SCOPE
Part 4 applies to elevators with other types of driving machines.
(a) Requirement 4.1 applies to rack-and-pinion elevators.
(c) Requirement 4.3 applies to hand elevators.
This Section applies to an elevator with a car raised and lowered by a pinion(s) on a rack.
NOTE: See also Part 8 for additional requirements that apply to rack-and-pinion elevators.
Hoistways, hoistway enclosures, and related construction shall conform to Part 2, except 2.7 (see 4.1.2) and 2.8 (see 4.1.3).
In jurisdictions not enforcing NBCC, the controller shall be permitted to be located on the exterior of the hoistway wall or other approved location apart from the hoistway, elevator machine room, or elevator machinery space. A controller so located shall be available to and used only by inspectors, maintenance personnel, and repair personnel.
In jurisdictions enforcing NBCC, the controller shall be permitted to be located on the exterior of the hoistway wall or other approved location apart from the hoistway, elevator machine room, or elevator machinery space. If the controller is located outside the hoistway, machine room, and machinery spaces, it shall be made accessible only to elevator personnel.
A rack-and-pinion machine and its controls, if located on the car, shall be protected by a noncombustible enclosure to prevent accidental contact. Openwork noncombustible enclosure material shall be permitted to be used for rack-and-pinion machines located on top of the car, provided the openwork material rejects a ball 50 mm (2 in.) in diameter.
Access shall be provided to the rack-and-pinion machine for maintenance. Access panels to rack-and-pinion control equipment located in the car shall be provided with an electric contact and lock. The access panel shall be kept closed and locked. The electric contact shall be designed to prevent operation of the rack-and-pinion machine when the access panel is open. The lock shall not be operable by a key that will operate locks or devices for other purposes in the building. The key shall be available to, and used only by, inspectors, maintenance personnel, and repair personnel (see 8.1).
Electrical equipment, wiring, pipes, and ducts in the hoistway shall conform to 2.8, except that the main feeder of a rack-and-pinion machine located on the car shall be permitted to be installed in the hoistway.
The supports and foundations shall be designed to support all loads imposed by the elevator (including impact loading in the event of a safety application, stop by a speed-limiting device, or drive nut failure) in accordance with the building code. Allowable stresses for machinery and sheave beams or floors and their supports shall be in accordance with 2.9.4.
The car shall be provided with a safety identified in 2.17.5 or a rack-and-pinion safety. The safety shall be attached to the car frame or supporting structure. All car safeties shall be mounted on a single car frame and shall operate on one pair of guide members or on one vertical rack.
The safety shall be located as required by 2.17.1, or if it is a rack-and-pinion safety, shall be permitted to be located above or in the car, provided that the members to which they are fixed are part of the car frame and are designed to withstand the forces imposed.
Rack-and-pinion safeties are safeties in which a freely rotating safety pinion, a governor, and a safety device shall be permitted to form an integral unit mounted in the car. The freely rotating pinion travels on a stationary rack mounted vertically on the hoist structure. The rotating pinion drives the governor. When the speed of the car reaches the tripping value, the rotating governor actuates the safety device that, in turn, brings the car to a gradual stop.
In jurisdictions not enforcing NBCC, stopping distances for rack-and-pinion safeties and the travel of the car measured from the governor tripping time to the full stop time shall not exceed the values based on rated speed given in Table 4.1.9.1.
