In this solo segment titled “This Week in HVAC History,” Mike Plezia explains how a pivotal meeting on October 14, 1946, in London—where 64 delegates from 25 countries convened—led to the creation of the International Organization for Standardization (ISO). He connects that historic moment to today’s HVACR practice by highlighting the importance of ASHRAE Standard 15 (refrigerant safety) and Standard 34 (refrigerant classifications). Plezia argues that these long‑standing standards set the baseline for equipment design, installation, and safe operation, distinguishing true professionals from unqualified handymen. He then ties the standards to the industry’s current shift toward low‑GWP refrigerants, especially A2L blends, emphasizing that consistent safety requirements remain essential. The segment ends with a safety reminder and a call for newcomers to understand the origins of the standards that govern their work.
Chapters
What's up, everybody? It's Mike, and I'm happy to bring to you a new segment to the show, and that is This Week in HVAC History. Of course, if you love what we do, the mechanical, electrical, thermodynamics, scientific part of everything that is HVACR, you've also gotta love What brought us here? So, on this first edition, today is October 11th, 2026. It's Sunday. But in October of 1946, October 14th to be exact, so about 80 years ago, 64 delegates representing 25 countries gathered in London, England to discuss a revolutionary idea. Why don't we establish an internationally recognized industrial standard. Their work would eventually lead to the establishment of the International Organization for Standardization. Of course, you may know them today as ISO, in 1947. So why does this matter to us HVAC technicians? Well, think about the standards we depend on today. Think about when we say, you know, whether a job is done right or wrong, when we talk about something as kind of boilerplate, as commonly accepted as you always braze with nitrogen. Those kind of standards began here. So ASHRAE Standard 15 establishes the refrigerant safety requirements, while Standard 34 provides refrigerant designations and safety classifications. These standards help to establish a consistent expectation for equipment design, installation, and operation, and safety. As our industry evolves, these are the standards by which we separate the real professionals from the hacks, the Johnny pickup trucks, the handymen and women. This is the stuff that makes us the real deal. So as we transition toward lower GWP refrigerants, including the A2Ls that we've been dealing with the last 2 years, standardized safety requirements remain absolutely essential. So the next time you're reviewing equipment specifications, refrigerant classifications, or installation requirements, or questioning what kind of refrigerant can I use with that kind of oil, or what size of a metering device Whether it be a piston orifice or a capillary tube, these standards go back a long time, and they're not just some arbitrary rules that somebody made, but there was a lot of thought that went back some 80 years before we even got here. And because of the decades of international cooperation, we have the industry standards that we have today. Now, what sets our profession apart is the fact that we have standards, and that goes back all the way to the— to 1946, this week in HVACR history. Above all else, be safe. And if you're new to the trade and nobody's told you about where these standards come from, now you know, and you can help somebody else know.
