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What is an MR-L?

Posted on: January 22nd, 2012 by AEadmin


One of the biggest changes that took place in recent years in the elevator industry was the introduction of the “MACHINE ROOM – LESS” ELEVATOR (MR-L). The name speaks for itself, literally, no machine room – when the code will allow it.

The initial thrust to sell the MR-L’s has been to the new construction market. Having said that, the MR-L’s are also planned for modernization projects, replacement of the “old” and installing the MR-L’s for the “new” as the upgraded systems for the replacement – modernization programs.

The traditional elevator systems have the main electrical control and drive systems located in a separate machine room either at the top or, at the bottom of the building. Generally referred to, as ‘overhead’ or, ‘basement’ location. For this article we will refer these as “traditional elevators” with “traditional machine rooms”

Over a decade ago, one of the world’s largest elevator manufacturers introduced the new technology systems MR-L. The other leading manufacturers eventually joined the ‘bandwagon’ and they promptly competed against each other vying for business with their newly introduced technology elevators. This has been strongly marketed by the global elevator companies and promoted essentially to architects and consultants specialized in the new construction industry. The architects and elevator consultants who have been sold on the new concept elevator systems, in turn convinced the developers, construction companies to buy into the MR-L’s and building owners, who participated at the front end, also listened and went along with the new generation of elevator systems. Before we know what has happened, MR-L’s are being installed by the 100’s. Those who were informed along with unfortunate building owners who were not participants at the front end of a new development, end up with holding the bag along with all the subsequent preventative maintenance issues described in the following:

Plenty of information is available on the web on this new type of MR-L elevator system from all the manufactures producing them. We will take a look at them along with issues from the perspective of what the building owners, property managers must face and deal with for the long-term operation of a building.

The marketing of the MR-L’s is essentially based on the following advantages:

