Ergodyne Men's Skullerz 8950 Safety Bump Cap with Long Brim (Multicolour, Free Size)

Q: does this hat work as a biysicale helmet

No, this is not a bicycle helmet. It is not a hard hat either. It is for preventing minor head contact while on the job, in light industry.

Q: do these bump caps adhere to OSHA standards?

No, it doesn’t comply to anything that I’m aware of, however, I will tell you, that it’s great for general protection when you don’t need a hard hat. When I’m on the job site, I don’t often need a hard hat as it’s rare for someone to be working over head. I haven’t used it yet, but I am always wearing a ball cap, so if I feel like my head is gonna hit something that I’m crouching or crawling near this is great. I’ve also dropped my own hammer on my head a few times. Today I actually was wearing it around for house work and my metal tool box lid fell while I was putting some tools away, didn’t feel a thing. Long story short, if you are required to wear a hard hat, but still feel like you should protect your head with good ventilation, this hat is great, and comfy.

Q: Is this a one size fits all style?

It has a velcro band on it. So the answer is it fits most sizes. The limiting factor is that the hard plastic inner liner. Since it is not very flexible, it will fit to the common percentile of head size. If you have a very large head size or super small head size it might not fit very well. I'm a standard head size or maybe just a little under and it fits me just fine.

Q: Would it work for sailing as protection against getting hit by the boom?

This is a lightweight hat that mostly protects against bumping your head on something you might walk under (wood beam, tree limb, etc). If your walking around on your boat while it's at the dock, it would help, but it's not heavy enough to help if the boom swings around at you while sailing. Also, it has no chin strap.