My 2p / 2c You’re presumably asking an NRTL to list your product so it can be a bit of a “their bat, their ball”, but I would ask them at what height are they applying the horizontal force as in my view it is unreasonable to do this above shoulder height, and even that is unrealistic for how people push things.
If I understand correctly, the top of the robot is 70” above the floor – that is a very high height to push anything. SEMI-S8-1116 (2016) states that 95th Percentile Male (US) standing shoulder height is 61.9 inches (citing Pheasant (1998), MIL-STD-1472D(1994) and SAE J833(1989)). Best regards Charlie Charlie Blackham Sulis Consultants Ltd Tel: +44 (0)7946 624317 Web: https://sulisconsultants.com/ Registered in England and Wales, number 05466247 From: Steve Brody <[email protected]> Sent: Tuesday, February 13, 2024 5:37 AM To: [email protected] Subject: [PSES] 61010-1 Stability test, Para 7.4 Stability Experts: I need your opinions on the following. I am having a 'discussion' with an NRTL on a product that I can't show you a picture of but here is a description: * the base of the unit is 20" w x 26" l x 29" hf * the base of the unit is mounted on caster/leveling feet devices that when positioned for use, the leveling feet are lowered and the casters come off the ground, and the leveling feet are sufficiently rated for more than 4x the load of each corner * in the middle of the top of the base there is a robot mast for the Z axis, and it measures roughly 4" square and is 41" tall * the whole product weighs 220 lbs The stability requirements in 61010-1 are as follows, and I highlighted the text of interest: Equipment and assemblies of equipment not secured to the building structure before operation shall be physically stable. If means are provided to ensure that stability is maintained after the opening of drawers, etc. by an OPERATOR, either these means shall be automatic or there shall be a warning marking to apply the means. Each castor and support foot shall be RATED to support a load of at least 4 times its normal load, or the castors and support feet shall be tested according to d) and e), below. Conformity is checked by inspection and by carrying out each of the following tests, if applicable, to ensure that the equipment will not overbalance. Containers contain the RATED amount of substance which provides the least favourable conditions of NORMAL USE. Castors are in their least favourable position of NORMAL USE. Doors, drawers, etc. are closed unless otherwise specified below. 1. * Equipment other than HAND-HELD EQUIPMENT is tilted in each direction to an angle of 10° from its normal * Equipment which has both a height of 1 m or more and a mass of 25 kg or more, and all floor-standing equipment, has a force applied at its top, or at a height of 2 m if the equipment has a height of more than 2 The force is 250 N, or 20 % of the weight of the equipment, whichever is less, and is applied to all surfaces in directions which could cause the equipment to topple. Stabilizers used in NORMAL USE, and doors, drawers, etc., intended to be opened by an OPERATOR, are in their least favourable positions. * Floor-standing equipment has a force of 800 N applied downwards at the point of maximum moment to: * all horizontal working surfaces; * other surfaces providing an obvious ledge and which are not more than 1 m above floor Doors, drawers, etc. are closed, except that those intended to be opened by an OPERATOR are in their least favourable positions. When the force was applied at the top of the robot mast, it unit started to topple at 38 lbs, which is less than the required 44 lb force according to the standard. The case I presented why this test was not applicable was: * because the robot mast is located in the center of of the unit, and not flush with the sides, that it did not represent the same situation as a bookcase, filing cabinet, or other product which if someone were to bump into it, they would not be contacting the robot mast to due to the location in the center of the top. * the robot mast is part of a component and not part of the structure of the product, and so the test should be done at the top of the base unit, and no higher. * there is text in the user manual that says not to push on the robot mast when moving the product to new location * and, if absolutely necessary, we an add do not push labels at the top sides of the robot mast The NRTL rejected my rationale so I am looking to you to get your thoughts on this before I press on with them. Do you think the test is applicable? You can respond here publicly or privately, or at [email protected]<mailto:stevenb@prduct> Thanks in advance, Steve Brody [email protected]<mailto:[email protected]> C - 603 617 9116 ________________________________ This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. 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To post a message to the list, send your e-mail to [email protected] All emc-pstc postings are archived and searchable on the web at: https://www.mail-archive.com/[email protected]/ Website: https://ewh.ieee.org/soc/pses/ Instructions: https://ewh.ieee.org/soc/pses/list.html (including how to unsubscribe) List rules: https://ewh.ieee.org/soc/pses/listrules.html For help, send mail to the list administrators: Mike Sherman at: [email protected] Rick Linford at: [email protected] For policy questions, send mail to: Jim Bacher: <[email protected]> _________________________________________________ To unsubscribe from the EMC-PSTC list, click the following link: https://listserv.ieee.org/cgi-bin/wa?SUBED1=EMC-PSTC&A=1
