Reference

OSHA never writes 'yellow A-frame' into a standard. What 29 CFR 1910.22 requires is that walking-working surfaces be kept clean, orderly, and — where possible — dry, and that hazardous conditions be corrected or guarded. Posted warnings during mopping and spills are the universally recognized way…

Matting works by contact steps: industry guidance converges on 10-15 feet of walk-off length to strip the large majority of tracked soil and moisture — roughly the first five to eight footfalls. One 3-foot doormat captures a fraction of that; the system captures most of it: