Fomabrom 113 has a different sensitivity than their other papers. Here's the quote from the data sheet:
"Safelighting
FOMABROM VARIANT 113 BO is orthochromatic sensibilized photo paper so if you work with it you should use safety illumination different from common black and white photo paper. It is routinely processed at indirect safety illumination with wavelength of 625 nm and higher, corresponding colour of safety illumination is orange or red. As to its high sensitivity the processed material has to be exposed to such illumination only for the time necessary for its processing. Length of exposure and a distance of the processed material from the illumination source should be tested."
("sensibilized," don't you just love British English...)
I'd only use red with this paper. Plus, I'd limit the exposure time to safelight by minimizing the time the paper is out, dimming the light or pointing it away from the tray area. I always develop prints face-down for most of the development time, turning the print face-up for just a few seconds at a time to check on the progress of development (at 20 sec., 1 minute, 1'45").
FWIW, I use Fomabrom 111 a lot and have found that a regular Kodak OC safelight fogs this paper very quickly. I've switched to Wratten #1 and 1A filters for my whole darkroom now. I haven't really tested for the Hershel effect. Maybe I'll do that today.
Best,
Doremus