Use the procedure that follows to determine whether the requirements that are specified in 32- SAMSS-011 and API-661 have been met. The paragraph references that are indicated are in API-661 unless otherwise noted. For each requirement, circle “Yes” or “No” depending on whether the requirement has been met or not.
Overall Tube Bundle Design Requirements
1. Par. 5.1.1.1. Is the tube bundle designed to be rigid for handling as a complete assembly? Yes/No.
2. Par. 5.1.1.3. Has provision for at least 6 mm (1/4 in.) of lateral movement in both directions and 13 mm ( 1/2 in.) of lateral movement in one direction been provided? Yes/No.
3. Par. 5.1.1.4. Has provision been made in the design to accommodate the thermal expansion of the tubes? Yes/No.
4. 32-SAMSS-011, Par. 5.1.1.4. Do the bundle and the structural mounting have Teflon slide plates at the moving end? Yes/No.
5. Par. 5.1.1.5. Are the tube supports no more than 1.83 m (6 ft.) from center to center? Yes/No.
6. Par. 5.1.1.6. Are structural hold-downs provided at each tube support? Yes/No.
7. Par. 5.1.1.7. Are tubes of single-pass condensers and all heating coils sloped downward at 10 mm per meter (1/8 in. per ft.) toward the outlet header? Yes/No. 8. Par. 5.1.1.8. Are air seals provided throughout the bundle to minimize air leakage?
Yes/No. Any air gap that is more than 10 mm (3/8 in.) wide is excessive.
9. Par. 5.1.1.9. Is 12 gage (2.8 mm [0.105 in.]) minimum thickness used for air seal construction? Yes/No.
10. Par. 5.1.1.10. Are bolts for removable air seals at least 10 mm (3/8 in.) nominal diameter? Yes/No.
11. 32-SAMSS-011, Par. 5.1.1.11. Do the tube ends extend beyond the tubesheet 3 mm ±1.5 mm (1/8 in. ± 1/16 in.)? Yes/No.
12. 32-SAMSS-011, Par. 5.1.1.12. Are tube spacers designed so that they do not rely on the outer periphery of the fins for bearing, and do the spacers prevent the fins from meshing? Yes/No.
Tube Wall Minimum Thickness
13. Par. 5.1.12.1. Does the diameter of the prime tube equal the recommended minimum of 25.4 mm (1 in.)? Yes/No.
14. Par. 5.1.12.3. Does the minimum tube wall thickness meet the requirements shown in Figure 24? Yes/No.
Tube Material Minimum Required
Thickness, mm (in.)
Carbon and Low-Alloy Steels (Through 9% Chrome) 2.74 (0.108) High-Alloys Steels (Austenitic and Ferritic) 1.65 (0.065)
Copper or Aluminum Alloy 2.11 (0.083)
Titanium 1.24 (0.049)
Minimum Required Tube Thicknesses
Figure 24
Selection of Tube Fins
15. 32-SAMSS-011, Par. 5.1.12.7. Do the type of tube fins meet the requirements specified in Figure 25? Yes/No.
Fin Type Use Limitations
Tension wound
Auxiliary coolers and lube oil coolers at temperatures less than 95°C (200°F)
Extruded Temperatures less than 260°C (500°F) Embedded Temperatures less than 400°C (750°F)
Other types Must be approved by the buyer. Consult CSD as required.
Limitations on Fin Types
Figure 25
Header Design Requirements
16. Par. 5.1.5.2. If the differential design temperature of any adjacent tube pass is over 111°C (200°F), is a split header design, U-tube design, or other means used to accommodate differential thermal expansion between the adjacent tube passes? Yes/No.
17. Par. 5.1.5.5. Are the minimum thicknesses of header box components in accordance with Figure 26 ? Yes/No.
Component Carbon or Low-Alloy Steel High-Alloy Steel or Other Materials
Tubesheet 20 mm (3/4 in.)* 16 mm (5/8 in. )*
Plug sheet 20 mm (3/4 in.) 16 mm (5/8 in.)
