Big Glass: Can You Handle It?

Key considerations when using vacuum lifters with large glass
Daniel Meuchel and Bryan Strobel
November 20, 2018
COMMERCIAL, FABRICATION

multi-story window wall installation

Above: A multi-story window wall installation with roof overhang using Wood’s Powr-Grip’s MR16 and counter-balancer option. Courtesy of Wood’s Powr-Grip.

Is a vacuum lifter the right tool?

Is a vacuum lifter the right tool for a big glass project? Vacuum lifters can be a practical solution for many large glass applications. Consider using them if a job benefits from the following:

  • Access to edges and backside of material
  • Support across the surface of the load
  • Lifting of loads with varying sizes and characteristics
  • Attachment without having to modify the load
  • Easy load manipulation
  • Fast attaching and releasing
  • Security of attachment that is monitored.

Glass is getting larger, with architects seeking jumbo glass in everything from stadiums to shopping malls to office lobbies and more. How can an installer know if they are ready to take on a big glass project? This article explores the essential steps and critical considerations a company should take before tackling such a job using vacuum lifters. 

Planning

“Planning is bringing the future into the present, so you can do something about it now,” said author and time-management guru Alan Lakein. In material handling, good planning prepares the team for both the expected and the unexpected. Completing a complex job with large, heavy glass requires a team of people, including glass manufacturers, installers and equipment manufacturers all working together. Team-wide, collaborative planning is an essential part of project success.

In planning, teams should:

1. Determine project requirements 

Before a project team can identify the type of equipment necessary and the process for installation, it must consider the project details. Is it a single- or multi-story building? What are the site conditions? Are there design elements such as an overhang that will affect the installation?  

Next, the team should consider the glass and glazing systems. How will the glass be delivered? What is the max weight that will be handled? Are there multiple sizes and shapes, mullions, or possible cutouts in the glass that might affect handling? Is the glass delivered in the same orientation that it will be installed? What is the load surface (smooth, irregular, etched, hydrophobic, etc.)?  

2. Consider equipment options

Once the project team better understands the details of the project, it can begin to choose the necessary equipment. Teams should consider the motion required, the capacity and the necessary load support. Additionally, project managers should consider equipment cost and lead time. 

Availability of equipment varies depending on how common it is. Dealers and distributors often stock the most popular equipment—typically for capacities under 1,500 pounds. Often, there are standard product lines that extend well beyond what is typically stocked. These non-stocked standard products have completed manufacturing drawings and can be built upon request. Custom products will be required for applications where off-the-shelf equipment doesn’t fit the bill.

Equipment can be bought or leased. When leasing, there are fewer options available. However, leasing may be practical if a lifter is only needed for one job, won’t be used regularly, or the company wants to try before they buy. Additionally, a company doesn’t have to store and maintain leased equipment. 

3. Plan for installation

An installation plan can help a project team identify challenges before installation begins. The plan will help determine, for example, if any hang angle accommodations will need to be made, and will help the team identify safe operating locations around the jobsite.

Hang angles are a particularly important factor to consider when working with heavy loads. When a lifter is hanging from a hook, the lifter and load often hang at an angle. As the glass gets heavier, thicker, or when it is a curved profile, the operator force required to hold the glass in a perfectly vertical orientation can become impractical, especially if above ground level. There are solutions to counteract this hang angle effect. It is important to evaluate each application and determine if these additional accommodations are necessary. 

Overhangs are another common site condition that should be addressed during planning. An overhang may block access to an opening, requiring the installation team to select specific equipment that accommodates the challenge. 

In the planning stage, an installer should set up the lifter and attach the load. The installation team should crosscheck safety measures, such as accessibility to lifter controls and visibility of vacuum lifter indicators. 

Equipment solutions

Installers can look to a number of lifting equipment tools to address on-site challenges, from overhangs and hang angles to crowded jobsites. Some equipment solutions to consider:

1. Mini crane or telehandler

One handling method that has become quite common, particularly in Europe, is the mini crane. Because of the close quarters and mature construction, mini cranes offer a way to avoid other buildings and obstacles. 

The equipment is portable and can be positioned on various floors. It fits in tight spaces and works with unlimited overhang. However, a mini crane has a limited reach, lower capacities and requires head room above a suspended lifter.

2. Counter balancer

A counter balancer moves the weight to balance the system, whether it is loaded or unloaded. 

A counter balancer typically features a long beam with two parts: the lifter, which is bolted onto the front, and the counter balancer, with moving counter weight to balance the load. The long beam accommodates reaching under an overhang while the moving counter weight offsets the effect of reaching out the extra distance.  The counter weight also eliminates the hang angle and corresponding large operator forces required to hold large, heavy glass vertically.

3. C-frames

C-frames are specifically designed for a project application. The frames are more commonly used when removing glass from a reusable crate (with a top on the crate). The “C” of the frame spans over the top of the crate so the installer can reach inside the crate to remove the glass.

Be aware that the hang angle of the C-frame lifter will change some from the loaded to the unloaded state. The weight of the backside of the C may make the top of the lifter hang back toward the operator when unloaded. The effects of this can generally be accommodated by using a moving lift point or opting for a lifter with powered tilt. 

Safety

Vacuum lifting has become an industry standard in glass lifting because it is effective and safe when used appropriately. To ensure safe operation:

1. Use equipment that complies with industry standards

Several industry standards apply to vacuum lifters. The standards regulate design and structural requirements, vacuum requirements, controls, labeling and indicators, instructions, testing, inspections and maintenance. 

Not all standards in all regions are law, so it may be optional for a manufacturer to comply with them. Installers should verify that their lifter manufacturer complies with the regional standards. 

There are several relevant standards installation teams should consider. 

The standards include:

  • ASME B30.20 – Safety standard for below-the-hook lifting devices, used in the United States 
  • ASME Bth-1 – Design standard for below-the-hook lifting devices, used in the United States
  • EN 13155 – Safety of non-fixed load lifting attachments, used in Europe
  • AS 4991 – Lifting devices, used in Australia.

2. Use equipment with all necessary safety features

Manufacturers offer equipment with a range of important features that will protect installers on the jobsite. Available features include: low vacuum level warnings, visual and audible indicators, redundant vacuum systems, leak rate detection and battery health monitoring. Some lifters also offer load weighing, remote monitoring of system status and onboard diagnostics for additional safety. 

3. Ensure correct operation and maintenance

Finally, there is no substitute for understanding the vacuum lifter operation and properly maintaining the equipment. Just like an automobile or any other sophisticated piece of equipment, regular maintenance is key to long-term, reliable operation. Make sure to plan each lift, keeping visibility of the indicators, access to the controls, and people in appropriate and safe locations. 

These simple considerations will go a long, long way in keeping everyone safe and making the project successful and profitable. 

Daniel Meuchel (left) is a product design engineer and Bryan Strobel is the new product development manager for Wood’s Powr-Grip Co. 
They can be reached at 406/628-8231.