In the example in this blog post, a 5 – story dormitory project at the University of La Verne, you can see the fully installed elevator hoistway going smack-dab in the middle of the building. Not only that, if you look at the conceptual drawing you won’t see even a hint of a hoistway. The duplexed modular elevators were simply placed on the inside of the building.
Perfection is a word that is not used very often. And it is also almost never used in the construction industry. But, there is such a thing as perfection even in the building trades and it is more common than you think. Its just not common with a traditional elevator installation. With MEM elevators however, perfection comes easy and it is a good thing it does.
Maybe we think of perfection being so rare because when the word is used in everyday conversation it is often associate with singular events or rarity at an extreme level. Think about a perfect game in baseball. In nearly 220,000 games played in Major League history, there have only been 23 official perfect games pitched and no hurler has thrown more than one.
No one claims to have ever had a perfect golf score…it would be 18 for a single round. Instead we measure ourselves against par. Even past North Korean leader Kim Jong-Il could only muster a score of 38 with 11 holes-in-one in his fabled round. Pretty good for the first time on a golf course, but still no where near perfection. Although if prevarication were a sport, Kim would at least come home with a medal.
Speaking of medals, in gymnastics perfection was so rare that when Romanian, Nadia Comaneci reached perfection in the 1976 Montreal – Summer Olympic games, there weren’t enough digits prior to the decimal point on the scoreboard. To the confusion of the crowd, after a seamless performance the score was shown as a paltry “1.00” instead of the ten she had earned.
But, astoundingly at Modular Elevator Manufacturing (MEM) perfection is commonplace, especially when it comes to the hoistway. So here’s why that accomplishment is so important and the how we daily accomplish such a seemingly rare feat; the feat of perfection.
A hoistway, otherwise known as an elevator shaft is the backbone of the elevator system. It must be perfectly plumb and level. Just like in human anatomy where everything hangs from the backbone, so too do many of the elevator components hang from the shaft.
Like the old song “The head bone’s connect to the neck bone.” etc. The elevator rails are connected to the walls of the shaft. On those rails the elevator car rides. How plumb, level, stable and sturdy that shaft is often determines how smooth and quiet the elevator car will go up and down.
If you have ever been in an elevator car that rumbles, or rattles it may be that the backbone (hoistway) is out of alignment. That can shorten the life of the elevator system and drive the passengers riding in it a bit crazy.
In simple terms, the reason for the rattling in traditional elevators is often that clips are attached to the inner hoistway wall and on those clips the rails are attached. The worse the alignment of the hoistway the more adjustment is needed. And the longer and more effort it takes to get the rails set right. If the hoistway is out of plumb or worse yet twisted even slightly, additional strain can be created on the rails and then on the clips. That can force the mechanism to be pulled loose as the elevator is used over time.
With a modular elevator the shaft is so plumb and level that the clips are not simply attached, but spot welded onto the frame of the hoistway and then bolted. They are adjustable, but aren’t going anywhere and there is no need for them to move. They can be welded because the hoistway is perfect every time. That means that modular (as usual) outperforms traditional.
First, to understand how perfection is possible it maybe helpful to know why traditional elevator hoistways are so often out of whack.
With the old way of putting in an elevator (and we have all seen this on a construction site) the elevator hoistway is one of the very first things that goes up. If it is cold, wet or snowy the elevator hoistway can heave and shift. One builder in Canada got tired of seeing shafts having to be redone because of heaving and the expense of hoarding heat while the hoistway cured. So he wisely opted for modular.
The opposite is true as well. If the temperatures are over 100 degrees special care and extra-effort must be made to keep the mortar hydrated with block construction. Failure to do so can “affect normal strength development of mortar, leading to a reduction in strength.” – cement.org. That’s a scary thought.
Extreme heat and cold say nothing about the poor folks laying all that block or pouring cement. They work in any number of foul weather conditions. And as we all know in less than optimal weather, work quality can diminish. In addition when it comes to the traditional hoistways work is done at heights on scaffolding. The human element cannot be ignored.
