Grab the ladder and climb to the top. Jump straight up to grab the top of the grating...

... then the valves above.

Move upwards and to the right, following the valves.

When you reach the end, jump up to grab the next set of valves above. Move upwards...

... then to the left to grab the metal bar. Traverse a bit to the left and jump to grab the ledge behind you.

Finally, jump to grab the ledge above and pull up.