Skip to content

PROTECTING YOUR WORLD

Secondary
Containment Guide

Everything facility managers, engineers, and applicators need to know about secondary containment what it is, when regulators require it, how polyurea coatings compare to alternatives, and how ArmorThane systems are specified and installed.

1989

Founded

30+

Countries Served

100%

Solids Zero VOC

1hr

Walk-On Time
Get a Quote

Get a quote for your project

Tell us what needs protecting and an ArmorThane coatings specialist will come back with the right product, the right system and a realistic price.

  • Product and system matched to your substrate
  • Coverage and budget guidance before you commit
  • A certified applicator near you
  • 30+ years of field-proven polyurea and polyurethane
Rather talk now? Call (417) 831-5090
Step 1 of 3

To help us prepare for a discussion with you, please provide some information on the type of Protective Coating business you are considering, including where your business would be located.

ArmorThane Technical Team

Certified Coatings Specialists · Polyurea Systems Since 1989 · Reviewed by ArmorThane Engineering Division

“Secondary containment is the last line of defense betweena facility and an environmental release. This guide covers every aspect from federal regulations to coating chemistry to compliance documentation so you can make the right specification decision.”

ArmorThane Technical Team

, Coatings Specialist

Updated April 25, 2026

Expert Reviewed

What’s Inside This Guide

What Is Secondary Containment?

Secondary containment is the backup barrier that catches a leak when a primary container fails. If the primary container is a fuel tank, chemical drum, or process vessel, the secondary containment is the berm, dike, sump, or lined pad around it. When the primary leaks, the secondary holds what escaped until it can be recovered.

The U.S. Environmental Protection Agency defines the standard clearly: secondary containment must be sufficiently impervious to contain leaks, spills, and accumulated precipitation until the collected material is detected and removed. That definition sets the bar for every coating system, liner, and design choice that follows.

Plain-English Definition

Secondary containment is any engineered system a berm, dike, sump, spill pallet, tray, or coated surface built to capture and hold a spilled liquid long enough for it to be cleaned up before it escapes into soil, groundwater, or a waterway.
Two layers of protection exist for a reason. The primary container does the day-to-day work. The secondary system exists because primary containers fail welded seams crack, gaskets degrade, operators overfill, equipment ages. Without secondary containment, one failure becomes an environmental release, a regulatory action, and a cleanup invoice that dwarfs the coating that would have prevented it.
Secondary Containment

When Is Secondary Containment Legally Required?

In the United States, secondary containment is not optional for most facilities that store oil, fuel, or hazardous chemicals. Two federal rules drive most requirements, with state and local codes adding further requirements on top.

1,320

Gallons aboveground oil storage SPCC trigger (40 CFR Part 112)

42,000

Gallons buried oil storage SPCC trigger for underground tanks

Line 72

SPCC RULE (OIL & FUEL)

The Spill Prevention, Control, and Countermeasure (SPCC) rule applies to non-transportation-related onshore facilities that could discharge oil into U.S. waterways. Covered facilities must provide containment sized for the largest single container plus precipitation freeboard.

Freeboard for Precipitation

Outdoor containment must add capacity for rainfall. The common engineering convention is to size for the largest container plus a 25-year, 24-hour storm event on the exposed containment footprint. Indoor containment: container volume only.

Bulk Storage Requirements

Under 40 CFR 112.8(c)(2), bulk storage container installations must have secondary containment to hold the entire capacity of the largest single container plus sufficient freeboard to contain precipitation.

SPCC RULE (OIL & FUEL)

The Spill Prevention, Control, and Countermeasure (SPCC) rule applies to non-transportation-related onshore facilities that could discharge oil into U.S. waterways. Covered facilities must provide containment sized for the largest single container plus precipitation freeboard.

Freeboard for Precipitation

Outdoor containment must add capacity for rainfall. The common engineering convention is to size for the largest container plus a 25-year, 24-hour storm event on the exposed containment footprint. Indoor containment: container volume only.

Bulk Storage Requirements

Under 40 CFR 112.8(c)(2), bulk storage container installations must have secondary containment to hold the entire capacity of the largest single container plus sufficient freeboard to contain precipitation.

SPCC RULE (OIL & FUEL)

The Spill Prevention, Control, and Countermeasure (SPCC) rule applies to non-transportation-related onshore facilities that could discharge oil into U.S. waterways. Covered facilities must provide containment sized for the largest single container plus precipitation freeboard.

