We could legally have skipped third-party certification in much of the United States. Then UL found something we had missed.
When we started building HOWL, we assumed an outdoor appliance combining propane, serious heat, and an open flame would require independent safety certification.
That seemed obvious. Then we started reading the regulations.
The U.S. Consumer Product Safety Commission lists the applicable ANSI Z21.97 / CSA 2.41 safety standard as voluntary. Local regulations vary, and Canada has different requirements, but we could have sold HOWL in much of the United States without paying an independent laboratory to test it.
Skipping certification would have saved tens of thousands of dollars and shortened development. It also would have let us avoid the possibility that UL would find something requiring another redesign.
Then UL found something requiring another redesign.
The Test We Had Never Run
The original HOWL R4 spent weeks at UL. It passed the endurance burn test, simulated torrential rain, strong wind, ground-temperature testing, and everything else the laboratory put in front of it.
We had already run versions of those tests ourselves, so none of the results surprised us. By the final day, we were confident the hard part was over.
Then the technicians mentioned a test we had missed.
For this test, UL opened the control box and intentionally ignited the propane at the BarCoal jet heads, roughly six inches upstream from where combustion normally occurs. The flame had to burn there for an hour while the technicians measured the temperature of the aluminum jet-head holders.
The holders needed to remain below 875°F.
Ours reached nearly 1,000°F.
Then the heat expanded the gas-line fittings. Propane leaked inside the control box and caught fire.
We failed catastrophically.
Our shop went silent while the UL technician showed us the burning control box over FaceTime. After years of development, our nearly finished product had just produced exactly the kind of failure certification exists to uncover.
The Easy Fix Wasn’t the Real Fix
The quickest route to certification was simple. If we replaced the aluminum jet-head holders with steel, that particular temperature test would no longer apply. We proposed the material change, and UL approved it.
Technically, we could move forward.
But changing the holder material did not explain why a gas line had leaked. The condition required someone to open the control box and deliberately ignite the fuel far upstream from its normal combustion point, so it was not something that would occur during proper operation. Still, we had watched the leak happen.
UL had done its job. We did not feel like we had finished ours.
We recreated the test in our shop and discovered that some jet-head assemblies could support a small standing flame while others immediately blew it out. The difference came down to the threads connecting the fuel lines.
A parts supplier had milled some of them incorrectly by only a few microns. You could not feel the difference while assembling the parts, but the imperfect threads allowed a tiny amount of propane to escape. That leak acted like a pilot light, repeatedly reigniting the fuel at the jet head and driving heat into the control box.
We changed suppliers and moved production to a machine shop specializing in Swiss screw machining, a process capable of producing the thread precision the system required.
The problem disappeared.
Without the certification process, we might never have found it.
That is why safety standards include tests that appear strange, excessive, or disconnected from normal use. They deliberately push products into abnormal conditions because normal operation is the easy part.
Then There Was the $40,000 Knob
The whole-appliance certification was not the only time an outside test found a problem.
We wanted HOWL’s controls recessed into the Mission Control Panel, where they could not get smashed by a cooler, boot, camp chair, tailgate, or whatever else was losing a fight in the back of the truck.
The best starting point was an American-made Kantleak ball valve originally designed for commercial HVAC refrigerants. It had the durability and protected control design we wanted, but it had never been certified for propane.
That distinction mattered because propane molecules are smaller than the refrigerant molecules the valve was designed to contain. When the valve went through propane certification, its original gasket failed.
We could have abandoned the recessed design and rebuilt HOWL around an ordinary off-the-shelf propane valve. That would have been considerably cheaper.
Instead, we engineered a new gasket and put the custom valve configuration through its own certification process. It had to survive 6,000 complete on-and-off cycles and then pass hydrostatic testing without leaking.
By the time we finished the engineering, testing, certification, and documentation, that little brass valve had cost us roughly $40,000.
All so you could turn a knob and never think about it again.
That is what good safety engineering usually looks like. The expensive work disappears into a product that behaves exactly as expected.
Why Our Own Testing Wasn’t Enough
We tested HOWL aggressively before UL ever touched it. We ran it in downpours, wind, cold, and high altitude. We dropped it onto concrete, smashed it from different angles, measured temperatures, and searched for ways to make it fail.
That work made the product better, but it did not make us independent.
We designed HOWL. We wanted it to pass. We wanted to stop spending money and start selling campfires. However careful we tried to be, we still knew how the product was supposed to behave and carried every assumption that had shaped its design.
UL did not share those assumptions. Its technicians followed a published testing protocol and cared only about what happened.
They found the paragraph we missed. They created a failure we had never seen. That failure exposed a machining defect measured in microns.
Any manufacturer can call its product safe. Certification gives another group of engineers the chance to disagree.
Certification Continues After the Test
UL certification is not based on one perfect prototype that passes the tests and then retires to a shelf.
UL Solutions maintains an ongoing Follow-Up Services program. Its inspectors visit manufacturing facilities and verify that certified products continue to match the construction, components, materials, markings, and processes documented during certification.
We cannot quietly substitute a cheaper critical component or change the design while continuing to apply the same certification mark. Significant changes require review.
That means the mark applies to the HOWL leaving our shop, not merely the original sample that survived the laboratory.
It costs more and makes manufacturing less flexible. That is also the point.
What UL Certification Does Not Mean
UL certification does not make HOWL safe indoors. It does not excuse anyone from following the manual, maintaining the required clearances, using the supplied regulator, or attending the fire.
It also does not overrule local fire restrictions. Rules vary by location, and the person enforcing them does not care what a product page promised you. Always check the current regulations before lighting any fire.
Certification means every HOWL has been independently evaluated under the outdoor decorative gas appliance standard, ANSI Z21.97-2017 (R2022) / CSA 2.41-2017 (R2022), and manufactured under UL’s continuing requirements.
“Outdoor Decorative Gas Appliance” is not the category name we would have chosen. Nothing producing this much heat should have to share a word with lawn flamingos. But it tests what matters: stability, weather performance, combustion, surface temperatures, ground heating, controls, shutdown, and structural durability.
Why We Chose the Hard Way
HOWL exists to keep the forest and the campfire alive. We ask people to use it in places where a wood fire may be prohibited, unwise, or too risky.
Making an untested propane appliance and sending it into dry forests would have saved us money. It also would have made our mission difficult to take seriously.
Certification delayed the launch. It cost us tens of thousands of dollars. It exposed problems we then had to spend more money fixing. It also limits what we can advertise, requires ongoing inspections, and forces us to document the components and processes behind every HOWL.
We accepted all of that voluntarily.
The most important fire in HOWL’s development may have been the one nobody wanted: the fire inside UL’s control box. It happened in a test laboratory, before production, and led us to fix a problem we did not know existed.
That is exactly where failures belong.
We did not certify HOWL because someone made us.
We certified it because propane does not care whether testing was legally optional.
