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Did You Know #8 - Minimum Door Closing Time Data Plate
Have You Seen One of These?    (09-27-2008)

Have you seen a data plate similar to this?

 Minimum Door Closing Time Data Plate
The data plate shall be "attached to the power door operator or to the car crosshead."

 

From: ASME A17.1 - 2004 Safety Code for Elevators and Escalators

 Start Citation  2.13.4.2.4 Data Plate. A data plate conforming to 2.16.3.3 shall be attached to the power door operator or to the car crosshead and shall contain the following information:
(a) minimum door closing time in seconds for the doors to travel the Code zone distance as specified in 2.13.4.2.2 corresponding to the kinetic energy limits specified in 2.13.4.2.1(b)(2);
(b) minimum door closing time in seconds for the doors to travel the Code zone distance as specified in 2.13.4.2.2 corresponding to the kinetic energy limits specified in 2.13.4.2.1(c)(2), if applicable [see 2.27.3.1.6(e) (see 2.27.3.1.6(e) for the 2004 code)];
(c) where heavier hoistway doors are used at certain floors, the minimum door closing time in seconds corresponding to the kinetic energy limits specified in 2.13.4.2.1(b)(2) and 2.13.4.2.1(c)(2), if applicable, for the corresponding floors shall be included on the data plate.   End Citation

If you have just recently started to comply with ASME A17.1 - 2004 Safety Code for Elevators and Escalators you may not be familiar with this data plate. I have seen it from time to time on elevators here in the State of California even though it was not a requirement until recently. I am always glad to see it because it means the manufacturer has calculated the minimum door close times. I just have to accurately time the doors and compare my results to their calculations. In the 'old days' we used a formula provided for us to calculate the minimum door times. I wrote a computer version of this formula using Visual Basic 6. Here is a screen shot of this calculator.

 Minimum Door Time Calculator

If you would like to download a copy of this calculator - you can do so.

 

If I am performing an inspection on an elevator and I do not have the door weights I use my Maximum Door Weight Calculator. This is just an approximation of the maximum possible door weight for the door close or door close nudge times. I just want to see if the measured times are in the 'ballpark'.

 Maximum Door Weight Calculator

If you would like to download a copy of this calculator - you can do so.

 Never!
As is always the case...

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Did You Know #9 - Door & Gate Closing Force
You'll Need a Tensiometer    (10-04-2008)

From: ASME A17.1 - 2004 Safety Code for Elevators and Escalators

 Start Citation  2.13.4.2.3 Door Force. The force necessary to prevent closing of the hoistway door (or the car door or gate if power operated) from rest shall not exceed 135 N (30 lbf) (see 2.13.3.1). This force shall be measured on the leading edge of the door with the door at any point between one third and two thirds of its travel.   End Citation

 

 Tensiometer
Tensiometer
Image 'borrowed' from: Carlisle Power Transmission Products, Inc.

 

Most of the mechanics and inspectors I know are using this type of a device to measure the door closing force. As you can see the stem is divided into one pound (pounds of force) increments.This tool is designed to measure v-belt tension. The following image demonstrates the proper way to use the tool on v-belts.

 Tensiometer in use
Tensiometer being used to measure a v-belt...
Image 'borrowed' from: Carlisle Power Transmission Products, Inc.

We turn the tool around and place the stem against the leading edge of the door. I usually stall the door with my foot at about mid course, place the tool on the leading edge of the door, apply some pressure against the door through the tool and then release the door to obtain a reading. This particular gauge will measure up to 35 lbf and is perfect for our needs as the door force should not exceed 30 lbf.

 

Ever wonder how the large 'O' ring is used on these devices?

 Tensiometer in use

 Tensiometer in use
Info & image 'borrowed' from: Carlisle Power Transmission Products, Inc.

 

More information on v-belt tensioning:
    V-belt Tensioning Guide - Detailed provided by Carlisle Power Transmission Products, Inc. (Long PDF article - 281KB )
    V-belt Tensioning Guide - 'Quickie' provided by Carlisle Power Transmission Products, Inc. (Short PDF article -   96KB )

 

Do you need to purchase a tensiometer? If so see...
    HVAC Maintenance & Supplies
    or do a Google search!

