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Hello, In R15.06-2012, it states that there is a maximum height a barrier can be above adjacent walking areas is 7". This is to ensure that no one can come in contact with the equipment inside. In applications where there could be large build ups of combustible dust or require routine cleaning of the area, is there a different height/ acceptable alternative to the 7"? Currently there is an installation which the eentire robot system is shutdown in order to clean the area due to the height of the guarding. This dramatically hinders production and could potentially cause employees to attempt to defeat the guarding to maintain the equipment. Thank you for your help
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From what I understand the 7” restriction is to protect against someone crawling under the fence. Maybe they could add a dust collection system or vacuum of some type to continually clean the area. Not knowing the layout it is difficult to understand where the issue is. If the dust is on just the floor, maybe a Roomba or multiple Roombas could run around the cell vacuuming up. If it piles on fixtures they may need a dust collection system. Is there a way to prevent or restrict the amount of dust being created. Just a couple of thoughts.
To the best of my knowledge the maximum allowable distance from the bottom of the guard to the adjacent standing surface is 7". ANSI RIA R15.06-2012 Part 2 18.104.22.168 states "ISO 13857 shall be used to determine the appropriate dimensions for the opening from the bottom of the guard to adjacent standing surfaces and any openings in the guard" (also shown in figure 12) RIA TR R15.406-2014 states "... the opening between the walking surface and the guard shall be no greater than 180 mm (7 in.)." Note 2 states " In Canada, CSA Z432 and Z434 require a lower dimension of 150 mm (6 in.) .."
The intent of the maximum height of 7 inches (180 mm) is to allow cleaning while preventing access. This applies to a mechanical guard. In the case of an AOPD, such as a vertical light curtain,, the maximum height from the walking or working surface is 11.8 inches (300 mm). Just remember there is a significant safety distance required at this height. Please refer to ISO 13855 and ANSI B11.19. Diane's suggestions offer additional alternatives. A dust collection system located in proximity to where the dust is generated would seem the best option.