• Elimination of the traditional elevator machine room – when the code will allow it.
• Faster installation process
• Environmentally friendly
Developers, architects, construction companies etc., are not the personnel involved in long-term building management once the building has been turned over to the owner. Owners who participated in the original concept of a building are relying in most cases on the expertise of the aforementioned professionals to install the right elevator system. More often than not, it is a developer out to make a profit while completing a project, reaping the reward and then selling the building and moving on to further projects. The eventual owner in the majority of these developments was never involved in the initial process.
With the heavy marketing strategies by the world leading elevator companies of their new technology MR-L’s to architects and developers etc., and no doubt encouraged by many elevator consultants, the unsuspecting building owners are now left with an array of issues to deal with, that were either, disregarded, not even considered or, a combination of both when the original decision makers were in the process of committing to the plans at the front end of a new building.
The elimination of the traditional elevator ‘machine room’ is one of the biggest promotions the elevator companies producing the MR-L’s have made to the new construction industry in recent years when comes to the vertical transportation in a building. Effectively, a grand promotional move with the carrot being space saving, when the code will allow it. If a machine room is required, the same problems exist as with the “closet” controller location; there is no visual observation of the elevator in motion while the mechanic is working on the control system. There are further claims of additional environmental gains, one being with new and improved gearless drive machine design along with faster installation meaning lower construction costs.
We’ll start with issues that were not considered for the longevity, reliability and eventual preventative maintenance requirements out in the field that should have been identified not only from the experienced gained from 150 + years of the elevator industry but, identified through the research, design, prototype, testing, manufacturing, production stages and operational requirements.
The MR-L’s are supposed to be, space saving and better for the environment. Certainly better for the environment in respect to hydraulic elevators, especially those hydraulic elevators with an in-ground piston that are very common in North America Reference: WHAT’S CURRENT IN THE ELEVATOR BUSINESS #4 – Coming soon.
Space Saving: The MR-L’s have no machine room, when the elevator code allows it. The machine room housing the controller is now a closet located in the building as close as possible to the elevator hoist-way. Closet or traditional elevator machine room, the mechanic and elevator field personnel need to work on the controller wherever it is located. Adjust, clean, trouble shoot, inspect. For that reason alone, they require a restricted space to work safely during all working procedures around the controller cabinet. This closet is not in a restricted area and requires barriers to be erected any time the closet door is open and the controller is being work on.
Compare the former “traditional elevator machine room” restricted to Authorized Personnel Only, complete with designed cross ventilation system, housing not only the controller but also the drive machine / motor and related equipment. Space requirements were set by codes of the time that the system was installed. Additional traditional equipment included a parts cabinet to house immediate parts requirements for preventative maintenance and small emergency requirements. More often than not, a small desk is included to accommodate the required schematic drawings for ease of reading when trouble shooting especially with multiple elevators in a single machine room. The desk is also there for ease of documenting the preventative maintenance work performed. Additional items such as cleaning materials, fire rated containers for clean and dirty rags and the fire rated garbage can. All functions together, all on hand and systems that took more than 150 years to develop and establish.
In the traditional elevator machine room, the mechanic can easily work on the controller, visually observe and even listen for the movement of the elevator, the condition of the rotating gear, adequate space for safety requirements to work around the equipment with all the necessary tools of the trade on hand; tools, spare parts and the required drawings plus, with the main disconnect switch in easy reach just seconds away for emergency situations.
The MR-L has no machine room in the traditional sense – when the elevator code allows it.
• It is now a closet containing the control system (controller) located in the building as close as possible to the elevator hoist-way.
• The machine location depending upon the manufacturer, is generally at the top inside of the hoist way / shaft or, at the bottom of the hoist way / shaft or, to the rear wall where on occasions it is visibly portrayed as a marvel of ingenuity for people to watch in an open planned spacious designed building.
• By having the control equipment in a closet where the rotating gear is NOT visible is just one of the preventative maintenance drawbacks – not mention potential safety issues with this machine room concept of the MR-L by not visibly seeing or hearing movement of the elevator.
• Another drawback is the requirements not only for preventative maintenance requirements and trouble shooting on the rotating gear, the drive machine is now located and only accessible in the elevator hoist way / shaft. Certainly not an accessible location.
• Also the potential and eventual service requirements for removing and replacement should a major break down occur and above all, the extra time to perform these tasks.
• Greater difficulty for maintenance requirements
• The closet could well be in an area with tenants, residents and visitors passing by. This in turn will require the extra time to erect suitable barriers or, the location will be tucked away in a corner of a hallway or, at any floor close to the elevator hoist way / shaft.
• Lack of storage requirements for: support / parts – tools – desk for drawings – garbage cans
• Potentially, more a two man “crew” to perform maintenance tasks and requirements.
• In the event of elevator “break-downs” with entrapments (passengers trapped) extraction of the passengers is potentially difficult.
• Noise levels of the MR-L’s can be noticeably higher than the traditional cable elevator.
