MohdYaseen2010
Mechanical
- Nov 26, 2007
- 101
Dears;
we are constructing new storage tank having the following data;
Design Code = API 650
Materials = A 283 C (Group I)
Design Temperature = 85C
Stressed Components include:
Shell = 12 mm, 10 mm, 8 mm
RF of Cleanout Door = 16 mm
RF of Flush-Type Shell Connections = 12mm (N9), 12mm (N10), 12mm (N11) & 12mm (N13)
Welded bottom plates to Shell =10mm
Appendix A didn't specified by the Purchaser
API 650 Clause 5.7.4 specify that Thermal Stress Relieve shall be applied either;
(1) Prior installation into the Tank to the Assembly.
Assembly = Clean-out Door + Attached Shell + bottom reinforcing plate (or annular plate) + flange-to-neck weld
(2) After installation into the Tank if the entire Tank is going to be Thermally Stress Relieved.
point (2) can't be applied, so point (1) (PWHT) applied on the factory.
Problem:
After dispatching the Cleanout Door to site, the Contractor did cutting/welding works on its reinforcement plat and neck (where little mismatch with the annular plate) without informing the Client.
The Contractor is suggesting to apply PWHT on the modified parts only (not to the assembly where is no furnace to occupy it).
What do you think? is it acceptable? if yes what is the reference? if not, are the available solutions?
Mohd Yaseen
we are constructing new storage tank having the following data;
Design Code = API 650
Materials = A 283 C (Group I)
Design Temperature = 85C
Stressed Components include:
Shell = 12 mm, 10 mm, 8 mm
RF of Cleanout Door = 16 mm
RF of Flush-Type Shell Connections = 12mm (N9), 12mm (N10), 12mm (N11) & 12mm (N13)
Welded bottom plates to Shell =10mm
Appendix A didn't specified by the Purchaser
API 650 Clause 5.7.4 specify that Thermal Stress Relieve shall be applied either;
(1) Prior installation into the Tank to the Assembly.
Assembly = Clean-out Door + Attached Shell + bottom reinforcing plate (or annular plate) + flange-to-neck weld
(2) After installation into the Tank if the entire Tank is going to be Thermally Stress Relieved.
point (2) can't be applied, so point (1) (PWHT) applied on the factory.
Problem:
After dispatching the Cleanout Door to site, the Contractor did cutting/welding works on its reinforcement plat and neck (where little mismatch with the annular plate) without informing the Client.
The Contractor is suggesting to apply PWHT on the modified parts only (not to the assembly where is no furnace to occupy it).
What do you think? is it acceptable? if yes what is the reference? if not, are the available solutions?
Mohd Yaseen