Table 4.1.9.1 Maximum and Minimum Stopping Distances for Rack-and-Pinion Safeties With Rated Load
| SI Units | Imperial Units | |||||||
|---|---|---|---|---|---|---|---|---|
| Rate Speed, m/s | Maximum Governor Trip Speed, m/s | Stopping Distance, mm | Rated Speed, ft/min | Maximum Governor Trip Speed, ft/min | Stopping Distance, in. | |||
| Min. | Max. | Min. | Max. | |||||
| 0.63 | 0.88 | 80.5 | 1 639.3 | 125 | 175 | 3.17 | 64.54 | |
| 0.76 | 1.06 | 116.0 | 1 703.5 | 150 | 210 | 4.57 | 67.07 | |
| 0.89 | 1.37 | 164.3 | 1 791.2 | 175 | 250 | 6.47 | 70.52 | |
| 1.01 | 1.42 | 206.2 | 1 866.9 | 200 | 280 | 8.12 | 73.50 | |
| 1.14 | 1.56 | 249.4 | 1 945.3 | 225 | 308 | 9.82 | 76.59 | |
| 1.27 | 1.71 | 298.7 | 2 034.2 | 250 | 337 | 11.76 | 80.09 | |
| 1.52 | 2.00 | 410.7 | 2 236.4 | 300 | 395 | 16.15 | 88.05 | |
| 1.77 | 2.29 | 537.2 | 2 466.5 | 350 | 452 | 21.15 | 97.11 | |
| 2.03 | 2.59 | 684.0 | 2 731.0 | 400 | 510 | 26.03 | 107.52 | |
| 2.28 | 2.86 | 848.3 | 3 029.9 | 450 | 568 | 33.40 | 119.29 | |
| 2.54 | 3.17 | 1 027.1 | 3 098.8 | 500 | 625 | 40.44 | 122.00 | |
| 3.04 | 3.75 | 1 439.9 | 4 101.5 | 600 | 740 | 56.69 | 161.48 | |
| 3.55 | 4.34 | 1 922.3 | 4 975.0 | 700 | 855 | 75.68 | 195.87 | |
| 4.06 | 4.92 | 2 473.9 | 5 974.5 | 800 | 970 | 97.40 | 235.22 | |
| 4.57 | 5.51 | 3 095.4 | 7 100.0 | 900 | 1,085 | 121.87 | 279.53 | |
| 5.06 | 6.09 | 3 786.3 | 8 305.8 | 1,000 | 1,200 | 149.07 | 327.00 | |
| 5.58 | 6.70 | 4 581.4 | 9 791.7 | 1,100 | 1,320 | 180.37 | 385.50 | |
| 6.09 | 7.31 | 5 452.3 | 11 379.2 | 1,200 | 1,440 | 214.66 | 448.00 | |
| 6.60 | 7.92 | 6 400.8 | 13 083.5 | 1,300 | 1,560 | 252.00 | 515.10 | |
| 7.11 | 8.53 | 7 421.1 | 14 935.2 | 1,400 | 1,680 | 292.17 | 588.00 | |
| 7.62 | 9.14 | 8 068.3 | 16 924.0 | 1,500 | 1,800 | 333.40 | 666.30 | |
| 8.12 | 9.75 | 9 642.8 | 19 050.0 | 1,600 | 1,920 | 381.61 | 750.00 | |
| 8.63 | 10.36 | 10 942.3 | 21 313.1 | 1,700 | 2,040 | 430.80 | 839.10 | |
| 9.14 | 10.97 | 12 266.4 | 23 713.4 | 1,800 | 2,160 | 482.98 | 933.60 | |
| 9.65 | 11.58 | 13 668.7 | 26 750.9 | 1,900 | 2,280 | 538.14 | 1,053.50 | |
| 10.16 | 12.19 | 15 145.2 | 28 925.5 | 2,000 | 2,400 | 596.27 | 1,138.80 | |
In jurisdictions enforcing NBCC, stopping distances for rack-and-pinion safeties and the travel of the car measured from the governor tripping time to the full stop time shall not exceed the values based on rated speed given in Table 4.1.9.1. When calculating stopping distances, the kinetic energy from the driving unit shall be taken into account.
Counterweights, where provided, shall conform to 2.21.
Guide rails, guide-rail supports, and their fastenings shall conform to 2.23.
The rack-and-pinion drive shall consist of one or more power-driven rotating pinions mounted on the car and arranged to travel on a stationary rack mounted on the supporting structure. The drive shall have at least one pinion, one rack, and two backup rollers, which shall act on the same section of rack as the drive pinion. Driving machines utilizing a two-sided rack, where two drive pinions are located so that they are opposite each other and act as backup rollers, shall be deemed to have met this requirement.
