It’s time to upgrade maintenance practices for vertical vessels. Like any routine maintenance, inspecting, removing and replacing refractory in vertical vessels places a costly burden on facilities in terms of downtime and lost productivity. One of the main reasons for this is the traditional solution for accessing vertical surfaces – scaffolding – severely limits efficiency. It also increases safety risks for employees.
Processing facilities are taking action to reclaim maintenance productivity and safety by investing in custom-manufactured suspended platforms for vertical-vessel operations. These systems feature a lightweight, heavy-duty metal platform that is erected inside the vessel and raised or lowered using manual or electric hoists for hassle-free maintenance and relining applications.
Suspended platforms offer a number of benefits over scaffolding systems, starting with effectively eliminating the protracted setup times that dominate scaffolding-based maintenance schedules. Here’s how these customized systems can boost productivity and safety throughout the maintenance process.
Speedy SetupThe amount of time scaffolding systems take to erect is their biggest deterrent and the greatest drain on maintenance productivity. This is due in part to the sheer complexity of the operation, which includes juggling a variety of pipes, hardware, boards and other materials to create the structure. Erection times vary based on vessel size and configuration, but even with an experienced crew, scaffolding can take several shifts all the way up to an entire week to construct. This puts significant stress on maintenance budgets and timelines.
To simplify the process and decrease setup times, suspended platforms implement a modular design and pin-together construction. This greatly reduces the number of components and tools required for erection and allows crews to complete setup in as little as two hours.
Modular components manufactured from high-strength 6061-T6 aluminum provide the same strength as steel at one-third of the weight. And, because vertical vessels often feature small access points, manufacturers limit the size of modular components. The resulting pieces are easy to maneuver, weighing 40 pounds (18 kg) or less, and fit through a 22-inch-diameter (560-mm-diameter) access hole. This provides a lighter, more easily maneuverable solution than scaffolding’s heavy wooden planks and steel pipes, some of which are up to 14 feet long.
In addition, pin connections allow for fast assembly and improve platform strength over welded connections by allowing for some flexibility while the platform is being raised or lowered. Welded joints are rigid, which increases stress on risers at platform joints. Pin-together joints are a better solution to help maintain safety and stability when dealing with varying speeds from the climbing hoists.
It is worth noting that suspended platforms require some initial site preparations. This can increase setup times the first go-round – sometimes up to a full shift for complicated systems. But in the long run, a suspended platform can save facilities significant time and effort with each use, leading to significant ROI potential.
For example, a copper plant replaced the scaffold system for their smelter with a suspended platform. This increased productivity and safety. Overall, the plant was able to save 320 man-hours per shut-down with the new system.
Room to Move
Even after the platform is assembled, the productivity benefits continue to add up. With scaffolding, tools and materials need to be hoisted up to working height a little at a time, often manually. This is a slow process with a heavy physical toll. It also limits productivity by restricting supply lines for materials, such as refractory brick, gunning equipment or other necessities.
Fig. 3. Suspended platforms from innovative manufacturers implement a modular design and pin-together construction that allows crews to complete setup in as little as two hours.
A suspended platform, on the other hand, can easily transport up to 6,000 pounds (2,722 kg) up and down, and the open design provides ample space for personnel, tools and materials. This allows several workers to operate in the same area comfortably, as well as have everything they need close at hand for efficient maintenance. Crews simply load all necessary materials at the start of the shift while the platform is positioned at the vessel’s access point. When more brick or other supplies are required, the crew lowers the platform, loads the necessary materials and then easily returns to height. This saves considerable time and energy and can increase productivity by limiting the number of trips up and down.
The platform also provides more room and easier positioning for equipment such as gunning machines for shotcrete applications. Crews simply set up the machine directly on the platform and maneuver the entire system up and down, eliminating downtime from repositioning while maintaining an ideal distance from the vessel surface for proper adhesion. Using a suspended platform for this application al-so eliminates the physical toll and risk to crews from heavy hoses hanging from the scaffolding.
In addition, the open platform and electric hoist system allow for infinitely variable height, resulting in unrivaled access for inspection, removal and replacement of refractory materials.
Scaffolding is inherently rigid. It has to be to create a sturdy base of operations. However, this rigidity restricts crew access to the burn surface. Pipes inhibit visual inspection and make it difficult to work on the area directly behind them. The scaffolding structure can also obstruct small flaws, causing them to be overlooked. Crews must squat down or reach up high when working on surfaces in between 8-foot scaffolding stories.
Suspended platforms provide crews with 360-degree access at a comfortable working height, regard-less of the task at hand. To optimize accessibility and productivity for a particular facility, manufacturers also customize designs to fit vessels up to 22 feet in diameter, so crews can get directly against the burn surface without risk of falling. This allows crews to inspect every inch, catching even the small flaws that could lead to bigger problems down the line if overlooked. Also, some suspended platforms allow crews to adjust the size of the platform by up to 3 feet while suspended by changing the outer panels. This results in better accessibility and easy transition between different widths of a vessel.
Fig. 4. a) A cement facility eliminated five days of double shifts installing a drip tube in a cyclone with the suspended platform, saving an estimated $15,000 an hour in downtime. b) With a suspended platform, crews enjoy 360-degree access at a comfortable working height, regardless of the task at hand.
Ergonomics for Better Economics
It goes without saying that having a platform, rather than a narrow scaffold, increases worker safety.
Falls continue to rank number one in workplace injury reports, and refractory repair is not immune to tragic accidents. Recent U.S. Bureau of Labor Statistics data identified 338 fatal falls to the lower level among 1,038 total construction fatalities for the year. That same year, falls on the same level or to lower levels amounted to $17.1 billion (29.2%) of the nearly $60 billion spent by employers on serious, non-fatal workplace injuries.
A suspended platform replaces narrow wooden catwalks with an aluminum surface that spans the entire vessel, eliminating the risk of falls or dropped objects. It also eliminates the need for workers to climb up and down carrying small tools and the need to haul materials and larger equipment up to height, hand over hand, resulting in a much safer jobsite.
There are long-term safety benefits that go beyond this. From setup through all aspects of refractory maintenance, a suspended platform puts less physical strain on employees. The lightweight, modular components are less cumbersome than long poles and heavy wooden planks. Easy access to materials and tools reduces the risk of repetitive-motion injuries as well as minor cuts, bruises or scrapes that come with manually moving refractory materials. Being able to position the platform at the ideal working height for the job at hand limits bending or reaching, providing an ergonomic solution instead.
All of these small but significant safety benefits lead to long-term savings in the form of worker’s compensation claims and insurance premiums.
Making the switch to a suspended platform requires some initial planning, but positive returns are al-most immediate. Facilities that have made the switch save tens of thousands of dollars with each maintenance cycle, providing a return on investment in one or two uses. The key is working with a reputable manufacturer that can provide a customized platform that fits a facility’s needs perfectly. Working together, these partners can revolutionize refractory maintenance in vertical vessels.
For more information: Contact Jeff Mirisola, technical sales manager, Bricking Solutions, Inc., 1144 Village Way, Monroe, WA 98272; 1-360-794-1277; firstname.lastname@example.org; www.brickingsolutions.com.
All images courtesy of Bricking Solutions, Inc.