IEC 60601-1 - Medical Electrical Equipment Safety 9.2: 9.2 Mechanical hazards associated with moving parts

Equipment with moving parts is so designed, constructed and arranged that, when correctly installed and used as the documents describe, or when misused in reasonably foreseeable ways, the risks those parts present are brought down to an acceptable level through protective measures chosen for ease of access, function, shape, energy and speed of motion and benefit to the patient, exposure needed for the intended function being acceptable residual risk, and warnings marked or given where hazards persist. A trapping zone is not a hazard where feasible if its gaps meet the Table 20 dimensions (adult or child values as appropriate), if safe distances per ISO 13857 separate operator, patient and others measured from their expected positions, if guards and other risk control measures such as light barriers or collision detection are robust, not easily bypassed and introduce no new risk (fixed guards removable only with a tool; movable tool-free guards staying attached, interlocked so parts cannot start while the zone is reachable and stop when opened, and failing safe on loss of a component; control-system measures stopping movement if the zone is reached, backed by an emergency stop or single fault safety), or if continuous activation is used with the movement in the operator's view, movement only while the operator holds the control where their response can be relied on, and a second measure where a single fault defeats the activation; where those measures conflict with the intended use, the speed of movements positioning parts or the patient is limited so the operator keeps control and the overtravel after a stop command creates no unacceptable risk, checked against the stopping distance calculations. Controls are positioned, recessed or protected against accidental actuation unless the usability process for the intended patient concludes otherwise or actuation is not risky; overtravel past range limits is prevented by end stops strong enough for normal use and foreseeable misuse in normal and single fault condition, tested loaded per Table 33 (6,000 cycles at maximum speed with no range limit system, 50 with a non-independent system defeated, 1 with two or more independent systems defeated, 50 for manual drive) and still functional afterwards. An emergency stopping device, where needed, reduces risk to an acceptable level, is within reliable reach and response of the operator, readily accessible, not part of normal operation, introduces no further hazard nor prevents removing the original one, breaks the full load including stalled motor currents, acts on a single action, has a red actuator distinct from other controls marked with the stop symbol or STOP unless it cuts all power, holds the equipment disabled until a different deliberate action resets it, and is shown suitable for its application. Means allow quick, safe release of the patient on breakdown, power failure, activation of a protective measure or emergency stop, preventing uncontrolled movement, entrapment by moving parts or loss of exit routes, and hazardous movement of other parts after counterbalanced parts are removed.