Our History


Houston Integrity Consultants LLC is a team of creative and innovative engineers and technical specialists. 

The team is led by John Tischuk, a 45-year veteran in the oil and gas industry. John started his career as a metallurgical and corrosion engineer with Phillips Petroleum and then moved to the North Sea with Occidental Petroleum. He initially held the position of corrosion engineer in the underwater construction department before becoming the Senior Corrosion Engineer responsible for two offshore platforms, subsea pipelines and a marine oil terminal. He then moved to Mobil North Sea, responsible for Mechanical Integrity of two offshore platforms, subsea pipelines and flowlines and a gas terminal.    

In 1988 John founded Tischuk International which he operated until 2009, when he moved to Houston and founded Houston Integrity Consultants LLC. 

1988 – Inspection Management based on Risk

Tischuk International worked with several North Sea operators to develop and manage mechanical inspection programs based on modeling corrosion rates using industry and proprietary models.  

A change in British regulations in 1988 required that all process piping in onshore hydrocarbon processing plants have a formal inspection program. Tischuk International did pioneering work with BP Chemicals, Grangemouth, Scotland to combine standard corrosion predictive models with a simple method of assessing consequences of failure. This was the first true application of Risk Based Inspection (RBI). This method was successfully piloted in Grangemouth and subsequently applied to all BP Chemicals facilities in the United Kingdom.  

1989 – First Risk Based Inspection Software

In 1989, Tischuk International and their subsidiary Three Rivers Systems Development Company developed the first version of T-OCA, a software application for managing the data and calculations required for RBI.  

This product was improved and developed over the next 30 years and was the basis for SHIELD.

In 1989 we applied RBI to oil refineries, offshore and onshore oil and gas production facilities and North Sea gas plants for the first time.

1992 – First Storage Tank Farm

Tischuk International applied RBI to storage tank farms using the T-OCA software and added the API 653 calculations to the software.  

Working with engineers from Shell and BP, we developed probability of failure models for rotating equipment, pressure safety valves and control valves. We applied these models to the equipment in the Shell Stanlow refinery over the next four years and then assisted Shell in the initial development of the Shell RBI methodology.

At the same time we kept the T-OCA system separate and continued its development. During this time we upgraded T-OCA to a Windows 3.1 application with the dBase 3 file format. 

1997 – Technology Transfer

We first began to develop the technology transfer process so that RBI implementers in other locations could use the T-OCA software.  

The Technology Transfer process is based on training and certification, standard operating procedures, and continuous support. John Tischuk was asked to join the API 580 risk-based inspection sub-committee. He served on the sub-committee and assisted in the writing of several drafts until the first issue of API RP 580 was published in 2002. 

Working at several large onshore oil and gas fields in Indonesia, we developed risk-based systems for pipelines, incorporating the ASME B31.4 and B31.8 calculations. We applied the analysis on thousands of individual flowlines and hundreds of trunk lines. 

1998 - First LNG Application

We began using RBI on Liquefied Natural Gas (LNG) plants in the Far East, Middle East and Caribbean.

2001 - Foreign Languages

We delivered our first foreign language version of T-OCA in Portuguese for a client Brazil. 

2002 - T-REx Family

Developed the T-REx family of simple qualitative risk assessment tools.

These were simple, configurable tools that allowed for expert driven, qualitative risk assessments. The main uses were for pipelines and atmospheric storage tanks.

2014 - T-OCA Updates

We updated T-OCA to include Integrity Operating Windows in conformance to API 584.

Additionally, we added the ability to select and customize the risk matrix size. Furthermore, we upgraded analysis capabilities for pipelines and atmospheric storage tanks.


We developed an additional Inspection Data Management System (IDMS) module to create a combined IDMS-RBI software product. This included a rebrand of our software to our current SHIELD software solutions.

Development of an IDMS product allows us to provide an all-in-one service to better track and manage inspections and increase efficiency for end users.

Our IDMS software can be provided as an integration to an RBI asset management solution or as a standalone product to utilize “fixed interval” inspection planning methods

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