Freeboard for Precipitation

Outdoor containment must add capacity for rainfall. The common engineering convention is to size for the largest container plus a 25-year, 24-hour storm event on the exposed containment footprint. Indoor containment: container volume only.

Bulk Storage Requirements

Under 40 CFR 112.8(c)(2), bulk storage container installations must have secondary containment to hold the entire capacity of the largest single container plus sufficient freeboard to contain precipitation.

SPCC RULE (OIL & FUEL)

RCRA Rule (Hazardous Waste)

Other Regulations

SPCC RULE (OIL & FUEL)

The Spill Prevention, Control, and Countermeasure (SPCC) rule applies to non-transportation-related onshore facilities that could discharge oil into U.S. waterways. Covered facilities must provide containment sized for the largest single container plus precipitation freeboard.

Freeboard for Precipitation

Outdoor containment must add capacity for rainfall. The common engineering convention is to size for the largest container plus a 25-year, 24-hour storm event on the exposed containment footprint. Indoor containment: container volume only.

Bulk Storage Requirements

Under 40 CFR 112.8(c)(2), bulk storage container installations must have secondary containment to hold the entire capacity of the largest single container plus sufficient freeboard to contain precipitation.

Legal Disclaimer: This guide summarizes federal rules at a high level. Confirm applicable regulations with your SPCC Plan preparer, state environmental agency, and local fire marshal before specifying a containment design.

Secondary Containment

6 Types of Secondary Containment Systems

Not every containment situation calls for the same design. Six configurations cover the majority of real- world applications. The right system often combines more than one approach.

01

Earthen Berms & Dikes

Raised barriers of compacted soil or clay surrounding tank farms. Earth alone is not “sufficiently impervious” must be lined with sprayed polyurea over geotextile reinforcing fabric to meet EPA standards.

02

Concrete Dikes & Containment Pads

Most common industrial construction. Strong and fire- resistant but porous to hydrocarbons unless coated. Applying polyurea over properly prepared concrete creates a seamless, impervious system meeting RCRA 264.175.

03

Sumps, Trenches & Catchment Basins

Sumps collect spills at low points for pump-out. Trench drains route spills to a central sump. Both require coating systems handling immersion, chemical exposure, and mechanical punishment of debris and cleaning.

04

Spill Pallets & Containment Trays

Raised barriers of compacted soil or clay surrounding tank farms. Earth alone is not “sufficiently impervious” must be lined with sprayed polyurea over geotextile reinforcing fabric to meet EPA standards.

05

Geotextile-Lined Containment

For large footprints frac tank pads, oilfield containment, mine leach ponds. Geotextile fabric provides tensile reinforcement; sprayed polyurea provides the impervious, chemically resistant surface. Installs faster than welded HDPE.

06

Prefabricated Modular Containment

Portable, bolted-panel systems for temporary operations rig moves, emergency response, construction staging. Fast to deploy but temporary. For permanent installations, spray- applied systems consistently win on total cost of ownership.

How Polyurea Secondary
Containment Coatings Work

Polyurea is a spray-applied elastomer formed by the reaction of an isocyanate component with an amine resin. The reaction is fast: on a heated plural-component sprayer, gel times are measured in seconds and tack-free times in minutes. Three properties make polyurea the dominant chemistry for secondary containment:

01

Seamless Monolithic Membrane

Sprayed wet-on-wet in overlapping passes no seams to fail. The continuous membrane adheres directly to the substrate and conforms to every corner, penetration, and transition in the containment geometry.

02

Fast Return to Service

Walk-on within one hour. Light service within 24 hours. For facilities where downtime has a per-hour cost, that cure profile fundamentally changes the economics of recoating work.

03

Bulk Storage Requirements

Under 40 CFR 112.8(c)(2), bulk storage container installations must have secondary containment to hold the entire capacity of the largest single container plus sufficient freeboard to contain precipitation.
Polyurea Secondary

Typical ArmorThane Polyurea Property Ranges

PROPERTY TYPICAL RANGE TEST METHOD
Tensile Strength 2,500 – 4,500 psi ASTM D412
Elongation at Break 300 – 600% ASTM D412
Shore D Hardness 45 – 60 ASTM D2240
Tear Resistance 300 – 500 pli ASTM D624
Solids Content 100% Zero VOC —
Gel Time 3 – 15 seconds Plural-component spray
Tack-Free Time 15 – 90 seconds At specified ambient
Walk-On Time Under 1 hour Application-dependent
Full Service 1 – 24 hours Application-dependent
ArmorThane Polyurea

Polyurea vs. the Alternatives

Most procurement teams evaluating secondary containment compare polyurea against four alternatives: epoxy coatings, HDPE sheet liners, concrete alone, and traditional paint. Here is where each chemistry stands.

