Boiler Certification, Tune-Up & Testing California | EES

Boiler Certification, Tune-Up & Testing California | EES

Boiler Certification, Tune-Up & Testing in California: 2026 Compliance Guide for Industrial & Commercial Facilities

Is your boiler operating efficiently—and is it meeting California air-quality requirements?

For industrial, institutional and commercial facilities, boiler compliance is more than keeping equipment running. Depending on the boiler size, fuel, location, permit and applicable air district rules, facilities may need certification, periodic tune-ups, emissions testing, recordkeeping and other compliance activities.

In Southern California, South Coast AQMD Rules 1146, 1146.1 and 1146.2 are particularly important for boilers, steam generators, process heaters and certain water heaters. South Coast AQMD’s current rule book lists Rule 1146 as amended in 2020, Rule 1146.1 as amended in 2018, and Rule 1146.2 as amended in 2024.

For facility owners and EHS managers, the key question is not simply:

“Does my boiler work?”

It is:

“Can my boiler demonstrate compliance with the applicable air-quality requirements?”

This is where professional Boiler Certification, Tune-Up and Testing services become valuable.


What Is Boiler Certification, Tune-Up & Testing?

These are related but different compliance activities.

Boiler Certification

Certification generally involves demonstrating that applicable equipment meets the requirements of the governing air-district rule or certification program.

For example, South Coast AQMD maintains a Certified Boilers List under Rule 1146.2, with the current equipment list updated December 30, 2025.

Boiler Tune-Up

A tune-up evaluates and adjusts combustion performance to help the boiler operate properly while controlling emissions.

Boiler Emissions Testing

Testing measures actual emissions—such as NOx, CO and oxygen—using the applicable regulatory test method.

These activities work together:

Certification → Tune-Up → Testing → Documentation → Compliance


Why Is Boiler Compliance Important in California?

Boilers are combustion sources.

Combustion can produce pollutants including:

  • NOx
  • Carbon monoxide (CO)
  • Particulate matter
  • Greenhouse gases
  • Other combustion-related pollutants

NOx is particularly important because it contributes to ozone and smog formation.

South Coast AQMD states that combustion sources are among the sources of NOx emissions in the region, and its Rule 1146.2 amendments were designed to achieve significant NOx reductions.

For businesses, this means boiler operation can have both:

Environmental consequences + Regulatory consequences


2026 California Boiler Compliance: What’s Changing?

California does not have one identical boiler requirement for every facility.

Requirements can differ between air districts, including:

  • South Coast AQMD
  • Bay Area AQMD
  • San Joaquin Valley APCD
  • Sacramento Metropolitan AQMD
  • San Diego APCD
  • Ventura County APCD
  • Other local air districts

Therefore, a boiler compliance strategy should always begin with:

Facility Location + Permit + Boiler Size + Fuel + Applicable Rule


2026 Update: South Coast AQMD Is Actively Reviewing Rules 1146 & 1146.1

One of the most important developments for 2026 is South Coast AQMD’s ongoing work on Proposed Amended Rule 1146 and Proposed Amended Rule 1146.1.

The proposed rules address:

  • Industrial boilers
  • Institutional boilers
  • Commercial boilers
  • Steam generators
  • Process heaters
  • Small boilers and process heaters

South Coast AQMD held Working Group Meeting #4 on June 25, 2026, as part of the Rule 1146/1146.1 rule-development process.

This is important for facility managers because future amendments could affect:

Emission limits → testing → compliance planning → equipment upgrades

Facilities operating older boilers should therefore monitor rule developments rather than assuming today’s requirements will remain unchanged.


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2026 Update: Rule 1146.2 Has Important Zero-Emission Requirements

South Coast AQMD amended Rule 1146.2 on June 7, 2024, establishing a transition toward zero-emission equipment for certain water heaters, boilers and process heaters.

A major 2026 milestone is:

January 1, 2026

South Coast AQMD’s 2026 compliance-deadline guidance states that certain Type 1 units ≤400,000 Btu/hr and qualifying instantaneous water heaters ≤200,000 Btu/hr installed in new buildings must comply with zero-emission limits.

