sappy
Petroleum
- Apr 5, 2015
- 3
1. Please describe the difference between Bowing and Sagging of tubes in Fired heaters and do the same acceptance limits apply for Bowed as well as sagged tubes.
In both sagging and bowing, tubes deformation is due to creep phenomenon as per API RP 573. So the acceptance limit of both sagged or bowed tubes should be same.
As per API RP 573 Edition 2003, TABLE 3 Acceptance limits for tube Deterioration Mechanisms, the acceptance limit for Sagged Tubes is given as 5 * Tube diameter.
Whereas according to ABSA code AB-507 (Edition: 1999, Revision 02) PAGE NO. 8, Tube Bowing acceptance limit is given as 1* Tube diameter.
2. Acceptance limit of Bowing is required in case of vertical tubes of heaters with reference to applicable code and standard.
In both sagging and bowing, tubes deformation is due to creep phenomenon as per API RP 573. So the acceptance limit of both sagged or bowed tubes should be same.
As per API RP 573 Edition 2003, TABLE 3 Acceptance limits for tube Deterioration Mechanisms, the acceptance limit for Sagged Tubes is given as 5 * Tube diameter.
Whereas according to ABSA code AB-507 (Edition: 1999, Revision 02) PAGE NO. 8, Tube Bowing acceptance limit is given as 1* Tube diameter.
2. Acceptance limit of Bowing is required in case of vertical tubes of heaters with reference to applicable code and standard.