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Did You Know #10 - Working Clearances
It's Not Always As Much As You Think    (10-20-2008)

From: NFPA 70 - National Electrical Code - 2008 Edition

View the entire 2008 edition here
View the entire 2005 edition here
View the entire 2002 edition here

Click on 'All Other Visitors' and proceed as instructed. Once you have access to
the document, click on the Table of Contents icon -  TOC - to navigate to Section 620.

 Start Citation   620.5 Working Clearances. Working space shall be provided about controllers, disconnecting means, and other electrical equipment. The minimum working space shall be not less than that specified in 110.26(A).   End Citation

**********

Table 110.26(A)(1) Working Spaces

Nominal Voltage to GroundMinimum Clear Distance
Condition 1Condition 2Condition 3
0 - 150914 mm (3 ft)914 mm (3 ft)914 mm (3 ft)
151 - 600914 mm (3 ft)1.07 m (3 ft 6 in.)1.22 m (4 ft)

Note: Where the conditions are as follows:

Condition 1 - Exposed live parts on one side of the working space and no live or grounded parts on the other side of the working space, or exposed live parts on both sides of the working space that are effectively guarded by insulating materials.

Condition 2 - Exposed live parts on one side of the working space and grounded parts on the other side of the working space. Concrete, brick, or tile walls shall be considered as grounded.

Condition 3 - Exposed live parts on both sides of the work space.

**********

620.5 continues...

 Start Citation  Where conditions of maintenance and supervision ensure that only qualified persons examine, adjust, service, and maintain the equipment, the clearance requirements of 110.26(A) shall be waived as permitted in 620.5(A) through (D).

(A) Flexible Connections to Equipment. Electrical equipment in (A)(1) through (A)(4) shall be permitted to be provided with flexible leads to all external connections so that it can be repositioned to meet the clear working space requirements of 110.26(A):

(1) Controllers and disconnecting means for dumbwaiters, escalators, moving walks, platform lifts, and stairway chairlifts installed in the same space with the driving machine
(2) Controllers and disconnecting means for elevators installed in the hoistway or on the car
(3) Controllers for door operators
(4) Other electrical equipment installed in the hoistway or on the car

(B) Guards. Live parts of the electrical equipment are suitably guarded, isolated, or insulated, and the equipment can be examined, adjusted, serviced, or maintained while energized without removal of this protection.

(C) Examination, Adjusting, and Servicing. Electrical equipment is not required to be examined, adjusted, serviced, or maintained while energized.

(D) Low Voltage. Uninsulated parts are at a voltage not greater than 30 volts rms, 42 volts peak, or 60 volts dc.   End Citation

 

As you can see, there is considerable 'wiggle' room for electrical equipment working clearances in the vertical transportation industry.

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Did You Know #11 - Urine Detection Devices
Pee Pee Police    (11-01-2008)

I have received numerous e-mails concerning this One Stop Elevator magazine cover...

 One Stop Elevator - Volume1 Issue 21
Volume 1 Issue 21

These devices are indeed real and can be purchased online.

 

 Urine detection in progress
Urine Detection - Standard Model
Distributed by: Lift Components Limited

 

 Urine detection in progress
Urine Detection - Timing Model
Distributed by: Lift Components Limited

Perhaps someday signs like this in an elevator will be a thing of the past!

 

 Different Sign
Truman State University - Kirksville, Missouri, U.S.A.
Image provided by: Don Quayle

 

 Different Sign
Truman State needs one of these...
Image provided by: Joe Sampras

But it could become more severe and slippery...

 

 Different Sign
...not me!!
Image provided by: Herbie T. Mann

 

 Different Sign
Oh...like I'm gonna get that lucky!!
Image provided by: Herbie T. Mann

 

 Different Sign
Looks like somebody got 'that lucky!!'
Image provided by: Herbie T. Mann

 

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Did You Know #12 - Terminal Stopping Devices
Normal Terminal Stopping Devices    (12-02-2008)

From: ASME A17.1 - 2004 Safety Code for Elevators and Escalators

A few definitions:

Electric Elevator: a power elevator where the energy is applied by means of an electric driving machine.

