Question for the shop lighting experts

[metlmunchr]

My shop is 9000 sq ft with about 1500 sq ft of offices, restrooms, etc and 7500 sq ft of work area. 60x150 with 18ft eave height. We built it around 1990 and used 400w HPS fixtures in the work area. Yeah, the color temp *****, but it was built primarily for heavy equipment maintenance and back at that time the HPS lights were the most efficient by far at 50,000 lumens per 400w fixture. But now I really need to convert part of the space to something in the 5000K range or get me a guide dog for when I go blind.

Now to the question... I see recommendations here for high bay led's that are usually some sort of rectangular fixture with 15K to 20K lumens. I've got a couple hundred 8ft 2 tube strips we removed from a large metal building we dismantled. If possible, I'd like to convert these to bypass led tubes and use them rather than spending a few thousand bucks on new fixtures.

But I'm not sure if I need high bays or if these strips will do the job if I use enough of them. I can hang them at 14 ft and have plenty of clearance if I need to move something in or out in the future. Is there some site that shows how to calculate light levels based on lumen output and fixture height? I've looked around a bit and haven't seen anything but I imagine its out there.

And, if the strips are a workable solution, would you recommend going with the 8ft single pin tubes that are available now, or would it be better to convert to use four 4 ft tubes per fixture. Cost of 4 tubes plus the conversion kit is about the same as 2 8ft tubes, but it seems to me there are more options available in the 4ft tubes and their price seems to be dropping faster as well.

Thanks in advance for guidance or suggestions.

 

[Platonic Solid]

Depends on the value you put on the labor involved in converting and mounting many fixtures to compensate for the lower lamp/fixture output at 14ft mounting height. If you are doing all the labor and you put a value of $0 on that labor then 4ft retrofits are your most cost effective solution. See post 1 of best light fixture sticky for bulb recommendations.

Here's the Visual Photometric Tool (link) for testing your layout.

 

[metlmunchr]

Thanks a bunch Platonic. Just the info I needed.

I'm semi retired, no employees to supervise anymore, so I've got plenty of time. Have a scissor lift too, so no rental expense there either. And, it gets me out of the house and out of the range of honey-do projects, so that's a net positive