The Performance Gap Is Not Close

Most procurement teams evaluating secondary containment compare polyurea against four alternatives: epoxy coatings, HDPE sheet liners, concrete alone, and traditional paint. Here is where each chemistry stands.

Property Polyurea Epoxy HDPE sheet Bare
concrete
Paint
Meets 40 CFR 264.175
"sufficiently impervious"
Yes Yes Yes No No
Seamless installation Yes Yes Welded seams N/A Yes
Typical cure to walk-on < 1 hour 12–24 hours Immediate once
installed
Days Hours
Elongation (flexibility) Very high Low High None Low
Resistance to thermal cycling Excellent Cracks under
cycling
Good Cracks Flakes
Chemical resistance to
hydrocarbons
Excellent Good to
excellent
Excellent Porous Poor
UV stability (outdoor) Aliphatic grades
required
Chalks Good N/A Requires
topcoat
Conforms to irregular geometry Yes (sprayed) Yes Difficult N/A Yes
Repairability Spot-repair on
site
Spot-repair Requires
specialist
Crack
repair
Repaint
Typical service life
(containment)
Decades with
inspection
10–15 years 20+ years if
protected
Not a liner 2–5 years
Polyurea Wins When…
You need a seamless, flexible, chemical-resistant membrane installed fast on irregular geometry. No seams to weld, no 24-hour cure wait, no cracking under thermal cycling.
Epoxy Is Viable When…
The application is interior, climate- controlled containment with minimal thermal cycling and budget is the primary driver. Expect 10–15 year service life before recoat.
HDPE Sheet Works When…
The footprint is very large and flat, a specialist crew can weld reliable seams, and there are no complex transitions, penetrations, or irregular geometry to detail.

Critical Spec Note:

Bare concrete is not a liner it is a substrate. Paint is not a containment coating. Any specification that calls for “containment paint” should be immediately corrected. Neither meets the 40 CFR 264.175 “sufficiently impervious” standard.

ArmorThane Systems for Secondary Containment

ArmorThane has been formulating pure polyurea and hybrid systems in Springfield, Missouri since 1989. We manufacture the coating, manufacture the proportioning equipment, and train the applicator network — not a franchise, all under one roof.

HighLine 510H Pure Polyurea

Two-component, 100% solids pure polyureaelastomer. The workhorse system for chemical containment, tank linings, secondary containment pads, and bermed areas where mechanical toughness and chemical resistance matter most.

Polyurea Over Geotextile System

For frac tank pads, oilfield containment, mine leach ponds, and agricultural runoff basins. Geotextile adds tensile reinforcement; polyurea provides the impervious, chemically resistant surface. Installs faster than welded HDPE on irregular terrain.

UltraBlast Blast-Mitigation Polyurea

Purpose-engineered for containment structures with blast-mitigation requirements ammunition storage, military fuel depots, high- consequence civilian infrastructure. Designed to absorb and dissipate blast energy while maintaining containment integrity.

Primers, Topcoats & Equipment

The complete system matched primers for concrete, steel, and geotextile substrates; aliphatic topcoats for UV-exposed outdoor installations; and plural-component proportioners designed and manufactured by ArmorThane in Springfield.

Direct Manufacturer No Franchise Fees

ArmorThane USA Inc. has been manufacturing polyurea, polyurethane, and spray foam systems in Springfield, Missouri since 1989. Coatings, equipment, training, and 24/7 technical support developed under one roof. Our global applicator network operates in more than 30 countries.
Secondary Containment

Applications by Industry

Secondary containment is a requirement across every industry handling oil, fuel, or chemicals. The design details shift by sector, but the coating strategy is consistent: a seamless, impervious membrane that holds what the primary container drops.

Oil & Gas

Well pads, tank batteries, refining, frac water pits, and transloading. Chemical resistance for crude, condensate, produced water, and frac chemistries.

Mining & Mineral Processing

Heap leach pads, solution ponds, concentrator sumps, reagent storage. Handles acidic/caustic chemistries and heavy mechanical abuse.

Water & Wastewater

Chemical feed areas, clarifier walls, and containment around sodium hypochlorite, ferric chloride, and polymer storage.

Agricultural

Fertilizer, pesticide, and herbicide storage. Dry fertilizer needs abrasion resistance; liquid crop protection needs chemical resistance.

