Secondary Containment Coating Systems for Industrial Contractors

Article 01 of 24

Secondary Containment: Purpose, Performance, and Contractor Responsibility

Secondary containment is the last controlled barrier between a released material and the surrounding facility, soil, drainage system, groundwater, or environment. The contractor’s work must help that barrier perform when the primary containment system no longer does.

Learning Objectives

After completing this article, you should be able to:

• Explain the difference between primary and secondary containment
• Describe the practical purpose of a containment coating or lining
• Identify the basic performance demands placed on a containment system
• Separate contractor responsibilities from engineering and regulatory decisions
• Recognize conditions that require written clarification before work proceeds

Primary Containment and Secondary Containment

Primary containment is the equipment that normally holds or transfers the material. Examples include tanks, vessels, drums, totes, process equipment, piping, valves, pumps, hoses, and transfer connections.

Secondary containment is the structure or system intended to control material that escapes from the primary containment. Examples include concrete dikes, berms, curbs, containment rooms, sumps, trenches, collection areas, lined pits, and specially designed membrane systems.

The secondary system normally waits unused. That does not make it unimportant. It means the system may receive little attention until a valve leaks, a hose ruptures, a tank overflows, a fitting fails, or a container is damaged. At that moment, every crack, joint, penetration, drain, termination, and thin area becomes important.

What the Containment System Must Accomplish

A secondary-containment system must do more than hold a calculated volume. It must remain sufficiently continuous and resistant for the expected material, exposure, temperature, and cleanup period.

Depending on the facility and specification, the completed system may need to:

• Prevent a released liquid from escaping before it can be recovered
• Resist chemical attack, softening, swelling, blistering, or dissolution
• Remain bonded to concrete, steel, or another approved substrate
• Remain continuous at joints, corners, penetrations, curbs, walls, and drains
• Tolerate anticipated temperature and thermal cycling
• Withstand expected traffic, cleaning, impact, abrasion, and maintenance activity
• Permit inspection, cleaning, decontamination, and repair
• Provide a documented, inspectable barrier after installation

Containment Capacity Is Not the Same as Lining Performance

A containment area may have adequate physical volume and still fail to contain a release. Capacity calculations do not prove that the floor, walls, joints, penetrations, or lining are sufficiently resistant or liquid-tight.

Likewise, a chemically resistant lining cannot correct a containment area that is too small, structurally unsound, improperly drained, or incorrectly designed. The containment structure and the protective lining must work together as one system.

The Coating or Lining Is Only One Part of the System

Contractors are sometimes given a product name and told to “coat the containment.” That instruction is not enough to define a complete containment system.

A properly specified system may include:

• Concrete repair materials or steel repairs
• Crack treatment and joint design
• Coves at floor-to-wall transitions
• Primers compatible with the substrate and lining
• High-build coating, reinforced lining, or flexible membrane layers
• Fabric or fiberglass reinforcement
• Termination, penetration, drain, and equipment-base details
• Protective wearing surfaces where traffic or abrasion is expected
• Inspection, testing, repair, and documentation procedures

Changing one component without written approval can change adhesion, flexibility, chemical resistance, cure, recoat compatibility, or warranty eligibility. A containment system should be treated as an approved assembly—not as a collection of interchangeable products.

Chemical Resistance Must Match the Actual Exposure

Statements such as “chemical resistant” or “industrial grade” are not enough to select a containment lining. Chemical resistance is specific to the material, concentration, temperature, contact time, mixture, contamination, cleaning process, and expected frequency of exposure.

A product that performs well against a dilute chemical at room temperature may not perform against the same chemical at a higher concentration or temperature. A lining suitable for occasional splash may not be suitable for prolonged pooling or immersion.

Contractors should obtain a written chemical-resistance recommendation from the lining manufacturer for the identified service conditions. When the stored material, concentration, temperature, or exposure time is unknown, selection should stop until those questions are answered.

Regulatory Requirements and the Contractor’s Role

Secondary containment may be required by federal, state, or local regulations; an owner’s spill-prevention plan; an insurer; a corporate engineering standard; an environmental permit; or a project specification. The applicable requirements depend on the facility, material, quantity, location, and operation.

For facilities subject to the federal Spill Prevention, Control, and Countermeasure rule, 40 CFR 112.7(c) states that the entire containment system, including its walls and floor, must be capable of containing oil and must prevent the discharge from escaping before cleanup occurs.

Specific bulk-storage provisions may also impose containment-capacity requirements. Determining applicability, calculating required capacity, designing drainage, and approving alternatives are not decisions an application contractor should make without appropriate authority.

The contractor’s role is to understand the project requirements, identify visible conflicts or missing information, execute the approved work correctly, and document what was installed. If the specification does not define the required system or performance, the contractor should request written clarification.

