ESD Floors: Understanding the Hidden Costs

David Long
Understanding the types of flooring available can help avoid unnecessary costs.

Photo courtesy JULIE INDUSTRIES

In selecting a flooring material to address electrostatic discharge (ESD), most buyers consider price among their key concerns. For ESD floors, the cost of the materials varies considerably, with relatively inexpensive ESD vinyl at the low end of the spectrum, and nitrile rubbers, which can run to five or six dollars per square foot installed, at the high end.

A cost matrix comparing the materials in question (taking into consideration ESD properties and other key interests) would seem to be a simple way to differentiate the products and work through this maze of price variation. And it is—if the matrix takes into account more than simply the material and average installation costs; that is, if the matrix also looks at the total cost of ownership of the floor (see Table 1).

Flooring Options Carpet Conductive Vinyl Epoxy Rubber Cost Low Lowest Moderate Highest Durability Not suitable for heavy loads Good Excellent Good Maintenance Vacuum only Requires wax or regular buffing Sweep or mop Easily cleaned. Mop with soap and water Installation Easiest Average Easy Average Slip resistance Greater than 0.6 0.5­0.6 Greater than 0.6 Greater than 0.6 Chemical resistance Poor Good Superior Superior Acid, alkali, and solvent resistance Poor Good Excellent Excellent Sound absorption Excellent 4 dB Not sound resistant 5­19 dB Antifatiguing Excellent No No Good PSI N/A 75­250 Greater than 1000 600­850 Plasticizer (off-gas) N/A Yes None None Wear layer N/A Minimum N/A Total thickness Color through, not surface (helps hide scratching) N/A No Yes Yes Halogen free, no chlorine, no corrosive gases in fire No No Yes Yes Color consistency for projects of any size Yes No Yes Yes

Table I. ESD flooring comparison.

Typically, buyers who are uninformed or use misleading information as a basis for comparison do not understand long-term costs of ESD floors. Sometimes the cost of ownership just isn't as urgent a concern as other issues at hand. Yet, over time, a number of factors add to the cost. Unexpected costs associated with installation, along with routine maintenance of the floor, can drive expenses to the point where the initial material cost becomes almost irrelevant.

Most ESD flooring selections are made by cost-driven general contactors or design and build landlords who have no stake in the long-term performance of the floor. Although these individuals usually provide the tenant or owner with a one-year warranty, there is no consideration for actual cost of ownership other than bringing the project in under budget. In many cases, these construction professionals do not even know what to look for relative to quality or ESD compliance.

Total Cost of Ownership

The total cost of owning any type of floor includes, in addition to materials, factors such as floor preparation, installation costs, and regular maintenance.

Preparation and installation costs differ for new projects and renovations. For a renovation project, buyers should ask:

For new floors, buyers should ask about subfloor conditions. Questions should include:

Maintenance Concerns

Vinyl. Vinyl offers the lowest total cost of ownership if maintenance costs are well controlled. Most suppliers of ESD vinyl discourage waxing the floor, suggesting, instead, occasional buffing. Although this is true in principle, buffed vinyl doesn't wear as well as a hard finish. Public spaces, such as grocery stores, provide a good indication of what happens when vinyl surfaces are not kept up.

Vinyl products contain a matrix of conductive material within the substrate. Regular buffing will wear the finish down. Buffing is also labor-intensive and can be expensive, although labor costs vary by location. Some companies find that, in order to maintain their standards for appearance, the janitorial service needs to buff the floor weekly. ESD formulations of standard spray and buff wax applications can last up to several weeks.

Strippers are required to remove old wax, which means the area must be evacuated prior to cleaning. The removal of damaged vinyl tiles is difficult. It requires a propane torch to heat the tile, and then the adhesive must be scraped and new adhesive laid down and cured before new tile can be installed.

Rubber. Rubber ESD tile requires minimal upkeep. Regular washing is sufficient, so rubber is the easiest and most cost-effective product to maintain. There are important differences between calender and molded nitrile rubber. Calender is formed in pinch rolls and has higher porosity than molded rubber. Molded-rubber tiles are formed in individual molds under high pressure. In addition, the material is tightly cross-linked, making it impervious to dirt retention.

A rubber's inherent high coefficient of friction prevents slips and falls associated with hard, slippery, or super-shiny floors. Physical characteristics such as elasticity enable a rubber to handle abusive applications in which pallet jacks and forklifts often dent or crack more-brittle materials.

A study conducted over a two-year period by Lucent Technologies (completed in 1996) rated rubber flooring highest when subjective and non-bottom-line factors such as appearance, ergonomics, and ease-of-care were part of the selection criteria.

Epoxy. Epoxy coatings are the most durable of ESD floor finishes—with the look of glass and the hardness of concrete. Epoxy supports heavy loads and works well in areas with heavy forklift traffic. It also offers low maintenance. Like rubber, epoxy requires only regular washing.

Epoxy is difficult to repair, however. Replacement requires professional, specially trained applicators. The entire floor must be recoated, which requires evacuation of all personnel, furniture, and machinery from the area under construction.

Carpet Tile. ESD carpet tiles are easy to maintain and repair. Although dirt and wear can be a problem, material cost is low and tiles are easily replaced. Broadloom carpets and older tiles had problems with dye-lot variation. Today, some manufacturers supply tile with mergeable dye lots: yarn colors are matched by a computer-generated process to ensure uniformity.

Keeping a small supply of carpet tiles on hand ensures immediate replacement. Carpet does not require professional installation, and the tiles are easily replaceable by a maintenance crew. The modular 18- and 24-in. tiles can be easily removed and replaced into the conductive-release adhesive without tools or special skills. Carpet adhesive dries in less than an hour and can remain uncovered for several days during installation.

Carpet, however, is not well suited for areas where aqueous cleaners are used, on loading docks, or in areas where pallet jackets are routinely used.

Conclusion

Idiosyncratic and constantly changing requirements of technology businesses challenge the expertise of even the most capable building professionals. Results are best when the people who will actually occupy and maintain the space make the final ESD flooring selection. Left in the hands of design and build construction specialists, black-and-white factors like low price and speed of installation will always prevail over criteria like performance, appearance, and cost of ownership.

David Long is vice president of new business development for Julie Industries Inc. (Wilmington, MA). He can be reached at 617-527-6299 or via e-mail at dave@staticsmart.com.