Continue to Site

Eng-Tips is the largest engineering community on the Internet

Intelligent Work Forums for Engineering Professionals

  • Congratulations pierreick on being selected by the Eng-Tips community for having the most helpful posts in the forums last week. Way to Go!

OSHA Guardrail Wood Grading

emart0429

Structural
Mar 22, 2007
10
Sorry if this has been asked and answered before, but I'm not finding it in any searches. I'm looking at fall protection requirements in OSHA Part 1926 and run into an appendix B which lists wood, pipe, and steel rail sections OSHA says meets their requirements for guardrail. Here's a link to the sections: 1926 Subpart M App B

The question I have is on the requirements for the wood members. It lists a 1500 lb-ft/in2 construction grade lumber. Here's a quote from App B, "Wood components shall be minimum 1500 lb-ft/in2 fiber (stress grade) construction grade lumber; the posts shall be at least 2-inch by 4-inch (5 cm × 10 cm) lumber spaced not more than 8 feet (2.4 m) apart on centers; the top rail shall be at least 2-inch by 4-inch (5 cm × 10 cm) lumber."

What is "1500 lb-ft/in2 construction grade lumber?" Construction Grade DF-L or HF (most popular materials around here) only have a Fb value of around 1000 lb/in2 which makes me wonder why OSHA has the units listed as lb-ft/in2?

Anybody have any experience with this?

Thanks,
Erik
 
Replies continue below

Recommended for you

Here’s a guess while you wait for someone with the knowledge:

I don’t see a single species with construction grade Fb greater than 1,500 psi. That’s the first clue. They’re likely referring to adjusted design values (F’b), not reference design values (Fb). Moreover, OSHA doesn’t care if you spring for Select Structural over Construction. Why would they?
 
"lb-ft" may be a corruption of "lbf" for pound-force, which is the numerator in psi.
 

Part and Inventory Search

Sponsor