That had to hit hard. F10T12's are very, very rare.
This reminds me... as I was replacing my Castor Metal Halide for the GE HALARC Metal Halide, I found myself doing the Fumble Dance, after taking out the Castor Metal Halide. "Fumble Dance: an unexpected dance move that naturally occurs when something of importance falls out of the human hands. The human tries to catch the important object while fumbling each and every time -- initiating the Fumble Dance. Unlike most dances, the Fumble Dance requires no skill. Although the dance can easily be achieved, this dance is usually found to occur during very... important... times."  Good thing I have quick reflexes. Had that Castor lamp fallen out of my hands, it would've likely shattered on my sportcar, or the ground.

Been extremely busy the past few months.  The City of Denver enacted a requirement that commercial and similar buildings within city limits must be converted to LED except for specialty type fixtures.  I have 4 church buildings within the city of Denver that I have to convert to LED.  Completed 1, and im the process of doing the 2nd.  over 900 Fluorescent tubes in one building that I am converting to LED.  These are Sylvania LEDVANCE ballast bypass tubes I am installing, so some wiring modifications.  Will be posting photos soon.  All 4 buildings were T8 modified about 10-20 years ago with a few rare exceptions where I come across a few T12s that were missed.  Got a few ballasts from some of them from 1975, which is cool, I'll be hanging onto those. 

That had to hit hard. F10T12's are very, very rare.
This reminds me... as I was replacing my Castor Metal Halide for the GE HALARC Metal Halide, I found myself doing the Fumble Dance, after taking out the Castor Metal Halide. "Fumble Dance: an unexpected dance move that naturally occurs when something of importance falls out of the human hands. The human tries to catch the important object while fumbling each and every time -- initiating the Fumble Dance. Unlike most dances, the Fumble Dance requires no skill. Although the dance can easily be achieved, this dance is usually found to occur during very... important... times."  Good thing I have quick reflexes. Had that Castor lamp fallen out of my hands, it would've likely shattered on my sportcar, or the ground.

The shop had a whole box of them so it wasn't that great of a loss, and even when I put tape on one side of all sleeves I had, I was holding this one upside down... My fumble dance did not last long and it shattered immediately 
My first reaction was to immediately try to get a new one. I have many one-off lamps in my collection and if any of those broke I would be doomed (cannot buy a similar one even from a different company). I remember my 16w cfl that broke, was able to partially recover because it was a simple 2U 6500K cfl.

@RyanF40T12, that's actually a bit closer to a fear of mine... I can't believe that the city of Denver requires that buildings switch to LED, forcing people to
switch to LED. I'm still hoping that there's no possibility of cities forcing... residents... to switch to LED. That would be my number one fear.
If that ever happened, I would do anything and everything to fight it.
@LightsAreBright27, at least you get the chance to buy new F10T12 lamps. That is not something that many other lighting enthusiasts can say. Although I do not
have a ballast that I can use for an F10T12 lamp, I still definitely want one. Smallest T12 lamp in my collection was recently bought... a new GE F14T12.
Still unused, but I have many magnetic Trigger Start HPF Rapid Start ballasts. Next paycheck, I may look around for F14T12 fixtures for sale.

Earlier today, I found out that I was incorrect... one of the Promax 5000k HID lamps I bought was actually bad, not the ballast. That Promax HID lamp failed
to ignite on my Zentec ballast too... so I replaced it with my previous 6000k HID lamp from Zentec. It's very difficult to take out the right headlight
housing, so until I do, the left headlight housing contains a 6000k HID lamp, while the right one contains the 5000k HID lamp. (Mixed colors, I know...
I hate it too.) The 6000k HID lamps are FAR brighter than the 5000k HID lamps, so something is certainly wrong here.

Not only has Denver rolled out those requirements, but the Governor of the state of Colorado signed stuff into effect that bans the sale of incandescent, CFL, and fluorescent lamps in the State of Colorado starting January, 2025. 

It wouldn't be feasible to demand conversion of residential properties. There are simply too many, and how would you enforce it..? I can't figure out how they're going to enforce it with commercial properties either, there must be thousands of them in a city the size of Denver 

They are indeed enforcing it and handing out fines to those not in compliance.  At least the commercial side of the fence.  Not the residential side.  They figure with the bulb ban coming, people will convert to LED over time. 

They must have plenty of people not doing much, then. It would never happen here, they just haven't got the manpower.

Update- I have bought two F10T12s .

Cool. Thats one of the sizes I'd love to find. Never seen one here though.

The City of Denver enacted a requirement that commercial and similar buildings within city limits must be converted to LED except for specialty type fixtures.

I knew about the upcoming state fluorescent sales/manufacture/etc ban, but hadn't heard about this Denver thing. .. Going to have to look into that try to see what the requirements are since I know someone who owns a business in Denver(in a leased space)

  I can't figure out how they're going to enforce it with commercial properties either, there must be thousands of them in a city the size of Denver 

All they'd have to do is make a very basic part of a regular inspection (say for example fire inspection). And yeah without a doubt there are 1000's of buildings in the city. I took a very quick look at things, and it depends on the size of the building as to how much you need to do.

Another thing Denver is trying to do is ban natural gas heating in commercial & large residential buildings (for new construction, and when systems need replacement).
There was an article in todays paper about this

 California is supposed to do something similar .

Today I dropped a green incandescent because it was too hot in my hand 



I will buy another.