The practical implication is significant:

Boiler and water-heating equipment planning is changing.

Facilities installing or replacing equipment should evaluate applicable requirements before purchasing equipment, rather than discovering a compliance issue after installation.


What Does a Boiler Tune-Up Actually Do?

A professional tune-up focuses on combustion performance.

Depending on the equipment and applicable rule, the process can include checking:

  • Fuel-to-air ratio
  • Oxygen concentration
  • Carbon monoxide
  • Stack temperature
  • Flame condition
  • Burner operation
  • Draft
  • Combustion-air supply
  • Fuel pressure
  • Operating load
  • Control settings

South Coast AQMD’s Rule 1146 tuning procedures specifically address operating the equipment at a representative firing rate and recording combustion parameters such as stack temperature, oxygen and CO.

The objective:

Efficient combustion + controlled emissions + reliable operation


Why Boiler Tune-Up Is More Than Maintenance

Routine mechanical maintenance keeps equipment operating.

A regulatory tune-up has an additional objective:

Emission control.

For example, poor combustion can contribute to elevated CO or inefficient operation.

Too much excess air can also reduce combustion efficiency.

Too little combustion air can create incomplete combustion and elevated CO.

A properly performed tune-up seeks an appropriate combustion balance while maintaining safe operation.

South Coast AQMD’s tuning procedures explicitly state that tuning must not create unsafe conditions or violate applicable safety requirements, manufacturer specifications or other relevant regulations.


When Is Boiler Tune-Up Required?

This depends on the applicable rule and the specific unit.

For example, Rule 1146.1 contains a tune-up option for certain qualifying units with annual heat input of 18,000 therms or less. Units using this option must be tuned at least twice per year, at intervals of four to eight months, according to the prescribed or manufacturer’s procedure, with records maintained for a rolling 24-month period.

That does not mean every California boiler requires two tune-ups every year.

This distinction is important.

The applicable:

Rule + Unit Size + Fuel + Operating History + Permit

determine what is required.


Boiler Emissions Testing: What Is Measured?

Depending on the applicable regulatory requirement, testing may include:

NOx

Nitrogen oxides are a major regulatory focus for combustion equipment.

CO

Carbon monoxide helps evaluate combustion performance and may be subject to emission limits.

Oxygen

O₂ measurements can be used for combustion analysis and, depending on the rule, emissions corrections.

Other Parameters

Depending on the source, testing may also evaluate:

  • Stack temperature
  • Exhaust flow
  • Fuel consumption
  • Heat input
  • Operating load
  • Control-device parameters

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How Often Does a Boiler Need Emissions Testing?

There is no single California-wide testing interval.

The frequency depends on the applicable rule and equipment.

For example, South Coast AQMD Rule 1146 provides specific compliance-testing provisions. Under one provision, certain units at or above 10 MMBtu/hr have a three-year compliance determination interval, while certain units from 5 to below 10 MMBtu/hr have a five-year interval.

Other requirements may apply depending on the boiler category, compliance option and regulatory program.

Don’t assume your neighbor’s testing schedule applies to your boiler.


Boiler Certification vs. Boiler Testing

These terms are often confused.

CertificationTesting
Demonstrates equipment meets a certification requirementMeasures actual emissions
Often associated with specific equipment categoriesUsually associated with operating equipment
Can apply to equipment models/configurationsMeasures field performance
May be required before installation/operationMay be periodic
Documentation-basedData/measurement-based

South Coast AQMD maintains certified equipment lists to help businesses identify equipment that meets applicable requirements. The current Rule 1146.2 certified-boiler list was updated December 30, 2025.


Why Boiler Testing Can Fail

A boiler doesn’t necessarily fail because it is mechanically broken.

Compliance problems can come from:

1. Incorrect Burner Settings

Improper combustion settings can increase emissions.

2. Excessive CO

Incomplete combustion can produce elevated CO.