Pharma & Chemical Manufacturing

Process areas, solvent storage, hazardous waste areas. Non-porous surface meets hygiene requirements; chemical resistance meets spill requirements.

Food & Beverage

Wash-down areas, chemical sanitizer storage. Polyurea survives hot water, caustics, and daily cleaning where epoxy fails in 2–3 years.

Military & Government

Fuel farms, munitions storage, vehicle maintenance under DoD UFC standards. Blast-rated and ballistic-rated configurations available.

Manufacturing & Heavy Industry

Hydraulic fluid storage, quench tanks, paint kitchens, solvent storage. Fast return to service minimizes costly plant downtime.
Secondary containment

Installation Process — Step by Step

A polyurea containment coating only performs to spec if substrate preparation and application are correct. This is what a compliant installation looks like on a typical concrete containment pad.

1. Site Assessment & Design Review ( BEFORE COATING )

Review the SPCC plan or RCRA plan, capacity calculation, substrate condition, and operating environment. Existing cracks, joints, penetrations, and drainage all drive the detailing approach.

2. Surface Preparation (CRITICAL)

Concrete prepared to SSPC-SP 13 / NACE 6 or ICRI CSP 3 to 5 profile. Steel abrasive blast-cleaned to SSPC-SP 10 near-white metal for immersion service. All oil, laitance, curing compounds, and incompatible coatings removed.

3. Crack, Joint & Penetration Detailing

Cracks routed and filled. Expansion joints detailed with backer rod and compatible sealant. Pipe penetrations, drains, and anchor bolts dressed with gasket or fillet bead so the coating ties in without a weak point.

4. Primer Application

A primer matched to the substrate is rolled or sprayed at the rate specified on the TDS. Primer selection is not optional and is not interchangeable between substrates — concrete, steel, and geotextile primers are different products.

5. Reinforcement Layer (If Specified)

On large lined areas, geotextile fabric is anchored and tensioned across the containment. On detail areas — inside corners, penetrations, crack repairs — fleece or scrim is embedded in the first polyurea pass for added reinforcement.

6. Polyurea Spray Application (PRIMARY STEP)

The plural-component proportioner heats and pressurizes A-side and B-side materials, meters them at the correct ratio, and delivers them to an impingement-mixing spray gun. Overlapping passes build the specified film thickness — typically 60 to 125 mils for a single-pass pure polyurea liner.

7. Film Thickness Verification

The plural-component proportioner heats and pressurizes A-side and B-side materials, meters them at the correct ratio, and delivers them to an impingement-mixing spray gun. Overlapping passes build the specified film thickness — typically 60 to 125 mils for a single-pass pure polyurea liner.

8. Holiday Detection & Integrity Testing (COMPLIANCE)

The plural-component proportioner heats and pressurizes A-side and B-side materials, meters them at the correct ratio, and delivers them to an impingement-mixing spray gun. Overlapping passes build the specified film thickness — typically 60 to 125 mils for a single-pass pure polyurea liner.

9. Aliphatic Topcoat (Outdoor Installations)

For outdoor exposure, an aliphatic polyurea or polyurethane topcoat is applied over the aromatic base coat to preserve color and reduce surface chalking over years of UV exposure.

10. Documentation & Turnover (REQUIRED)

Applicator documents surface preparation, ambient conditions, batch numbers, film thickness, holiday test results, and any repairs. The documentation package becomes part of the facility’s SPCC or RCRA compliance file.

Inspection, Maintenance & Compliance

Secondary containment is only as effective as its inspection program. Regulators expect documentation. Insurers expect documentation. And in the event of an actual spill, the paper trail demonstrates the facility met its duty of care.

Routine Monthly Inspection

Periodic Integrity Testing

Repair Protocol

Inspection, Maintenance & Compliance

How to Size a Secondary Containment Area

Capacity sizing is where many projects get tripped up. Two rules apply depending on which regulation

SPCC Sizing

40 CFR 112.8(c)(2) Oil & Fuel Storage

For oil and petroleum product storage subject to SPCC:

Precipitation freeboard: typically the 25-year, 24-hour
rainfall event volume over the exposed containment
footprint. Check your state SPCC guidance for stricter
local requirements.

Overlay 17

RCRA Sizing

40 CFR 264.175 Hazardous Waste Storage

For hazardous waste container storage, use the greater of:

Plus a means to remove accumulated liquid in a timely manner. Add precipitation freeboard for outdoor installations.

