fall protection

[RMPE]

need a guide performance spec for fall arrest system for use in aircraft hangars. Replacing old iinsufficient 1/4" cable and brackets. Any suggestions where to look/go helpful vendors??

 

[svc430]

If you’re going to be specifying any type of Personal Fall Arrest System, then reading and understanding OSHA 29CFR1910.66, Appendix C is an absolute must. This standard is very ‘performance’ oriented and can be found at OSHA’s web site (

http://www.osha.gov).

Miller/Dalloz Fall Protection is a very reputable supplier for these kinds of systems and you can get some good information at their web site (

http://www.christiandalloz.com/CDalloz_Internet/fall/fallmill.htm).

Other suppliers include Rose Manufacturing and DBI/SALA; though I’m not as familiar with their product line.

Some things to consider with these systems include the number of workers for which the system should be designed and the clear distance below the system (you don’t want a worker to hit something below the system before the fall is arrested). You also need to be aware of the ‘free fall’ distance, which is that distance a worker will fall before the system begins to apply an arresting force. This distance, which depends on the lanyard length and point of attachment, is limited to 6 feet by OSHA.

If you’re talking about horizontal life lines, I think most suppliers can provide ‘pass-thru’ provisions at the intermediate life line supports. This is a great feature that enables a worker to walk past the intermediate supports without detaching and then reattaching his or her lanyard. Miller does this with their ‘Transfastener’, a sort of carrier that rides on the cable and can pass-thru the support brackets (workers lanyard attaches to the carrier). Horizontal life line systems will likely include ‘energy absorbers’ at the ends of the line (without these, line tension loading can get pretty high). These types of systems must also include some sort of turnbuckle and tension indicating device for installation.

In my experience, the system supplier will provide all the hardware, but the design of the support structure is up to the Owner. Typically, the supplier will provide the loadings from the system (if they don’t, find someone else). When reviewing these loadings, be aware of the direction in which they are applied and whether or not they include a safety factor.

Whatever you do, don’t let a contractor simply string a cable down the length of the building and call it done. The proper design and installation of these systems will take some effort on the part of the Owner’s engineer, who must work closely with the supplier of the system.

 

[RMPE]

Thanks for the tips. I understand the basics. We're replacing a line strung down the middle of the building. In one case, I think were stuck with a cable because we have a very high arched truss for the hangar and no lateral bracing other than more cables.

In the second hangar, we have a flat bottom roof trusses we can use to support a trolley ( I believe would be the preferred system) or a cable system.

We contacted tritechfallprotection and they're "helping" somewhat. Looking for a model performance spec to use. We were going to add the Vendor supply PE stamed structural calcs for proposed system. That way, we're not limiting their options. I'll review all calcs of course.