Hydraulic Elevator: a power elevator in which the energy is applied, by means of a liquid under pressure, in a hydraulic jack.

Normal Terminal Stopping Device: device(s) to slow down and stop an elevator, dumbwaiter, or material lift car automatically at or near a terminal landing, independently of the functioning of the normal stopping means.

Normal Stopping Means: that portion of the operation control that initiates stopping of the car in normal operation at landings.

Leveling Device, Elevator, Dumbwaiter, or Material Lift Car: any mechanism that will either, automatically or under control of the operator, move the car within the leveling zone toward the landing only, and automatically stop it at the landing.

A few sections of the code pertaining to normal terminal stopping devices (NTSD):

 Start Citation  2.25.2.1.1 Normal terminal stopping devices shall be provided and arranged to slow down and stop the car automatically, at or near the top and bottom terminal landings, with any load up to and including rated load in the car and from any speed attained in normal operation (see 2.16.8).   End Citation (Emphasis added)

 Start Citation  2.25.2.1.2 Such devices shall function independently of the operation of the normal stopping means...   End Citation (Emphasis added)

The following section is found in the requirements for the final terminal stopping device:

 Start Citation  2.25.3.2 The device shall be set to function as close to the terminal landing as practicable, but so that under normal operating conditions it will not function when the car is stopped by the normal terminal stopping device.   End Citation (Emphasis added)

From: ASME A17.22004 Guide for Inspection of Elevators, Escalators, and Moving Walks

 Start Citation  Item 2.28 Terminal Stopping Devices

2.28.2 Periodic Test
2.28.2.1 Electric Elevators
(a) Yearly Test of Normal Terminal Stopping Devices (for A17.1d-2000 and Earlier Editions); Category 1 Test of Normal Stopping Devices (for A17.1-2000 and Later Editions).
Check normal terminal stopping devices as follows:
(1) Render inoperative the normal elevator stopping means.
(2) Render inoperative the emergency terminal stopping device. Do not disable the emergency terminal speed limiting device.
(3) Run the car at contract speed into the bottom terminal and demonstrate that the car slows down and stops in the vicinity of the bottom terminal.
(4) Repeat the above test at the top terminal.
(5) Restore the normal stopping means and emergency terminal stopping device. Check normal elevator operation.   End Citation

(Please note...all the tests in 2.28.2 are performed with no load in the car.)

 Start Citation  2.28.3 Acceptance
2.28.3.1 Electric Elevators.
Perform the test in Item 2.28.2(a) for the bottom normal terminal stopping device in the down direction at 125% of rated load for passenger elevators and freight elevators permitted to carry passengers. The bottom normal terminal stopping devices of freight elevators not permitted to carry passengers are to be tested with rated load. The top normal terminal stopping devices for all elevators must be tested with no load. The car should stop at or near the terminal landings with all loads, except where an automatic leveling device is provided, in which case the normal terminal stopping device should stop the car within the range of the leveling device.   End Citation (Emphasis added)

My thoughts:

1 - Testing a direction or final limit switch by hand does not prove that the cam will actually open the switch as intended and you can't possibly know where the car will stop in relation to the landing. You can, however, find out how the switch feels - will it return to the normal position in a positive manner. You can also 'exercise' the contacts - clean them off a bit.

2 - The A17.1 code only prohibits an automatic restart after operating the final terminal stopping device (final limit). It is permissible for the car to restart automatically after operating the normal terminal stopping device, emergency terminal stopping device, or emergency terminal speed-limiting device. However, most modern controllers have a specific protocol for these devices and in most cases will only allow the car to recover to the terminal landing, open the doors and then remove the car from service.