Worked Example: 12-Drum RCRA Hazardous Waste Storage Area

Scenario

12

RCRA Calculation

66 gal

Design Minimum

66 gal+

ArmorThane technical support works with facility engineers on containment sizing as part of the specification process.
Call before the concrete is poured:  417.831.5090

Secondary Containment

Frequently Asked Questions

Primary containment is the vessel that holds the product in daily service — a tank, a drum, a tote, a pipe. Secondary containment is the backup barrier around that vessel that catches a leak or spill if the primary fails. Primary containment does the work; secondary containment prevents an environmental release when primary fails.

The SPCC rule (40 CFR Part 112) applies to non-transportation-related onshore facilities with more than 1,320 gallons of aboveground oil storage capacity in containers of 55 gallons or more, or more than 42,000 gallons of buried oil storage capacity, that could reasonably be expected to discharge oil into U.S. waterways.

Film thickness depends on the substrate, the stored chemistry, and the mechanical exposure. For pure polyurea secondary containment systems on concrete, 60 to 125 mils in a single pass is common. Highly aggressive chemical service or heavy mechanical abuse may call for 125 to 250 mils or more. Always refer to the current Technical Data Sheet for the specified product and service.

Yes. EPA does not dictate a specific coating chemistry. It sets a performance standard — containment must be sufficiently impervious to contain leaks, spills, and accumulated precipitation until the collected material is detected and removed (40 CFR 264.175). A correctly specified and installed polyurea liner meets that standard.

Properly specified, installed, inspected, and maintained polyurea systems deliver decades of service. Actual service life depends on the chemistry stored, the operating temperature, the UV exposure, mechanical abuse, and the quality of the original installation. A lined containment area inspected monthly and repaired when damage is found will outlive most of the other assets on the site.

Yes, and it is the most common application. Existing concrete must be clean, structurally sound, and mechanically prepared to the surface profile specified for the coating system. Cracks, joints, and penetrations are detailed. A matched primer is applied, and the polyurea topcoat is sprayed to the specified film thickness.

The 1,320-gallon threshold is the SPCC trigger for aboveground oil storage. If a facility has aggregate aboveground oil storage capacity exceeding 1,320 gallons in containers of 55 gallons or more, it is covered by 40 CFR Part 112 and must develop and implement an SPCC Plan, which includes secondary containment requirements.

Yes. 40 CFR 112.8(c)(2) requires sufficient freeboard to contain precipitation on outdoor bulk storage containment. The common engineering convention is to size the containment for the largest container plus a 25-year, 24-hour rainfall event over the containment footprint.

Polyurea can be sprayed in temperatures down to freezing and in some cases below, provided the substrate is dry, dew point is controlled, and the coating material is at the correct application temperature. Cold-weather installation requires experienced crews, heated spray equipment, and weather protection for the work area.

HDPE sheet liners are welded geomembranes used on large flat containment areas. They work well when a specialist crew can weld reliable seams and the geometry is simple. Polyurea is seamless, conforms to complex geometry, and installs faster on irregular terrain. For most industrial containment pads with tanks, piping, drains, and transition details, polyurea outperforms HDPE on both installation speed and long-term integrity.

Ready to Specify or Install?

We’re the manufacturer — coatings, equipment, and technical support under one roof since 1989. Not a franchise. Global applicator network. 24/7 technical support.

References & Further Reading

ArmorThane Technical Team

Certified Coatings Specialists · Since 1989 · Reviewed by ArmorThane Engineering Division, April 2026

ArmorThane USA Inc. has been manufacturing polyurea and polyurethane protective coatings, spray foam systems, and plural-component application equipment in Springfield, Missouri since 1989. We operate as a direct manufacturer — not a franchise network. Our coatings and equipment are installed by a global network of trained applicators across North America and more than 30 countries. Technical support is available 24/7 at (417) 831-5090. This guide was reviewed and updated by the ArmorThane Engineering Division in April 2026 to reflect current EPA regulations, best practices, and ArmorThane product specifications

CONTACT US

REQUEST A QUOTE OR

BECOME AN APPLICATOR

ArmorThane has built a strong reputation over the past 30 years for producing high-quality, durable protective coatings.

group 115 660555abebfe4
Phone Number

Tel: 417.831.5090

group 115 1 660556c21395c
Email Us

moreinfo@armorthane.com

Step 1 of 3

To help us prepare for a discussion with you, please provide some information on the type of Protective Coating business you are considering, including where your business would be located.

RV Find An Applicator

Protective Coating Applications

Products

Applicator Opportunities

Knowledge Center

Galleries