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RE: Fall Protection System - Loading

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Raj,

I forgot to say -- We have installed proprietary fall arrest systems
that used cables.  However, those fall under the "engineered systems" of
OSHA and probably don't impart the full OSHA loading on the structural
elements.  They have springs to absorb energy and other special devices
to allow an elongation in the cable system without damage.  The system
we used also limited the falling distance to about 1 or 2 feet.  This
also keeps the forces lower than OSHA.

Michael Ritter, PE

> -----Original Message-----
> From:	RajSTC(--nospam--at)aol.com [SMTP:RajSTC(--nospam--at)aol.com]
> Sent:	Tuesday, November 16, 1999 10:36 AM
> To:	seaint(--nospam--at)seaint.org
> Subject:	Fall Protection System - Loading
> 
> Recently, I was involved with the design of a fall protection system,
> for 
> personnel engaged in activities on top of trucks in petroleum product
> loading 
> rack.  I was asked to follow OSHA guidelines.  According to OSHA,
> "Lifelines 
> shall be secured above the point of operation to an anchorage or
> structural 
> member capable of supporting a minimum dead weight of 5,400 pounds".
> Design 
> based on this requirement resulted in lot of structural steel, which
> seems to 
> me to be an overkill.  The project was on a fast track, so I could not
> do 
> enough research before sketching the details.
> 
> Now that the project is behind me (except for comments from all those 
> self-styled structural engineers, like "which idiot designed this ?")
> I can 
> get to the bottom of the design philosophy.  I am curious to know the
> basis 
> on which OSHA came up with their recommendation.  Yes, it is a dynamic
> 
> problem, but what assumptions or tests led to the 5,400 load?  Am I
> justified 
> in stressing the steel members to their yield limit, considering the
> loading 
> to be extraordinary?  Is it possible to get theoretical basis for the 
> recommendation etc.  I am looking forward to some lively discussions
> on the 
> topic.  Thanks, in advance.
> 
> Raj.
>