Top, bottom, and end
plates 12 mm (1/2 in.) 10 mm (3/8 in.)
Removable cover
plates 25 mm (1 in.) 25 mm (1 in.)
* 25.4 mm (1 in.) minimum thickness including corrosion allowance per Par. 5.1.5.5 of 32-SAMSS-011.
Minimum Required Thickness of Header Box Components
Figure 26
18. Par 5.1.5.6. Does the minimum pass partition plate thickness meet the requirements in Figure 27? Yes/No.
Pass Partition Plate
Material Minimum RequiredThickness, mm (in.)
Carbon and Low-Alloy Steels 12 (1/2) * Nonferrous High-Alloy Steel 6 (1/4)
* Includes up to 3 mm (1/8 in.) corrosion allowance on each side.
Pass Partition Plate Thickness
Exchanger Service Header Box Type
Process Cooler Plug Type Header
Lube Oil Cooler or Seal Oil Cooler Removable Cover or Cover Plate if less than 1 750 kPa (250 psig)
Header Box Type
Figure 28
Headers: Removable-Cover-Plate and Removable-Bonnet-Type
20. Par 5.1.6.5. Are jackscrews or a 5 mm (3/16 in.) clearance provided at the cover periphery to facilitate dismantling? Yes/No.
21. Par 5.1.6.8. Is the minimum diameter of stud bolts 20 mm (3/4 in.)? Yes/No. Is the minimum diameter of through bolts 16 mm (5/8 in.)? Yes/No.
22. Par 5.1.6.9. Does the bolt spacing exceed the maximum spacing requirements (refer to API-661 directly)? Yes/No.
23. Par 5.1.6.10. Is the bolt spacing less than the minimum spacing that is specified in Table 1 of API-661? Yes/No.
24. Par 5.1.6.11. For bolts that straddle the corners, does the diagonal distance meet the maximum bolt spacing criteria? Yes/No.
Headers: Plug-Type
25. Par 5.1.7.2. Does the diameter of the tube plug holes equal the nominal outside diameter of the tube plus 0.8 mm (1/32 in.) minimum? Yes/No.
26. Par 5.1.7.3. Is the gasket surface of the tubesheet plug hole spot faced? Yes/No. 27. Par 5.1.8.7. Are threaded plugs that are 40 mm (1-1/2 in.) and less in diameter Unified
Gasket Requirements
29. Par 5.1.9.1. Are gaskets for tube access plugs solid metal or double-metal-jacketed type and of the same material classification as the plug? Yes/No.
30. Par 5.1.9.2. Are cover plate gaskets for flat covers and bonnets double-jacketed, non- asbestos filled type? Yes/No. Per 32-SAMSS-011, if the pressure does not exceed 2 100 kPa (300 psig), a synthetic gasket with parting agent on both sides of the gasket may be used in water, lube oil, and seal oil services.
31. Par 5.1.9.3 and Par 5.1.9.4. Are cover plate gaskets a minimum width of 9 mm (3/8 in.), and are the gaskets of one piece construction? Yes/No.
Nozzles and Other Connections
32. 32-SAMSS-011, Par. 5.1.10.4. If nozzles are made from pipe, is only seamless pipe used? Yes/No.
If the connections are 50 mm (2 in.) or smaller, is the thickness Schedule 80 minimum? Yes/No.
33. 32-SAMSS-011, Par 5.1.10.15. For small diameter connections, are bosses used per Saudi Aramco Standard Drawings AE-036175 or AE-036367? Yes/No.
34. 32-SAMSS-011, Par. 5.1.10.18. Do nozzles protrude beyond the inside surface of the header? Yes/No. If “Yes,” they are in violation of this requirement.
35. 32-SAMSS-011, Par. 5.1.10.19. If the header is lined with a corrosion resistant material, are the nozzles also lined in the same manner? Yes/No.