Rope Brakes, Platform Guards & Shallow Pits

I always knew them as toe guards.  Like many things in elevators, the codes and AHJs have different names for things than I had known them to be.  Spreader brackets are actually called “tie brackets.”  Sump pumps are called “water removal systems.”  We won't even go into what I learned as the name for hoistway door unlocking devices - which are disallowed in California anyway.  

Toe guards are called "Platform Guards (Aprons)" in ASME A17.1, section 2.15.9 as well as in CCR Title 8, Rule 3033(i).  I guess calling them toe guards comes from the perspective of an elevator person who might run cars up and down on hoistway access and without the toe guard, it would seem a lot easier to run the platform down on your toe if your were absent minded enough to stick your foot over the edge of the hoistway sill.  There was probably even a point early in my career were I actually thought this was the purpose of a platform guard – which is what I will call it that for the rest of this blog. 

As I'm sure all of you know, the real purpose of a platform guard is to prevent elevator passengers from going down the hoistway in the event they become entrapped in an immobilized elevator.  In brief, what happens is that an elevator malfunctions and comes to rest above a floor.  The passenger attempts to exit the car by forcing open the doors and climbing out to the floor below.  For example, say the car is 4 feet above the landing and it is an older car not equipped with a door restrictor device.  Depending on the door operator, it may be fairly easy to palm the car door open.  It wouldn't take too much trial and error to figure out how to open the hoistway door for most systems; usually it's a matter of pulling on the pickup rollers or pushing on the roller lever to release the swing door interlock. 

Then what happens is the passenger attempts to let themselves down to the  floor below by hanging onto the car sill and hoisting themselves down.  This is the rub.  If you’ve ever suspended yourself by your hands you know what happens.  Your body will rotate forward toward the car platform due to the natural location of your body’s center of gravity.  And where would that leave you – under the platform well within the hoistway.  The plan was to lower oneself down to the floor but instead the hapless passenger finds themselves inside the hoistway sill and down they go…  This is, I believe, the most common cause of death or major injury in elevator accidents.

Thus, the platform guard!  I haven’t done the research to be able to tell you when this essential safety feature was added to the code (Dee, do you know?).  I see early 20^th century elevators all the time with no platform guard, running, perfectly legally as this device was never made a retroactive requirement.   The code had been consistent for probably half a century requiring a platform guard with a height of “not less than the depth of the leveling or the truck zone, plus 3 inches.”  The problem is that with a 7 foot typical entrance, that would leave ample room for one to get out of a car and still go under the platform guard and down the hoistway.

As no doubt all of you know, starting with the ASME A17.1-2000 code the ascending car overspeed and unintended car movement (ACO-UCM) protection has been a requirement.  The platform guard section, 2.15.9, was modified to take into account the new ACO-UCM provision with the added requirement for a 48 inch platform guard.  The logic here is that 48 inches is the maximum allowed car travel upon activation of ACO-UCM.  The affect of this new code is that essentially all new traction elevators will have 48 inch platform aprons and pit deep enough to accommodate them.

All right, here’s the original reason I started this blog.  How does all of this play out when altering an existing elevator to add ACO-UCM?  There are five (5) alteration events that trigger the requirement to add ACO-UCM (Can you name these?  If you give up, go to my website articles to find the answer).   It is widely believed that when altering an existing elevator and ACO-UCM is added that a 48 inch platform apron is also required.  Not true. 

This gets to a very common error in reading the elevator code.  When altering an existing elevator, people will often automatically reference the full body of the current elevator code, A17.1, Part 2 or 3.  Wrong.  When altering an existing elevator one first must go to what local or state codes that applies.  In California, one must start with CCR Title 8 which in turn currently references ASME A17.1-2004, Alterations, Section 8.7.  This section will send you wherever you will need to go for any work performed, based on what is being altered.

In our discussion here, for instance, say the work is the classic new fixtures, door equipment and controls.  The existing elevator is a Ward-Lenard system with a motor-generator and a DC motor on a geared machine.  The alteration includes replacing the M-G with a Vector AC system and installing a new AC motor on the machine.  One of the sections you will have to go to is 8.7.2.27.5 Change in Type of Motion Control.  To confirm this go to A17.1, Part 1, Section 1.3 Definitions, “control, motion” which lists and defines all of the different types of motion control.  The elevator will be modified from a “control, generator field” to a “control, variable voltage, variable frequency (VVVF).”

Note section 8.7.2.27.5(e) sends you to section 2.19 ACO-UCM.  This is the most common trigger that requires the addition of an emergency brake, which if most often met when the machine is being retained by adding a rope brake.  Further note that nowhere in section 2.19 does it send you to section 2.15.9, the requirement for a 48 inch platform guard.  Nor does any other part of section 8.7 send you there for the scope of work described.  The authors of the code were very clever in how they constructed these code revisions so as not to create a trap whereby one would be required to deepen a pit simply because one wants to install new controls and motor on an existing elevator. 

There are a number of alteration sections in 8.7 that do send you to 2.15.9, such as 8.7.2.15.2 and 8.7.2.16.4.  These clarify the requirement that one “shall conform to 2.15.9 only to the extent the existing pit shall permit…”  Section 8.7.2.27.5 probably should include this same language but it doesn’t.  I make it a practice to do it anyway – install a new platform guard of the maximum length up to 48 inches, to the extent the existing pit depth will allow.   

Another place this language should be included, but it isn’t, is section 8.7.2.15.1 Alterations to Car Frames and Platforms.  That section simply sends you to 2.15 (which obviously includes 2.15.9).  So, what does that mean?  If one alters a platform, say cuts off 6 inches of the leading edge so as to install power-operated doors, does that then require you to deepen the pit so as to install a 48 inch platform guard?  Also, what if you install a complete new platform on an existing elevator?  Curiously, there is no language in 8.7 that specifically address a new platform, only alterations to car frames and platforms.  I assume that section 8.7.2.15.1 includes replacing the platform as well as altering one.  I recommend getting a clarification from your AHJ for this code omission.  The times I’ve done that the inspector rightly uses the logic clearly set out elsewhere in the alteration section and accepts that a platform apron of the maximum length be installed.

My business, Smart Elevator Tech, LLC, manufactures and supplies unique elevator products that I have invented, such as the Retracta Ladder®, Low-Profile Fishplate™ and a Deflector Sheave Isolator™.  I’m beginning to get a number of requests to invent a viable retractable platform apron.  I’ve given it some thought and, at least for the moment, have decided to pass.  First, why would anyone need one as they would not be needed in an alteration – as I’ve just shown.  For new construction, all companies would have the same requirement and should be able to specify the necessary pit depth that will be built.  Finally, there are many complications to designing a rise and fall or hinged platform apron that would be viable.  It would have to be activated with each run to the lowest landing, which is more often the lobby – the highest traffic landing.  There would be huge wear factors.  It would have to be failsafe, probably switched so the elevator couldn’t run if the device failed (or simply wore out).  And that’s just the beginning of the problems with such a device.

Cheers,
Your Code Reporter
Rich Blaska