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UL 2344-2017 pdf free download
UL 2344-2017 pdf free download.Material Lifts.
19.2 Manually-operated lifts
19.2.1 The mechanical advantage offered by the gear reduction system and manual crank or lever operator shall not permit lifting of a load in excess of three times the rated working load of the lift. For a lever-operated lift, a force of 200 pounds (890 N) is to be applied to the end of the ‘ever at 90 degrees and in the direction to raise the lift. For a crank-operated lift, a force of 75 pounds (337 N) is to be used.
20.1 The maximum average lowering speed of a material lift shall be 20 ft/minute when it is loaded to its rated load capacity and fully extended. In case of power or other lifting failure a device shall be mounted on or integral to the lifting mechanism to limit the average lowering speed to 20 ft/minute. The average is to be determined from three trials.
21 10-Day Moist Ammonia Test
21.1 After being tested as described in 21.2 — 21.4, a brass part containing more than 15 percent zinc shall show no evidence of cracking when examined using 25x magnification.
21.2 Each test sample is to be subjected to the physical stresses normally imposed on or within a part as the result of assembly with other components. Such stresses are to be applied to the sample prior to and be affective during the test.
21.3 Three samples are to be degreased and then continuously exposed in a set position for ten days to
a moist ammonia-air mixture maintained in a glass chamber approximately 12 by 12 by 12 inches (305 by
305 by 305 mm) having a glass cover.
21.4 Approximately 600 ml of aqueous ammonia having a specific gravity of 0.94 is to be maintained at the bottom of the glass chamber below the samples. The samples are to be positioned 1-1/2 inches (38.1 mm) above the aqueous ammonia solution and supported by an inert tray. The moist ammonia air mixture in the chamber is to be maintained at atmospheric pressure with the temperature constant at approximately 93°F (34°C).
ELECTRICALLY POWERED LIFTS
22 Electrically Powered Lifts
22.1 Electrically powered material lifts shall comply with Sections 15 through 32. and 49 through 62 of the Standard for Scaffold Hoists, UL 1323. Lifts marked for indoor use only are not subjected to the rain test.UL 2344-2017 pdf free download.
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