See below for requirements/details of what is going on with commercial properties for city of denver, within a certain size-  The below is from a letter sent to property owners/property managers.  it is general info and not private. 


Dear Building Owner/ Property Manager,
All commercial and multifamily buildings in Denver 5,000 sq. ft. and larger have to comply with
some aspect of the Energize Denver Performance policy. We have many recent updates and
upcoming milestones for you to be aware of.
We can work with you!! We want to help you navigate this complicated program so target
adjustments, renewable options, and timeline adjustments are here to help. Please call or email our
help desk to talk through your options at 1-844-536-4528 or [email protected].
Prescriptive Requirements for Building 5,000-24,999 Sq. Ft.
1
What we've been doing: We spent the last year talking with small building owners and the
building industry to build out the rules and technical details for buildings 5.000 to 24.999 sq. ft.
The short version: You have two main options to comply with Energize Denver:
• Improve your Lighting: a minimum of 90% of the building's total lighting load should be
provided by LED lights
• Improve your Energy Source: Utilize renewable power generation to meet a minimum of
20% of the building's annual site energy usage
What if the Lighting and Renewable options don't work for me: We've designed alternate
compliance options for special situations.
Next Steps:
• Claim your building so we have up-to-date contact and building information
• Check out the Compliance Guide for step-by-step instructions for compliance and links to all
compliance documents and submission portals
• Read the technical guidance document for the in-the-weeds details
• Check our resource directory to find support programs - such as free energy audits,
rebates, financing opportunities, and more - apply to your specific building type
• Watch the recorded webinar describing the requirements, compliance pathways, and other
frequently asked questions
I'm a service provider for these buildings: Fantastic! We have developed training materials
for you to understand how you can help building owners comply. Get listed in our directory of
trained service providers when you take our training and pass the comprehension quizzes.
Important Dates for Buildings 25,000 sq. ft. and larger
Your 2025 EUI Target: Your first Energy Use Intensity (EUI) target year is 2025. That means
your projects must be completed by December 31, 2024.
Wait, what? Compliance with the 2025 target is measured by examining a full 12 months of
energy data in the calendar year 2025. Check out your next steps.
Check in on your EUI Target: There is still time to apply for a target adjustment! We assigned
your building its EUI Target based on how you benchmarked in 2019. But you may want to consider
a target adjustment if:
• Your square footage or energy use was incorrect in 2019
• Your high intensity building types and square footage were not broken down
• You forgot to exclude electric vehicle charging stations and parking energy use
• Your building has a data center, swimming pool, or a parking lot you can't exclude
New for Manufacturing, Agricultural, and Industrial Buildings: You will need to Benchmark
(many of you for the first time) by December 1, 2023!
What Changed? The benchmarking exemption for MAI buildings went away with the June rules
update. We launched a new Alternate Compliance Option for these buildings.
What's next? Read the new MAI guidance and watch a video overview of the compliance
pathways.
2
New Tools to Help You Plan
Energize Denver Lookup Tools: Our new Lookup Tool for buildings 25.000 sq. ft. and larger has
basic info about your building, your current status on compliance, and your future EUI targets. The
Lookup Tool for buildings 5.000-24.999 sq. ft. has basic building information, your Building ID
number, and your compliance status.
Energize Denver Forecasting Calculator: Find out how the electrification or renewables credits
will affect your progress towards compliance. The calculator will help you look at the work you've
already done and see how future upgrades will affect your EUI. Use this to work towards your
compliance and predict possible future penalties.
Third-Party Data Verification updates
On August 30, we will release updates to the technical guidance for third-party data verification.
This is needed for performance year benchmarking and target adjustments. Register to attend a
presentation and Q&A session to learn more about the process and new options. Wednesdar,
August 30 at 12:00pm
Heat Pump Rebates for Commercial and Multifamily Buildings
Switching to a heat pump can have a huge impact on your EUI. Plus, you can qualify for an
electrification credit if you've electrified at least 80% of your total energy use. Check out how you
can save thousands when you upgrade to a heat pump.
Celebrating the Equity Priority Buildings Program!
We've reached the first six-month mark for the Equity Priority Buildings technical assistance
program and wanted to celebrate our progress! We've identified more than 450 buildings that could
qualify for this program - 155 of them are now enrolled and working with our team. We've already
helped 44 Equity Priority Buildings correctly benchmark for the first time!
If you qualify for services, you gain access to:
• Expert guidance to implement energy-efficient measures customized to your building's
unique needs and goals
• Up to a level 2 ASHRAE Energy Audit
• Assistance filling out benchmarking reports and target adjustment forms
Go to our Equity Priority Building page to learn more about the program and fill out an application.
Thank you,
Building Performance Help Desk
Office of Climate Action. Sustainability. Resiliency
City and County of Denver

Have you got any hair left after reading that.!! 

I ordered a bunch of Iwasaki 50w clear MV lamps from CP lighting
(and some nice ceramic sockets, and some little 8w warm white halophosphate fluorescents, and a 97 CRI LED bulb...)

One of the Iwasakis is for myself, 2 to keep at work as spares for the Narva NF80 that's in use for various things. The Narva isn't likely to burn out, but if it gets dropped, a replacement specialty made Osram high pressure mercury lamp will run 500 euro which is a bit silly, compared to the 27 euro of the Iwasaki so i got the green light to buy a pair while they were still available.