This episode explores ten of the most surprisingly specific international standards, revealing the hidden rules that make modern life work. The list includes ISO 3103, the infamous standard for brewing tea for sensory testing, which specifies everything from pot material (porcelain) to steep time (six minutes) to pour rate. The discussion also covers ISO 5775 for bicycle tyre sizing, which acts as a "peace treaty" between incompatible historical measurement systems, and ISO 7010, which standardises safety symbols like the iconic "running man" on exit signs. The conversation highlights how these standards, while often appearing absurd at first glance, solve real-world problems of compatibility and safety, from pet microchips (ISO 11784/11785) to barcode placement on packages (ISO 28219). Other standards examined include the ergonomic design of keyboards (ISO 9241-410), general tolerances for machined parts (ISO 2768), and the global identification code for shipping containers (ISO 6346). The episode argues that a good standard is invisible, and these weird ones only become noticeable once you learn their specific, committee-approved details.
#2802: The Tea Standard and 9 Other Weird ISO Rules
Ten hyper-specific international standards that make you question what humanity does with its collective time.
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New to the show? Start here#2802: The Tea Standard and 9 Other Weird ISO Rules
Daniel sent us this one — he wants a top ten rundown of the weirdest, most narrowly-scoped international standards. The kind where you read the title and think, wait, someone actually sat in a committee room and standardised that? And then explain why on earth it had to exist.
Oh, this is my kind of territory. Standards bodies are where civilisation's quiet obsessives go to live.
I knew you'd say that. You probably have a favourite ISO committee.
I have several. But let's start with the premise — most people encounter dozens of ISO standards every day and never notice. That's actually the point. A good standard is invisible. A weird standard is invisible until someone tells you about it, and then you can't un-see it.
Like learning that the little arrow next to the fuel gauge on your car is an ISO standard. And then you look for it on every car you ever ride in.
ISO 7000, graphical symbols for use on equipment. The fuel pump icon, the defrost symbol, the little fan speeds — all standardised so a rental car in Osaka works the same as one in Oslo.
Alright, let's do this properly. Ten standards, roughly ranked by how much they make you question what humanity does with its collective time.
I want to open with a crowd-pleaser. ISO 3103 — the standard for brewing tea.
You're joking.
I am absolutely not. ISO 3103 specifies a method for brewing tea for sensory testing. It was published in 1980 by Technical Committee 34, Subcommittee 8, which is the tea subcommittee.
The tea subcommittee.
Of course there's a tea subcommittee. The standard specifies that you use a porcelain or earthenware pot, you add two grams of tea per 100 millilitres of boiling water, you let it steep for six minutes, and then you pour it into a white porcelain bowl.
That's not tea, that's a dare.
The standard exists because if you're comparing teas from different regions, different harvests, you need a consistent preparation method. Otherwise you're tasting the brewer, not the tea. The British Standards Institution originally developed it, and ISO adopted it.
The British Empire's final legacy isn't a language or a legal system, it's a six-page document on how to make a cuppa that's too strong for human consumption.
Six pages, including diagrams. And it's been parodied endlessly, but here's the thing — it's genuinely useful. Every tea company's quality control lab uses something like it. The weird part isn't that it exists, it's how specific it gets. The standard specifies the dimensions of the pot, the material, the pour rate.
The pour rate.
The tea shall be poured through the pot's built-in strainer. If the pot doesn't have one, you use a separate stainless steel strainer. This is the level of detail we're dealing with.
My leaf medicine practice has less documentation than that, and I actually believe in leaf medicine.
You believe in it the way people believe in horoscopes — enthusiastically but without evidence.
Number nine — what have you got?
ISO 5775, bicycle tyre and rim designations. This one's a mess with a standard wrapped around it. Bicycle tyres are labelled with two numbers — like 700 by 25C. The 700 is the approximate outer diameter in millimetres. The 25 is the width. The C is...
Historical is always a worrying word in standards.
It comes from an old French system where A, B, and C designated different widths of tyre on the same rim. The A and B widths died out, but C stayed. So you have 700C, which is actually 622 millimetres at the bead seat, not 700 millimetres anywhere meaningful. The standard tries to make sense of this by defining the actual rim diameter and letting the nominal size float as a label.
