What makes a floor chemical resistant?

A resin chosen for the specific chemicals it will meet, applied as a continuous film with no route through it, detailed at every edge and joint, and fully cured before the first spill. The resin gets the attention, but it is only one of those four. A novolac topcoat with a pinhole in it, or a joint that was left open, lets the chemical reach whatever is underneath, and the rating on the data sheet stops applying at that spot.

How do I describe the exposure?

Four things, in writing, before any product is chosen. The chemicals, by name, including cleaning chemicals. Their concentration, because a dilute acid and a concentrated one are different exposures. Their temperature, because heat speeds up chemical attack. And the contact: an occasional spill wiped up promptly, a regular splash, standing liquid in a containment area, or continuous immersion. With those four answers, a manufacturer can say what will survive. Without them, "chemical resistant" is a description of a brochure, not of your floor.

How do I read a chemical resistance chart?

As a rating for one chemical at one concentration under one kind of exposure, and nothing wider. Charts commonly separate a spill or splash that is cleaned up within a stated time from continuous or immersion exposure, and mark some chemicals as not recommended at all. A product rated for splash of a chemical is not rated for standing in it, and a rating at one concentration does not carry over to a stronger one or a hotter one. Some chemicals discolor a floor without attacking it. If a rating mentions staining, ask the manufacturer whether it means appearance or damage, because the answer decides whether it matters to your client.

Is novolac always the answer?

No. Standard epoxy already handles most of what floors meet, and novolac is for concentrated acids, aggressive solvents and steady heat. Our novolac glossary entry covers when it is worth its cost and when it is not. Novolac is not the top of the range either. For the most aggressive exposures, including strong oxidizing acids, manufacturers move to other chemistries such as vinyl ester, which has its own demands: a strong styrene odor that needs ventilation, and an installation that needs an experienced crew. And where the floor sees hot water, steam or fast temperature swings, the answer is urethane cement, whatever the chemicals are.

What if my chemical is not on the chart?

Ask the manufacturer before specifying the product, and give them the full exposure: chemical, concentration, temperature and contact. For a significant exposure, the dependable check is a test patch of the actual cured system, exposed to the actual chemical under conditions like the real ones. It is slower than reading a chart, and cheaper than finding out on the finished floor.

When can a chemical-resistant floor go into service?

When the data sheet says it is ready for chemical service, which is not the same moment it is ready for foot traffic. The resistance on the chart belongs to a fully cured film. A floor that takes a spill while it is still curing can be attacked by something the finished floor would have shrugged off. On a plant that is waiting to restart, that date needs agreeing with the client before the work begins, not on the day.

Chemical-Resistant Floor Systems

Nobody can say whether a floor is chemical resistant until someone says which chemical, how strong, how hot and for how long. The resin comes last. This page is the system around it: the exposure, the chart, the build, and the details where these floors actually fail.

Quick answer

Start from the exposure, not the resin: which chemicals, how concentrated, how hot, and whether they are spilled, splashed, left standing or immersing the floor. Check each one against the manufacturer’s chemical resistance chart for that kind of exposure, build the system to match, keep the film continuous at every joint, cove and drain, and keep chemicals off it until the data sheet says it is ready for chemical service.

Start from the exposure

“Chemical resistant” means nothing until it says resistant to what. Every decision on this page follows from four answers, so get them in writing before a product is named.

The chemicals, by name. Include the cleaning chemicals. They can reach the floor every day.
Their concentration. A dilute acid and a concentrated one are different exposures and often get different ratings.
Their temperature. Heat speeds up chemical attack, so a chemical that a floor handles cold can be a different problem hot.
The contact. An occasional spill cleaned up promptly, a regular splash, liquid left standing in a containment area, or continuous immersion. These are separate categories on most charts, and moving up one can change the product.

Reading a chemical resistance chart

Every manufacturer of these systems publishes a chart, and each line in it is narrower than it looks.

One chemical, one concentration, one kind of exposure. A rating for splash is not a rating for standing liquid, and a rating at one strength does not carry over to a stronger one.
A cleanup limit is part of the rating. Splash and spill ratings commonly assume the chemical is cleaned up within a stated time. If nobody on the client’s site will do that, the exposure is really a longer one.
Staining is not always damage. Some chemicals discolor a floor without attacking it. If a rating mentions staining, ask whether it means appearance or damage, because only the client can say whether a stained floor is acceptable.
Ratings are for the cured system. They describe the full build as tested, fully cured. A thinner film, a missing coat or a different topcoat is a different system.

If a chemical is not on the chart, ask the manufacturer before specifying, and give them all four answers above. For a serious exposure, a cured test patch of the real system, exposed to the real chemical, is the dependable check.

Choosing the build

The build is set by how severe the exposure is, and the severity is mostly the contact category.

Occasional spills of everyday chemicals. A standard epoxy system with a suitable topcoat usually covers it. Most floors are this floor.
Regular splash of stronger chemicals, washdown. A standard epoxy body with a chemical-resistant top layer, very often a novolac. The novolac glossary entry explains why that arrangement works and the defect it makes more expensive.
Containment, standing liquid, immersion and the harshest acids. Chemical-resistant resin through the whole build, or a chemical-resistant mortar where the floor also has to be rebuilt. For the most aggressive exposures, including strong oxidizing acids, manufacturers move beyond novolac to other chemistries such as vinyl ester. Vinyl ester has a strong styrene odor that needs ventilation, and it wants an experienced crew.
Hot water, steam or fast temperature swings. That is a thermal problem as much as a chemical one, and the urethane cement system is built for it.

Mortar builds are covered on the epoxy mortar and slurry page.

Continuity: where these floors actually fail

A chemical floor is only as resistant as its weakest square inch. Once a chemical finds a route through the film, it reaches a layer or a slab that was never chosen for it, and the rating stops applying at that spot.

Holidays and pinholes. A gap in the film is a route. The holiday glossary entry explains why they are hard to see. For containment and immersion, continuity testing of the cured lining with a holiday detector is an established method, and the specification should say whether it is required and how.
Joints. A joint is a gap by design. It needs a chemical-resistant joint sealant or a detail that carries the system across it, as the manufacturer specifies.
Coves and walls. Liquid runs to the edge. Containment floors are normally turned up the wall as a continuous cove, so the floor and the wall base are one surface.
Drains, trenches, pump pads and penetrations. Every place the floor meets something else. Manufacturers publish specific details for each, because these are where chemical floors fail first. Use them rather than improvising.

Cure before chemicals

The ratings belong to a fully cured film. The data sheet gives a time to chemical service, and it is not the same as the time to foot traffic. A floor that takes a spill before then can be attacked by something the finished floor would have resisted.

The mix matters more here than on almost any other floor. Chemical resistance is a property of the cured network, and an off-ratio batch leaves that network incomplete. The resin mixing ratio calculator gives exact part quantities for any batch size, and the film thickness calculator checks each coat is laid at the thickness the system was rated at.

On a plant waiting to restart, agree the chemical service date with the client before the work begins.

What this page does not cover

Figures. Ratings, cure times, temperatures and thicknesses are specific to each product and chart, so none is printed here. The manufacturer’s chart and data sheet are the authority.
Regulation. Secondary containment can carry legal requirements where the building is. Those are for the owner and their engineer, not a flooring guide.
The resin itself. What novolac is and how it installs is in the novolac glossary entry.