ESD flooring: conductive or static dissipative, grounding and testing

An ESD floor is a resin coating made conductive or dissipative and tied into the building ground, which drains electrostatic charges from people and equipment. A conductive floor, with the lower resistance, mainly serves spark-hazard areas; a dissipative floor, with higher resistance, suits most electronics rooms. The resistance range to meet comes from the client's ESD program (often built on ANSI/ESD S20.20) and is verified to ASTM F150.

An electrostatic discharge can damage an electronic component without leaving a visible mark, or cause a spark where combustible vapours or dusts are present. The floor is one of the control measures: it gives charges a path to ground. But it only works if it is chosen correctly, grounded correctly, matched with staff footwear and cleaned with products that do not insulate it. This guide is for plant, laboratory and maintenance managers who need to install or restore an antistatic industrial epoxy floor in Quebec and Ontario.

What is the difference between a conductive and a dissipative floor?

The difference is electrical resistance: a conductive floor lets charges flow to ground very easily, while a dissipative floor drains them more slowly, in a controlled way. Both are called antistatic, but they meet different needs.

The numeric ranges for each family are defined in the client's reference documents and in the standards of its sector; we do not set them on the client's behalf. The choice is therefore made first with the site's ESD program or safety lead.

How does an ESD floor drain charges?

An ESD floor drains charges through a continuous path: the person, ESD footwear or heel straps, a topcoat loaded with conductive particles or fibres, a conductive primer, then copper strips tied into the building grounding system. If one link is missing, the floor does not do its job.

• Topcoat. Loaded resin that conducts at the surface and through its thickness.
• Conductive primer. Spreads charges across the whole surface to the ground points.
• Copper strips. Bonded to the prepared concrete under the primer and connected to ground by an electrician per the layout.
• Footwear. The floor cannot control a person wearing insulating soles: the ESD program requires suitable footwear or heel straps.

Chairs, carts and shelving must also be dissipative or grounded so the zone is consistent. The layout of the copper strips and ground points is agreed before work starts, because it depends on room size, partitions and where the building ground can be reached.

Which standards govern ESD flooring?

Two references govern most projects: ANSI/ESD S20.20, which describes an organization's electrostatic discharge control program and points to test methods, and ASTM F150, which describes how to measure the electrical resistance of conductive and dissipative resilient flooring and is commonly used as the reference for resin floors too. The specification states which apply and which values to target.

• ANSI/ESD S20.20. Sets the framework of the ESD program: protected areas, grounding elements, verification. The floor is one element among others.
• ASTM F150. Method for measuring point-to-point and point-to-ground resistance, with defined electrodes and recorded test conditions.
• Client program. Electronics, defence or healthcare sectors often have their own requirements, which take precedence.

Ambient conditions, especially relative humidity, affect readings; the standard and the program state how to record them.

How is an ESD floor installed?

An ESD floor is installed like a resin floor, with the addition of the copper network, the conductive primer and measurements during and after application. Careful concrete preparation remains the basic condition.

1. Assessment. Concrete condition survey, moisture testing, location of available ground points.
2. Preparation. Shot blasting or grinding to the required profile; see our article on concrete surface preparation and CSP profiles.
3. Repairs. Cracks, joints and spalls treated with products compatible with the system.
4. Copper network. Strips laid per the layout, then connected to ground.
5. Conductive primer. Applied and checked for continuity before the topcoat.
6. ESD topcoat. Applied at the thickness on the data sheet; thickness outside the range can change resistance.
7. Acceptance testing. Measurements to ASTM F150, recorded in a report handed to the client.

Concrete moisture is a critical point, as explained in our article on concrete moisture before epoxy coating.

How is an ESD floor checked at acceptance and in service?

An ESD floor is checked with point-to-point and point-to-ground resistance measurements to ASTM F150 at acceptance, then with periodic checks set in the client's ESD program. Results are recorded with date, location, humidity and instrument used.

• Acceptance. A grid of points across the surface, both near and away from the copper strips.
• Periodic checks. Frequency set by the client program, tighter in critical areas.
• Person-footwear-floor system. Some programs also measure the resistance of a person standing on the floor in their footwear.
• Out-of-range readings. Trigger a search for the cause: contamination, wear, a break in the ground network.

Our coating inspection service can document the condition of an existing floor before refurbishment.

Which uses justify an antistatic floor?

An antistatic floor is justified wherever a discharge can damage a product or ignite an atmosphere: circuit board assembly and repair, server and telecom rooms, laboratories, clean rooms, component warehouses and some areas where solvents or combustible powders are handled.

• Electronics. Assembly, testing, repair and storage of sensitive components.
• Technical rooms. Server, control and telecom rooms.
• Explosive atmosphere areas. A conductive floor is one of the measures against sparks and fits into the site risk analysis. Our article on ATEX zone repair without hot work covers job site precautions in these areas.
• Pharmaceutical and fine chemicals. Handling of powders and solvents.

Floor coating families are compared in our guide to industrial floor coating types.

What maintenance preserves antistatic properties?

Maintenance that preserves antistatic properties relies on neutral cleaners compatible with the ESD floor, no wax or film-forming products, and periodic measurements. A wax or a cleaner that leaves an insulating film can push the floor out of its range. Cleaning staff should be briefed, and the approved products listed in the zone's maintenance procedure.

• Cleaners. Products recommended by the system manufacturer, with thorough rinsing.
• No wax. Unless the product is expressly designed for ESD floors.
• Wear. Cart aisles wear faster; an ESD topcoat is renewed locally after preparation.
• Changes. Any new partition, foundation or repair is tied back into the ground network.

ESD flooring is part of our protective coatings service; the budget depends mostly on area, concrete condition and the ground network, as our article on industrial epoxy flooring cost explains.

Frequently asked questions

Is an ordinary epoxy floor antistatic?

No. Ordinary epoxy is insulating. It takes a system designed to conduct, with a conductive primer, a loaded topcoat and grounding.

Can an existing floor be made antistatic?

Often, yes, if the existing coating is sound and compatible: it is prepared, the copper network is laid and a conductive primer and ESD topcoat are applied. Otherwise it must be removed.

Is special footwear needed?

Yes, in most programs. The floor drains charges only if staff wear ESD footwear or heel straps.

Who sets the resistance value to meet?

The client, through its ESD program or risk analysis, based on its sector's standards. We apply the system that achieves it and measure to ASTM F150.

Our crews and qualified subcontractors work from LaSalle, including in Sherbrooke, Quebec City and Ontario, in industrial settings only. Send the area, the room's use, the target resistance range and photos of the concrete through the request a quote form: pricing on consultation, reply within 24 business hours.