The standard exists to explain why the number on the tyre is wrong.
In a sense, yes. And it gets worse with mountain bikes — you have 26-inch, 27.5-inch, and 29-inch tyres, none of which are actually those sizes. ISO 5775 is the Rosetta Stone that lets you know if a tyre will physically fit your rim. Before it existed, you just had to guess.
"Will this fit?" "It says it's the same size." "It is not the same size.
The bicycle industry spent a century creating incompatible sizing systems and then asked ISO to sort it out. The standard is basically a peace treaty.
ISO 7010, graphical safety symbols. This is the standard that gives you the running man on fire exit signs.
Wait, the running man is standardised?
ISO 7010 specifies exactly what the running man looks like — the proportions, the angle of the limbs, the fact that he's running toward a door. It was designed in the late 1970s by a Japanese designer named Yukio Ota, and it's now used globally. Before that, different countries had different exit symbols. Some used text, some used arrows, the Soviet Union had its own thing.
There was a moment where someone sat down and said, "The universal symbol for 'leave the building immediately' should be a man who looks like he's late for a train.
They were right. Studies show the running man is recognised faster than text in emergencies. The standard also covers the colour — green for safe condition, the specific shade is defined. And it covers dozens of other signs. The no smoking symbol, the emergency phone symbol, the baby changing station symbol.
The baby changing station is in the same standard as the fire exit.
ISO 7010 covers all safety signs. The baby changing symbol is technically a "safe condition" sign, same category as first aid and emergency exits. It's a mother bending over an infant on a surface, and it's standardised so you can find it in an airport in any country.
I've seen that symbol a thousand times and never once thought a committee debated the mother's posture.
That's the whole point. If you notice the standard, it failed. But someone had to notice it enough to design it.
ISO 11784 and 11785 — the RFID standards for animal identification. This is the microchip in your dog.
There's a standard for what frequency the dog chip uses?
Yes, and it's a important one. ISO 11784 defines the code structure — 64 bits, with a country code and a unique animal ID. ISO 11785 defines the transmission protocol, 134.Before these standards, different manufacturers used different frequencies, different code formats, different everything. A dog chipped in France couldn't be read by a scanner in Germany.
The dog was effectively unchipped across borders.
And for pet travel within the EU, that's a real problem. The standard means any ISO-compliant scanner can read any ISO-compliant chip. The weird detail is that the United States uses a different frequency — 125 kilohertz — for a lot of its pet chips, so there's still a compatibility gap. But the ISO standard is what made the European pet passport system workable.
There's a country code in the chip. So the chip doesn't just say "this is dog number whatever," it says "this dog is from Belgium.
The first three digits of the code identify the country. It's the same principle as ISO 3166 country codes, applied to pets. The standard also covers livestock — cattle, sheep, goats. The same chip technology in your neighbour's golden retriever is in millions of cows.
The cow doesn't know it's ISO compliant.
The cow is blissfully unaware of the entire standards ecosystem.
ISO 28219 — labels for transport packages, specifically barcode placement.
You're telling me there's a standard for where to put the sticker.
There's a standard for where to put the sticker. And it's more important than it sounds. If you're a warehouse with automated scanning, the barcode needs to be in a predictable location so the scanner can find it. ISO 28219 specifies that the barcode should be placed on the lower right-hand corner of the largest face, a certain distance from the edges, at a certain minimum height from the bottom.
What happens if you put it on the wrong corner?
The package enters a sorting facility and the automated scanner misses it. It gets kicked to manual handling. That costs time and money. Multiply that by millions of packages and you understand why the standard exists. The standard also covers the font for human-readable text, the contrast ratio, the quiet zone around the barcode.
The quiet zone.
The blank space around the barcode that tells the scanner where the code begins and ends. If you violate the quiet zone, the scanner can't read the code. It's like trying to read a sentence with no spaces between words.
Somewhere there's a warehouse worker who's been yelled at for violating the quiet zone.
