A relief valve provides pressure relief when a fluid line exceeds a predetermined pressure. The valve includes a body which defines a cavity between inlet and outlet flowpaths. The valve includes a lever arm, which pivots around a pivot point as the valve changes between open and closed positions. A plunger assembly is disposed in the cavity and seals the cavity from the inlet and outlet flowpaths in the closed position. Fluid pressure from the inlet flow path causes the plunger assembly to contact the lever arm to urge the lever arm to rotate. The lever arm engages a spring at a further distance from the pivot point than the plunger assembly, the spring resisting pivoting of the lever arm and urging the valve to remain in the closed position unless a predetermined pressure is exceeded.