The hoistway tends to shift, twist or lean ever so slightly.
With a modular elevator or modular shaft or hoistway weather is never a problem. The entire hoistway is built inside a factory. The hoistways are made of tough construction-grade steel, laid out on jigs and are then welded together. There is no working at heights as the shaft is simply rotated as needed.
They are laid out horizontally in fifty foot sections or shorter depending on the project. If a hoistway over 50′ is needed the sections are laid out together to insure they are plumb and straight. Connecting plates are added at the joints for perfect fit every time.
Next metal c-studs and additional bracing is attached followed by the exterior sheathing. Usually a mold resistant drywall is used for either one or two hours of fire protection. The hatches get elevator doors next, then the rails go in. They are then aligned and welded to the interior and then the interior walls are finished out.
This perfect hoistway makes a solid, stable, plumb and level backbone for the elevator system. It ensures a great elevator every time. You will never get that promise from any GC or elevator company regarding the hoistway they build on-site. If this process intrigues you in the least and you have a project in mind just click the button. We can send you a quote in 24 hours. Or contact us at MEM where we produce elevators taking you to a higher level.
It is a tough chore deciding on what kind of elevator conveyance you should have in your next building project. As I have said before the elevator industry is very secretive about many aspect of vertical transportation. The wrong elevator is often placed in buildings because the information is guarded so closely. Too many resources can be spent on the improper type of elevator conveyance, not to mention the ongoing cost of maintenance and other factors if a bad fit is chosen. I hope to illuminate just some aspects of that decision in this blog, but let me warn you. Elevators are complex so I can’t cover everything in just one sitting. This will be a continuing series with this being the just the first.
Let’s start with the basics. There are three types of elevator conveyance systems (ways the elevator moves). This is regardless of the cab size or capacity of a commercial quality elevator. I am purposely excluding home elevators from this discussion, however there is a lot of transferable knowledge so stick with me. Any cab or weight capacity can utilize any of the three modes of movement. Those three are traction, hydraulic and roped hydraulic.
Traction is the type of conveyance that most people imagine when they think about elevators. It is the one from the movies with the ropes that people are constantly dangling from. Though the term “ropes” can be a little misleading. Here we go again with the elevator industry using terms that can confuse. Ropes are not what cowpokes use to lasso cattle or magicians use to tie up all too willing assistants. Ropes are actually cables. Elevator professionals understand ropes as highly engineered strands of wire wrapped together. A typical cable or rope can have over 150 strands of wire designed to be strong and flexible for a long time.
Ropes fill the hoistway of a traction elevator. That is because although one rope and pulley could in theory lift an elevator car, it would be inefficient and unsafe. So, in the hoistway you will find several hoisting ropes attached to the car and the counter weights. If you were paying attention in sixth grade science class and learned about pulleys and multiplication of force, you know why. Ropes are also redundant for safety.
Then there is a governor rope used to stop the car if there is a failure. If the elevator starts traveling too fast, the governor rope’s movement tells the brakes to stop the car. Lastly there are compensating ropes. Ropes can get heavy (up to 1.85 pounds per foot). Compensating ropes are attached to the car and counterweights to make up for the weight difference. All these ropes and sheaves (really pulley wheels) raise and lower the car.
However, despite appearing with Bruce Willis, Keanu Reeves and Spiderman (see the link at the end for a fun video on elevators in movies) traction elevators may be a star but, is not the the most common type of elevator conveyance. This is due to the attributes that make this type of elevator more conducive to taller buildings. As there are more low-rise or short buildings than high-rise buildings, hydraulic is much more common.
Hydraulic elevators are simply one or two hydraulic jacks pushing the elevator car up in the hoistway and then releasing hydraulic fluid to allow it to move down.
The jacks can either be in-ground or above-ground, depending on how high you need the elevator to go. But think about what a hydraulic jack is. In simplest terms it is a cylinder with a piston inside. As you push hydraulic fluid in, the piston goes up. So if you want to move something up ten feet you have to have a piston at least that tall. This means the whole jack must be at least that tall as well. Hence the in-ground jack.