And the quiet zone dimensions are specified in tenths of a millimetre, depending on the barcode symbology.
ISO 9241, part 410 — the ergonomic design of physical input devices. This is the standard for how a keyboard should feel.
How a keyboard should feel.
Key travel distance, actuation force, the shape of the keycaps, the spacing between keys. ISO 9241-410 specifies all of it. A standard office keyboard should have a key travel of between two and four millimetres, an actuation force between 0.5 and 1 newton, and the keys should be dished — slightly concave — to centre your fingers.
Mechanical keyboard enthusiasts are basically in a theological argument with an ISO standard.
They are, and they're often on the losing side of the ergonomics. The standard is based on decades of research into repetitive strain injury and typing efficiency. The keyboard you're using right now almost certainly complies with it, unless you're using one of those flat laptop keyboards that violates the key travel requirement.
Which I am.
Which you are, and your wrists will eventually file a complaint with the relevant committee. The standard also covers mice, trackballs, touchpads, and stylus inputs. There's a whole section on how much force a mouse button should require.
When I click a mouse and it feels right, that's not an accident.
That's a committee in Geneva deciding what "right" feels like. And they update it — the current version is from 2018, and it accounts for touchscreens and gesture inputs now.
ISO 2768 — general tolerances for machined parts. The subtitle could be "how wrong is allowed to be.
That's a philosophical question dressed as engineering.
When you machine a metal part, you specify a dimension — say, a hole that's ten millimetres in diameter. But you can't make it exactly ten millimetres. There's always some deviation. ISO 2768 defines four tolerance classes — fine, medium, coarse, and very coarse — and for each one, it tells you how much deviation is acceptable based on the nominal size.
"very coarse" is the engineering equivalent of "eh, close enough.
For a ten millimetre dimension, very coarse tolerance allows plus or minus 0.Fine tolerance allows plus or minus 0.That's a factor of ten difference. The standard exists so that a drawing doesn't have to specify the tolerance for every single dimension — you just write "ISO 2768-m" and everyone knows what acceptable means.
If you don't specify, someone shows up with a part that's technically the right size but doesn't fit, and you have no recourse.
The standard is the legal framework for "this doesn't fit and it's your fault." It's been around since 1973, revised in 1989, and it's one of the most-cited standards in mechanical engineering.
ISO 6346 — shipping container identification codes. Every shipping container in the world has a code on it, like MSCU 123456 7. That code is defined by ISO 6346.
The four letters and seven digits.
The first three letters are the owner code — MSC is Mediterranean Shipping Company, MAE is Maersk, and so on. The fourth letter is always U for freight containers. Then six digits for the serial number, and then a check digit.
A check digit, like a credit card.
The check digit is calculated from the owner code and serial number using a specific algorithm. If the check digit doesn't match, the container code was entered wrong somewhere. Which matters because container codes are how ports, customs, and shipping companies track millions of containers globally.
What happens when the check digit fails?
Somewhere in a port, a container is effectively invisible to the system until someone manually verifies it. The standard also specifies the physical markings — where on the container the code goes, how big the letters are, what font.
The font again.
Standards people care deeply about fonts. The markings have to be at least 100 millimetres high, in a sans-serif typeface, and they go on specific locations on the container — the right-hand door, the front, the roof. So a crane operator can read them from a distance.
The entire global supply chain runs on a specific sans-serif font.
A check digit algorithm. And if either one fails, your package from Singapore doesn't arrive.
ISO 8601 — the date and time standard. This one is surprisingly contentious.
Date formats, contentious?
The standard says dates should be written YYYY-MM-DD, descending order of magnitude. 2026-05-13. It's unambiguous, it sorts correctly in file names, and it avoids the whole American-versus-European month-day confusion.
Yet almost nobody uses it in daily life. The United States uses month-day-year. Europe uses day-month-year. Japan and China use year-month-day, which is actually ISO 8601 compliant. The standard was published in 1988, and it's been slowly winning in computing — it's the default in many programming languages and databases — but it's lost everywhere else.
Because people are stubborn.
