Making Changes to Equipment or Operations? Do You Need a Construction Air Permit?
Before you install, modify, or debottleneck equipment, you likely need a construction air permit — and it must be approved BEFORE the change. Here's how to know and how to apply.
⚡ In short: Construction air permits are required before most equipment changes that affect emissions — new, modified, or debottlenecked. They must be issued before construction starts, applications can take months to a year+, and the word “construction” is misleading: any operational change counts.
What Are Construction Air Permits?
Whenever you plan changes to equipment or operations, before you ever get started, your company should determine whether you need a construction air permit from your state (or local) environmental agency.
⚠️ Why this matters: The number one construction-permit mistake is starting the change before the permit is issued. “We didn’t think we needed one” is not a defense — once the change is made, EPA or your state can require shutdown until the permit issues, plus back-dated penalties. Lead times of 3–18 months mean the project schedule has to plan around the permit, not the other way around.
Air Permit Regulations
The Clean Air Act sets standards to prevent significant deterioration (PSD) of air quality. EPA has regulatory authority to enforce it, but can delegate authority to states by approving their enforcement plans.
Air permits are required any time a company will exceed criteria for the six criteria pollutants, or any of 187 hazardous air pollutants. The six criteria pollutants are:
- Sulfur dioxide (SO₂)
- Carbon monoxide (CO)
- Particulate matter (PM)
- Lead (Pb)
- Nitrogen oxides (NOₓ)
- Ozone (volatile organic compounds)
Permits outline the emission sources at a facility and can include emission limitations, equipment maintenance requirements, and references to applicable Maximum Achievable Control Technology (MACT) standards and New Source Performance Standards (NSPS).
Activities That May Need an Air Permit
Examples of equipment or processes that may produce emissions requiring an air permit:
- Compressors
- Paint booths
- Degassing vessels or lines
- Engines
- Generators
- Ovens
- Incinerators
- Boilers
Activities that may produce emissions requiring an air permit:
- Loading/unloading operations
- Material storage/transfer
- Painting
- Solid wastes
- Tank loading/unloading
- Truck loading/unloading
- Valves, vents, vessels, and tanks
- Wastewater treatment
- Welding
- Asphalt mixing/rock crushing
Operating Permits vs. Construction Permits
Air permits required for regular operations are called operating permits and apply to the entire facility. Types vary based on whether you’re in an EPA area of nonattainment, how much you emit, and what you emit.
Permits can also be required for specific projects making changes or additions — these are called construction permits/approvals. Even though the word “construction” is used, you don’t have to technically be doing construction activities. “Construction” here means the process of making any change to an operation. Once the change is made, it becomes part of the operating permit.
State approaches vary:
- Some states issue operating and construction permits at the same time to prevent time loss
- Some states do them separately
- Some states require construction permits be incorporated into the facility’s operating permit
- Others issue combined construction/operating permits
When a Construction Permit Is Required
Except in limited situations, air construction permits must be received before construction or change can commence. Changes that commonly require a construction permit:
- Installation of new process equipment
- Modification to existing process equipment
- Installation of or change in an emission control device
- Debottlenecking of a process that allows for increased production
- Increases to throughput or operating hours (if currently limited by an operating permit)
Unsure whether your upcoming equipment change needs a construction permit? iSi runs PTE calculations, applicability reviews, and full application preparation. See our environmental compliance services →
Determining If You Need a Construction Air Permit
One of the first steps is determining how the change will affect your Potential to Emit (PTE) — the maximum design capacity of a stationary source to emit a pollutant under its physical and operational design. Calculate the PTE for each pollutant associated with the source. Multiple calculation methods exist; your state may have a preferred method.
Once the PTE for the project or modification has been calculated, compare it to the construction permitting thresholds. In some cases you may still need a construction permit even if potential emissions fall below thresholds — the type of equipment or process may affect status. Check your state’s rules.
Obtaining the Permit
If your calculations show the project requires a construction permit, submit the customary application. If the project triggers Major Source or Major Modification thresholds, you may need to obtain a Federal Air Permit — a lengthy application where approval can take several months to well over a year or two depending on your state and workload. Apply well ahead of the planned change.
If you already have an operating permit, know that the change may require simultaneous operating permit modifications. Know exactly what the conditions of your operating permit are and see how the changes will affect it, so that in states that handle operating and construction permits separately, you can get started on operating permit changes early.
Some states have streamlined construction permit application processes for specific equipment like emergency generators or boilers. These are short applications that typically receive agency approval quickly. If the project qualifies for exemption from air construction permitting, retain all documentation — state or federal regulations may still have source requirements and paperwork.
Reviewing the Draft Permit
Once you submit, be prepared to wait. The state agency checks for completeness and may have questions. Once issues are resolved, you should receive a draft permit to review and comment on.
Read the draft carefully. You will be held to what this permit says. Verify:
- All equipment details are correct
- No inconsistencies
- No unclear language or typos
- Ambiguities are clarified
- Conditions are as broad as possible
Any errors could cause issues later during inspections — an inspector may conclude you’re operating differently than what’s allowed. Once the draft is approved, there may be a public notice period depending on state policy, then your permit issues.
💰 What starting early costs vs. starting late: A missed construction permit on a debottlenecking project commonly results in EPA enforcement actions running $10K–$100K+ per day in some cases, plus required shutdown until permitting resolves. A well-prepared application typically runs a fraction of a single day of unplanned shutdown.
Frequently Asked Questions
Q: What is a construction air permit and when is it required?
A construction air permit is required when a facility modifies existing equipment, installs new process equipment, changes emission control devices, or increases production or operating hours in ways that affect emissions. Despite the name, it applies to any operational change — not just physical construction.
Q: What are the six criteria pollutants covered by Clean Air Act regulations?
The six criteria pollutants are sulfur dioxide (SO₂), carbon monoxide (CO), particulate matter (PM), lead (Pb), nitrogen oxides (NOₓ), and volatile organic compounds (as ozone precursors). Facilities must obtain permits if equipment or operational changes cause emissions of these pollutants or any of 187 EPA-listed hazardous air pollutants to exceed regulatory thresholds.
Q: What is Potential to Emit (PTE) and why is it important?
PTE is the maximum design capacity of a facility to emit a pollutant under its physical and operational design. Facilities must calculate PTE for each pollutant associated with a proposed change and compare it against state and federal permitting thresholds to determine if a construction air permit is required before making the change.
Q: How long does it take to obtain a construction air permit?
Timelines vary by state and complexity. Standard applications typically take several months. Major Source or Major Modification determinations requiring Federal Air Permits can take months to over a year. Apply well before planned equipment changes — construction cannot commence until the permit is issued.
Q: What happens if I install new equipment before getting the permit?
Enforcement. State and EPA can require shutdown until permitting resolves, assess back-dated penalties, and classify the violation as willful if your team knew a permit was required. The cost of a 60-day delay at a facility that’s already tooled up for production is usually orders of magnitude larger than the permit application cost.
Q: Does my operating permit need to change too?
Often yes. If the new equipment or modification creates an emission source the operating permit doesn’t cover, the operating permit needs a parallel revision. In states that handle the two permits separately, start the operating permit revision early so you can actually run the equipment once construction finishes.
Need a PTE calculation, applicability review, or full construction permit application? Run the 60-second Compliance Gap check or get a scoped proposal from our team.
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