3 - The single switch that you think is the normal terminal stopping device is more than likely just the last portion of this device. Most elevators with a fair amount of speed will need to have several switches, be they mechanical, optical, magnetic or solid-state to 'slow down and stop the car automatically, at or near the top or bottom terminal landings...'

 NTSD
Sometimes the various contacts are contained in one device 'A'
and are operated by a single cam 'B' at the top and bottom landings.

4 - Once I have all of my hoistway and pit measurements (runbys, buffer strokes, car and counterweight overhead clearances, etc.) I like to have the adjuster run the car to the terminal landing and then slowly run the car onto the directional limit - jump it out - and then onto the final limit. I take sill to sill measurements at both positions and I know just where the car would stop at this speed. If you have spring buffers (200 FPM or less) you should not engage the buffer once you open the final limit switch.

5 - Remember to retest your direction limit switch once you move the car in the opposite direction. I have traveled all the way to the bottom of the hoistway to find that I could not come back up because the up direction switch did not make back up after I opened it. That only happened once! (I think...) Now I always 'exercise' both the normal and final switches several times because we might be the only ones to open that switch between inspections visits.

6 - Why is it called the normal terminal stopping device? In the State of California, Division of Industrial Safety, Elevator Safety Orders, circa 1947, the definition for this device is:

 Start Citation  A normal terminal stopping device is an automatic device for stopping the elevator car within the top and bottom run-by independently of the operating device.   End Citation

I think in those days the NTSD was used to 'normally' stop the car at the terminal landings with car switch operation. The operator would leave the car switch in the up or down position and just sail into the terminal.

 

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Did You Know #13 - Escalators and Moving Walks
Tandem Operation    (12-16-2008)

From: ASME A17.1 - 2004 Safety Code for Elevators and Escalators

A definition:

Escalators, Tandem Operation: escalators used in series with common intermediate landings.

 Start Citation  6.1.6.6 Tandem Operation. Tandem operation escalators shall be electrically interlocked where traffic flow is such that bunching will occur if the escalator carrying passengers away from the intermediate landing stops. The electrical interlocks shall stop the escalator carrying passengers into the common intermediate landing if the escalator carrying passengers away from the landing stops. These escalators shall also be electrically interlocked to assure that they run in the same direction.   End Citation

 Start Citation  6.2.6.6 Tandem Operation. Tandem-operation moving walks shall be electrically interlocked where traffic flow is such that bunching will occur if the moving walk carrying passengers away from the intermediate landing stops.
The electrical interlocks shall stop the moving walk carrying passengers into the common intermediate landing if the moving walk carrying passengers away from the landing stops. These moving walks shall also be electrically interlocked to assure that they run in the same direction.   End Citation

As you can see, escalators and moving walks have identical requirements for units in tandem to prevent bunching.

They are:

1 - Stop the unit carrying passengers into an intermediate landing if the unit carrying passengers away from this landing stops.
2 - Units in tandem must be arranged to run in the same direction.

 Tandem Operation
Longqing Gorge near Beijing, China    Click to view a larger and higher resolution image
These are reportedly the longest series of escalators in the world.
I am told that there are eight sets of escalators (258m in 8 sections) housed in this 'dragon'...
I wonder if they are all electrically interlocked because they appear to be in series...

 

 Tandem Operation
Valencia, Spain    Click to view a larger and higher resolution image
I wonder if this configuration is required to be interlocked to prevent bunching?
If only one escalator 'carrying passengers away from the intermediate landing'
stops there is a way to prevent bunching...but what if both escalators carrying
passengers away from the intermediate landing stop?

 

 Tandem Operation
Paris, France    Click to view a larger and higher resolution image
A similar situation here...

 

 Tandem Operation
Escalators to Heaven!    Click to view a larger and higher resolution image (1 of 2)
(Exclusive image to One Stop Elevator magazine)
These units will definitely be installed to code but would they have to be?
You know God used the best installers available...ex-Otis men from the U.S.A!

 

 Escalators to Heaven
Escalators to Heaven! (2 of 2)
(Exclusive image to One Stop Elevator magazine)
As you can see they are quite ornate...and fast!

 

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