Because people are stubborn, and also because date formats are deeply cultural. The way you write a date feels natural in a way that's hard to override with a standard. But ISO 8601 has one genuine victory — it's the standard for internet time. The RFC for email dates uses a variant of it.
It also handles time zones, right?
Yes, and that's where it gets really specific. Times are written with a time zone offset — 14:30:00 plus 02:00 for Jerusalem. Or you can use Z for UTC, which is called Zulu time. The standard also covers week numbering, ordinal dates where you just write the day of the year, and durations. You can represent "two years, three months, four days, five hours, six minutes and seven seconds" as P2Y3M4DT5H6M7S.
That looks like a password.
It looks like a password, but it's machine-readable and unambiguous. The P stands for period. The T separates the date part from the time part. It's elegant in a deeply nerdy way.
Number one — what's the strangest standard of all?
I have to go with ISO 3103, which we already covered, so let me give you a bonus that's even weirder. ISO 18916 — imaging materials, specifically the photographic activity test for enclosure materials.
Say that again in English.
It's the standard for whether a photo album is safe for your photos. The test determines if the materials in a photo album, a sleeve, or a storage box will chemically react with your photographs and destroy them over time.
There's a standard for photo albums not eating your photos.
The test involves incubating the material with a detector that senses chemical reactivity. If the material fails, it'll cause your photos to yellow, fade, or become brittle. The standard exists because in the 1980s and 90s, a lot of photo albums were made with PVC plastics and acidic papers that were basically slow-motion photo destroyers.
Somewhere, a lab technician is baking photo album samples in an incubator to see if they're safe.
They've been doing it since 2000 when the standard was published. It's used by archives, museums, and anyone selling "archival quality" photo storage. The standard is the reason that label means something.
Alright, we've done nine. Let me throw in number ten — ISO 5800, photographic film speed. This is the ISO number on your camera, or what used to be on your film canister.
ISO 100, ISO 400, ISO 3200.
Before ISO 5800, there were two competing systems — the American ASA and the German DIN. ASA was linear — 400 was twice as sensitive as 200. DIN was logarithmic — 21 DIN, 24 DIN, 27 DIN. The standard merged them into ISO, which initially gave you both numbers — ISO 100 slash 21 degrees.
The slash notation. I remember that on film boxes.
Eventually the DIN part was dropped in consumer contexts, and now everyone just says ISO. But the standard unified the two systems, which meant a film photographer could buy film anywhere and know what they were getting. Before that, it was chaos — different countries, different scales, different measurements.
It's still in use for digital cameras. The ISO setting on a digital camera is simulating film sensitivity, and it's calibrated to the same standard. When you set your camera to ISO 6400, you're invoking a standard that goes back to 1974 and ultimately to two competing national systems that couldn't agree on how to measure light sensitivity.
It's a peace treaty between American and German engineers.
Most ISO standards are peace treaties of one kind or another. That's what I find compelling about this whole category. These aren't just arbitrary rules — each one represents a moment where people looked at a mess of incompatible systems and said, "we need to fix this.
Then spent years in committee rooms arguing about pour rates and quiet zones.
ISO 3103, the tea standard, took six years from proposal to publication. Six years to standardise making a cup of tea.
To be fair, it's a very specific cup of tea.
The specificity is the point. A standard that says "make tea however you like" isn't a standard. It has to be specific enough to be reproducible. That's what makes them weird to read — they're written in this deadpan technical language about things that are otherwise totally mundane.
There's something almost beautiful about it. The idea that somewhere, someone cared enough about the exact posture of the running man on an exit sign to define it in millimetre-level detail. And now billions of people see that running man and know what it means without ever thinking about it.
That's the paradox of standards work. If you do it perfectly, no one knows you did it at all. The running man is invisible. The shipping container code is invisible. The keyboard under your fingers is invisible. But each one represents an enormous amount of careful thought.
Let's not romanticise it — there were arguments.
Standards committees are famously contentious. You have representatives from different countries, different companies, different technical traditions, all with their own interests. The ISO 216 paper size standard — A4, A3, and so on — has never been adopted by the United States and Canada, and it's been a quiet bureaucratic war for decades.
