Our Story

Zachry Integrity Engineering Ltd is a Canadian owned engineering and consulting firm based in Calgary, Alberta.

Since 1988, we have been providing professional engineering and management services to our clients in Canada and around the globe. We take pride in offering complete project solutions to our partners in the energy, mining, and forest industries.

We specialize in engineering design, project management, industrial equipment fabrication, construction material handling, international labor sourcing, and training.

We are also well versed in the areas of SAGD, oil sands, refineries, petrochemicals, pipelines and cover both engineering and operational aspects.

We strive to develop long term relationships with our clients and we recognize that their success is also our success.

Our Specialties Include:

Extraordinary Solutions

We are one of the few Canadian engineering firms with LNG design experience.

We are experienced in Level 1 to 3 Fitness For Service (API 579, ASME FFS-1) assessments.

We are experts in the use of Finite Element Analysis from brittle fracture prevention to optimizing equipment design.

Zachry Publications


On the Effect of Rising Liquid on Coke Drum Skirt Fatigue Life

This study compares two methodologies for modeling heat transfer in coke drums to estimate the fatigue life at the skirt-to-vessel attachment weld. Findings revealed up to 20% discrepancies between the two methods, suggesting the use of a more complex model incorporating non-uniform thermal fields for higher accuracy, while a simpler method could be used for quick, conservative estimates.

Local Post Weld Heat Treatment of a Pressure Vessel: A Postmortem Evaluation

This research evaluates a process tower that distorted significantly following a local post weld heat treatment (PWHT), testing several analytical techniques using Finite Element Analysis (FEA) to best predict such deformation. The study concludes with findings from these techniques and suggests potential optimization for PWHT design and execution.


Coke Drum Keyhole Optimization with Alloy Weld Overlay

The study investigates a novel design for coke drums involving the use of N06625 overlay at keyhole locations to delay crack initiation and prolong fatigue life. The results reveal that this design, when coupled with increased keyhole fillet radii, significantly improves the fatigue life by an order of magnitude compared to previous designs, offering potentially substantial cost-effectiveness benefits.

Reliability Improvement Concept on Welded Lip-seal Heat Exchanger Flange Joints

This study proposes and evaluates new design features for lip-seal flange joints, commonly used in high-pressure heat exchangers, to improve their reliability and fatigue life. The modifications, which include machined pockets, a self-alignment feature, and strict fabrication tolerances, are assessed through Finite Element Analysis simulations comparing stress distributions in the conventional and redesigned joints.

On the Effect of Hot-Box Size on Coke Drum Skirt Fatigue Life

This study explores the effect of “hot-box” emissivity and height on fatigue life in the weld of coke drum skirts, specifically the influence of design features like “keyholes.” The results indicate that while fatigue life is not significantly affected by hot-box height without keyholes, the presence of keyholes introduces variable fatigue performance, offering guidance for optimizing hot-box size.


Integral Mean of Yield Concept Applied to Thermal Hot Spots: Validation of a Level 2 Damage Assessment Method

The study evaluates the accuracy of Seshadri’s Level 2 assessment for detecting local thermal hot spots in pressure vessels by comparing it with a Level 3 assessment. Findings reveal minor differences between the two methods, with Level 2 providing a more conservative estimate of load capacity reductions due to hot spot damage.


Engineering Associations

Zachry Engineering is proud to be an active and contributing member of the following engineering associations:


Zachry Engineering is proud to be an active and contributing member of the following associations:

Asset Integrity | FFS Solution | PVP Solution | FEA Solution | Big Data Solution

Let’s Work Together​

Thank you for your interest in Zachry Integrity Engineering. If you wish to contact us about the services we provide, please email us at