Continuous Measurement Work Since the Post-War Era
MSI's lineage begins in post-war Tulsa with Tank Service, Halmor Meter Proving, a four-way valve, and a Marine Raider who learned the business from his father-in-law. Today, the company operates from Houston and proves the meters that keep Texas energy moving.
A Praxis CMG Company
After World War II, Tulsa remained one of America's working centers for oilfield service, fabrication, and measurement. John A. Halpine operated Tank Service, a metal salvage and tank shop, before the family's work evolved into Halmor Meter Proving.
By the 1950s, Halmor became known for mobile meter proving work serving producers, pipelines, refiners, and marketers. Its equipment centered around the four-way valve — the mechanical heart of a prover unit — associated with engineer Beef Morony.
Robert "Bob" Klasen, a returning WWII Marine Raider and Halpine's son-in-law, entered the petroleum business after the war. Before carrying the proving trade forward, Bob managed DX Sunray experimental full-service stations. He later learned meter proving at Halmor the way the trade has always been learned: hands-on, in the field, under operating conditions.
In the 1960s, Bob Klasen moved the work to Houston as the Gulf Coast became the center of gravity for refining, pipelines, petrochemicals, and aviation fuel logistics.
By the early 1970s, the Halmor legacy transitioned into Measurement Services, Inc. The company continued through the 1980s and 1990s as a family-run measurement business serving refinery, pipeline, and aviation fuel customers.
David "Dooley" Klasen later carried the business forward, reincorporating it in Houston in 2003 as Measurement Systems & Services, Inc. Under Dooley, MSI extended the family trade for another generation and deepened its aviation fuel calibration and field measurement work.
A metal salvage and tank shop serving the post-war Mid-Continent oilfield. The roots of the family's measurement trade.
Mobile meter proving across the Mid-Continent for producers, pipelines, refiners, and marketers. Equipment centered around the four-way valve.
Following the migration of the global energy industry to the Gulf Coast.
The Halmor legacy carries forward under a Houston-based operating identity that serves refinery, pipeline, and aviation fuel customers.
Business relationships throughout the Gulf Coast region expand — refinery, pipeline, terminal, and airline fuel consortium customers all added across these two decades of recurring service.
David "Dooley" Klasen reincorporates the business in Houston, extending the family trade for another generation.
A few name changes later, MSI still serves airline fuel consortiums, pipeline operators, and refinery customers across Texas and our Nation. In 2026, MSI joined Praxis Custody Measurement Group, pairing decades of field knowledge with a platform built to scale.
In 2026, MSI joined Praxis Custody Measurement Group to preserve the field knowledge built over generations while giving the business the capital, compliance infrastructure, and back-office support needed to grow.
For customers, the core promise does not change: accurate measurement, field accountability, and experienced technicians. What changes is the platform underneath — faster reporting, cleaner documentation, stronger dispatch, and a broader service footprint.
Work With MSI Today
Custody transfer is a financial instrument. Every calibration carries documented uncertainty analysis. Every report stands up to audit. No shortcuts.
This is a specialized craft, learned over decades. MSI's technicians carry institutional knowledge that doesn't exist in a textbook — and we invest in passing it forward.
Customers measured in decades, not quarters. The relationships we serve today have been with the company since the 1980s and 1990s. That's the standard.
Bob Klasen came home from the Pacific in 1946 and built his career on what the Marine Raiders taught him about precision, accountability, and looking after the people next to you. Eight decades later, that ethic still shapes how we show up — on the job and off.
MSI is a proud sponsor of the Houston Chapter's Joshua Chamberlin Society's Ruck the Bayou and supports veteran-focused efforts across the Gulf Coast. From working with veterans in the field, to backing the ruck marches and community events that fund their reintegration, we put labor and capital behind the values our founder lived.
Partner With UsWhether it's a routine prove, a new LACT skid, or a multi-year service program — MSI has done this work since the post-war era. We'd be honored to do it for you.