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BMS Pico/Nano-Rack (pat.pend.)
(Paper delivered at 1998 NATRS)
The Nano/Pico-Rack was developed to provide firefighters and other emergency workers with a compact, safe, and durable personal escape descender. Early in the development of the Pico, it was realized that greater friction from each bar could be realized by essentially using each bar twice. It was then quickly realized that to do this however, none of the bars could be openable.
In regular brake bar racks this would be a serious disadvantage, since a device constructed this way can only be rigged by threading the rope through the device from the end of the rope. In the case of a personal escape device this becomes a major advantage in that it cannot become accidentally de-rigged without pulling the rope through it. To avoid any chance of the rope being pulled through the Pico in use, a stopper knot should be tied in the end of your personal escape line.
After many different methods of rigging the Pico were experimented with, the "standard configuration" was adopted as providing the greatest number of advantages . The primary advantage being the "self compensating" nature of this configuration. This simply means that the friction generated by the device is proportional to the load the Pico is supporting. In other words, a heavy individual rappelling on a Pico has to exert about the same braking force as a light person. Other personal escape descenders do not share this feature and must be "tuned" to the user's weight and then re-tuned if that weight changes.
A secondary advantage to this configuration is its ability to be adjusted quickly and easily to any position on the rope. This is accomplished by simply spreading the bars and pulling the rope through the Pico. This can save critical time in establishing an anchor especially if it is not near the exit point.
A third advantage to the "standard configuration" is that it is symmetrical . This means that it is very easy to visually check for proper configuration in both training and in actual use. A further aspect of this symmetry is that it makes no difference which end of the rope is loaded and which is used to control descent. They are interchangeable.
The concept of the Pico proved to be so well suited to personal escape that it quickly spawned two larger versions for other uses on larger diameter rope. The Nano-Rack was created to accommodate 10 mm personal escape line and the Nano-Plus to be used on 1/2" rescue rope.
Both the Pico and the Nano both pass the NFPA 1983 (95 ed) requirements for "personal use" descent control devices. The Nano-Plus will pass the "general use" specification.
Further applications of the Pico/Nano family of devises include: pre-rigged slope rescue kits, pre-rigged lowering kits for the fire service, as well as bailout kits for ski patrol and utility workers.
The Pico/Nano-Racks, as well as all descent control devices made by BMS, are constructed of high tensile stainless steel alloys. Not only does this material provide superior abrasion resistance over aluminum but also improves the smoothness of operation.
~ Carroll C. Bassett ~
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