The A4 versus letter format cold war.
Which letter format is winning, by the way. Most of the world uses A4. The US uses letter. They're slightly different shapes — A4 is a little narrower and a little longer. And the difference is just enough that documents don't format correctly across the two systems.
Every time someone in Europe opens a US document and the margins are wrong, they're experiencing the fallout of a standards dispute.
A standards dispute that's been running since the 1920s. The A-series paper sizes are based on a German standard from 1922, which became ISO 216 in 1975. The aspect ratio is one to the square root of two, which means when you fold it in half, the proportions stay the same. It's mathematically elegant. US letter is based on...
Tradition is a polite word for "we've always done it this way.
That's the fundamental tension in standardisation. Do you go with what's mathematically optimal, or do you go with what's already installed? The metric system is objectively better, but the US still uses imperial units for most things.
Let's not re-litigate the metric system.
But it's the same dynamic. Standards are only useful if people adopt them, and adoption is never purely rational.
We've covered tea, tyres, fire exits, pet microchips, barcode placement, keyboard feel, machining tolerances, shipping containers, date formats, photo albums, and film speed. And somewhere out there, Daniel is either delighted or deeply concerned about how we spend our time.
I think he knew what he was asking for. The prompt specifically asked for the "weirdly specific" ones.
Though I will say, the more I learn about these standards, the more I appreciate them. They're not weird for the sake of being weird. Each one solves a real problem that was causing real headaches.
The pet microchip standard is a perfect example. Before ISO 11784, if you moved from France to Germany with your dog, the German vet literally couldn't read the chip. That's not a minor inconvenience — that's a system failure that could result in a lost pet.
The solution was a 64-bit code structure and a 134.2 kilohertz frequency agreed upon by a committee.
Civilisation runs on committees. That's the uncomfortable truth.
It's comforting and uncomfortable at the same time. Comforting that someone is thinking about this stuff. Uncomfortable that it's often one person in a windowless room in Geneva.
The ISO headquarters in Geneva has about 150 full-time staff, but the actual standards work is done by tens of thousands of volunteers worldwide. Engineers, scientists, industry experts who serve on technical committees. Most of them are doing it alongside their day jobs.
The tea standard was probably written by a tea industry quality control person who thought, "this is a mess, I'm going to fix it.
Six years later, the world had a standard for brewing tea. There's something heroic about that, in a very small way.
In a very small, very specific, six-page-document-with-diagrams way.
Now: Hilbert's daily fun fact.
Hilbert: During the Cold War, the Soviet embassy in São Tomé and Príncipe maintained a full Byzantine-style ceremonial court for visiting dignitaries — complete with rigid protocols for who could stand where, how many steps of approach were permitted, and the exact angle of bow required — despite the fact that the island nation had fewer than a hundred thousand residents and hosted perhaps one state visit every three years.
Hilbert: During the Cold War, the Soviet embassy in São Tomé and Príncipe maintained a full Byzantine-style ceremonial court for visiting dignitaries — complete with rigid protocols for who could stand where, how many steps of approach were permitted, and the exact angle of bow required — despite the fact that the island nation had fewer than a hundred thousand residents and hosted perhaps one state visit every three years.
...right.
The Soviets exported Byzantine court ceremonial to a tropical island of ninety thousand people for the benefit of one visitor every three years. That's a level of bureaucratic commitment that even ISO would respect.
I think we've found a new standard to nominate. Anyway — the thing I keep coming back to with all these standards is that they represent a kind of optimism. The belief that if we just define things clearly enough, the world will work a little better. The running man will save someone in a fire. The dog chip will reunite a family with their pet. The shipping container will get where it's going.
The tea will be too strong, but consistently too strong, everywhere on Earth.
Consistently too strong is still consistent. That's the whole project.
This has been My Weird Prompts. Thanks to our producer Hilbert Flumingtop. If you enjoyed this, leave us a review wherever you listen — it helps. We'll be back next week.
Until then, check your photo albums for ISO 18916 compliance.
This episode was generated with AI assistance. Hosts Herman and Corn are AI personalities.