Elevator Hoist Beam Factor of Safety

[Robcat71]

Hello,

There are some conflicting opinions/approaches to designing elevator hoist beams with my co-workers. I have read some that implement a factor of safety by doubling the required beam rating, and following either LRFD or ASD design which results in a FOS of 3+. I have read that some engineers use a FOS of 5 for such loading, which seems a bit excessive in my opinion for the use of the beam.

Does anyone have a reference that clearly states that requirement, and what have you typically done in the past?

Thanks in advance for your input!

 

[SlideRuleEra]

There are some conflicting opinions/approaches to designing elevator hoist beams with my co-workers.
I have read some that implement a factor of safety by doubling the required beam rating, and following either LRFD or ASD design...
I have read that some engineers use a FOS of 5 for such loading, which seems a bit excessive in my opinion for the use of the beam.

1) Does anyone have a reference that clearly states that requirement...

2) ...what have you typically done in the past?

1) Starting in 1921, all aspects of elevator design are covered by ASME 17.1 Safety Code for Elevators and Escalators (about 600 pages).

In the 2016 edition, Paragraph 5.3.1.16.1 "Overhead Machinery, Beams, and Supports" states:

Also, Paragraph 1.3 "Definitions" states:

So, Factor of Safety is 5, and calcs are preformed using "old" ASD (Allowable Stress Design) but based on the steel's ultimate strength instead of yield strength... not LRFD or "modern" ASD (Allowable Strength Design).
For example, allowable bending stress for A992 beam is 65 KSI / 5 FOS = 13 KSI.

2) Require strict compliance with the current version of ASME 17.1.

 

[dik]

...and for mining purposes, if over the shaft, then you might need a FOS = 10.

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[JStephen]

I don't know anything about elevators, but googled "elevator hoist beam" just to see exactly what that is. And evidently, it's an optional beam used in installing/rigging/personnel anchorage, not for actually operating the elevator, which explains the original question relative to the responses above.
Also see this thread, note the discrepancies there:

https://www.eng-tips.com/viewthread.cfm?qid=502764

For what it's worth, in powered scaffolding design, the anchorage has to be adequate for the stall load of the hoist, which is another potential criteria.