3. Excess NOx

Combustion conditions may result in NOx above an applicable limit.

4. Poor Maintenance

Dirty burners, fouled surfaces or degraded components can affect combustion.

5. Incorrect Operating Conditions

A test performed under the wrong load or process conditions may not demonstrate compliance.

6. Aging Equipment

Older boilers may have difficulty meeting newer emissions requirements.

7. Inadequate Documentation

Even when equipment performs properly, missing records can create compliance complications.


The Cost of Ignoring Boiler Compliance

For a facility manager, a boiler compliance problem can quickly become an operational problem.

Potential consequences may include:

Failed emissions test

Investigation

Corrective maintenance

Retesting

Production disruption

Additional engineering expense

Possible regulatory enforcement

The exact consequences depend on the applicable air district, rule, permit and circumstances.

The smarter approach is preventive compliance.


Pros of Professional Boiler Certification, Tune-Up & Testing

✅ 1. Helps Demonstrate Regulatory Compliance

Measured data and proper documentation provide evidence of compliance with applicable requirements.

✅ 2. Improves Combustion Performance

A properly tuned boiler can operate more effectively.

✅ 3. Helps Identify Problems Early

Testing can reveal elevated emissions before they become a larger compliance issue.

✅ 4. Supports Better Maintenance Decisions

Testing data can help identify when burners, controls or other components need attention.

✅ 5. Reduces Compliance Surprises

A planned testing program is safer than waiting for a regulatory deadline.

✅ 6. Supports Equipment Planning

Testing can help determine whether an older boiler can continue operating within applicable limits.


Challenges / Cons

Professional testing also involves costs and planning.

ChallengePotential Impact
Testing costBudget required
Tune-up costTechnician/engineering expense
Production coordinationBoiler access may require scheduling
RetestingAdditional cost if results are unsatisfactory
DocumentationRequires organized recordkeeping
Regulatory changesExisting equipment may face future requirements
Equipment upgradesOlder boilers may require modernization

But there is a difference between a compliance cost and an unexpected compliance crisis.

Planning usually gives a facility more options.


Which Industries Need Boiler Compliance Services?

Potential clients include:

Manufacturing

  • Food processing
  • Pharmaceutical manufacturing
  • Chemical manufacturing
  • Automotive
  • Aerospace
  • Textile
  • Paper
  • Plastics

Institutional

  • Hospitals
  • Universities
  • Schools
  • Government facilities

Commercial

  • Hotels
  • Large commercial buildings
  • Laundry facilities
  • Food-service operations

Industrial

  • Refineries
  • Industrial processing plants
  • Warehouses with process heating
  • Energy facilities

The exact requirements depend on the equipment and jurisdiction.


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Why Hospitals and Large Facilities Should Pay Special Attention

Hospitals, universities and large commercial buildings often rely heavily on boilers for:

  • Steam
  • Hot water
  • Heating
  • Sterilization
  • Laundry
  • Process applications

A boiler compliance issue can therefore affect more than emissions.

It can affect:

Operations + Energy Use + Maintenance + Compliance

This makes proactive testing particularly valuable.


How EES Helps With Boiler Certification, Tune-Up & Testing

Energy Environmental Solutions, Inc. (EES) can support industrial and commercial facilities through the boiler compliance process.

1. Regulatory Review

EES can review:

  • Boiler size
  • Fuel type
  • Permit conditions
  • Applicable air-district rule
  • Testing frequency
  • Emission limits

2. Boiler Certification Support

For applicable equipment, EES can help facilities understand certification requirements and documentation.


3. Boiler Tune-Up

EES can support combustion tune-up programs designed around applicable regulatory and equipment requirements.

The process can evaluate:

O₂ + CO + Stack Temperature + Firing Rate + Combustion Conditions


4. NOx Testing

EES can perform applicable boiler NOx emissions testing to determine whether the source meets its regulatory requirements.


5. CO Testing

Carbon monoxide testing can help evaluate combustion performance and applicable compliance limits.


