This is a pretty complex item, and it is long, any thoughts (helpful or humorous) would be appreciated.
I work on controls for different pieces of Material Handling Equipment. One of the items I work on is called a Vertical Reciprocating Conveyances (VRCs) but to a layman it would be called a freight elevator or a very large dumbwaiter.
However, the industry specifically steers clear of either of these terms hence it is a VRC which is defined as follows:
"Vertical Reciprocating Conveyors move materials in factories, warehouses, industrial plants, institutions or anywhere that products or supplies need to move from one level to another. Vertical Reciprocating Conveyors are not elevators. In fact, they have their own national code (ANSI/ASME B20.1) and are specifically exempt from the national elevator code. Vertical Reciprocating Conveyors provide fast, efficient, convenient and safe access to/from mezzanines, balconies, basements, and between levels in multiple story buildings. They can be installed for through-floor, interior or exterior applications. The principal components of Vertical Reciprocating Conveyors include guide columns, carriage and a mechanical or hydraulic actuating mechanism."
From a personal opinion, these are freight elevators that cannot carry people. The "NO RIDERS" and lack of controls on the lift seems to be what separates this from "freight elevators" but in this case it really is a big dumbwaiter.
Now the title to 620.11 includes Elevators and Dumbwaiters... but dumbwaiters cannot carry people either... to include fire fighters. Here is the article and the passage that I am wondering about:
"ARTICLE 620 Elevators, Dumbwaiters, Escalators, Moving Walks, Wheelchair Lifts, and Stairway Chair Lifts?
II. Conductors?
620.11 Insulation of Conductors?
(A) Hoistway Door Interlock Wiring. The conductors to the hoistway door interlocks from the hoistway riser shall be flame retardant and suitable for a termperature of not less that 200 degrees C (392 degrees F). Conductors shall be Type SF or equivalent."
What is the logic for having 200 degree C wire in any elevator shaft and why would this only go to the door interlock?
If you consider fire fighters, the need to go to manual override comes to mind which would bypass door controls and door have manual releases and manual overides. And even if this was a people issue, then why would you put this wire on a dumbwaiter door?
With regards to MOST VRCs (that resemble freight elevators and dumbwaiters) they typically have a mechanical door lock to keep the door closed when the lift is not present, so the ability to open the door from the inside or outside has nothing to do with the wiring. However, MOST VRCs also have an electric switch so the lift will not operate if a door is open but this doesn?t lock the door just the lifting controls.
So if the interlock is mechanically released/locked, is the control switch that says whether the door is open or closed part of the interlock wiring?
Now contrary to the previous paragraph some VRCs do have electrical locks that are locked when de-engerized? in this particular case you would not trap people in the lift as there are NOT people in the lift, even a fire fighter would be retarded (or extremely poorly trained) to attempt to ride a VRC or a dumbwaiter in a fire!
So even if this 200 degree wire does have logical reason for existance in an elevator system that I am not aware of, it has none that I can see in a dumbwaiter or for my purposes a VRC.
I know this issue is pretty specialized, so my last inquiry is how do you get info to the NEC panels that write these rules?
I work on controls for different pieces of Material Handling Equipment. One of the items I work on is called a Vertical Reciprocating Conveyances (VRCs) but to a layman it would be called a freight elevator or a very large dumbwaiter.
However, the industry specifically steers clear of either of these terms hence it is a VRC which is defined as follows:
"Vertical Reciprocating Conveyors move materials in factories, warehouses, industrial plants, institutions or anywhere that products or supplies need to move from one level to another. Vertical Reciprocating Conveyors are not elevators. In fact, they have their own national code (ANSI/ASME B20.1) and are specifically exempt from the national elevator code. Vertical Reciprocating Conveyors provide fast, efficient, convenient and safe access to/from mezzanines, balconies, basements, and between levels in multiple story buildings. They can be installed for through-floor, interior or exterior applications. The principal components of Vertical Reciprocating Conveyors include guide columns, carriage and a mechanical or hydraulic actuating mechanism."
From a personal opinion, these are freight elevators that cannot carry people. The "NO RIDERS" and lack of controls on the lift seems to be what separates this from "freight elevators" but in this case it really is a big dumbwaiter.
Now the title to 620.11 includes Elevators and Dumbwaiters... but dumbwaiters cannot carry people either... to include fire fighters. Here is the article and the passage that I am wondering about:
"ARTICLE 620 Elevators, Dumbwaiters, Escalators, Moving Walks, Wheelchair Lifts, and Stairway Chair Lifts?
II. Conductors?
620.11 Insulation of Conductors?
(A) Hoistway Door Interlock Wiring. The conductors to the hoistway door interlocks from the hoistway riser shall be flame retardant and suitable for a termperature of not less that 200 degrees C (392 degrees F). Conductors shall be Type SF or equivalent."
What is the logic for having 200 degree C wire in any elevator shaft and why would this only go to the door interlock?
If you consider fire fighters, the need to go to manual override comes to mind which would bypass door controls and door have manual releases and manual overides. And even if this was a people issue, then why would you put this wire on a dumbwaiter door?
With regards to MOST VRCs (that resemble freight elevators and dumbwaiters) they typically have a mechanical door lock to keep the door closed when the lift is not present, so the ability to open the door from the inside or outside has nothing to do with the wiring. However, MOST VRCs also have an electric switch so the lift will not operate if a door is open but this doesn?t lock the door just the lifting controls.
So if the interlock is mechanically released/locked, is the control switch that says whether the door is open or closed part of the interlock wiring?
Now contrary to the previous paragraph some VRCs do have electrical locks that are locked when de-engerized? in this particular case you would not trap people in the lift as there are NOT people in the lift, even a fire fighter would be retarded (or extremely poorly trained) to attempt to ride a VRC or a dumbwaiter in a fire!
So even if this 200 degree wire does have logical reason for existance in an elevator system that I am not aware of, it has none that I can see in a dumbwaiter or for my purposes a VRC.
I know this issue is pretty specialized, so my last inquiry is how do you get info to the NEC panels that write these rules?
