Wood Group Engineering Services LLC-Abu DhabiRCA ReportDate: 30.11.2011 Customer:PDO Oman Description:8 -900#x 8-300# Make::Master Flo ValveSer. Nos: P5-928 Qty:1 off Model No: 58R9S-8R3YT72PM1 WGES Job No:AD8001919 Findings: The above valve was stripped and found with severe rust in the body cavity, bonnet , stem and packing chamber cavity is filled with sand and debris Due to Debris and rust formation on the stem and packing chamber sealing surfaces is uneven,thus damaging sealing lips of the packings. The choke seems to be handling very corrosive product. There is no mechanical damage on any parts, Root Cause of Failure .Rust formation on Stem and Packing chamber sealing surfaces. Stem OD sealing surfaces is attacked with corrosive product. and pitted. Wear out, damage on packing sealing lips , hence preventing to seal.

Suggestion and Recommendation: Sincethere is no mechanical damage on parts, and workmanship, this is not considered as warranty, the leakage is purely due to corrosive product passing through the valve and require upgrading of these two areas to withstand corrosive product , if we rectify this using same material , problem will occur again, hence our proposal to upgrade choke stem with Inconel 718 and packing chamber with corrosion resistant inlay. Upgrading of stem material from 17- 4 PH toInconel 718 and packing chamberand faceweld inlay with corrosion resistance from carbon steel to Inconel 625.

Prepared By F. X. Rebello