Factor of Safety on Scaffolding

[Bigcobaltsea]

I have a question regarding Factor of Safety on steel scaffolding. The resources I find state FS=4 on the structure. It is unclear whether this is FS=4 on the yield or ultimate stress of the steel. Thanks!

 

[bimr]

Typically, the factor of safety on scaffolds is 4. Factors of safety, however, can vary with a manufacturer's experience.

Handbook of rigging: lifting, hoisting, and scaffolding for construction and ... By Joseph A. MacDonald

The factor of safety is the ratio of the ultimate stress to the allowable stress:

FS = Ultimate Stress/Allowable Stress

Where:

•Ultimate Stress: is the maximum stress which a member can withstand before failure (can be tensile or yield strength)
•Allowable Stress: is the maximum stress which a member is designed to handle

 

[Bigcobaltsea]

That makes sense of course. So say then for top-quality manufacturer, prequalified welds, A36 steel, FS = 4 on ultimate strength of the steel?
Regarding A36, is the compressive yield strength 36 ksi as well as tensile?

 

[cvg]

according to OSHA, safety factor means the ratio of the ultimate breaking strength of a member or piece of material or equipment to the actual working stress or safe load when in use 1926.32

per 1926.451(a)(1) each scaffold and scaffold component shall be capable of supporting without failure, its own weight of at least 4 times the maximum intended load aplied or transmitted to it

 

[bimr]

For A36, Fy=36 ksi.

 

[BigH]

Guess Hong Kong scaffolding won't work . . . - isn't normally steel. Just make sure they don't deliver water pipe instead of scaffolding pipe.

 

[chicopee]

It kind of makes me wonder what kind of safety of factor is there with bamboo scaffolding used in Asia?

 

[BigH]

That's what I was getting at. They have, if I remember correctly, 1`year apprenticeship before they can start doing small stuff . . .

 

[MiketheEngineer]

I have also heard that if one fails and someone dies - it is up to the builder to recuse himself - if you know what I mean!!

 

[cvg]

if there is no posted load on the scaffold, then it is up to the user to determine the appropriate max load / FS