In sensitive processing and storage spaces, little electric shocks can cause big problems.

Same concept as dancing on carpet in your socks, but with far more dramatic results: Fried servers in a data center could corrupt whole networks. Damage to sensitive medical or laboratory instruments could delay delivery of care. Sparks in chemical processing or munitions plants could cause catastrophic explosions.

So designers, engineers, builders, and facilities personnel all have a role in understanding the main types of concrete floor coatings that address the buildup and release of static electricity.

Those types are electrostatic dissipative (ESD) and conductive, and they are the source of much confusion both in theory and practice.

So let’s clear it up. And we’ll start it very simply: Both types of coatings direct static electric discharges to ground.

The ANSI S20.20 standard describes a program to control electrostatic discharges. It characterizes dissipative floor coatings as those with a resistance of between one million and one billion ohms.

Ohms of resistivity indicate how restrictive a conductor is to electricity passing through it.

Dissipative floor coatings are comparatively more resistive than conductive coatings. They still direct electricity to ground, but the flow of that electricity is more restricted than in a conductive coating.

Very simply stated, dissipative floor coatings are specified anywhere that electrostatic discharges need to be prevented, but where there is no explosion risk. That includes:

• • Data centers or server rooms
• • Electronics manufacturing facilities
• • Pharmaceutical processing or laboratory spaces
• • Medical laboratories

Qualities and applications for conductive floor coatings

Conversely, conductive floor coatings are those with a resistance of between 25,000 and one million ohms.

That’s a lower range of resistivity compared to dissipative coatings, meaning that conductive flooring is less restrictive to electricity flowing through it. The current reaches ground much more readily.

Conductive flooring is designed to completely eliminate the risk of electrostatic discharges and is specified when electric shocks could spark explosions. Common applications include:

• • Certain chemical processing or storage areas
• • Rocket fuel feedstock storage or fuel blending spaces
• • Munitions factories

Of course, it’s possible that certain facilities will require both types of coatings and not simply one or the other. For example, a conductive coating might be necessary in segregated spaces where something flammable or combustible is stored, while dissipative coatings are sufficiently protective of the rest of the envelope.

A quick note on neat concrete

You might have guessed that needing to choose either dissipative or conductive floor coatings to control electrostatic discharges implies that leaving a concrete floor uncoated is a bad idea.

It is: Due to its composition and curing process, concrete is an insulator. The current from sudden electrostatic discharges would travel elsewhere.

Other protective measures do exist, such as encasing sensitive electrical equipment in insulated cages or workers wearing special gear. But the best electrostatic discharge control plans are comprehensive, and comprehensive plans include floor coatings.

Whole or partial dissipative/conductive floor coating systems?

It’s almost always multi-layer systems that protect concrete floors, not single layers.

During project planning, be ready for a coating manufacturer to suggest a system where one or more layers within a nominally electrically protective system lack conductive or dissipative properties.

A main reason this might come up is when other risks aside from electrostatic discharges, such as chemical exposure or impact damage, need to be managed within the same protective floor coating system. It’s perfectly doable to mitigate these other risks without compromising the conductive or dissipative properties of a coating system.

Another reason might be to control cost. Conductive or dissipative properties come from fillers added to floor coatings. These fillers do not represent a huge cost increase, but some modest savings are possible if only one or two layers of a coating system require them as opposed to three or four.

Engage with the experts

The “early and often” communication approach with coating manufacturers is best.

Even if you’ve now grasped the basics of dissipative vs. conductive floor coatings, there remain layers of detail that will influence what system is ultimately specified.

Good thing is, you aren’t the one who’s supposed to know everything about it.

That’d be the Dudick technical experts who have provided dissipative and conductive floor coating solutions for aerospace, pharmaceutical, electronics, and other safety-critical environments around the world.

Hear one of those experts—Richie Cropp—discuss this subject on The Red Bucket podcast.