6. Source-Test Protocol Development

Before testing, EES can prepare a test protocol addressing:

  • Applicable rule
  • Pollutants
  • Test methods
  • Operating conditions
  • Sampling requirements
  • QA/QC
  • Calculations
  • Reporting

7. Compliance Testing

EES can coordinate the field-testing program with facility personnel to minimize operational disruption.


8. Engineering Calculations

Testing data can be evaluated and converted into the required regulatory units.


9. Compliance Reporting

EES can prepare technical documentation for applicable regulatory reporting and compliance records.


EES Boiler Compliance Process

STEP 1 — REVIEW

Permit + Boiler + Rule

STEP 2 — IDENTIFY

Emission Limits + Testing Requirements

STEP 3 — PLAN

Test Protocol + Operating Conditions

STEP 4 — TUNE

Optimize Combustion

STEP 5 — TEST

NOx + CO + O₂ + Applicable Parameters

STEP 6 — ANALYZE

Review Results + QA/QC

STEP 7 — REPORT

Compliance Documentation

STEP 8 — IMPROVE

Corrective Action / Retesting if Required


Why Choose EES for Boiler Testing?

A boiler test should not be treated as an isolated laboratory exercise.

Your testing company should understand:

The boiler → the combustion process → the air district → the rule → the test method → the compliance limit

That’s the difference between simply collecting emissions data and building a useful compliance program.


2026 Boiler Compliance Checklist

Before your next boiler test or tune-up, ask:

  • Is the boiler properly permitted/registered?
  • What is the rated heat-input capacity?
  • What fuel does it use?
  • Which California air district regulates the facility?
  • Which boiler rule applies?
  • Is certification required?
  • Is a tune-up required?
  • When was the last tune-up?
  • When was the last emissions test?
  • What are the applicable NOx limits?
  • What are the applicable CO requirements?
  • Is a source-test protocol required?
  • Is agency notification/approval required?
  • Are operating conditions specified?
  • Are records current?
  • Has the boiler or burner been modified?
  • Has the applicable rule changed?

2026: Why Facilities Should Review Their Boiler Compliance Program Now

The regulatory environment is moving toward lower-emission and zero-emission technologies.

South Coast AQMD’s 2026 rule-development work includes proposed amendments to Rules 1146 and 1146.1.

At the same time, Rule 1146.2 has already introduced significant zero-emission requirements for certain equipment categories, including requirements taking effect January 1, 2026.

This creates a strategic question for facility owners:

Should you continue maintaining the existing boiler, upgrade it, replace the burner, or transition to another technology?

Current emissions-testing data can help answer that question.


Don’t Wait for a Failed Boiler Test

A failed compliance test is often the worst time to start investigating your boiler.

Instead:

Test → Analyze → Tune → Verify → Document

This approach gives facility managers a better opportunity to identify problems before they become emergencies.


Need Boiler Certification, Tune-Up & Testing in California?

EES Can Help Your Facility Stay Ahead of Compliance Requirements

Energy Environmental Solutions, Inc. (EES) provides professional environmental testing and compliance services for industrial, institutional and commercial facilities.

Our related services include:

Boiler Certification
Boiler Tune-Up
Boiler Emissions Testing
NOx Testing
CO Testing
O₂ Testing
Source Testing
Air Quality Compliance Testing
Test Protocol Development
Rule 1146 Compliance
Rule 1146.1 Compliance
Rule 1146.2 Compliance
Process Heater Testing
Steam Generator Testing
Thermal Oxidizer Testing
RTO Testing
CEMS / RATA / CGA
Particulate Matter Testing
Air Toxics Testing

Tune Your Boiler. Test Your Emissions. Protect Your Compliance.