This elevator “concept” change – no matter if it is a real MR-L or, due to the code not allowing it, a separate machine room is required, has nevertheless, created the elevator mechanics nightmare. This nightmare for the mechanic, not only makes it far more difficult to service, thus increasing the safety risks for mechanics that is essentially due to the substantial decrease in restricted work space that otherwise would have been performed in the restricted work environment of the traditional elevator machine room. To make matters worse, the mechanic has to work extensively in the hallway of the building with tenants and visitors passing close by. Inconvenience to all, passers by and the mechanic on the job. Trouble shooting a problem can be very difficult but also to repair an electrical or, mechanical issue in a confined space such as the elevator hoist way / shaft is another issue in the event drive motors and related machinery have problems. All this is without the inconvenience that the owners, tenants, visitors will have to encounter with the net result causing the building managers headache.
There are issues with the MR-L’s when it comes to removing entrapments (passengers trapped in the elevator) The reality is that all vertical transportation systems, as the MR-L’s are electrical – mechanical devices. Things can go wrong, especially when systems like the MR-L’s are rushed into production and general operational usage with new untried and unproven systems and components. Note the following paragraph:
To maintain some of these MR-L elevators special training is required. The MR-L’s are more complicated than the traditional elevator systems. This special training is required for maintenance personnel; mechanics; supervisors and includes independent regulatory inspectors who perform the required code and regulatory inspections. All this special training is over an above all other elevator industry requirements.
On occasions, necessity requires the rotating gear needs to be removed and repaired “off-site” – Due to the reduction in space this means extra time to complete service work will result in more down time and higher maintenance costs.
Normally a large percentage of this kind of elevator maintenance, service and repair work would have been performed in the traditional separate elevator machine room. This transition into new age technology of the MR-L’s, we strongly believe is without sufficient thought and due diligence for the reasons discussed above.
The elevator industry has capitalized on the term “new technology” like many industries that have genuinely brought to society great advancements. How well were the “new technologies” in the elevator industry thought out? What are the consequences of hastily producing an untried and unproven system?
A good example is the MR-L units manufactured and installed by one multinational elevator company. This particular model, now with an estimated 1500 installed in North America, with literally “ROPE” to haul the elevator, minute by minute, hour after hour, day after day, week after week, month after month up and down the elevator hoist way / shaft, before the company pulled production of the “rope” units. Well, trouble came, the “rope” wore out quickly. Quickly meaning, in months. Aside from fair wear and tear on such a short life of the “hoist ropes” – other influences such as potential environmental conditions can easily affect the rope, (steel cables can be affected as well but withstand far more than rope) was that ever a consideration? The “rope” installations in service are operating along with grandiose promises that have not met the OEM’s own deadlines for improvements and upgrades. Not forgetting, all improvements and upgrades must be accepted, approved and passed by regulators in the many different jurisdictions the first wave of rope MR-L’s were installed.
When Elisha Otis invented the Safety Device for elevators way back in the early 1850’s, elevators were equipped with rope. If the rope broke, down went the elevator. Otis with his ingenuity & his invention allowed for higher buildings to be built. Even higher buildings when steel cables were introduced.
The re-introduction of “rope” in recent years to haul elevators traveling multi floors was to say the least a real step backwards of great magnitude for all those building owners who have these particular units installed in their buildings. As they say “back to the future”. They are safe no doubt. There are safeties on these elevators with the same principal as OTIS invented over 150 years ago, along with added sensors to monitor the condition of the ropes. The word is, there are now additional sensors to monitor the sensors on this particular model!
Other than the original equipment manufacturer (OEM) – which other elevator company, large or small would entertain taking on the responsibility to maintain some of these units that can only be described by an experienced mechanic as “an experimental contraption”? Another comment has been, it was designed by a group of grade 12 students as a project prior to going onto engineering college using an old set of “meccano” as the prototype. Not only is the “proprietary” control equipment to contend with, there is the issue of the design configurations that no other company would ever want to lay their hands on. This in turn restricts the building owner / property manager to “go to market” for competitive pricing. On the other hand, great for the elevator companies as they are the only ones to service and maintain them and makes the owner / property manager at the mercy of the prices the OEM is charging.
The new updated version of these “rope” units now marketed has steel cables. Other companies have their own product to compete for a market share that they have established, what leaves the appearance of an element of “combine” has been created. All have a different twist, all claiming they are the worlds leader in innovation coupled with patents for different components or, systems. Whether they are better or, worse than the “rope” hauled units, none of them really have the long-term interests of a building operation in mind and neither, was much thought and consideration ever given for mechanics having to work on them.
Other companies products have other issues that would normally never have occurred had a traditional cable elevator been installed in their building. Traditional cable elevator systems would normally be designed with one single drive sheave for small capacity elevators, and larger capacity units would have a deflector sheave. By and large these traditional elevator systems were well engineered. The MR-L has anywhere up to seven (7) small (small for the elevator industry), deflector sheaves of a synthetic material plus the drive sheave for the cables of either rope or steel to loop around. This area of the system, including the cables of rope or, steel is potentially vulnerable for increase replacement repair and service due to the small diameters in use and typical, where dirt & grime from the hoist way / shaft can fall into and damage the pulley system of the elevator.