An in-ground jack configuration is a single jack usually attached directly to the bottom of the elevator car. So to increase the height the car can travel, a taller jack must be used and must then be placed in a hole. The travel distance of the elevator dictates the depth of the hole.
Above-ground jacks (as you can tell by the name) are not in a hole. They are usually two jacks at the bottom of the elevator pit (the area at the bottom of the shaft) and attached above the car on either side, or more properly attached to the car’s sling several feet above the car itself on stiles. Logically, the higher the travel distance – the taller the jacks – the higher above the car the jacks must be attached – the taller the hoistway must be to accommodate the system. You may want to re-read that again. I wrote it and had to peruse it several times to make sure it was right.
In any case, to reduce the need of a real deep hole or a real tall hoistway, jacks can be and often are telescopic. Elevators can typically have up to four-stage telescopic jacks. This ultimately increases the useful range of hydraulic elevators overall.
Lastly, roped hydraulic elevators borrow from both systems. Again keeping it simple, this system of elevator conveyance uses hydraulic jacks, not to push the elevator car up directly, but to push an elevator sheave or pulley up that then with ropes raises the car.
How does it work? It has a pulley wheel or sheave mounted at the top of the piston or pistons and instead of it being directly connected to the bottom of the car or above the car on the sling. The sheave goes up or down as the jack is raised or lowered. A rope goes over the sheave and then is anchored to the hoistway below the lowest level of the piston and to the car.
There are clear benefits to this type of elevator, the most important being the 2:1 ratio of car to jack movement created by the use of sheaves and ropes. This provides a greater range of travel and allows for a shorter jack. Because shorter jacks are used greater travel distances can be achieved without an in-ground jack with its associated drilling costs. Also the travel speed is faster than hydraulic elevator at 200+ feet per minute, but the travel distance can easily be over 80 feet as the ropes and sheaves double the effective length of the jacks.
Your head maybe spinning a bit, especially if you generally view elevators as an annoyance that should be avoided at all costs. But, the above can help you start getting a picture of what type of elevator conveyance should be used in a project based on total travel. And let’s face it, cost and travel are the primary factors. Other factors may include speed, design flexibility and even building codes, but nothing can disqualify an elevator type faster than the practical inability for the elevator to travel the needed distance.
Regarding the cost briefly there are several factors to consider. The initial investment, work space interruption, the value of taking the elevator off the critical path, maintenance contracts and even operating costs. We will explore each of these in future posts, but again to keep it simple. Traction elevators are far and away the most expensive to buy and maintain. Roped hydraulic is next and finally the workhorse of the industry hydraulic is the least expensive. You must however, consider overall travel capabilities when deciding on your elevator. Take a look at the chart below.
The chart is for general guidelines. But as you can see the right elevator conveyance choice starts to take shape. For instance, for a two or three stop elevator, traction can be used but is highly impractical. There is simply no valid benefit for a traction elevator at that height. Likewise, an above-ground or holeless hydraulic elevator maybe less expensive, but impractical terms the limit is less than 30 feet. Also keep in mind that just because you can, does not mean you should. There are massive in-ground single stage hydraulic jacks. But, at the upper end it can get expensive, not only for the jack, but for drilling to nearly China.
So with all that said, hopefully you have a better understanding of the various ways an elevator moves and can start making clearer decisions on which should be employed in your next project whether you use Modular Elevator Manufacturing or not. If you would like a deeper conversation about what would be the best for your project, give us a call or get a fast track number by clicking the button below. We are looking forward to speaking with you.
By the way here is that fun video about the movies and elevators I promised click here.
MEM elevators come with a hoistway and all of the components of the elevator already installed. That it is the fastest set and start up in the elevator industry. There is no traditional installation as the installation of the components has taken place in our factory.
The elevator is completely wired, the car is already inside and the rails are already in place.
The difference with our product is quality. Other can say it, but we deliver it.