The pinions and racks shall be of steel or of material having equivalent mechanical properties or better with a minimum factor of safety of 8 based on ultimate stress for the pinion and the rack. They shall be designed to conform to AGMA 218.01, including surface hardening and an assumption of a minimum of 200 000 life cycles.
All moving parts of the driving machine shall be properly protected with solid or perforated metal that will reject a ball of 13 mm (0.5 in.) diameter and shall be securely fastened.
The rack and pinion shall be so designed that the separation of the pinion from the rack in all directions in excess of 25% of the tooth depth of 6 mm (0.25 in.), whichever is the lesser, cannot occur. A guard shall be provided to prevent foreign material from lodging between the teeth, and clearance between the moving parts and the guard shall not exceed 5 mm (0.1875 in.).
Rack sections shall be fastened to the supporting structure with a factor of safety of 5 based on ultimate stress, and with dowels at each joint.
The manufacturer shall provide the measurement for checking tooth wear on pinion and rack. The measuring instruction shall be indicated on a metal plate securely fastened and conspicuously displayed on top of the car with letters not less than 3 mm (0.125 in.) high.
Normal and final terminal stopping devices shall be provided conforming to 2.25.1, 2.25.2, and 2.25.3, except 2.25.3.3. Normal and final terminal stopping devices shall be permitted to be located on the car and operated by cams attached to the hoistway structure.
Operating devices and control equipment shall conform to 2.26 and to the following:
Where the rack-and-pinion machine and its controller are located on the car, the disconnecting means shall be located adjacent to the controller. Auxiliary disconnect means shall be provided at the main landing whenever the main power supply disconnect means (required by NFPA 70 or CSA-C22.1, as applicable; see Part 9) is mounted adjacent to the controller on the car. Auxiliary disconnect means shall be accessible to authorized personnel only in order to be available for their protection and emergency use.
Voltage permitted in control and operating circuits shall not exceed 300 V on rack-and-pinion equipment.
Emergency operation and signal service shall conform to 2.27.
Elevator layout drawings shall, in addition to the other data required by 2.28, indicate
(a) the dimensions of the rack and location with respect to the guide rail
(b) the magnitude of the loads on the rack imposed on the building structure
Welding shall conform to 8.8.
This Section applies to an elevator having an uncounterweighted car that is supported by a screw column and is raised and lowered by screw thread means.
Hoistways, hoistway enclosures, and related construction shall conform to 2.1, 2.2, 2.10, 2.11, 2.12, and 2.13.
The bottom car clearance shall conform to 2.4.1, provided that, in the determination of the required clearance, any undercar machinery and bracing that is located within 150 mm (6 in.) horizontally from the edge of the car platform or 75 mm (3 in.) horizontally from the centerline of the guide rails is not considered.
The minimum bottom and top car runby shall be not less than
(a) 75 mm (3 in.) for rated speeds not exceeding 0.5 m/s (100 ft/min)
(b) 150 mm (6 in.) for rated speeds exceeding 0.5 m/s (100 ft/min)
The maximum bottom and top car runby shall be not more than 600 mm (24 in.).
The top car clearance shall be not less than the sum of the following two items:
(a) the top car runby
(b) the height of the refuge space on top of the enclosure (see 4.2.2.4) or the clearance required for equipment projecting above the top of the car to prevent its striking any part of the overhead structure or equipment located in the hoistway, but in no case less than 1 070 mm (42 in.)
A refuge space shall be provided on top of the car enclosure conforming to 2.4.12.
The screw column, and any associated framing, shall be supported by a structure of sufficient strength to support the entire load imposed upon it, including the impact if the drive nut should fail.
The guide rails shall be supported by a structure of sufficient strength to withstand, without permanent deformation, the impact of a safety application with a fully loaded car.
Motors and other integral mechanical or electrical equipment shall be permitted to be located in machinery space within the hoistway, on the car, in the pit, or in a separate machine room or machinery space.
The controller shall be permitted to be located on the car or on the exterior of the hoistway wall or other location apart from the hoistway, machine room, or machinery space. A controller so located shall be readily accessible for maintenance and inspection at all times. Controllers located apart from the hoistway, machine room, or machinery space shall be housed in a locked metal cabinet. The key shall be Group 1 Security (see 8.1).
