cylinder attached to manifold and vented cylinder goes through a vacuum n 2 fill cycle vacuumed cylinders filled with 5000 ppm h 2 s in n 2 to 100 psig and maintained for 9 days manifold vented through a scrubber and vacuumed step 4 h 2 s removal cylinder attached to manifold and vented out through scrubber cylinder goes through a vacuum n 2 fill cycle cylinder vacuumed for at least 2 hours step 5 standard filling filled with 89 5 ppb h 2 s in cp grade ethylene step 1 vacuum bake size 16 cylinder goes through a vacuum fill bake cycle for a minimum of 4 hours step 2 silane passivation cylinder attached to manifold and vacuumed cylinder filled with 1 silane in n 2 to 100 psig and maintained for 3 days manifold vented and vacuumed step 3 silane removal and h 2 s passivation cylinder attached to manifold and vented cylinder goes through a vacuum n 2 fill cycle vacuumed cylinders filled with 5000 ppm h 2 s in n 2 to 100 psig and maintained for 8 days manifold vented through a scrubber and vacuumed step 4 h 2 s removal cylinder attached to manifold and vented out through scrubber cylinder goes through a vacuum n 2 fill cycle cylinder vacuumed for at least 2 hours step.