supply and delivery of compressed purified hydrogen gas along with maintenance of hydrogen gas cylinders under operation department, stps. , compressed hydrogen gas gr-i as is -1090 compressed hydrogen gas,conforming to is: 1090-2002 with latest revision,if any , having purity : 99.98 % minm.by volume , moisture content 4 mg/m3 maxm., oxygen : 4ppm by volume maxm. & rest of the parameters as per said is. , replacement of def v/v, safety guard , replacement of def/broken v/v spindle , replacement of defective gland nuts , replacement of def/bent/damaged valves , purging of cylinders , cleaning of cylinders with oil in v/v , testing charges , painting charges , replacement of ptfe washer , replacement of brass washer