A screw machine and its controls, if located on the car, shall be protected by a noncombustible enclosure to prevent accidental contact. Openwork enclosures of noncombustible material shall be permitted to be used for screw machines located on top of the car, provided the openwork material rejects a ball 13 mm (0.5 in.) in diameter.
Access shall be provided to the screw machine for maintenance. Access panels to screw machines located on the car shall be provided with an electric contact and lock. The electric contact shall be designed to prevent operation of the screw machine when the access panel is open. The access panel shall be kept closed and locked. The key shall be Group 1 Security (see 8.1).
Electrical wiring, pipes, and ducts in hoistways, machine rooms, and machinery spaces shall conform to 2.8, except, the main feeder of a screw-column elevator shall be permitted to be installed in the hoistway if the screw machine is located in the hoistway, provided there is no intermediate access to the conductors between the disconnecting means and the termination at the motor or controller.
The supports and foundations shall be designed to support all loads imposed by the elevator in accordance with the building code, including impact loading in the event of a car safety application, stop by a safety nut, or controlled descent by a speed-limiting device. The unit stresses in elevator-supporting members and their supports, based on two times the normal loading, shall not exceed those permitted for static loading in accordance with the requirements of the following standards:
(a) AISC Book No. S326 or CAN/CSA-S16.1, whichever is applicable (see Part 9) for structural steel
Where stresses due to loads, other than elevator loads supported on the beams, floor, or structure, exceed those due to the elevator loads, 100% of the permitted stresses shall be permitted to be used.
NOTE: In determining unit stresses, the maximum normal loading is doubled to take care of impact, accelerating stresses, etc.
A car safety device and speed governor shall be provided, which shall conform to the design and performance requirements of 2.17 and 2.18, except as specified in 4.2.11.1 and 4.2.11.2.
For elevators driven by an alternating- current squirrel cage induction motor and having a down speed of not more than 0.37 m/s (75 ft/min), the car safety and governor are not required if another safety device is provided to either
(a) limit the down speed of the car with rated load to not over 0.87 m/s (175 ft/min) in the event of failure of the driving means; or
(b) limit the fall of the elevator in the event of failure of the driving nut to a distance not exceeding 13 mm (0.5 in.), by utilizing a safety nut or other equivalent means.
The capability of the alternate safety devices described in 4.2.11.1(a) and (b) to function as required shall be verified by engineering tests as described in 8.3.10.
A safety nut is required on all screw machines that utilize a driving nut made of a material other than metal and shall be permitted to be provided on all screw machines. The safety nut shall be made of metal and designed to withstand the impact without damage if the driving nut should fail.
A metal data tag shall be securely attached to each screw machine equipped with a safety nut bearing the following data:
(a) date of installation of driving and safety nuts
(b) spacing between driving and safety nuts
Guide rails, guide-rail supports, and their fastenings shall conform to 2.23, except 2.23.4.2, 2.23.4.3, 2.23.9.1, and 2.23.10.
The fastening of guide rails to brackets or to the elevator-supporting frame shall be by clips, welds, or bolts. The rail structure and the structural members to which it is attached shall withstand the forces specified in 2.23.5.2, and the application of the car safety shall be within the deflection limits specified.
The screw machine shall function to raise or lower the elevator car acting in conjunction with a screw column that directly supports the elevator car.
Screws shall be made of steel. Nuts shall be made of bronze or other materials having an elongation of at least 14% in a length of 50 mm (2 in.).
Means shall be provided to maintain the screw in its vertical position under all conditions of operation. Screws suspended from their upper end shall be restrained at their lower end.
A vertical casing, closed at the end, shall be provided to enclose and protect the screw column in cases where the screw column extends outside the hoistway and machine room.
The screw column and nut and their attachments to the car frame, car platform, or other structure shall provide sufficient strength to support the loads imposed on these connections with a factor of safety of 5.
Factors of safety for the driving machine, excluding the screw column and nut, their attachments to the car frame, car platform, or other structure, shall conform to 2.24.3, except that the load used in determining the factor of safety shall be based on the total weight supported with rated load in the car.
