UL-60950-23:2016 pdf free download – STANDARD FOR SAFETY Information Technology Equipment一Safety – Part 23: Large Data Storage Equipment.
6 Emergency stop system
This clause only applies if a SAFETY INTERLOCK override is provided as specified in Clause 5.
An emergency stop system shall override all other controls, remove drive power from hazardous moving parts and employ automatic braking, if necessary, to cause all these moving parts to stop.
Components of the emergency stop system shall be of an electromechanical type. An emergency stop control may consist of:
— a switch complying with lEG 61058-1, that also meets the requirements of 2.8.4, 2.8.7, 2.8.8 of IEC 60950-1, and that is provided with a latching type mechanism
meeting the requirements of IEC 60947-5-5, or equivalent, or
— an emergency stop device in accordance with IEC 6094755a…
— a switch complying with either UL 508. UL 1054. UL 61 058-1. CAN/CSA C22.2 No.
61 058-1 or CSA C22.2 No. 14 and provided with a latching type mechanism meeting
the requirements of IEC 60947-5-5.
NOTE 1 In the United Kingdom an emergency stop system complying with the requirements of lEG 60204-1 and ISO 13850 is required where there is a risk of personal injury.
Restarting of the mechanical system shall only be possible by initiating a start control procedure after the emergency stop control has been manually reset.
For equipment where a person may completely enter the WORK CELL, the emergency stop system shall include a minimum of two emergency stop controls, one outside the WORK CELL and one within the WORK CELL. The system start up procedure shall include a non-hazardous method to ensure no person is present in the WORK CELL. If it can be shown, after application of the 7.1 single fault tests to the movement control circuitry or other sensing means, that such tests do not by-pass the non-hazardous start up procedure, the emergency stopping distance test of this subclause is not required.
For equipment where a person may only partially enter a WORK CELL or compartment, a minimum of one emergency stop control shall be provided outside of the WORK CELL. The emergency stop system shall be operable by the person needing to have access to the WORK CELL.
An emergency stop control provided outside the WORK CELL shall be readily visible and shall be
located on the equipment such that the person operating it can see if the WORK CELL is occupied.
The installation instructions shall require that space be provided around the control so that an
OPERATOR or SERVICE PERSON can easily reach and activate it.
An emergency stop control provided inside the WORK CELL shall be readily accessible from anywhere inside the WORK CELL and shall be provided with lighting to permit easy identification. It shall consist of a red palm or mushroom head button or be provided with an indirect arrangement, such as an easily identifiable red safety cable, that activates the emergency stop system.
Compliance is checked by inspection and, if necessary, the following tests.
While the mechanical system is operating at its maximum kinetic energy (carrying maximum
load capacity at maximum speed) the emergency stop system is to be activated, and the
distance to stop measured. The results of the distance measurements shall show that after
activation of the emergency stop system, any subsequent motion in any direction would be
unlikely to present a risk of injury.