Elevator Doors

Special Topic: Elevator Doors Vertical Freight Door Protective Devices by Henry E. Peelle III, DM Can the United Parcel Service or slide-up-to-open counterweighted car Federal Express delivery person gates for freight elevators not intended operate a freight elevator? Under for general public use. current ASME A17.1-2007/B44-07 Current Requirements code requirements, the answer is Current ASME A17.1-2007/B44- “no.” Only the operator and persons 07 requirements for bi-parting land - authorized to transport freight can ing doors permit simultaneous or ride a freight elevator. Yet, building sequential closing. During simul - owners and tenants are increasingly taneous operation, the car gate and asking if package delivery personnel landing door close together. In con - and over-the-road truckers can trast, sequence operation requires operate their freight elevator. To the car gate to be at least two-thirds heed this call, substantive changes closed before the landing door begins in door protective requirements will to close. Continuous pressure on the appear in the next addenda to ASME closing push button is required for A17.1-2007/B44-07. This update not simultaneously closing the car gate only improves user safety, but also and landing doors. Bi-parting landing permits package deliverers, over- doors with sequence operation can the-road truckers and other adult close by either continuous pressure users not part of the general public 1 on the door-close button, by auto - to operate freight elevators. matic initiation through the operation This article begins with an over view control or dwell timer, or by momen - of existing door protective require - tary pressure on the door close but - ments for vertical freight elevator ton. Doors closed by automatic or doors and the changes approved for momentary pressure also require a inclusion in the next addenda to reopening device, advance-of-closing ASME A17.1/B44. The article then audible warning, limited average turns to detailed discussions of closing speed and a door button that, the new requirements and related upon initiation, will stop closing, or rationale. Admittedly, these new stop closing and initiate reopening. requirements are complex and tech - Current safety requirements assume nical. Before concluding, the article the presence of freight operators and overviews one approach to compli - freight handlers familiar with the ance and a corollary method of in - elevator, including door operation. Henry E. Peelle III is CEO spection. This approach demonstrates Continuous-pressure close gives the of The Peelle Co., a manu - that practical implementation is far freight-elevator operator control facturer of freight-elevator simpler than users and regulators might over the initiation, continuation and doors. Peelle holds a BS in Mechanical Engineering from anticipate. The new ASME A17.1/ cancellation of door closing. In sum, Bucknell University, an MBA B44 requirements address both verti - continuous-pressure close passes re - from University of North cal counterbalanced bi-parting and sponsibility for safe door closing to the Carolina-Charlotte and a vertical slide-up-to-open landing operator. Simply releasing the door close DM from the University of Phoenix. Address cor - doors. This article will focus on the button will initiate door reopening. respondence to: [email protected]. more prevalent and popular vertical For freight elevators with auto - bi-parting landing door coupled with matic or momentary pressure closing, 148 | WWW.ELEVATOR-WORLD.COM | October 2008 Codes & Standards trained freight operators and freight handlers understand To mitigate the risk of potential injury to this broad - the meaning of door close warnings, how to cancel door ened base of users, new requirements add detection close and how to initiate reopening. Sequence operation devices able to sense the presence of an adult user within blocks egress and warns of pending landing door closure or immediately adjacent to the closing car gate, without by placing an obstruction (i.e., the car gate) into the en - regard to the location of the door or gate. Once the user trance path before closing the bi-parting landing door. enters the plane of the car gate, detection devices prevent Contact-type reversal devices mounted on the leading closing or initiates reversal to open, if closing is under - edge of the car gate stop and initiate reopening should way. Reversal becomes independent of the actions or the closing car gate encounter an obstruction. While awareness of the user, rendering moot operator knowl - code-mandated limits on average closing speed mitigate, edge of the system and reaction time. in part, the level of imparted kinetic energy caused by im - The new code requirements, by creating zones of pact, the current code permits the obstruction to experi - detection independent of the door or gate leading edge, also reduce the probability of incidental contact resulting ence the full kinetic energy of the closing car gate before from travel inertia. A moving system with mass cannot