Screw machines of the indirect drive type shall conform to 2.24.9. The elevator shall be so designed that the elevator car, while carrying 125% of rated load and traveling at rated speed, shall decelerate and stop in the event the driving-belt system or driving-chain system should break.
Means shall be provided to prevent the disengagement of the nut from the screw column. This means shall be so designed and constructed as to prevent disengagement in the event of overtravel at full speed and without damage to any part of the elevator installation. Any additional loads imposed by this action shall also be considered in the computations made in accordance with 4.2.15.8.
Where the screw column is a compression member, column formulas of 8.2.8.1.1 shall be used in the design with the words "screw column" substituted for the word "plunger" and:
| A | = net cross-sectional area of screw at root of thread, mm2 (in.2) |
| L | = maximum free length of screw, mm (in.) |
| R | = radius of gyration of screw at root of thread, mm (in.) |
| W | = the total weight with rated load plus one-half the weight of the screw column, kg (lb) |
| W/A | = maximum allowable fiber stress |
Where the screw column is a tension member, the unit stress (considering the root dimension and any associated stress concentration and/or the reduced section at any joints in the screw) shall not exceed one-fifth of the ultimate strength of the material with a maximum fiber stress not to exceed 124 MPa (18,000 psi).
Positive mechanical means shall be provided to prevent rotation or separation of sections of a multiple section screw column.
Means shall be provided to permit authorized personnel from a position outside the elevator car to raise or lower the car manually in the event of a power failure, unless emergency or standby power is provided, except that for private residence elevators and special purpose personnel elevators, means to allow a passenger within a stalled car to manually move the car to a landing is acceptable and no other means of moving the stalled car is required.
Final terminal stopping devices, conforming to 2.25.3.1 and 2.25.3.3, shall be provided for elevators having a rated speed exceeding 0.5 m/s (100 ft/min). Final terminal stopping devices shall be located in the hoistway and operated by cams attached to the car.
Elevators having a rated speed of 0.5 m/s (100 ft/min) or less shall be designed so that the elevator car will be brought to a stop without damage to the elevator system in the event of overtravel of the elevator at either terminal due to a malfunction.
Emergency terminal speed-limiting devices shall be installed where reduced stroke buffers are used (see 2.22.4.1.2). These devices shall conform to 2.25.4.
Operating devices and control equipment shall conform to the following:
(a) Requirement 2.26.1.1, Types of Operating Devices.
(b) Requirement 2.26.1.4, Inspection Operation, except that a top-of-car operating devices are not required on private residence elevators and special purpose personnel elevators. Top-of-car operating devices are not required on any screw-column elevator if there is no mechanical or electrical equipment that requires maintenance from the top of the car.
(c) Requirements 2.26.2.5, 2.26.2.7 through 2.26.2.10, 2.26.2.12 through 2.26.2.15, 2.26.2.18 through 2.26.2.21, 2.26.2.25, and 2.26.2.28, Electrical Protective Devices.
(d) Requirement 2.26.3, Contactors and Relays in Critical Operating Circuits.
(e) Requirement 2.26.4, Requirements of Electrical Equipment and Wiring.
(f) Requirement 2.26.5, System to Monitor and Prevent Automatic Operation of the Elevators With Faulty Door Contact Circuits.
(g) Where the screw machine and its controller are located on the car, in the hoistway, or outside the hoistway, the disconnecting means shall be located adjacent to the controller.
(h) Requirement 2.26.6, Phase Protection of Motors.
(i) Requirement 2.26.7, Installation of Capacitors or Other Devices to Make Electrical Protective Devices Ineffective.
(j) Requirement 2.26.8, Release and Application of Driving-Machine Brakes.
(k) Requirement 2.26.9, Control and Operating Circuits.
(m) Requirement 2.26.13, Operating Device Symbols.
Emergency operation and signaling devices shall conform to 2.27.
Elevator layout drawings shall, in addition to the other data required by 2.28, indicate the following:
(a) the material and dimensions of the screw column, including thread dimensions
(b) the location and amount of the maximum loadings on the building structure
All welding shall conform to 8.8.