36 in OD x 1350 PSI Vertical Stainless Vessel

The design basis is ASME Section VIII Division 1, 2023 Edition in U.S. Customary units, with internal pressure as the governing load case. The pressure summary records MAWP of 1350 psi at 130 F, design MDMT of -20 F, rated MDMT of -20 F at 1350 psi, and a user-imposed MAWP limit of 1350 psi in the Set Mode dialog.

The shell and heads are SA-240 304 austenitic stainless with full radiography on the longitudinal shell seam and spot radiography on the circumferential seams, giving RT2 required marking under UG-116. The settings summary records a UG-99(b) shop hydrotest at 1.3 times MAWP, 90 percent of yield as the maximum test stress, UG-22 weight and wind loadings where supports are present, and no seismic or external-pressure design for this chamber.

• Registration: CRN AA2082.2, dated July 31, 2024.
• Permit reference: APEGA Permit 15926.
• Main construction: 36 in OD shell with two 2:1 semi-ellipsoidal heads, skirt, optional base ring.
• Marking basis: UG-116(e) RT2 radiography designation.

The chamber MAWP is set equal to the design pressure, 1350 psi at 130 F, through the Maximize MDMT / No MAWP setting in the stainless material toughness dialog. The thickness summary shows design thickness of 1.1867 in for the 36 in OD shell and straight flanges under Appendix 1-1, and about 1.146 to 1.149 in for the 2:1 semi-ellipsoidal heads under Appendix 1-4(c), all without corrosion allowance.

The thickness tables also include combined-load checks with pressure, weight, and wind, which give required thickness around 0.650 in in tension and slightly less in compression, confirming that internal pressure still governs. The weight summary records new empty weight of 6674 lb, test and operating weight of 10,119 lb, and a geometric capacity of 411 US gal, excluding nozzles and attachments.

• Main shell: 36 in OD, 1.5 in nominal, 1.1867 in required at design condition.
• Heads: 36 in OD, 1.4375 in minimum after forming, about 1.15 in required at design condition.
• Support: SA-240 304 skirt, 0.375 in nominal with wind-governed stress and thickness checks.
• Chamber rating: 1350 psi MAWP hot corroded, rated MDMT -20 F per design limit.

The primary pressure boundary, including shell, heads, and skirt, is SA-240 304 stainless plate with no corrosion allowance. Nozzles are stainless as well, with SA-182 F304 long-weld-neck flanges for the 6 in, 4 in, and 3 in shell and head nozzles, and SA-312 TP304 pipe on the 2 in shell nozzle and the XXS option sets.

The nozzle schedule lists a 3 in long-weld-neck nozzle in the top head, one 6 in, one 4 in, and one 3 in long-weld-neck nozzle in the shell, and a 2 in Schedule 80 shell nozzle, all with Class 600 stainless flanges. The calculation file also carries several unregistered XXS nozzle options in 3 in, 4 in, and 6 in sizes, which are useful for design envelopes but do not appear on the registered CRN drawing.

• Main pressure parts: SA-240 304 shell, heads, skirt, and optional base ring.
• Nozzle forgings: SA-182 F304 Class 600 long-weld-neck flanges.
• Pipe nozzles: SA-312 TP304 Schedule 80S and XXS pipe where listed.
• Corrosion allowance: 0 in on all stainless pressure parts.

The registered file includes cylindrical shell and straight-flange pressure checks under Appendix 1-1, two 2:1 semi-ellipsoidal head checks under Appendix 1-4(c), and stainless austenitic MDMT treatment under UHA-51(d)(1)(a) and UHA-51(g). Nozzle reinforcement is checked under UG-37 with UG-40 limits of reinforcement and UG-45 minimum neck thickness, and weld sizing under UW-16 with UG-76(c) inside-edge rounding.

Hydrotest calculations follow UG-99(b) with 1.3 times MAWP and 90 percent of yield as the stress cap, plus corroded vertical field-test checks at 2025 psi user pressure. Selected nozzles and lifting and tailing lugs are checked for local external loads using WRC 107 methods, and the combined primary plus bending plus secondary stresses are compared against Division 2 limits within the COMPRESS WRC module.

• Appendix 1-1, shell and straight-flange pressure thickness and MAWP.
• Appendix 1-4(c), 2:1 semi-ellipsoidal head pressure thickness and MAWP.
• UHA-51(d)(1)(a) and UHA-51(g), stainless MDMT and impact-exemption stress-ratio path.
• UG-37, UG-40, UG-45, UG-76(c), UW-16 for nozzle reinforcement and weld sizing.
• UG-99(b) and UG-99(h) for hydrotest basis,, WRC 107 for nozzle and lug local-load checks.

1. Shell required thickness, Appendix 1-1

The 36 in OD SA-240 304 shell has a required thickness of 1.1867 in at 1354.18 psi effective shell pressure and 130 F, using the outside-radius form of the Appendix 1-1 cylindrical-shell equation and 0 in corrosion allowance.

t = P R_o / (S E + 0.40 P) + c

t = (1354.18 x 18) / (20000 x 1.00 + 0.40 x 1354.18) + 0

t = 1.1867 in

2. Head required thickness, Appendix 1-4(c)

The 36 in OD 2:1 semi-ellipsoidal heads have required thickness of about 1.146 to 1.149 in at the design condition, with a nominal formed thickness of 1.4375 in and no corrosion allowance. The head calculations use Appendix 1-4(c) with a K factor computed from the head geometry.

t = P D K / (2 S E - 0.2 P K) + c

For the registered head geometry, K is evaluated in the COMPRESS head module.

At 1354.18 psi and 130 F, the required corroded thickness is about 1.149 in.

3. Stainless MDMT exemption, UHA-51(d)(1)(a) and UHA-51(g)

For the shell and straight flanges, the stainless toughness check uses UHA-51(d)(1)(a) with carbon content not exceeding 0.10 percent, giving a rated MDMT of -320 F and no impact testing required at the design MDMT of -20 F. For selected nozzles, UHA-51(g) stress-ratio paths are used with coincident ratios in the 0.16 to 0.35 range.

t_r = P R_o / (S E + 0.40 P)

Stress ratio = (t_r E*) / (t_n - c)

Rated MDMT per UHA-51(d)(1)(a) = -320 F

Shell stress ratio example: 0.7911
Nozzle stress-ratio examples: 0.16 to 0.35

4. Shop hydrotest pressure, UG-99(b)

The vertical shop hydrotest is based on 1.3 times MAWP at 70 F, with a listed gauge pressure of 1755 psi at the top head. The shell and heads see slightly higher local test pressures once the static head is included, up to about 1759 psi at the bottom head and shell, all within the 27,000 psi allowable test stress for the stainless material.

P_test = 1.3 x MAWP x LSR

P_test = 1.3 x 1350 x 1.0

P_test = 1755 psi (gauge at the top head)