A vertical sag curve joins a -3.0% downgrade with a 2.0% upgrade. The Chainage at Vertical Intersection Point (VIP) is 1100 m, and the reduced level of the VIP is 122 m above mean sea level. The centreline of the road must clear a stormwater pipe located crossing the road at chainage 1140 m. The required clearance between the top of the pipe and road surfaces is 1.2 m. The reduced level of the top of the pipe is 123.5 m above mean sea level. Determine the minimum length of the vertical curve that can be used. The length of the sag curve =