Energy Environmental Solutions, Inc. (EES)
Phone: 714-630-5210 | 714-630-7844
Email: info@sourcetester.com
Website: sourcetester.org

Rule 1147.1 California 2026 | Aggregate Dryer NOx Testing | Source Tester | EES

Rule 1147.1 California 2026 | Aggregate Dryer NOx Testing | Source Tester | EES

Rule 1147.1 in California 2026: Latest Updates, Pros, Cons & How EES Helps Aggregate-Drying Facilities

Rule 1147.1 — NOx Reductions from Aggregate Dryers is an important South Coast AQMD regulation affecting certain aggregate-drying operations in Southern California. The rule establishes NOx and CO emission limits, source-testing requirements, monitoring provisions, recordkeeping, and compliance obligations for applicable aggregate dryers.

For 2026, there is an important distinction to make: Rule 1147.1 is not a statewide California regulation. It is a South Coast AQMD rule that applies within the District’s jurisdiction when the equipment meets the rule’s applicability requirements. South Coast AQMD’s current Regulation XI rulebook identifies Rule 1147.1 as “NOx Reductions from Aggregate Dryers,” adopted August 6, 2021.

At the same time, South Coast AQMD’s current proposed-rules pages continue to list Proposed Rule 1147.1 among rules in the proposal process. The dedicated proposal page, however, contains rulemaking documents dating primarily from 2020–2021. Therefore, businesses should not interpret that listing alone as evidence that a new Rule 1147.1 amendment was adopted in 2026.

For aggregate producers, asphalt and construction-material facilities, and other operations using regulated dryers, the practical message is simple:

Know your applicable NOx limit, know your testing deadline, and verify that your aggregate dryer can demonstrate compliance.

Energy Environmental Solutions, Inc. (EES) can help facilities with Rule 1147.1 source testing, NOx testing, CO testing, compliance test protocol development, emissions measurements, CEMS/RATA support, engineering studies, QA/QC and regulatory reporting.


What Is Rule 1147.1?

Rule 1147.1 was adopted by the South Coast AQMD Governing Board on August 6, 2021. It specifically addresses NOx reductions from aggregate dryers and was created as part of South Coast AQMD’s broader strategy to transition NOx sources away from the RECLAIM trading program toward more direct, source-specific controls.

The rule applies to qualifying gaseous-fuel-fired aggregate dryers with more than 1 pound per day of NOx emissions and a rated heat-input capacity greater than 2 million Btu/hour, subject to the rule’s detailed applicability provisions and exemptions.

Aggregate dryers are used to remove moisture from materials such as sand, gravel, crushed stone and other aggregate products. Because the drying process commonly involves high-temperature combustion, the burners can generate NOx.

And here’s the important part:

The larger the combustion system and the higher its emissions, the more important compliance testing becomes.


Why Does Rule 1147.1 Matter in 2026?

NOx is a major air pollutant involved in the formation of ground-level ozone and particulate matter. Southern California has historically faced significant challenges meeting federal and state air-quality standards, so stationary combustion sources remain an important part of regional emission-reduction strategies.

South Coast AQMD specifically developed Rule 1147.1 to establish NOx and CO requirements for aggregate dryers at non-RECLAIM, RECLAIM and former-RECLAIM facilities, together with monitoring, reporting and recordkeeping provisions.

The District’s planning documents estimate that Rule 1147.1 contributes additional NOx reductions as part of the transition from RECLAIM to command-and-control requirements. One South Coast AQMD emissions-inventory document identifies an estimated 0.01 tons/day of NOx reduction by 2030 attributable to Rule 1147.1, with implementation beginning in 2025 and reductions continuing toward 2057.

So while Rule 1147.1 is not a brand-new 2026 regulation, its compliance requirements remain relevant.


Explore the latest 2026 Rule 1147.1 updates for California aggregate dryers, NOx and CO testing, pros, cons, compliance requirements and how EES helps industries.

Latest 2026 Rule 1147.1 Update: What Facilities Should Know

1. The Current Adopted Rule Is Still Dated August 6, 2021

South Coast AQMD’s current official Regulation XI listing identifies:

Rule 1147.1 — NOx Reductions from Aggregate Dryers
Adopted: August 6, 2021

Unlike several other South Coast AQMD rules that received amendments in 2025 or 2026, the current rulebook does not identify a 2026 amendment to Rule 1147.1.

