Comparative study of Pressure Vessel Design Software – Case Study for Vessels in Creep

Objective
The purpose of this study is to perform a detailed comparison of pressure vessel design workflows using two different software tools – VCLAVIS and a leading industry-standard software (latest available as of April 2025). The focus is specifically on the design of vessels operating under creep conditions, which involve long-term exposure to elevated temperatures, as outlined in the EN 13445, the European standard for unfired pressure vessels.

Designing for creep presents unique challenges, such as the need for time-dependent material behavior modeling, interpolation of allowable stresses at specific temperatures, and incorporation of complex stability scenarios. These challenges often lead to increased engineering hours, the need for auxiliary spreadsheets, and manual intervention in conventional software environments.

This study assesses how each software application handles:

• Material property management and creep data input
• Allowable stress calculations
• Code compliance checks and stability analysis
• Workflow automation and report generation

By executing the same design scenario on both platforms, the study quantifies the time required for each task and identifies bottlenecks or inefficiencies. The ultimate goal is to evaluate not only time savings but also the robustness and user-friendliness of the tools involved in pressure vessel design under demanding thermal operating conditions.

Sample vessel specifications
Cylindrical vessel with two torispherical heads per DIN28013 supported on cylindrical skirt, equipped with trunions and tailing lug to facilitate lifting. The following technical characteristics apply:

Design Data
Internal Design Pressure:	1 MPa
Internal Design Temperature:	410°C
External Design Pressure:	0.1 Mpa
External Design Temperature:	410°C
Corrosion Allowance:	1 mm
Creep Design:	No lifetime monitoring for operations of 100000 hrs

Dimensional Data
Component	Diameter	Thickness	Length	Material
Shell	OD=1500	T=16	L=5000	EN10028-2 P265GH
Heads	OD=1500	T=16 (af)	sf = 50	EN10028-2 P265GH
Skirt	OD=1500	T=10	L=2000	EN10028-2 P265GH

Example Nozzle Index (Nozzles with Pads)
Tag	Description	Dimension	Make	Nozzle material	Flange Rating	Flange material
1M	Manway	DN600	Plate 16mm	EN10028-2 P265GH	PN40	EN10222-2 P245GH
1N	Inlet	DN200	Pipe 12.7mm	EN10216-2 P265GH	PN40	EN10222-2 P245GH
2N	Outlet	DN200	Pipe 12.7mm	EN10216-2 P265GH	PN40	EN10222-2 P245GH
3N	Drain	DN50	Pipe 8.74mm	EN10216-2 P265GH	PN40	EN10222-2 P245GH
4N	Vent	DN50	Pipe 8.74mm	EN10216-2 P265GH	PN40	EN10222-2 P245GH

Design Execution Time: Industry Software vs. VCLAVIS
Industry software (2025 edition)
Examination Point		Time	Issues spotted
1	Find how to apply creep stresses	10 min	Different tab, not in material tab, poor GUI placement.
2	Calculate material allowable stress in creep	60 min	Linear interpolation of Rp0.2 at 410°C is not performed by the software, making it impossible to set creep stresses. A dedicated spreadsheet is required for calculating creep stresses
3	Set material allowable stress	20 min	10 minutes per material in order to user-set the creep stress
4	Consider joint efficiency factors	10 min	Not readily available in software, user needs to open the Code
5	Design of primary components	20 min	Delay is spotted due to missing elasticity input. User needs to check with dedicated spreadsheet in order to verify the elasticity for the material, which is necessary to evaluate the components for external pressure.
6	Design of nozzles	20 min	No problems spotted there. Typically 5 min per nozzle
7	Assign EN13445 stability scenarios	45 min	Not readily available in software, user needs to open the Code and manually set the software scenarios
8	Design for each stability case	45 min	User needs to prepare separate files for each scenario in order to verify the skirt component and the skirt to head junction, since only operation (worst of seismic or wind) and test is presented.
9	Design trunions and tailing lug	40 min	There is no check of the tailing lug interaction with the skirt base ring. A dedicated spreadsheet is required per Denis R. Moss procedures.
10	Time to print final report	30 min	Delay is spotted in order to merge reports from various files into a single engineering report.
Aggregate time:			300 min (5 hrs)

Design Execution Time: Industry Software vs. VCLAVIS
VCLAVIS
Examination Point		Time	Solutions adopted
1	Find how to apply creep stresses	5 min	Simply when selecting the material, creep data is directly input by user
2	Calculate material allowable stress in creep	0 min	Software performs linear interpolation of Rp0.2
3	Set material allowable stress	0 min	Automatically set
4	Consider joint efficiency factors	0 min	Readily available
5	Design of primary components	10 min	Material elasticity tables are provided within input
6	Design of nozzles	20 min	Typically 5 min per nozzle
7	Assign EN13445 stability scenarios	0 min	Readily available
8	Design for each stability case	15 min	Vessel stability checks are automatically produced, but it takes some computing time to run and check all scenarios at once. However user does not need to perform any actions.
9	Design trunions and tailing lug	15 min	Readily available Denis R. Moss procedures
10	Time to print final report	10 min	It takes some time printing all output into final report and merging summary and calculations reports. However user does not need to perform any actions.
Aggregate time:			75 min (1.25 hrs)

Results
The comparative analysis reveals a significant efficiency gap between the two software tools. Traditional industry software, while capable, necessitates considerable manual effort, including the use of auxiliary spreadsheets, manual code checks, and separate analyses for each stability scenario. In contrast, VCLAVIS streamlines the process with built-in capabilities for creep design, stability analysis, and automated reporting. By reducing the total design time from 5 hours to just 1.25 hours – a 75% reduction – VCLAVIS | Software for Pressure Vessel Design demonstrates its superiority in both speed and usability. These savings are not merely time-related; they also reduce the chance of user error, standardize compliance procedures, and free up valuable engineering resources for higher-level analysis and optimization.

In high-demand engineering environments where accuracy, speed, and compliance are non-negotiable, adopting a robust and modern tool like VCLAVIS is not just beneficial – it’s strategic.

Author: Dassa Isaak

Co-Founder & Lead Engineer at VCLAVIS O.E. Experienced Mechanical Engineer with a strong track record in the pressure vessel industry, specializing in the design and analysis of heat exchangers. Proficient in leading engineering tools including VCLAVIS.com, Autodesk Inventor, PVElite, VVD Ohmtech, and HTRI. Highly knowledgeable in international design codes and standards, including ASME, AD2000, PD5500, and EN13445. Holds a Master’s degree in Mechanical Engineering from the Aristotle University of Thessaloniki. Lead Engineer and Co-Founder of VCLAVIS.com, a specialized software platform for pressure vessel calculations.