Taking into account the so-called ‘space gain’ by eliminating the traditional elevator machine room, what further consequences are there?
Greater difficulty to perform the all required preventative maintenance (PM) plus service and repair issues (It is an electrical mechanical device and to keep it operational that must have planned PM) culminating in greater difficulty to maintain, computes out to more time being spent and in turn, means a higher cost to building owners. All these additional difficulties to deal with at the expense of eliminating the traditional elevator machine room. Not forgetting the compounded problem facing the elevator mechanic with having increased exposure to safety issues when working on the MR-L’s, working in a confined space and protruding themselves out into hallways with people coming and going in close proximity to passers by. The separation from a work environment to ‘passers by’ with the use of the removable barrier with an elevator company LOGO and the statement: ELEVATOR UNDER REPAIR!
Engineering production designers and engineers design and configure these units. Marketing research gets involved “eliminating the so called wasted space of an elevator machine room” elevator companies manufacture and installed them and safety authorities and regulators twist the code to allow them to be installed. Architects were sold on it and elevator consultants participated. Variances to the elevator code are required from regulators. Then modifications are made for safety reasons and more approvals and variances to allow them to be operational for public usage. The truth is, who in this sophisticated chain of command considered the long-term ramifications? None-of-the-above. Now the unsuspecting building owner with MR-L’s, commercial – residential, co-op, and strata are stuck with the long-term problem. The “rope” units, how long will they last? Another question; how long were the MR-L’s even planned to last? It wasn’t to long ago that one renowned manufacturer designed their elevator systems to last the lifetime of the building – as long as the preventative maintenance was carried out as per their instructions.
The space saving claim: “MACHINE ROOM – LESS” ELEVATOR (MR-L) when the code allows it, creates the mechanics nightmare as described above. Really, it has won nothing in comparison to the long-term costs to maintain these units. The extra inconvenience to all users of a building especially with the “closet” controller location and the restrictions it places on owners to obtain competitive pricing, if and when the promises by the elevator company are not kept and the owner wants, “cannot choose”, to move onto another elevator service supplier. Yes, quote from one of these manufacturers “the entire lifting system is guaranteed for 25 years, if maintained by us, the OEM” – It seems to us, the building owner is stuck with them anyway.
The elevator industry has done a wonderful job in the marketing, especially to the people who bought in at the front end of a development (developers – architects – elevator consultants), who don’t have to live with the after sales service issues of the MR-L’s.
As far as the environmental issue of no oil, it is more than 100 years ago that gearless machines were in production. Now under the guise of environmental concerns, the elevator companies have re invented a wonderful new drive machine that the basic technology was invented and has been in use for over a century. Say no more. Admitted the motors are smaller, but at what cost for future maintenance when considering where they are now located, inside and at the top of the elevator hoist way / shaft.
With today’s current expertise and available technology from experience gained over the last century, the existing gearless machines have been improved anyway for the traditional elevator configuration. Claiming an environmental advantage for today’s current “green” requirement for buildings as part of the advantages of the MR-L’s, have proven to be nothing short of an excellent marketing tool for the elevators companies producing this “new technology” elevator systems.
Lower construction costs at the front end. At what expense to the long – term operation and management of a building, is it worth it considering the downside of the long-term? In the scheme of things, taking into account the size of a traditional elevator machine room and the square footage of a building, effectively they was no gain whatsoever. How much time saving at the front end for installation? At what cost is there for the long-term? Increased safety issues for elevator mechanics working on this “new technology” along with the eventual owner dealing with all the subsequent headaches that come with the MR-L’s over the following 10 – 20 – 30 years of operating a building.
There are numerous documented accounts by experts of increased noise levels from the MR-L units. The noticeable noise levels are generated from those units designed with the increased number of deflector sheaves in the pulley system arrangement and neither has it helped, with the drive machine at the top of the elevator hoist way / shaft, with the resulting noise resonating down the hoist way / shaft out into the hall ways / lobby and the rest of the building.
The final question is:
How much thought really went into the MRL elevators? Not just from the standpoint of designing, or the production of so much new “non-standard” parts and components to build the system, the testing etc., etc. What about the mechanic in the trenches having to work on them and what about the inconvenience factor associated within building operations?
For us, a “thumbs down” on this one, until we hear that it is the building owners raving about the success of the MR-L’s and not the elevators companies applauding themselves on a wonderful new concept. All in the name of change “new technology” out with the old and in with the new, that in turn has given building owners / building managers / building operators / property managers more to deal with when managing and operating a building for the long-term with this new technology “MR-L” vertical transportation systems installed in their buildings.
In the last couple of years, at least one of the elevator companies producing these MR-L’s was faced with major design improvements / retrofits on those units already supplied and installed into buildings. It was back to the drawing board in an effort to bring them into acceptable level of operation to meet all elevator code requirements.