the area increases to 25 per cent of TBSA, the inflammatory reaction causes a fluid loss in vessels remote from the burn injury.Bailey and love 26e pg: 387