How Shop-Applied Fireproofing Beats Field Applications

By Troy Marshall, Fire Segment Director – The Americas, and Carl Burrell, Global Product Manager – Fire

The practice of where and when to fireproof structural steel for buildings, hotels, stadiums and other multi-story structures has evolved significantly around the globe over the past several decades. Today, steel fabricators, general contractors, asset owners and architectural designers are realising lower costs and enhanced safety, quality and aesthetics. These benefits can be directly tied to a shift from applying passive fire protection (intumescent) coatings in the field to applying them in a controlled shop environment. And stakeholders who have not yet made the shift are missing out on streamlined operations and lower overall costs.

Reap the Rewards:

Cost, Safety and Aesthetics

Major fabricators in the United Kingdom started applying passive fire protection coatings to structural steel within the shop environment—as opposed to within the construction zone—around the late 1990s/early 2000s. Soon afterwards, the steel fabrication and construction industries began embracing fireproofing in the shop as a standard business model. It is now widely adopted in the U.K. and much of Europe, the Middle East and Asia.

Compared to the application of passive fire protection coatings in the field—which is relatively common in the United States—fireproofing in the shop enables stakeholders to reduce costs and enhance the overall quality of applications. The gains realised in the U.K. and other parts of Europe make a viable case for major U.S. fabricators to adopt a similar strategy in greater numbers, so the myriad cost, safety and aesthetic benefits derived from the shop-applied model become more widespread across North America.

It’s About Time

One important advantage of restricting the fire protection process to the shop environment is that it allows the construction team to complete buildings much faster, lowering costs for builders. This swifter speed-to-completion is made possible by eliminating the need for much of the equipment and hassle associated with coating steel after it has been erected within a structure.

With coatings already applied in the shop, applicators do not need to set up a full containment system around the steel structure to protect the substrate from dust, rain and snow prior to coating. Nor do they have to invest in setting up environmental controls to ensure conditions are suitable for applying coatings. The containment process alone can be time-intensive and cost-prohibitive. Plus, within the shop, applicators can control temperatures and humidity to fireproof steel during any season of the year.

Up Your Game:

Enhancing Application Quality

Applying passive fire protection within a controlled shop also improves the overall quality of the surface preparation and the coating application. To begin with, it is much easier for coating applicators to prepare each piece of steel in the shop, as opposed to the more haphazard process of coating assembled steel structures, which can contain tight corners and other difficult-to-reach areas. During field application, applicators run the risk of working with an imperfect surface preparation, which can compromise the quality of the fireproofing process.

By contrast, when spraying intumescent coatings in the shop, applicators can control the surface preparation and enhance the quality of the fire protection application, which thereby improves safety for building occupants. For example, applying fireproofing in the shop helps applicators better ensure that coatings are applied to the right thickness for each piece of steel and that the entire structure therefore conforms to the specified fire resistance rating.

Another significant benefit of applying the coatings in an indoor controlled environment—as opposed to in the construction zone—is that it removes the necessity of coating the steel while other tradesmen are working. Fireproofing in the shop reduces the number of trades that must operate simultaneously on a construction site. Doing so enhances safety for the roofers, plumbers, electricians, excavators and other tradesmen labouring at the site. When coating applicators are working simultaneously with others, the process can be inefficient and hazardous. Accidents are more likely to happen.

Table 1. Comparison of Shop- and Field-Applied Passive Fire Protection Coatings

Advancing Innovation in Building Design

Given the cost, quality control and long-term safety benefits of using shop-applied passive fire protection coatings, this controlled application process has an added benefit for architects. It frees them up to incorporate more steel into building designs, allowing them to be more innovative. Sherwin-Williams witnessed such architectural creativity while working with its construction partners to fireproof the Leadenhall Building and the Shard of Glass skyscrapers in central London.

In fact, a unique fire protection challenge occurred while collaborating with architects and engineers during the construction of the Leadenhall Building, a modern glass and steel structure. Many of the iconic building’s design elements—its beams, columns and large transitional nodes within a sloping mega-frame—were highly complex. The team needed to develop precise intumescent coating thickness specifications for each piece of steel, depending on its size and incorporation into the structure.

Our fire engineering team engaged in painstaking and complex fire protection analysis and coating application methodology in conjunction with the project’s structural steel specialist. This process yielded specific coating thickness guidelines for each piece of steel. Then, by applying the coatings in a shop environment, the fabricator was able to ensure the Leadenhall Building’s unusual design elements had the appropriate thickness of coatings applied and therefore the highest level of fire protection.

A greater percentage of construction companies in the U.S. could benefit from adopting the shop-applied fireproofing model that is now prevalent in the U.K. By embracing the shop-applied approach, major fabricators in the U.S. are sure to see a difference in the quality of the coated steel used during construction, while passing a host of benefits down the construction chain.