Date: 31.07.2011
Valve:Gate / Size: 16” / Rating: 900 / Cat No: 193
Customer: Chiyoda Corporation
Order Ref: 30002301
Quantity :2
Complaint Description:
Stem bent
Background:
Customer has reported that stem got bent in 2 valves of 16” CL900 Gate supplied to PearlGTL Site. Order details are given below.
Sale order : 30002301
Item : 960 (MMN) & 520 (MPK)
Valve sl. no : 1090 62
Dispatched : 29.05.2008 & 13.03.2008
BDN : 3103699 3098382
Preliminary Analysis & Interim Containment Action(s):
VALVE DETAILS AND MATERIAL OF CONSTRUCTION:
Reference specifications / SIZE &
Rating / Description / MOC as per data sheet / AIL Supply
1) 772033.169.Q
(Data sheet)
2)MESC SPE 77/102 2005(Specification) / 16” #900 / Valve type / Flanged Wedge Type
Bolted Bonnet Gate Valve – Extended Bonnet / Flanged Wedge Type
Bolted Bonnet Gate Valve – Extended Bonnet
Body / ASTM A350 GR. LF2, CL 1
ASTM A352 GR. LCC / ASTM A352 GR. LCC
Stem / ASTM A182 GR. F 316
ASTM A182 GR. F316L / ASTM A182 GR. F316
Wedge / ASTM A182 GR. F316L
ASTM A182 GR. F316
ASTM A350 GR. LF2, CL 1
ASTM A352 GR. LCC / ASTM A352 GR. LCC
Seat rings / ASTM A276 TYPE 316
ASTM A276 TYPE 316L
ASTM A350 GR. LF2, CL 1 / ASTM A276 TYPE 316
The material of stem supplied is as per ASTM A182 GR. F316 inline with MESC specification.
The test certificate of stem reviewed and found compliance with specifications.
GEAR UNIT MODEL
Gear unit selection basis:
1. To meet valve torque and thrust
2. To meet manual effort of 350N as per project specification
SAMBO Gear Unit Model SBV6-1S with spur gear arrangement and hand wheel dia. 800mm
was selected based on valve torque requirement and to meet MESC SPE 77/102 2005 Clause
5.12.2 Which calls for maximum operating force shall not exceed 350N
Valve Data / Gear Unit Data
for the selected model
SBV6-1S / Gear Unit Data
for the next lowest model
SBV5-1S *
Valve torque at max rated pressure (2250 psi) / 4328 Nm / Gear Unit
Torque / 13000 Nm / 7800 Nm
Valve thrust at max rated pressure (2250 psi) / 627 KN / Gear Unit
Thrust / 2310 KN / 510 KN
* Lower size Gear Unit Model SBV5-1S is not meeting the valve thrust requirements hence it was not selected.
DESIGN VALIDATION
16” #900 Bolted Bonnet Gate valve LCC valve with SS316 stem valve was successfully tested and qualified as per SHELL TAT procedures during Nov 2007. The TAT valve had undergone testing at rated pressures and temperatures as well as cycling carried out. Finally strip test carried out and found satisfactory.
MOST PROBABLE CAUSE FOR THE STEM BEND
With selected gear unit for every 100 N extra effort, there will be an increase of 1068 Nm at stem
and in case of excessive force applied on the hand wheel intentionally or un intentionally can
lead excess torque development on valve stem and thereby lead to the mechanical damage to the
Stem.
Proposed by : Approved by:
Date :
RCA - ROOT CAUSE ANALYSIS SHEET
PROBLEM DESCRIPTION
/description area
/description data
WHAT / What object has the defect?What is the defect?
WHERE / Where specifically on the valve do you see the defect?
Where geographically is the defective object observed?
WHEN
/ First seen - By the customer?When did we make the part?
When seen since?
When is the defect seen in the valve- while testing @ site, operation (i.e. when the valve is used)?
When is the defect seen in the life of the object?(eg.when new or after few years of service)
HOW BIG
/ How many objects have the defect?How many/much defect(s) per object?
Similar Parts
/ Could this problem affect other similar parts on other lines / plants? List those areas or parts you consider at risk and communication with concerned.
ddd
SIGNIFICANT ROOT CAUSE-1 / SIGNIFICANT ROOT CAUSE-2
Corrective Action Plan / Date:
Prepared by : Verified & Approved by:
Effectiveness of Corrective Action / Date
Verified by: Approved by:
QAF 070 Rev1