initiating reversal 2. New Requirements for Freight stop instantaneously. Initiation of reversal of a closing Elevator Door Object Detection door or gate will cause the motor operators to reverse direction and impose braking. Factors such as gate mass In the new code requirements, the sign limiting freight and speed, electro-motive forces, friction and electrical elevators to operators and freight handlers will now read, device response time impose a delay between initiation “THIS IS A FREIGHT ELEVATOR, NOT A PASSENGER of reversal and actual physical reversal of the door or ELEVATOR, AND NOT FOR GENERAL PUBLIC USE” [Pub - gate to the open direction. lic Review Draft November 2007, A17.1a-200x, Addenda In current requirements, initiation to open may com - to A17.1-2007, Requirement 2.16.5.1.2, Capital letters in mence when the reversing device physically contacts the the original] 3. This altered signage permits use by the obstruction. These devices are typically mechanical and non-trained adult user. However, this requirement still require the force of contact to signal the presence of an prohibits use of freight elevators by the general public. obstruction. Reversal systems employing a single infrared These new requirements open freight-elevator use to pack - age delivery personnel and other non-employee freigh t beam located just below the leading edge of the car gate handlers, while excluding the general building tenant, eliminate the necessity for physical contact to initiate re - visitor, passersby, child or other members of the public. versal. However, even this arrangement holds a probabil - The new ASME A17.1/B44 door protective require - ity that inertia of the closing car gate will carry the car gate ments remove the assumption of a vigilant and aware leading edge into the obstruction located just below the freight elevator operator. Unlike trained operators, pack - leading edge, albeit at a much lower level of kinetic energy. age delivery persons might have limited understanding In contrast, new code requirements impose immediate of freight elevator operation and functionality. Package initiation of reversal to the open direction as soon as a delivery persons might not attend to persons entering or person places his or her body part in a zone of detection, leaving the freight elevator when he or she is closing the regardless of the relative location of the body part to the doors. Package delivery personnel might not understand door or gate. Entry of a body part into the detection zone the meaning of advance-of-door-close warning, nor, in will prevent the fully open door or gate from closing or high ambient noise environments, hear such warnings. initiate reversal to open if the car gate is closing. A per - Package delivery persons might be unaware that action son placing his or her head into a detection zone will on the door push buttons can initiate reopening. More - initiate reversal of a closing landing door or car gate, even over, package delivery personnel might not react with if the leading edge of the door or gate is at a distance well sufficient speed, even if aware of persons within the above that person’s head. opening, while door closing is in process. While these new requirements do not eliminate the In sum, extending usage of freight elevators to pack - potential of incidental contact caused by inertia, inci - age delivery personnel limits the effectiveness of many dental contact will only result if the person intentionally traditional safety devices employed on freight elevators, places his or her body in a position immediately adjacent such as continuous pressure close and advance-of-close to the leading edge of an already closing car gate. No warnings. Moreover, current code requirements permit - longer will the reversal system wait until the leading edge ting contact-type reopening devices leave the unaware approaches or makes contact with the obstruction. Instead , and untrained user vulnerable to the full kinetic energy of reversal to open will occur upon detection of an object in the closing car gate. the detection zone, regardless of door or gate location. Continued October 2008 | ELEVATOR WORLD | 149 Special Topic: Elevator Doors Continued With impact mitigation dependent on detection devices, table provides a comparison of current and new require - new code requirements incorporate detection device func - ments for freight elevators with bi-parting landing doors. tion checking prior to closing. Should function testing fail, Detection Zones the landing door and car gate will not close. During each The new requirements describe object sizes and detec - open-close cycle, function testing validates wiring tion zones, instead of proscribing the characteristics of between the light curtain and the operational control, the detection device. While this approach added consid - light-curtain output relay, light-curtain internal control erable complexity to the new requirements, proscriptive and light-curtain transmitting and receiving elements.

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