That is an important SEO and compliance point because online articles sometimes describe old proposed-rule documents as if they were new 2026 regulations.

For 2026, facilities should work from:

The currently adopted Rule 1147.1 + their current South Coast AQMD permit + any applicable compliance conditions.


2. Proposed Rule 1147.1 Still Appears on South Coast AQMD’s Proposal Page

There is an unusual point worth highlighting.

South Coast AQMD’s current Active Proposed Rules page lists Proposed Rule 1147.1.

However, the dedicated Rule 1147.1 proposal page presents the original rulemaking materials, including the August 6, 2021 Notice of Public Hearing, July 2021 draft language and 2021 staff documents.

Therefore, companies should be careful when reading search results about “new Rule 1147.1 updates.”

The safest interpretation in 2026 is:

Rule 1147.1 remains an adopted South Coast AQMD rule, while the District’s website also retains/list its proposed-rule project materials. There is no verified evidence in the current official rulebook that a new 2026 amendment has replaced the adopted August 2021 rule.

This distinction is particularly important when preparing a compliance test.


3. NOx and CO Limits Remain Central

Rule 1147.1 establishes a 30 ppm NOx limit and 1,000 ppm CO limit, corrected to 3% oxygen on a dry basis, for the applicable gaseous-fuel-fired aggregate dryers under the rule’s relevant provisions.

The rule also established interim requirements for certain facilities during implementation.

The 2021 adoption materials identify:

RequirementRule 1147.1 Provision
Primary NOx limit30 ppm
CO limit1,000 ppm
Oxygen correction3% O₂, dry
Applicability threshold>1 lb/day NOx
Rated heat-input threshold>2 MMBtu/hr
Source testingRequired for applicable units
Large dryers ≥40 MMBtu/hrAnnual testing

The precise applicability and compliance pathway should always be confirmed against the current rule and permit.


4. Source Testing Frequency Depends on Dryer Size

One of the most important Rule 1147.1 requirements for facility managers is the periodic source-testing schedule.

The current rule provides different testing frequencies based on the aggregate dryer’s rated heat-input capacity.

Aggregate dryer below 10 MMBtu/hr

Source testing is required every 5 calendar years, with the rule restricting how early the subsequent test can occur.

Aggregate dryer ≥10 and <40 MMBtu/hr

Source testing is required every 3 calendar years, again subject to the minimum interval specified by the rule.

Aggregate dryer ≥40 MMBtu/hr

Source testing is required every calendar year.

For a large dryer that has not operated for at least six consecutive months, the rule also provides a provision allowing the source test to occur within 90 days after operations resume, subject to the rule’s conditions and fuel-use documentation.


Why This Matters for 2026

Imagine an aggregate dryer operating at 45 MMBtu/hr.

Its operator cannot treat compliance testing as something to think about every three or five years.

The applicable rule calls for annual source testing.

Now consider a facility operating several dryers of different sizes. The testing calendar can become complicated very quickly.

That is why environmental managers should maintain a centralized compliance schedule containing:

  • Equipment identification
  • Burner age
  • Rated heat input
  • Applicable NOx limit
  • Applicable CO limit
  • Last source-test date
  • Next source-test deadline
  • Permit conditions
  • Protocol approval
  • Test report submission date
  • Maintenance records

Missing a testing deadline can turn a technical compliance requirement into an operational problem.


5. Source-Test Reports Must Be Submitted

Rule 1147.1 requires source-test reports to be submitted to the Executive Officer within 60 days of completion of the test.

That means the project does not end when the field testing is complete.

The complete compliance cycle is:

Plan → Protocol → Test → QA/QC → Calculations → Report → Submission → Recordkeeping

A technically excellent field test can still create headaches if the final report is incomplete, inaccurate or submitted late.


6. Five-Year Recordkeeping Requirement

Rule 1147.1 requires source-test records to be maintained for five years and made available to South Coast AQMD personnel upon request.

This is especially important for companies with multiple facilities or multiple aggregate dryers.

