Existing Joist Tag

[Once20036]

Good Morning Eng Tips,
I`m starting off a new project in an existing building, circa 1975.
I retrieved a joist tag that reads as follows:

24H8 39 11-1/2 (as a stacked fraction) J3​

Ceco Corp Pittsburgh PA​

I`ve worked with a lot of historic joists and I`m generally familiar with tags, but there are a couple here things I haven't seen before.
1) I`ve been saying for years that I wished these joist tags included the joist size. I intend to double check everything, but it looks like that happened here and I have a 24H8 joist.
2) I`ve never seen a stacked fraction before. Typically this middle portion is the job number.

Has anybody seen "39" or "39 11-1/2" before? This doesnt feel like a job number, but I don't know what it is.

 

[KootK]

Pure speculation:

1) 39'- 11 1/2" joist length?

1) 39' joist with 11 panels and 1/2" diameter bent rod webbing?

 

[Once20036]

Thanks for weighing in Koot.
I love your option 1. Rough plans we have scale to 40-0" grid spacing, so 39 11-1/2 could well be the physical length of the joist. I was focused on traditional joist tag information and hadn't considered something along those lines.

I`ll be on site in a couple weeks and will update if I have any better ideas after walking to site.