Elevator cable lubrication & maintenance

At the last NAEC convention in Boston I had the opportunity to sit in on a cable lubrication seminar put on by Martin Rhiner of Brugg Lifting/Elevator rope.  The company I work for, Colley Elevator, does not maintain high rise buildings, however, we do low to mid rise traction elevators and we inherit buildings on maintenance that typically have deferred cable maintenance.  While I am getting more knowledgeable on traction elevators, my expertise is not in traction elevator so I try to sit in any educational opportunities available.  There is a wealth of knowledge within our industry so any chance I get to sit through someone talking about what they are experts in, it is great!

Over the years I have heard different takes on cable maintenance from mechanics, sales people, etc, many of these takes typically are close to being on the right path, but had some wrong turns that are detrimental in the cables life.  Many of the takes I have heard have a mix of good and bad practices. 

The big take away here is that once a cable begins to deteriorate it cannot go back to being a cable in good condition.  In this picture it shows once a banana is going bad, it cannot be brought back to its original condition, much like cables. 

Another large point was the lubricant being used on the cable.   These points are assuming you are using the proper lubrication.

1.    A lubricant keeps its chemical and physical properties for a long period of time.

2.    Does not affect the traction between rope and sheave

3.    Lubricates all rope components such as core, wires and strands.

4.    Minimizes rope and groove wear

5.    Protects ropes from the environment

6.    Prevents corrosion

Do not use

1.    Lubricant with bitumen

2.    Lubricants with Molybdenum, Telflon or Graphite – Impact on traction is unpredictable

Do use

1.    Factory applied lube and field dressing from the same manufacturer

a.    Guarantees compatibility of lubricants

2.    Key specifications

a.    ISO grade of 10

b.    Viscosity index[ASTM D-2270) of NO LOWER than 80

c.    Viscosity @104 degrees/40 degrees C CST/SUS(ASTM-D445/D2270) of 10/59

Moisture can drown a rope – Elevator cables are made of “bright” (uncoated) wires and vulnerable to the effects of moisture including

1.    AC exhaust into the hoistway

2.    Coastal air

3.    Fire extinguishers and sprinklers

4.    Touch

In the past I have had conversations with different consultants doing water damage audits and it is important that if the cables have been exposed to water during an event, they should be changed.  Get them on the list for damage and have them on the insurance docket.  If you do not replace them immediately you may inherit bad cables in the next time period and if it is covered in your maintenance agreement you might have a difficult conversation with the building owner in the future.  Bring it up right away and if insurance will not cover it or the building owner chooses to punt on the replacement at least you have brought it up.

There also is a difference between rouging and rusting. 

Rouging – A sign of internal rope deterioration

1.    Fine red oxide dust on rope surface[not rust]

2.    Indication of metal abrasion within rope

3.    Metallic powder deposits on surface

4.    Indication that core got wet

5.    Core is deteriorating – reduction in rope diameter

6.    A17.6 only allows half of the diameter reduction

                                        Other causes of rouging

Rust = Corrosion

1.    Corrosion on wire surface means metal is deteriorating.

2.    Wire surface is pitted

3.    Reduced strength and bending fatigue life

4.    Breaking strength is reduced

5.    Irregularities on wire surface will shorten rope life

6.    Lubrication cannot reverse the corrosion

When to apply field lube?  Once per year or every 250,000 cycles.  There are some good references to gauge how much lubrication is needed based on how much rope you have and the diameter of rope.  Over lubrication causes its own problems.

How to lubricate cable?  There are many ways we have lubricated cables in the past, some are ineffective and dangerous.  Do not use lube in a can it may have degreasers and most likely are not compatible with the existing lubricant on the rope.  Solvents/degreasers will deteriorate rope cable.  Most common and correct ways would be to use a paint roller or a permanent lubrication device.  You need to be careful when setting up the lubrication device to not have it in too deep on the cables.  The permanent lubrication device should be set away from the cables and not touch them.

[The picture above is the wrong way to install a permanent cable lubrication device]

How to clean cables?  This is a messy but necessary process.  If cables are maintained properly you should not have to clean cables.  Due to the hoist way environments and different lubrication methods the reality is that cleaning will be requited.

I would like to thank Brugg for taking the time to talk to us about cables because it is helpful to remind us of all the dynamics that go into cable maintenance.   Brugg does manufacturer cables in the USA in Rome, GA.   More information about Brugg at http://www.bruggcables.com/.

If you have any questions or would like information from Colley Elevator you can go to www.colleyelevator.com, email Craigz@colleyelevator.com or call 630-766-7230.