Environmental records should not be scattered across emails, maintenance folders and individual computers.

A better approach is to maintain a centralized compliance file for every regulated unit.


7. Existing CEMS and Monitoring Systems Matter

Rule 1147.1 does not simply require every aggregate dryer to install a brand-new CEMS.

However, qualifying facilities with existing continuous in-stack emissions monitoring systems or equivalent verification systems must retain and operate them according to the applicable requirements.

The rule also allows certain other required testing or monitoring activities to satisfy a source-test requirement under specified conditions.

For example, qualifying:

  • Title V periodic monitoring/testing, or
  • RATA associated with CEMS

may be used to satisfy one instance of periodic source testing when the requirements of the rule are met.

This can potentially reduce duplicate testing—but only when the regulatory conditions are satisfied.


Rule 1147.1 Compliance: Pros

1. Reduces NOx Emissions

The biggest environmental advantage is straightforward: lower NOx emissions from aggregate-drying operations.

NOx reductions support South Coast AQMD’s broader efforts to improve regional air quality.

2. Encourages Modern Combustion Technology

Older burners can have substantially different emissions performance from newer low-NOx systems.

Rule 1147.1 creates an incentive for facilities to evaluate burner technology and combustion performance.

3. Provides Measurable Compliance

Instead of relying entirely on equipment specifications, source testing gives the facility actual emissions data.

4. Identifies Equipment Problems

Testing can uncover issues involving:

  • Burner performance
  • Combustion-air ratios
  • Fuel/air control
  • Temperature
  • Draft
  • Excess oxygen
  • Maintenance
  • Instrumentation

5. Improves Regulatory Documentation

A well-prepared test report provides evidence that the facility is monitoring its environmental performance.

6. Supports Long-Term Air-Quality Planning

South Coast AQMD’s Rule 1147.1 strategy is part of the District’s broader transition from RECLAIM to direct emissions limits.


Rule 1147.1 Compliance: Cons & Challenges

1. Source Testing Costs Money

Qualified source testing requires trained personnel, specialized instruments, calibration, field work, calculations and reporting.

2. Production Scheduling Can Be Difficult

Aggregate facilities cannot always stop or modify production simply to accommodate a test.

Testing must often occur under representative operating conditions.

3. Burner Replacement Can Be Expensive

Facilities with older burners may need to evaluate replacement or upgrades to maintain compliance.

4. Multiple Dryers Increase Complexity

A facility operating several aggregate dryers may have different:

  • Heat-input ratings
  • Burner ages
  • Permit conditions
  • Testing frequencies
  • Compliance deadlines

5. Compliance Data Must Be Defensible

Incorrect oxygen correction, sampling problems, calibration issues or unsuitable operating conditions can compromise a test.

6. Regulatory Interpretation Can Be Complex

Rule 1147.1 interacts with permits, monitoring requirements and the broader South Coast AQMD regulatory structure.

That is why facilities should not rely solely on a generic internet summary.


What Does an Aggregate Dryer Test Measure?

A Rule 1147.1 compliance test can involve measurement of NOx and CO, along with supporting measurements necessary to establish compliance under the applicable test method and permit.

Depending on the test protocol, testing may involve:

  • NOx concentration
  • CO concentration
  • Oxygen
  • Carbon dioxide
  • Stack gas conditions
  • Gas flow
  • Moisture
  • Fuel usage
  • Production rate
  • Dryer operating temperature
  • Burner operating conditions

The data are then evaluated against the applicable regulatory limit.

The goal is not simply to produce numbers.

The goal is to produce defensible compliance evidence.


Why Compliance Test Protocol Development Matters

Before testing begins, facilities should determine exactly how the test will be performed.

A compliance test protocol can identify:

  1. Applicable regulations
  2. Permit conditions
  3. Emission limits
  4. Sampling locations
  5. Test methods
  6. Number of test runs
  7. Operating conditions
  8. QA/QC requirements
  9. Calculations
  10. Reporting requirements

Rule 1147.1 requires applicable source testing and approved testing procedures under its compliance provisions.