Contractor Responsibilities Before Work Begins

Before mobilizing or ordering material, the contractor should confirm:

• The limits of the containment area
• The substrate type and its existing condition
• The chemicals and mixtures that may be released
• Chemical concentrations and maximum service temperatures
• The expected duration of exposure before cleanup
• Required system components and minimum thicknesses
• Treatment of cracks, joints, penetrations, drains, and terminations
• Required surface-preparation and acceptance criteria
• Environmental limits and ventilation requirements
• Required inspections, tests, records, and hold points
• The responsible parties authorized to accept the work
• The procedure for handling unforeseen conditions and changes

Contractor Responsibilities During Installation

During installation, professional responsibility includes:

• Using only approved materials and system components
• Verifying material identity, batch numbers, shelf life, and storage condition
• Documenting ambient temperature, substrate temperature, humidity, and dew point
• Confirming that preparation meets the specified acceptance criteria
• Protecting prepared surfaces from moisture, dust, oil, and recontamination
• Measuring components and mixing materials according to written instructions
• Observing induction time, pot life, recoat windows, and cure requirements
• Applying the specified number of coats and required thickness
• Completing approved detail work at discontinuities and transitions
• Stopping and reporting conditions that differ from the contract documents

Contractor Responsibilities at Completion

Completion should include more than removing equipment from the site. Depending on the specification, turnover may require:

• Final visual inspection
• Dry-film-thickness or applied-thickness records
• Holiday or discontinuity testing
• Adhesion testing when specified
• Repair and retesting of identified defects
• Daily reports and environmental records
• Material batch and quantity records
• Photographs of preparation, details, testing, and completed work
• Written confirmation that minimum cure requirements were met
• Owner or inspector acceptance before the system enters service

Common Ways Containment Systems Fail

• The lining was selected without complete exposure information
• The concrete contained excessive moisture or contamination
• The surface profile or cleanliness was inadequate
• Cracks or deteriorated concrete were covered instead of repaired
• Joints and penetrations were treated as ordinary flat surfaces
• The applied film was thinner than specified
• Pinholes, holidays, or missed areas were not detected and repaired
• Materials were mixed incorrectly or applied after useful pot life
• The system was exposed before reaching the required cure
• Unapproved substitutions changed the performance of the system

Know When to Stop and Ask

Stop and request written direction when:

• The chemical exposure has not been identified
• The specified system conflicts with manufacturer instructions
• The substrate is weaker or more deteriorated than expected
• Moisture or contamination exceeds the acceptance criteria
• Joint, drain, penetration, or termination details are missing
• Environmental conditions are outside the approved limits
• A product substitution or system change is proposed
• The contractor is being asked to make an engineering or regulatory decision

Stopping work under these conditions is not a lack of experience. It is evidence of professional judgment.

Practical Prejob Questions

1. What material could enter this containment area?
2. At what maximum concentration and temperature?
3. How long could the material remain before cleanup?
4. What substrate will receive the protective system?
5. What repairs and detail work are required?
6. What system has been approved for this exposure?
7. What surface-preparation standard must be achieved?
8. What thickness and number of coats are required?
9. What inspection and testing will be performed?
10. Who has authority to approve changes and accept the finished work?

Technical References

• U.S. Environmental Protection Agency, Secondary Containment Under the SPCC Rule
• Electronic Code of Federal Regulations, 40 CFR 112.7—General Requirements for SPCC Plans
• American Concrete Institute, ACI PRC-515.2-24, Selecting Protective Treatments for Concrete—Guide
• American Concrete Institute, ACI PRC-515.3-20, Guide for Assessment and Surface Preparation for Application of Protection Systems for Concrete
• Association for Materials Protection and Performance, Coatings and Linings over Concrete for Chemical Immersion and Containment Service
• Occupational Safety and Health Administration, 29 CFR 1910.1200—Hazard Communication

Standards, regulations, specifications, and manufacturer instructions may be revised. Verify the current edition and all project-specific requirements before using them for design, bidding, or field work.

Key Takeaways

• Primary containment holds the material during normal service
• Secondary containment controls material released from the primary system
• Adequate volume does not automatically mean adequate lining performance
• Chemical resistance must be confirmed for the actual exposure conditions
• Joints, penetrations, cracks, drains, and terminations are critical system details
• Contractors must install and document the approved system—not redesign it in the field
• Unclear or conflicting requirements require written clarification

Professional responsibility: This article provides foundational contractor education. It does not replace project specifications, engineering design, regulatory interpretation, manufacturer recommendations, site-specific safety requirements, or decisions made by the authority having jurisdiction.

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