A poorly planned test can create unnecessary risk.

Protocol first. Testing second.


How EES Helps Industries With Rule 1147.1

Energy Environmental Solutions, Inc. (EES) provides environmental testing and compliance support for industrial facilities.

Rule 1147.1 Source Testing

EES can support compliance testing for applicable aggregate dryers, including NOx and CO measurements.

NOx Testing

Accurate NOx measurement is at the center of Rule 1147.1 compliance.

CO Testing

The rule also establishes CO requirements, making reliable CO measurement important.

Compliance Test Protocol Development

EES can help prepare protocols covering:

Sampling → Methods → Operating Conditions → QA/QC → Calculations → Reporting

CEMS / RATA / CGA

Where applicable, EES can support continuous emissions monitoring and associated performance testing.

Engineering Studies

EES can help facilities evaluate combustion equipment, emissions trends and potential control strategies.

Regulatory Reporting

EES can assist with technical documentation and reporting following source testing.


Industries That May Need Rule 1147.1 Support

Potentially affected operations can include facilities involved in:

  • Aggregate production
  • Sand and gravel processing
  • Crushed stone production
  • Construction materials
  • Asphalt-related material production
  • Mineral processing
  • Aggregate drying
  • Other operations using qualifying aggregate dryers

Applicability must be confirmed against the actual equipment and permit.


Rule 1147.1 vs. Rule 1147

These rules are easy to confuse.

RulePrimary Focus
Rule 1147NOx reductions from miscellaneous combustion sources
Rule 1147.1NOx reductions from aggregate dryers
Rule 1147.2NOx reductions from metal melting and heating furnaces

South Coast AQMD adopted Rule 1147.1 specifically to separate aggregate dryers from the broader miscellaneous-source framework.

This distinction matters when determining the applicable emission limits and testing requirements.


2026 Rule 1147.1 Compliance Checklist

If your facility operates an aggregate dryer in the South Coast AQMD jurisdiction, review:

  • Is the dryer subject to Rule 1147.1?
  • What is its rated heat-input capacity?
  • Is its NOx emission level above the applicability threshold?
  • What NOx limit applies?
  • What CO limit applies?
  • When was the burner installed?
  • When was the last source test?
  • When is the next test due?
  • Is the testing contractor appropriately qualified/approved?
  • Is the test protocol ready?
  • Are operating conditions representative?
  • Are calibration records current?
  • Are CEMS/RATA requirements applicable?
  • Are source-test reports submitted within the required timeframe?
  • Are five years of records available?

The 2026 Takeaway for Aggregate Facilities

The biggest misunderstanding about Rule 1147.1 is thinking:

“It is a 2021 rule, so it isn’t a 2026 issue.”

That’s not how environmental compliance works.

A rule can remain unchanged while its testing deadlines, permit conditions and operational obligations continue year after year.

For applicable aggregate dryers, Rule 1147.1 establishes a structured framework around NOx and CO emissions, periodic source testing, monitoring, reporting and recordkeeping. South Coast AQMD’s current rulebook continues to identify the adopted rule, while the District’s current proposal pages still reference Proposed Rule 1147.1 materials.

Don’t wait for the next compliance deadline.

If your aggregate dryer is approaching its source-test date, now is the time to verify:

Your permit.
Your emission limits.
Your testing frequency.
Your protocol.
Your equipment condition.
Your records.


Need Rule 1147.1 Testing in California?

Energy Environmental Solutions, Inc. (EES) helps industrial facilities with:

Rule 1147.1 Source Testing | Aggregate Dryer Testing | NOx Testing | CO Testing | Compliance Test Protocol Development | Source Testing | Stack Testing | CEMS | RATA | CGA | Engineering Studies | QA/QC | Regulatory Reporting

Measure Emissions. Verify Compliance. Protect Your Operations.

Energy Environmental Solutions, Inc. (EES)

Phone: 714-630-5210 | 714-630-7844
Email: info@sourcetester.com
Website: sourcetester.org